Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hieu van » hieu va, thien van, hieu ve
cau treo » cau theo, cau tren, cau triet
cua viet » ca viet, hoa viet, cua vat
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di

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 ky nang xa hoi. ((hieu van) OR (lieu va)) pham duc va hanh di ((cau treo) or (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ky nang xa hoi. ((hieu van) OR (lieu va)) pham duc va hanh di ((cau treo) OR (cua viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ky nang xa hoi. ((hieu van) OR (lieu va)) pham duc va hanh di ((cau treo) or (cua viet))".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ky nang xa hoi. ((hieu van) OR (lieu va)) pham duc va hanh di ((cau treo) or (cua viet))*.