Perhaps you should try some spelling variations:
thien van » thi van
nam thuc » nam thuoc, am thuc, nam thu
van hanh » van thanh, van anh, van ban
ban hanh » ban hang
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
cuu tre » cua tre, cau tren, cau treo
y nang » ky nang, ly nang, v nang
nang o » nang co, nang ho, nang ro
vi cuu » vi luu, vinh cuu
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y nang o hoi. ((hieu va) or (thien van)) nam thuc ((van hanh) OR (ban hanh)) vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang o hoi. ((hieu va) OR (thien van)) nam thuc ((van hanh) OR (ban hanh)) vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang o hoi. ((hieu va) or (thien van)) nam thuc ((van hanh) OR (ban hanh)) vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: su sach y nang o hoi. ((hieu va) or (thien van)) nam thuc ((van hanh) OR (ban hanh)) vi cuu tre*.