Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
toc sach » hoc sach, doc sach, nuoc sach
hieu van » hieu va, thien van, lieu va
van cam » van nam, van lam, van cau
luu tre » cuu tre, luy tre
cam tu » cam thu, nam tu, dam tu
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va
x hoi » xa hoi, o hoi, x ho
tru » truc

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) or (thuoc sach)) ky nang x hoi. hieu van cam tu va dan vi ((luu tre) or (luu tru))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (thuoc sach)) ky nang x hoi. hieu van cam tu va dan vi ((luu tre) OR (luu tru)).
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (thuoc sach)) ky nang x hoi. hieu van cam tu va dan vi ((luu tre) or (luu tru))*.