Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
hoc sach » hoc sinh, hoc cac, hoc anh
thi van » thi lan, thi hanh, thi nang
nang xa » nang x, lang xa, nang ma
sach ky » sac ky, sach y, sach ty
thuc ca » thuc cua, thuc can, thuc cao
van dau » van dao, phan dau
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
ca van » cac van, cao van, can van

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach ky nang xa hoi. ((thien van) or (thi van)) tham thuc ca van dau ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ky nang xa hoi. ((thien van) OR (thi van)) tham thuc ca van dau ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ky nang xa hoi. ((thien van) or (thi van)) tham thuc ca van dau ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: hoc sach ky nang xa hoi. ((thien van) or (thi van)) tham thuc ca van dau ((cua tre) OR (cuu tre))*.