Perhaps you should try some spelling variations:
chiet tach » chieu sach
nhieu tang » chieu sang, hieu lang, nhiet nang
nhung cong » dung cong, thong cong, hang cong
truong va » truong dai, truong cao, truong dao
trung va » trang va, trung ha, trung tam
cong tap » cuong tap, cong tac, cong tan
tap toan » tap doan, tap quan, bai toan
toan tap » toan ban

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((chiet tach) or (nhieu tang)) - hanh ((trung va) OR (truong va)) nhung cong tap toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chiet tach) OR (nhieu tang)) - hanh ((trung va) OR (truong va)) nhung cong tap toan tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chiet tach) or (nhieu tang)) - hanh ((trung va) OR (truong va)) nhung cong tap toan tap".
• Adding a wildcard symbol may retrieve word variants: hoc ((chiet tach) or (nhieu tang)) - hanh ((trung va) OR (truong va)) nhung cong tap toan tap*.