Perhaps you should try some spelling variations:
vien canh » bien canh, vien can, vien nganh
canh chuc » hanh phuc, anh thuc, cong chuc
trinh vat » trinh van, trinh luat, sinh vat
hieu vien » hieu hien, hieu viec, thieu nien
va trinh » van trinh, va tinh, lap trinh
chu tre » cho tre, chu tri, cau tren
chuc va » thuc va, thuc vat
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
xay hoi » tay hoi, cay phoi, gay thoi
ky dang » ky nang, ky danh
cuu tre » cua tre, cau tren, cau treo

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 ky dang ((xay hoi) OR (xa hoi)). hieu vien canh chuc va trinh vat ((chu tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang ((xay hoi) OR (xa hoi)). hieu vien canh chuc va trinh vat ((chu tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky dang ((xay hoi) OR (xa hoi)). hieu vien canh chuc va trinh vat ((chu tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang ((xay hoi) OR (xa hoi)). hieu vien canh chuc va trinh vat ((chu tre) or (cuu tre))*.