Perhaps you should try some spelling variations:
sach truc » cach thuc, sach tren, sach thu
van dinh » van minh, van dich, va dinh
sach tru » sach thu, sach tu, sach tren
va hanh » van hanh, va thanh, va danh
hieu va » lieu va, hieu qua
va cua » va chua, via cua, ca cua
cua te » cua tu
co duc » co duoc, cao duc, do duc
x hoi » xa hoi, o hoi, x ho
va co » vo co

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 tru) OR (sach truc)) nang x hoi. hieu va co duc ((van dinh) or (va hanh)) va cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach tru) OR (sach truc)) nang x hoi. hieu va co duc ((van dinh) OR (va hanh)) va cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach tru) OR (sach truc)) nang x hoi. hieu va co duc ((van dinh) or (va hanh)) va cua te*".