Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
thu nang » thi nang, thu hang, thu bang
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
va pham » van pham, va phat, va phap
va dinh » van dinh, va kinh, va tinh
dinh vi » dinh ve, dinh viet, dinh tri
cua tre » cua triet, dua tren, cua thep
cuu tre » cau tren, cau treo
cua te » cua tu
x hoi » xa hoi, o hoi, x ho

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 thu nang x hoi. hieu va pham duc va dinh vi ((((cua tre) or (cua te))) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thu nang x hoi. hieu va pham duc va dinh vi ((((cua tre) OR (cua te))) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: tu sach thu nang x hoi. hieu va pham duc va dinh vi ((((cua tre) or (cua te))) or (cuu tre))*.