Perhaps you should try some spelling variations:
nhan tong » nhan trong, nhan thong, nhan tuong
hieu van » hieu va, thien van, lieu va
hanh doi » thanh doi, hanh noi, hang doi
tong hoa » thong hoa, trong hoa, tong hop
van hanh » van thanh, ban hanh, van anh
cau luc » cau truc, cau phuc
doi cua » dai cua, hoi cua
luc van » luoc van, luu van, duc van
tu sach » thu sach, su sach, tu cach
hoa hoi » khoa hoi, hoa hoc, hoa doi
te sach » toc sach
cua tre » cua te, cuu tre, cua triet

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) or (te sach)) nhan tong hoa hoi. ((hieu van) or (hieu qua)) cau luc van hanh doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) nhan tong hoa hoi. ((hieu van) OR (hieu qua)) cau luc van hanh doi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (te sach)) nhan tong hoa hoi. ((hieu van) or (hieu qua)) cau luc van hanh doi cua tre*.