Perhaps you should try some spelling variations:
hieu quan » hieu qua, lieu quan, thien quan
quan cau » quang cao, toan cau, quan ha
dat tren » dat trong, dua tren
tu sach » thu sach, su sach, tu cach
te sach » toc sach
cau tuc » cau truc, cau tu, cau luc
va doan » va doanh, van doan, va dan
doan vi » doan va, don vi, doan thi
tuc va » thuc va, truc va, tuc xa
vi dat » voi dat, vi dai, va dat

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (te sach)) ky nang x ho. hieu quan cau tuc va doan vi dat tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) ky nang x ho. hieu quan cau tuc va doan vi dat tren.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (te sach)) ky nang x ho. hieu quan cau tuc va doan vi dat tren*.