Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
dien cuc » dien tu, dieu cua, vien cac
doc sach » toc sach, nuoc sach, dac sac
dan dien » doan dien, danh dien, dan den
tang ho » tang cho, tung ho, tang ha
cao luc » bao luc, cao duc, cao suc
hieu va » lieu va, hieu qua
cuc tre » duc tre, cua tre, cuu tre
nang ho » nang hoc, nang co, nang cao
va cao » va cac, va co, va dao
luc va » duc va, tuc va, loc va
va dan » ca dan, va dao, va dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((hoc sach) or (doc sach)) vu ((nang ho) or (tang ho)) hoc. hieu va cao luc va dan dien cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc sach) OR (doc sach)) vu ((nang ho) OR (tang ho)) hoc. hieu va cao luc va dan dien cuc tre.
• Adding a wildcard symbol may retrieve word variants: ((hoc sach) or (doc sach)) vu ((nang ho) or (tang ho)) hoc. hieu va cao luc va dan dien cuc tre*.