Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
van phan » van phong, van thanh, luan phan
phan duc » pham duc, phan tu, phan dau
cau tren » cu tren, dau tren, ca tren
cua viet » ca viet, hoa viet, cua dieu
sach ky » sac ky, sach y, sach ty
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
x hoi » xa hoi, o hoi, x ho

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 ky nang x hoi. hieu van phan duc va hanh di ((cau tren) or (((cua viet) or (cua vat))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang x hoi. hieu van phan duc va hanh di ((cau tren) OR (((cua viet) OR (cua vat)))).
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang x hoi. hieu van phan duc va hanh di ((cau tren) or (((cua viet) or (cua vat))))*.