Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
dang xay » dang van, van xay
cua tre » cua te, cua triet, dua tren
va hanh » van hanh, va thanh, va danh
van cam » van nam, van lam, van cau
sach ky » sac ky, sach y, sach ty
su sach » so sach, vu sach
lang ha » long ha
cuu tre » cau tren, cau treo
cam lo » nam lo, cam ly, cam o
lo va » lo van, lao va, ly va

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((lang ha) OR (dang xay)) hoi. hieu van cam lo va hanh vi ((cua tre) OR (cuu tre))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((lang ha) or (dang xay)) hoi. hieu van cam lo va hanh vi ((cua tre) OR (cuu tre))~".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((lang ha) or (dang xay)) hoi. hieu van cam lo va hanh vi ((cua tre) OR (cuu tre))*.