Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
danh tai » doanh tai, dinh tai, hanh tai
hieu van » hieu va, thien van, lieu va
cuc tieu » muc tieu, cac tieu, cach tieu
nang xa » lang xa, nang ma, mang xa
sach ty » sach y, sach tu, sach thu
cau tuc » cau truc, cau tu, cau luc
va danh » va dinh, va dan, va hanh
van cau » van dau, van hau, van chat
tuc va » thuc va, truc va, tuc xa
cuc te » cua te, cuc thue

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: doc sach ty ((nang xa) OR (nang x)) hoi. hieu van cau tuc va danh tai ((cuc te) OR (cuc tieu))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ty ((nang xa) or (nang x)) hoi. hieu van cau tuc va danh tai ((cuc te) OR (cuc tieu))~".
• Adding a wildcard symbol may retrieve word variants: doc sach ty ((nang xa) or (nang x)) hoi. hieu van cau tuc va danh tai ((cuc te) OR (cuc tieu))*.