Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
dang viet » nang viet, danh viet, mang viet
dinh kien » linh kien, dinh dien, dinh ket
doc sach » hoc sach, toc sach, nuoc sach
hieu van » hieu va, thien van, lieu va
van tham » van thanh, van tuan, van chat
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
thuc va » thuc vat, thuc dan, thuc day
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: doc sach ky nang xa hoi. hieu van tham thuc va ((dang viet) or (dinh kien)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ky nang xa hoi. hieu van tham thuc va ((dang viet) OR (dinh kien)) cua tre.
• Adding a wildcard symbol may retrieve word variants: doc sach ky nang xa hoi. hieu van tham thuc va ((dang viet) or (dinh kien)) cua tre*.