Perhaps you should try some spelling variations:
te sach » toc sach
va dinh » van dinh, va kinh, va tinh
hieu ve » hieu va, hieu van
cac tuc » cac toc, cac tu, cac tac
nang ma » tang ma, sang ma, nang cao
ve cac » va cac, vien cac
tuc va » thuc va, truc va, tuc xa
di cuu » di cau, dinh cuu
di cua » dai cua, doi cua, de cua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y ((nang x) OR (nang ma)) hoi. hieu ve cac tuc va dinh ((di cuu) OR (di cua)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y ((nang x) or (nang ma)) hoi. hieu ve cac tuc va dinh ((di cuu) OR (di cua)) tre~".
• Adding a wildcard symbol may retrieve word variants: te sach y ((nang x) or (nang ma)) hoi. hieu ve cac tuc va dinh ((di cuu) OR (di cua)) tre*.