Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
cac ban » cac dan, cac van, can ban
cam cac » ca cac, nam cac, cam chan
van cam » van nam, van lam, van cau
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
luu tre » luu tru, cuu tre, luy tre
anh vi » anh va, anh ve, anh vu

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