Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
dang xay » dang van, van xay
hanh di » hanh vi, hanh de, hang di
va hanh » van hanh, va thanh, va danh
hieu va » hieu qua
te sach » toc sach
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach thu ((nang ma) or (dang xay)) hoi. ((hieu va) OR (lieu va)) cac nuoc va hanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach thu ((nang ma) OR (dang xay)) hoi. ((hieu va) OR (lieu va)) cac nuoc va hanh di cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach thu ((nang ma) or (dang xay)) hoi. ((hieu va) OR (lieu va)) cac nuoc va hanh di cua tre*".