Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
hieu van » hieu va, thien van, lieu va
chat tuc » chat xuc, luat tuc, chat huu
van chat » cao chat
cau tren » cu tren, dau tren, ca tren
cao hoc » co hoc, chat hoc
cho hoc » co hoc, khoa hoc
tu sach » su sach, te sach, tu cach
va hanh » van hanh, va thanh, va danh
hanh ve » hanh vi, hanh va, hanh kem
tuc va » thuc va, truc va, tuc xa
ve cau » ke cau, va cau, ve cac

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