Perhaps you should try some spelling variations:
bac trung » ba trung, dac trung, bao trung
hieu van » hieu va, thien van, lieu va
trung va » truong va, trang va, trung ha
cua tre » cua te, cua triet, dua tren
va hanh » van hanh, va thanh, va danh
van bac » van ban, van bao, van hac
sach ky » sac ky, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
cuu tre » cau tren, cau treo

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) OR (sach y)) nang xa hoi. hieu van bac trung va hanh vi ((cua tre) OR (cuu tre))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) or (sach y)) nang xa hoi. hieu van bac trung va hanh vi ((cua tre) OR (cuu tre))~".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sach y)) nang xa hoi. hieu van bac trung va hanh vi ((cua tre) OR (cuu tre))*.