The dictionary that I use primarily is http://dictionary.goo.ne.jp/ . I wanted to know of good sources online for looking up how different aspects of Japanese grammar work. I would prefer it if the site were completely in Japanese. I understand Japanese well enough that I should be able to figure out what is being said if the explanations are in Japanese. At this point for me I feel it is a waste of study time to look up Japanese words in English, which is why I use http://dictionary.goo.ne.jp/ . I would like to do the same thing when studying grammar.
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We generally do not deal with resource questions on JLU.
These sorts of questions are relatively common, though, and to provide a starting point, a number of us have created a resource list on the meta site as a part of this site's FAQ.
In this particular case, you will find a few sites like what you're looking for in the Japanese section of the Websites section.
For questions like this, as well as the other types of questions considered offtopic, feel free to drop by the chatroom, although you may need to link your account to another stackexchange site to get enough rep to chat freely.