Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
thac hoc » thai hoc, than hoc, thao hoc
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
va thac » van thac, va thuc, va tac
va danh » va dinh, va dan, dia danh
va hanh » van hanh, va thanh, ban hanh
cuu tre » cua tre, cau tren, cau treo
vi cuu » vi luu, vinh cuu
x hoi » xa hoi, x ho, 5 hoi
o hoi » co hoi, o hoc, o hai

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) or (o hoi)). hieu va thac hoc ((va danh) OR (va hanh)) vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ((x hoi) OR (o hoi)). hieu va thac hoc ((va danh) OR (va hanh)) vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang ((x hoi) or (o hoi)). hieu va thac hoc ((va danh) OR (va hanh)) vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang ((x hoi) or (o hoi)). hieu va thac hoc ((va danh) OR (va hanh)) vi cuu tre*.