Help me where to research these topics.

Since these are nursing diagnoses, I'm thinking that your textbook will be your likely best bet. However, I googled "alterations in neuromuscular function" and got 124,000 hits.

medscape.com it's free, it's a legit source... and anyone that tells you to use wiki, forget it, it's NOT, NOT a credible source by any means, it can be written by the gardener.

I disagree about wikipedia. It's a GREAT source for initial information, particularly if it is well written. The well-written wiki entries have footnotes (which you can then seek out for more in depth information) and a subsequent list of sources, often with direct links, at the bottom of the page.

I have often used wikipedia as my starting point for some sort of research. I typically looked up the sources and clicked on the external links (also provided at the bottom of each page). Sometimes, too, the wiki article simply explained something more clearly than another source I found. While I couldn't necessarily use some of the info, the wiki article contributed to my understanding of my subject.

While yes, anyone can edit or add an article, it is also a user-moderated website. It operates on the notion that people want to share knowledge. A minute percentage of articles are blatantly false or hacked. True, some info is outdated or suspect...but you can find plenty of info in journals that is outdated or suspect as well.

You best bet would be to use research articles. You should have access through your school or medical center. You can also find a lot of free ones on googlescholar, pubmed, etc.