Last day i serach one page in google,i just put the url in the box,i can see it ,but today i search the same page again,i can not found it,why? And i know generally we used "site:url" to search whether the page has indexed,but sometimes i search the url directly,i can not see any information about it? Anyone can tell me the difference about those?
im not quite sure i understand your question, but looking at it, your basically asking the difference between site:yoursite.com & yoursite.com when you google yoursite.com without the site: command at the bottom there is the chance to get results of other pages that have you on the title etc... when you put site: on the front you get all the resutsl from your site
If what you're saying is that one day you find your site by typing in the URL in google and another day you are not... then .. you should know that google has more than one server and that your site gets indexed differently on different servers. For example you might search a keyword and see your site say ranked 5th in results and later do it again and see it on page 3 or something. That is because there are multiple servers and results vary.
Well, Google has tonnes of servers for sure, but the index doesn't change drastically for sure! Guess what, try typing "16GB RAM Dell Laptop" and Google it, you'll always find my post on 3rd rank and it has been there since 11months, and you will find it every single time! Try it if you wanna verify