Perhaps you should try some spelling variations:
sach tham » sach nha
toc sach » hoc sach, doc sach, thuoc sach
hanh tai » thanh tai, hang tai, han tai
cua tre » cua te, cua triet, dua tren
va hanh » van hanh, va thanh, va danh
cam tuc » cam xuc, cam tu, nam thuc
cuu tre » cau tren, cau treo
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
tuc va » thuc va, truc va, tuc xa
va cam » va cham, va cac, va cao

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach tham ((nang xa) or (nang ma)) hoi. hieu va cam tuc va hanh tai ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach tham ((nang xa) OR (nang ma)) hoi. hieu va cam tuc va hanh tai ((cua tre) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: toc sach tham ((nang xa) or (nang ma)) hoi. hieu va cam tuc va hanh tai ((cua tre) or (cuu tre))*.