Your site probably is caught in Everflux. Everflux is a term used when you see your site fluctuating in the rankings. This is because Google does two types of crawls: a "fresh crawl" daily and a "deep crawl" monthly. Towards the end of each month, depending on what's cached and which data center your search results reach, your rankings will fluctuate. Hence the name, Everflux.
These query operators are great tools to aid in the analysis of your site's optimization, as well as those of your competitors. Another interesting function, the cache query can retrieve lost Web pages. Some Webmasters have used the Google cache query to retrieve pages that have been lost due to computer crashes, with no back-ups.
Additionally, since the cache query will save any information that you had on your Web site, be careful of putting any confidential information on your site. It will remain viewable for a certain period of time. Criminal investigators have used the cache query to collect incriminating evidence.
If you want to prevent Google from caching your Web site, you can use the "no cache" tag. Although, some SEO professionals are afraid to use the "no cache" tag for fear of losing search engine rankings. But, Google says the "no cache" tag won't affect rankings.
The LINK query is used to check how many sites are linking to your site. Or, in Google language, backlinks. Google and the other engines place a heavy emphasis on this, and that has an impact on the search engine rankings. The syntax for this is "link:http://www.namehere.com." When this query is used on Google, only the links indexed by Google will show in the results. If you want a more comprehensive list, Marketleap has a nice Link Popularity Tool where you can see the backlinks from other search engines' indexes. If you want to see how many pages of your site have been indexed by Google then use the SITE query. The syntax is "site:http://www.namehere.com." The SITE query will also find a specific term you're looking for within a site. For example, if I want to find where the word "dynamic" is mentioned on namehere.com, then I would use the search syntax: "dynamic site:http://www.namehere.com."
If you are looking for a specific phrase on one site, then the INURL query is useful. The syntax is: "INURL:www.namehere.com validation." That will produce all of the site's pages with the word "validation" in the URL. If you are looking for a particular keyword within the title tag of a site, then the correct search query is "INTITLE:name" or "INTITLE:here."
The allinurl and allintitle are variations of the above search queries. These are helpful if you are looking for a string of keywords in a site or title tag. The syntax for these queries is: "allinurl:namehere.com dynamic pages." Using that search query will only produce documents that have "dynamic" and "pages" in the URL. However, INURL will return the same results.