Perhaps you should try some spelling variations:
nang tai » hang tai, tang tai, sang tai
dua tren » dung tren
dau tren » dau tien, dat tren, dau tieng
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
tai hoi » tai khoi, dai hoi, tai hai
hieu va » lieu va, hieu qua
va danh » va dinh, va dan, va hanh
danh vi » hanh vi, dinh vi, danh di
cuu tre » cua tre, cau tren, cau treo
va dat » va dao, va dau, va dap
nuoc » quoc, duoc, ngoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang tai hoi. hieu va dat nuoc va danh vi ((dua tren) or (((cuu tre) or (dau tren))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang tai hoi. hieu va dat nuoc va danh vi ((dua tren) OR (((cuu tre) OR (dau tren)))).
• Adding a wildcard symbol may retrieve word variants: su sach ky nang tai hoi. hieu va dat nuoc va danh vi ((dua tren) or (((cuu tre) or (dau tren))))*.