Perhaps you should try some spelling variations:
dau tieng » dau tien, cau tieng, day tieng
te sach » toc sach
sach ky » sac ky, sach y, sach ty
qua cac » cua cac
luc va » duc va, tuc va
loc va » hoc va
dan vi » doan vi, don vi, gan vi
dan va » doan va, dan ca, ban va

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 ky nang x ho. hieu qua cac ((luc va) or (loc va)) ((dan vi) or (dan va)) dau tieng~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang x ho. hieu qua cac ((luc va) OR (loc va)) ((dan vi) OR (dan va)) dau tieng.
• Adding a wildcard symbol may retrieve word variants: te sach ky nang x ho. hieu qua cac ((luc va) or (loc va)) ((dan vi) or (dan va)) dau tieng*.