Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
van tham » van thanh, van tuan, van chat
va thanh » gia thanh, ban thanh, va tinh
hieu van » hieu va, thien van, lieu va
va danh » va dinh, va dan, va hanh
sach ty » sach y, sach thu, xach tay
nang xa » nang x, lang xa, nang ma
sach tu » sach thu, cach tu, sach uu
cua tre » cua te, cuu tre, cua triet
va cua » va chua, via cua, ca cua

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 ty) or (sach tu)) nang xa hoi. hieu van tham thuc ((va thanh) or (va danh)) va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sach tu)) nang xa hoi. hieu van tham thuc ((va thanh) OR (va danh)) va cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ty) or (sach tu)) nang xa hoi. hieu van tham thuc ((va thanh) or (va danh)) va cua tre*.