Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hieu van » hieu va, thien van, lieu va
hanh dai » hanh tai, hanh dao, vanh dai
cua viet » ca viet, hoa viet, cua vat
cao hoi » cau hoi, co hoi, cao hoc
van cau » van dau, van hau, van chat
truc va » thuc va, thuc vat, trung va
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau tren, cau treo
y nang » ky nang, ly nang, may nang
v nang » va nang, vu nang, van nang

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

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