Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
sach tu » sach thu, cach tu, sach uu
sach ty » sach y, sach thu, xach tay
vi tham » vi pham, va tham, vi than
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
vai cua » hai cua, lai cua, bai cua
hieu vi » hieu voi, hieu va, hieu ve
x hoi » xa hoi, o hoi, x ho

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 ty) OR (sach tu)) nang x hoi. hieu vi tham thuc va hanh ((vai cua) or (dai cua)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((sach ty) OR (sach tu)) nang x hoi. hieu vi tham thuc va hanh ((vai cua) OR (dai cua)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((sach ty) OR (sach tu)) nang x hoi. hieu vi tham thuc va hanh ((vai cua) or (dai cua)) triet".
• Adding a wildcard symbol may retrieve word variants: doc ((sach ty) OR (sach tu)) nang x hoi. hieu vi tham thuc va hanh ((vai cua) or (dai cua)) triet*.