Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
tinh voi » trinh voi, tinh doi, binh voi
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
cua tre » cuu tre, cua triet, dua tren
va tinh » may tinh
van cau » van dau, van hau, van chat
cau tuc » cau truc, cau tu, cau luc
nang xa » nang x, lang xa, nang ma
tuc va » thuc va, truc va, tuc xa
cua te » cua tu

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 thu ((nang xa) or (nang cao)) hoi. hieu van cau tuc va tinh voi ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach thu ((nang xa) OR (nang cao)) hoi. hieu van cau tuc va tinh voi ((cua tre) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: su sach thu ((nang xa) or (nang cao)) hoi. hieu van cau tuc va tinh voi ((cua tre) or (cua te))*.