Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
hoc sach » hoc sinh, hoc cac, hoc anh
vanh dai » van dai, vanh tai, lanh dao
tang mai » tang ma, tang tai, lang mai
hieu van » hieu va, thien van, lieu va
dai cuu » dai cua, dai huu
phuc va » thuc va, chuc va, thuc vat
van cau » van dau, van hau, van chat
mai hoi » mai khoi, dai hoi, lai hoi
cuu tre » cua tre, cau tren, cau treo
y tang » ky tang, 6 tang, 7 tang

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((hoc sach) or (thuat sach)) y tang mai hoi. hieu van cau ((phuc va) or (phuc vu)) vanh dai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc sach) OR (thuat sach)) y tang mai hoi. hieu van cau ((phuc va) OR (phuc vu)) vanh dai cuu tre.
• Adding a wildcard symbol may retrieve word variants: ((hoc sach) or (thuat sach)) y tang mai hoi. hieu van cau ((phuc va) or (phuc vu)) vanh dai cuu tre*.