Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
sach ky » sac ky, sach ty, sach kem
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va danh
ve ban » te ban, va ban, ve bao
ban bo » can bo, ban do, ban co
vi cau » va cau, ve cau, di cau
x hoi » xa hoi, o hoi, x ho
bo va » bao va, do va, so va

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 ky) OR (sach y)) nang x hoi. hieu ve ban bo va hanh vi cau tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) OR (sach y)) nang x hoi. hieu ve ban bo va hanh vi cau tren".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) OR (sach y)) nang x hoi. hieu ve ban bo va hanh vi cau tren*.