Remember to use the drug name for pharmaceuticals with the brand name. Brand names are not always used in research articles.

• (adalimumab OR humira)

EtCO2 may mean end-tidal carbon dioxide to you, but it could be something else in a different field.  Instead of searching only the abbreviation type out the terms and place them inbetween quotation marks, then include the abbreviation using an OR and surround the terms with parentheses.

• (“end-tidal carbon dioxide” OR “EtCO2”)

To search for time it is more useful to use controlled vocabulary such as:

PubMed

• "Preoperative Period"[Mesh]
• "Postoperative Period"[Mesh]

CINAHL

• (MH "Postoperative Period")
• (MH "Preoperative Period")

Searching phrases like "9 months" or "3 years" in a database is not helpful.