Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
doanh va » doan va, doanh tai, doanh cua
va cham » va chat, va tham
duc van » duc va, duc tan, duc manh
duc vay » duc va, duc vy
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
te sach » toc sach
su tien » su kien, su hien, tu tieng

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) or (te sach)) ky lang xa hoi. hieu va cham ((duc vay) OR (duc van)) doanh va su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (te sach)) ky lang xa hoi. hieu va cham ((duc vay) OR (duc van)) doanh va su tien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (te sach)) ky lang xa hoi. hieu va cham ((duc vay) OR (duc van)) doanh va su tien".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (te sach)) ky lang xa hoi. hieu va cham ((duc vay) OR (duc van)) doanh va su tien*.