Perhaps you should try some spelling variations:
dang xay » dang van, van xay
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, nam thu, nam tu
hang dai » hoang dai, hang tai, hang dau
te sach » toc sach
bo sach » co sach, hoc sach
ky dang » ky nang, ky danh
xay hoi » xa hoi, tay hoi, cay phoi
va hang » van hang, va nang, va lang
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (bo sach)) ky dang xay hoi. hieu van ((nam thuc) or (am thuc)) va hang dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (bo sach)) ky dang xay hoi. hieu van ((nam thuc) OR (am thuc)) va hang dai cua te.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (bo sach)) ky dang xay hoi. hieu van ((nam thuc) or (am thuc)) va hang dai cua te*.