Physics does not have a current standard style, but those submitting manuscripts to American Institute of Physics (AIP) journals utilize AIP Style Manual, 4th edition (c) 1990-1997. It employs a numbered, superscript, in-text format that references a list at the end of the publication. Note: Journal titles are always abbreviated. Appendix G (page 49 of the PDF) of the Style Manual offers a list of journal abbreviations. You can also find a list of abbreviations at https://d22izw7byeupn1.cloudfront.net/files/rmpguapb.pdf
Princeton has a useful guide for deciding when a citation is necessary: https://pr.princeton.edu/pub/integrity/pages/cite/ . The general rules are to cite direct and indirect quotations, paraphrased ideas, and summaries. When in doubt, cite!
Some citation styles require you to use the journal abbreviation instead of the full title. Use these websites to help you find the abbreviations.
Cite While You Write is a Microsoft Word plug-in that allows you to use your EndNote Online library as you write your paper, inserting citations and creating a bibliography along the way.
Exporting from Web of Science databases
Web of Science databases offer a direct export option to EndNote Online.
Exporting from other databases
Some databases don't offer Direct Export to EndNote Online.
Importing References from other databases into EndNote Online
Under the Collect tab in EndNote Online, click on the Import References link.