Perhaps you should try some spelling variations:
thien van » thi van
vat hanh » vat thanh, van hanh, va hanh
su sach » so sach, vu sach
vu nang » vuc nang, va nang, vu dang
hieu ve » hieu va, hieu van
cuu tre » cua tre, cau tren, cau treo
v nang » va nang, van nang, voi nang
vi cuu » vi luu, vinh cuu
x hoi » xa hoi, o hoi, x ho
thuc » thu

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 ((v nang) OR (vu nang)) x hoi. ((hieu ve) or (thien van)) am thuc vat hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((v nang) OR (vu nang)) x hoi. ((hieu ve) OR (thien van)) am thuc vat hanh vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((v nang) OR (vu nang)) x hoi. ((hieu ve) or (thien van)) am thuc vat hanh vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: su sach ((v nang) OR (vu nang)) x hoi. ((hieu ve) or (thien van)) am thuc vat hanh vi cuu tre*.