Perhaps you should try some spelling variations:
sach tham » sach nha
sach thue » sach thu, sach thieu, cach thuc
hanh lam » thanh lap, hanh kem, hanh va
can hanh » ban hanh, van hanh, dan hanh
chang xu » chang xue, chao xu, thong xu
cau hoc » cau hoi, cau hoa, cuu hoc
cao hoc » co hoc, cho hoc, chat hoc
hieu ve » hieu va, hieu van
lam phu » lam chu, cam phu, am phu
xu ho » x ho, xu co, su ho
tho » thoi, theo

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 thue) or (sach tham)) chang xu ho. hieu ve ((cau hoc) OR (cao hoc)) can hanh lam phu tho~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach thue) OR (sach tham)) chang xu ho. hieu ve ((cau hoc) OR (cao hoc)) can hanh lam phu tho.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach thue) or (sach tham)) chang xu ho. hieu ve ((cau hoc) OR (cao hoc)) can hanh lam phu tho".
• Adding a wildcard symbol may retrieve word variants: tu ((sach thue) or (sach tham)) chang xu ho. hieu ve ((cau hoc) OR (cao hoc)) can hanh lam phu tho*.