Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
van chat » cao chat
hieu van » hieu va, thien van, lieu va
chat tuc » chat xuc, luat tuc, chat huu
cho hoc » co hoc, khoa hoc
cao hoc » co hoc, chat hoc
sach ky » sac ky, sach y, sach ty
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
ca tren » cau tren, cu tren, la tren
ve ca » ve cac, ve cai, ve cau

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

• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ((cao hoc) OR (cho hoc)). hieu van chat tuc ((va hanh) OR (va danh)) ve ca tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang ((cao hoc) or (cho hoc)). hieu van chat tuc ((va hanh) OR (va danh)) ve ca tren~".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang ((cao hoc) or (cho hoc)). hieu van chat tuc ((va hanh) OR (va danh)) ve ca tren*.