I really like http://ejje.weblio.jp online dictionary. I use it every day. What I like about it is that it has a ton of example sentences. So I type in a phrase in English and it will show sentences in japanese and it's corresponding English translation. It has a Chinese japanese dictionary as well, but it's not nearly as helpful, due to lack of sample sentences. If you know the phrase in English though I highly recommend this website. I hope it helps you

I don't know a dictionary where you can look up phrases, but I use these: http://tangorin.com (you can find many examples) http://jisho.org

I don't know of any dictionaries for phrases, but jisho.org can look common expressions. Also, there is book release in the united states for phrase and core words, which maybe helpful to you. It is called Core Words and Phrases: Things You Can't Find in a Dictionary by Kakuko Shoji. The book is in English, not Chinese.