Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
toc sach » hoc sach, doc sach, thuoc sach
ky tang » ky dang, kho tang, ky trong
van cam » van nam, van lam, van cau
cam cac » ca cac, nam cac, cam chan
cac ban » cac dan, cac van, can ban
ban anh » ban hanh, ban banh, ban danh
luu tre » luu tru, cuu tre, luy tre
anh vi » hanh vi, anh va, anh ve
vi luu » vi lua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) or (toc sach)) ((ky tang) OR (ky nang)) xa hoi. hieu van cam cac ban anh vi luu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (toc sach)) ((ky tang) OR (ky nang)) xa hoi. hieu van cam cac ban anh vi luu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (toc sach)) ((ky tang) OR (ky nang)) xa hoi. hieu van cam cac ban anh vi luu tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (toc sach)) ((ky tang) OR (ky nang)) xa hoi. hieu van cam cac ban anh vi luu tre*.