Perhaps you should try some spelling variations:
lam truoc » lam thuoc, nam truoc, lam truong
va triet » va thiet, va trien, ve triet
hanh mai » hanh ma, hanh mau, hanh may
nam truc » nam truoc, nam thuc, nam trung
va hanh » van hanh, va thanh, va danh
su sach » so sach, vu sach
sach xa » sach dao, sach nha, sach bai
sang ma » tang ma, sang tao, mang may
nang ma » tang ma, nang cao, mang may
hieu va » lieu va, hieu qua

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach xa ((nang ma) OR (sang ma)) hoi. hieu va ((lam truoc) or (nam truc)) va hanh mai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach xa ((nang ma) OR (sang ma)) hoi. hieu va ((lam truoc) OR (nam truc)) va hanh mai va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach xa ((nang ma) OR (sang ma)) hoi. hieu va ((lam truoc) or (nam truc)) va hanh mai va triet".
• Adding a wildcard symbol may retrieve word variants: su sach xa ((nang ma) OR (sang ma)) hoi. hieu va ((lam truoc) or (nam truc)) va hanh mai va triet*.