Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
dang van » hoang van, hang va
danh gia » dan gian
hieu van » hieu va, thien van, lieu va
nang xa » nang x, lang xa, nang ma
sach ty » sach y, sach tu, sach thu
van bac » van ban, van bao, van hac
va danh » va dinh, va dan, va hanh
su tien » su kien, tu tieng, dau tien
su hien » su kien, thu hien, nhu hien
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: doc sach ty ((nang xa) or (dang van)) hoi. hieu van bac xuc va danh gia ((su tien) or (su hien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ty ((nang xa) OR (dang van)) hoi. hieu van bac xuc va danh gia ((su tien) OR (su hien)).
• Adding a wildcard symbol may retrieve word variants: doc sach ty ((nang xa) or (dang van)) hoi. hieu van bac xuc va danh gia ((su tien) or (su hien))*.