Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
khien cua » khien qua, khien tu, trien cua
doc sach » hoc sach, toc sach, nuoc sach
bien cua » ben cua, bien sua, bieu cua
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
va tham » van tham, va cham, va thanh
thuc va » thuc vat, thuc dan, thuc day
va danh » va dinh, va dan, va hanh

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