Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » thien van, lieu va, hieu ve
chau phu » chau phi, chau au, chau tho
cau tren » cu tren, dau tren, ca tren
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau treo
y nang » ky nang, ly nang, v nang
phu va » phuc va, phu la, phu da

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach y nang x ho. ((hieu van) or (hieu va)) chau phu va hanh vi ((cuu tre) OR (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y nang x ho. ((hieu van) OR (hieu va)) chau phu va hanh vi ((cuu tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach y nang x ho. ((hieu van) or (hieu va)) chau phu va hanh vi ((cuu tre) OR (cau tren))".
• Adding a wildcard symbol may retrieve word variants: thu sach y nang x ho. ((hieu van) or (hieu va)) chau phu va hanh vi ((cuu tre) OR (cau tren))*.