Perhaps you should try some spelling variations:
vat hanh » vat thanh, van hanh, va hanh
te sach » toc sach
lai cua » dai cua, hai cua, lai chau
vai cua » dai cua, hai cua, bai cua
mo thuc » mot thuc, do thuc, co thuc
sach tu » sach thu, cach tu, sach ty
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
va mo » va mot, va moi, vi mo

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 tu ((nang xa) or (nang ma)) hoi. hieu va mo thuc vat hanh ((vai cua) or (lai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach tu ((nang xa) OR (nang ma)) hoi. hieu va mo thuc vat hanh ((vai cua) OR (lai cua)) tre.
• Adding a wildcard symbol may retrieve word variants: te sach tu ((nang xa) or (nang ma)) hoi. hieu va mo thuc vat hanh ((vai cua) or (lai cua)) tre*.