Perhaps you should try some spelling variations:
cac truc » cau truc, cac tru, cac trung
danh vai » danh sai, danh va, doanh van
hieu van » hieu va, thien van, lieu va
truc va » thuc va, thuc vat, trung va
cua tre » cua te, cua triet, dua tren
va danh » va dinh, va dan, va hanh
so sach » so sanh, bo sach, co sach
van cac » van hac, van cau, van bac
nang ma » tang ma, sang ma, nang cao
cuu tre » cau tren, cau treo

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach y ((nang x) or (nang ma)) hoi. hieu van cac truc va danh vai ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y ((nang x) OR (nang ma)) hoi. hieu van cac truc va danh vai ((cua tre) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: so sach y ((nang x) or (nang ma)) hoi. hieu van cac truc va danh vai ((cua tre) or (cuu tre))*.