Perhaps you should try some spelling variations:
viet sach » viet anh, dien sach, viet tech
sach nuoc » sach duoc, cac nuoc, bach tuoc
lieu viet » sieu viet, lieu vien, tieu viet
diem cau » dieu can
lang xa » lang ha, dang xay, lang van
sach ky » sac ky, sach y, sach ty
nang xa » nang x, nang ma, mang xa
vu sach » vu bach, su sach, vu khach
va anh » van anh, va hanh, va danh
di cau » da cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ky ((nang xa) or (lang xa)) hoi. lieu viet sach nuoc va anh ((di cau) or (diem cau)) tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky ((nang xa) OR (lang xa)) hoi. lieu viet sach nuoc va anh ((di cau) OR (diem cau)) tren.
• Adding a wildcard symbol may retrieve word variants: vu sach ky ((nang xa) or (lang xa)) hoi. lieu viet sach nuoc va anh ((di cau) or (diem cau)) tren*.