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, am thuc, nam thu
te sach » toc sach
xay hoi » xa hoi, tay hoi, cay phoi
nha hoc » nha thuoc, khoa hoc, thai hoc
dan vai » dan va, dan tai, dan vat
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
sach 2 » sach y
2 dang » 2 danh, _ dang, b dang
va dan » ca dan, va dao, va dau
nuoc » quoc, duoc, ngoc

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 2 dang xay hoi. hieu van ((nam thuc) or (((nha hoc) or (nha nuoc)))) va dan vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach 2 dang xay hoi. hieu van ((nam thuc) OR (((nha hoc) OR (nha nuoc)))) va dan vai cua tre.
• Adding a wildcard symbol may retrieve word variants: te sach 2 dang xay hoi. hieu van ((nam thuc) or (((nha hoc) or (nha nuoc)))) va dan vai cua tre*.