The mixed methods paradigm is still in its adolescence, and, thus, is still relatively unknown and confusing to many researchers. In general, mixed methods research represents research that involves collecting, analyzing, and interpreting quantitative and qualitative data in a single study or in a series of studies that investigate the same underlying phenomenon.Over the last several years, a plethora of research designs have been developed. However, the number of designs that currently prevail leaves the doctoral student, the beginning researcher, and even the experienced researcher who is new to the field of mixed methods research with the challenge of selecting optimal mixed methods designs. This paper presents a three-dimen -sional typology of mixed methods designs that represents an attempt to rise to the challenge of creating an integrated typology of mixed methods designs. An example for each design is included as well as a notation system that fits our eight – design framework.

Introduction: One of the main pillars of the study is the correct choice of study design. This study aimed to give an overview of different type of study designs in medical research. Methods: In this tutorial study, all applied research designs in terms of quantitative and qualitative study were reviewed. Accordingly, terms related to "Research Designs" were searched in the online databases such as Google Scholar, PubMed, Web of Science and Scopus. Results: Based on the findings of the present study, the types of studies are generally divided into two groups: quantitative studies and qualitative studies. Quantitative studies are divided into two categories: primary and secondary studies. Preliminary studies include observational and non-observational studies. Observational studies are divided into two categories: descriptive and analytical studies. Descriptive studies include case reports, cross-sectional studies, cross-sectional correlational studies and ecological studies, and analytical studies include retrospective and group studies. Non-observational studies also include laboratory studies, clinical trials, field trials, and community trials. Conclusion: With a good understanding of the types of studies, it is easy to decide which type of study is appropriate for the research. Choosing proper study design can reduce the costs of the executive process, increase the accuracy, quality of research and give more reliable results.

Introduction: One of the main pillars of the study is the correct choice of study design. This study aimed to give an overview of different type of study designs in medical research. Methods: In this tutorial study, all applied research designs in terms of quantitative and qualitative study were reviewed. Accordingly, terms related to "Research Designs" were searched in the online databases such as Google Scholar, PubMed, Web of Science and Scopus. Results: Based on the findings of the present study, the types of studies are generally divided into two groups: quantitative studies and qualitative studies. Quantitative studies are divided into two categories: primary and secondary studies. Preliminary studies include observational and non-observational studies. Observational studies are divided into two categories: descriptive and analytical studies. Descriptive studies include case reports, cross-sectional studies, cross-sectional correlational studies and ecological studies, and analytical studies include retrospective and group studies. Non-observational studies also include laboratory studies, clinical trials, field trials, and community trials. Conclusion: With a good understanding of the types of studies, it is easy to decide which type of study is appropriate for the research. Choosing proper study design can reduce the costs of the executive process, increase the accuracy, quality of research and give more reliable results.

Qualitative and quantitative development of research activities in knowledge-based developing societies is a continuous process. So, diversification of research methods needs new research methods and models. Using mixed and integrated methods to achieve research goals and a more profound understanding of research subject represents a new movement in the scientific research and meeting this research need is a basic requirement of every research.The mixed method combining qualitative and quantitative approaches has enabled researchers to simultaneously consider methodology, designs, models and methods used in a single research. This paper, first, studies research paradigms and methodology before focusing on mixed research as new methodology of interdisciplinary studies. Moreover, the paper deals with development of different designs and methods in mixed research and explains how qualitative and quantitative data should be combined.

The purpose of present research was to study relationship model of policies, priorities, supportives, and evaluation researches projects with perceived commercialization researches projects. The method of research was correlation all of the statistical community selected as sampling (155). The Instrument of research include of tree types: 1. made questionnaire of efficiency factors influencing developing the researches projects2 (a=0.94),. made questionnaire of strategies for developing relationship between university and industry3  (a=0.86),. made questionnaire of the commercilization researches projects (a=0.92). The validity of all of the questionnaires provided by specialists. The data analyzed by multiple regression test, pearson correlation test and structural model. The total results showed that there were relationship between policies, priorities, supportives, and evaluation researches projects with perceived commercialization researches projects (p<0.05). Also the results showed that the relationship between university and industry mediated the forth factors influencing the perceived commercialization researches. The experienced model of research included good fitness.

Over the past decade, mixed methods research has gained particular attention in social and behavioral research as a considerable number of studies investigated theoretical and methodological aspects of conducting mixed methods research. In applied linguistics, however, mixed methods research is a new approach and little research exists on theoretical and methodological issues related to mixed-method designs. The present study has explored the research designs in which qualitative and quantitative components were combined in the field of applied linguistics. A qualitative analysis of 205 research articles published in seven peer reviewed applied linguistics journals over a period of 14 years revealed that two major categories of mixed-method designs were used in the studies (i.e., sequential and concurrent). Also, subcategories similar to those used in social research emerged in a good number of studies (i.e., triangulation, embedded designs, exploratory designs, explanatory designs). However, the findings further indicated that applied linguistics researchers did not draw on the previously known designs from social research and adopted a pragmatic approach to integrating qualitative and quantitative strands. The findings of this study may help us develop an enhanced understanding of how mixing can be systematically utilized in applied linguistics research.