Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien canh » bien canh, vien can, vien nganh
chuc va » thuc vat
tinh va » tich va, trinh van, trinh vat
thuc va » thuc vat, thuc dan, thuc day
tu sach » thu sach, su sach, te sach
xay hoi » xa hoi, tay hoi, cay phoi
ky dang » ky danh
cho tre » cho thue, khoe tre
va cho » van cho, va co, va che

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