Here is a short video demonstrating this search.
Step 1: Use PICO to formulate the search strategy; start with the Patient problem(s) and Intervention
Enter the term for the patient problem and the intervention: obesity AND diabetes type 2 AND bariatric surgery. PubMed attempts to map your terms to appropriate Medical Subject Headings (MeSH). MeSH is the standard terminology used by the indexer and helps find articles on specific topics, regardless of the exact wording used by the authors.
Step 2. Look at Search Details to verify MeSH terms
Look in the Search Details box (lower right column; click on "See more" to expand) to see the terms that PubMed actually used in its search. You want to be sure PubMed found the appropriate MeSH terms. PubMed will automatically also search for your terms as words in the title and abstract. Obesity is a MeSH term, diabetes type 2 is translated to the MeSH term of diabetes mellitus, type 2, and bariatric surgery is a MeSH term. If your search did not find the appropriate MeSH terms, you would need to look up the topic in the MeSH database.
Step 3. Limit to appropriate study design
This is a therapy question. We know from the previous discussion that the best evidence for a therapy question is a randomized controlled clinical trial (RCT). Use the Filters column from the main results page to limit to Randomized Controlled Trial as an article type. You may need to click on "more" to see additional filters if RCT is not listed.
You can also use the Clinical Queries function to limit the results to study methodologies relevant to therapy questions. Copy your last search strategy obesity AND diabetes type 2 AND bariatric surgery. Click on Advanced under the search box; then click on More Resources near the top of the page; then select Clinical Queries. Paste the search strategy in the Clinical Query search box and hit Search. The first column of results is Clinical Study Categories. Select the type of question (Therapy) and the type of search (Narrow). You may get more search results using the Clinical Queries function. Both methods limit your results to RCTs.
If you are not familiar with searching PubMed, you may want to review the PubMed tutorials at http://www.nlm.nih.gov/bsd/disted/pubmedtutorial/ or contact your the library for help.
You may also want to search in the CINAHL database to look for resources. Click the "Next" arrow below to learn more about this other valuable database.