Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
dang xay » dang van, van xay
cua tre » cuu tre, cua triet, dua tren
va hanh » van hanh, va thanh, va danh
cam duc » cam xuc, cao duc, pham duc
van cam » van nam, van lam, van cau
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
dang xa » lang xa, dang ha, dang va
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 ky ((dang xa) or (dang xay)) hoi. hieu van cam duc va hanh vi ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((dang xa) OR (dang xay)) hoi. hieu van cam duc va hanh vi ((cua tre) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: su sach ky ((dang xa) or (dang xay)) hoi. hieu van cam duc va hanh vi ((cua tre) or (cua te))*.