Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
cuu tre » cau tren, cau treo
va hanh » van hanh, va thanh, va danh
nam luc » nang luc, nhan luc, nam thuc
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
tang xa » trang xa, lang xa, tang ha
tang ma » mang may, tang van
cua tre » cua te, cua triet, dua tren
va nam » van nam, ha nam, va nay
luc va » duc va, tuc va, loc va

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 ky ((tang xa) or (tang ma)) hoi. hieu va nam luc va hanh vi ((cuu tre) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((tang xa) OR (tang ma)) hoi. hieu va nam luc va hanh vi ((cuu tre) OR (cua tre)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((tang xa) or (tang ma)) hoi. hieu va nam luc va hanh vi ((cuu tre) or (cua tre))*.