Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
sach ty » sach y, sach tu, xach tay
hieu va » lieu va, hieu qua
va danh » va dinh, va dan, va hanh
danh di » danh du, xanh di, danh dien
cua tre » cua te, cuu tre, cua triet
di cua » dai cua, doi cua, de cua
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ty) OR (sach thu)) nang x hoi. hieu va ((cao su) or (giao duc)) va danh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sach thu)) nang x hoi. hieu va ((cao su) OR (giao duc)) va danh di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ty) OR (sach thu)) nang x hoi. hieu va ((cao su) or (giao duc)) va danh di cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ty) OR (sach thu)) nang x hoi. hieu va ((cao su) or (giao duc)) va danh di cua tre*.