Perhaps you should try some spelling variations:
thanh lap » thanh san, phan lap, thanh hai
cau tren » cu tren, dau tren, ca tren
sach thu » sach thue, sach thieu, sach tham
va thanh » gia thanh, ban thanh, va tinh
vu pham » su pham, vi pham, vu kham
cuu tre » cua tre, cau treo
sach ty » sach y, sach tu, xach tay
tang ma » mang may, tang van
hieu vu » hieu va, hieu ve, hieu su
ma hoi » mai hoi, xa hoi, ma hoa

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 ty) OR (sach thu)) tang ma hoi. hieu vu pham duc va thanh lap ((cuu tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ty) OR (sach thu)) tang ma hoi. hieu vu pham duc va thanh lap ((cuu tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ty) OR (sach thu)) tang ma hoi. hieu vu pham duc va thanh lap ((cuu tre) or (cau tren))".
• Adding a wildcard symbol may retrieve word variants: su ((sach ty) OR (sach thu)) tang ma hoi. hieu vu pham duc va thanh lap ((cuu tre) or (cau tren))*.