Perhaps you should try some spelling variations:
sach thien » sach thieu, cach thien, sach tren
sach tien » sach tren, sach thieu
dua tren » dung tren
hieu van » hieu va, thien van, lieu va
danh vi » hanh vi, dinh vi, danh di
va danh » va dinh, va dan, va hanh
van cam » van nam, van lam, van cau
bang xa » lang xa, bang va, mang xa
cuu tre » cua tre, cau tren, cau treo
xuc va » duc va, tuc va, luc va

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 thien) OR (sach tien)) bang xa hoi. hieu van cam xuc va danh vi ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach thien) OR (sach tien)) bang xa hoi. hieu van cam xuc va danh vi ((dua tren) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach thien) OR (sach tien)) bang xa hoi. hieu van cam xuc va danh vi ((dua tren) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: su ((sach thien) OR (sach tien)) bang xa hoi. hieu van cam xuc va danh vi ((dua tren) or (cuu tre))*.