Perhaps you should try some spelling variations:
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
cau tren » cu tren, ca tren, cau treo
dau tren » dau tien, dat tren, dau tieng
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
hieu va » lieu va, hieu qua
va doan » va doanh, van doan, va dan
doan vi » doan va, don vi, doan thi

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 ty nang x ho. hieu va cac nuoc va doan vi ((cau tren) or (dau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang x ho. hieu va cac nuoc va doan vi ((cau tren) OR (dau tren)).
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang x ho. hieu va cac nuoc va doan vi ((cau tren) or (dau tren))*.