Perhaps you should try some spelling variations:
hanh tinh » hanh trinh, nhanh tinh, thanh tinh
hieu quan » lieu quan, thien quan, hieu luat
tinh cuu » trinh cuu, dinh cuu, tinh cua
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, nang ma
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau tren, cau treo
y nang » ky nang, ly nang, v nang
thu va » thuc va, thue va, tu va
lien » bien, vien, tien

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 y nang xa hoi. ((((hieu quan) or (lien quan))) or (hieu qua)) nam thu va hanh tinh cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang xa hoi. ((((hieu quan) OR (lien quan))) OR (hieu qua)) nam thu va hanh tinh cuu tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang xa hoi. ((((hieu quan) or (lien quan))) or (hieu qua)) nam thu va hanh tinh cuu tre*.