Frequent issues on search strategies

Language restrictions

Limiting search strategies to “only English” introduces a language bias and this is not recommended by Cochrane handbook ( (Chapter 4: Searching for and selecting studies | Cochrane) nor Campell collaboration (Searching for studies: a guide to information retrieval for Campbell systematic reviews - Kugley - 2017 - Campbell Systematic Reviews - Wiley Online Library).

Filters

Filters are useful to exclude systematically any study design (e.g., only randomized clinical trials), patient groups (e.g, only adult population), animal studies...etc. Many of these filters are found here in the ISSG Search Filter Resource (https://sites.google.com/a/york.ac.uk/issg-search-filters-resource/). Adaptation might be necessary. 

Conference abstracts and Clinical trial registries

While excluding conference abstracts might be tempting and quite frequently done in searches, it is better to re-consider such exclusion if those type of publications might add additional information to your study. For example, it might be important to get familiar with any ongoing clinical trials that might be even get published later during your study or that readers would be interested to know if any future study might change the current conclusions.