Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
xuat tuc » xuat thuc, luat tuc, xuat tu
van xuat » san xuat, va xuat, phan xuat
tu sach » thu sach, su sach, te sach
tang ma » mang may, tang van
ky tang » ky nang, ky dang, kho tang
ma hoi » mai hoi, xa hoi, ma hoa
va dan » ca dan, va dao, va dau
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: ((tu sach) or (thuat sach)) ky tang ma hoi. hieu van xuat tuc ((va thanh) or (va dan)) di cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thuat sach)) ky tang ma hoi. hieu van xuat tuc ((va thanh) OR (va dan)) di cua vat.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thuat sach)) ky tang ma hoi. hieu van xuat tuc ((va thanh) or (va dan)) di cua vat*.