Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
ve triet » va trien, su triet
vu sach » vu bach, su sach, vu khach
ky hang » ky nang, ly hang, ky dang
cau luc » cau phuc
va hanh » van hanh, va thanh, va danh
hieu va » lieu va, hieu qua
va hoi » xa hoi, va hoc, va hoa
vi ve » va ve, gi ve, ve ve

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((hoc sach) or (vu sach)) ky hang va hoi. hieu va ((cau luc) OR (cau truc)) va hanh vi ve triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc sach) OR (vu sach)) ky hang va hoi. hieu va ((cau luc) OR (cau truc)) va hanh vi ve triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((hoc sach) or (vu sach)) ky hang va hoi. hieu va ((cau luc) OR (cau truc)) va hanh vi ve triet".
• Adding a wildcard symbol may retrieve word variants: ((hoc sach) or (vu sach)) ky hang va hoi. hieu va ((cau luc) OR (cau truc)) va hanh vi ve triet*.