Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
dua tren » dung tren
hanh sai » hanh san, hanh tai, danh sai
dang xay » dang van, van xay
va hanh » van hanh, va thanh, va danh
hau loc » huu loc, phau hoc
hieu ve » hieu va, hieu van
xay hoi » xa hoi, tay hoi, cay phoi
ky dang » ky nang, ky danh
te sach » toc sach
ve hau » ve cau, ve dau, ve ha
loc va » hoc va, luc va
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: ((thu sach) or (te sach)) ky dang xay hoi. hieu ve hau loc va hanh sai ((dua tren) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (te sach)) ky dang xay hoi. hieu ve hau loc va hanh sai ((dua tren) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (te sach)) ky dang xay hoi. hieu ve hau loc va hanh sai ((dua tren) or (cua te))*.