More research is not needed
Try typing the search term "more research is needed" (with the quote marks) into PubMed: http://www.ncbi.nlm.nih.gov/pubmed?db=pubmed . You should get over 62,000 hits, and that's only for papers which have the phrase in their abstract. Countless more will have it buried in the discussion section of the full text. In fact, it would be interesting to know which papers don't advocate carrying out further research. To be fair, sometimes this conclusion may be appropriate. More research is needed if one reports an equivocal result or a finding which is unexpectedly negative or unexpectedly positive. More research is needed if insufficient information has been obtained in order to come to a reasonable conclusion as to what clinical interventions may be appropriate or what theoretical insights have been gained. More research is needed if one has obtained a positive result but its exact implications require further clarification. However more