Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nhan tuc » nhan thuc, nhan luc, nhanh thuc
nang ly » hang ly, nang y, bang ly
va nang » van nang, da nang, cam nang
ve nhan » ve nha, de nhan, va nhan
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
cuu tre » cua tre, cau tren, cau treo
y tang » ky tang, 6 tang, 5 tang
ma hoi » xa hoi, ma hoa, me hoi
7 tang » 6 tang
tuc va » thuc va, truc va, tuc xa
ly cuu » ly cua

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 ((y tang) or (7 tang)) ((ma hoi) or (mai hoi)). hieu ve nhan tuc va nang ly cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((y tang) OR (7 tang)) ((ma hoi) OR (mai hoi)). hieu ve nhan tuc va nang ly cuu tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ((y tang) or (7 tang)) ((ma hoi) or (mai hoi)). hieu ve nhan tuc va nang ly cuu tre*.