Perhaps you should try some spelling variations:
sach thue » sach thieu, sach tham, cach thuc
sach thu » sach thieu, sach tham, cach thuc
va trinh » van trinh, va tinh, lap trinh
trinh di » trinh do, trinh dien, trinh dinh
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
xang x » nang x
di cua » dai cua, doi cua, de cua
x hoi » xa hoi, o hoi, x ho
du va » dau va, tu va, su va

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach thu) or (sach thue)) xang x hoi. hieu va cac du va trinh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach thu) OR (sach thue)) xang x hoi. hieu va cac du va trinh di cua tre.
• Adding a wildcard symbol may retrieve word variants: te ((sach thu) or (sach thue)) xang x hoi. hieu va cac du va trinh di cua tre*.