Perhaps you should try some spelling variations:
vat thanh » dat thanh, gat thanh, tat thanh
nam thuc » nam thuoc, am thuc, nam thu
so sach » so sanh, bo sach, co sach
hoi cua » hoi chuc
doi cua » dai cua
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
ve nam » he nam, va nam, le nam
y nang » ky nang, ly nang, may nang
v nang » va nang, vu nang, van nang

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) or (v nang)) mai hoi. hieu ve nam thuc vat thanh ((doi cua) or (hoi cua)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ((y nang) OR (v nang)) mai hoi. hieu ve nam thuc vat thanh ((doi cua) OR (hoi cua)) te.
• Adding a wildcard symbol may retrieve word variants: so sach ((y nang) or (v nang)) mai hoi. hieu ve nam thuc vat thanh ((doi cua) or (hoi cua)) te*.