Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
than hoc » toan hoc, thai hoc, than doc
tham hoc » thai hoc, tham hoa, thao hoc
danh vi » hanh vi, dinh vi, danh di
va danh » va dinh, va dan, va hanh
su sach » so sach, vu sach
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
vi su » va su, ve su, ki su

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y ((nang ma) or (tang ma)) hoi. lieu va ((tham hoc) OR (than hoc)) va danh vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang ma) OR (tang ma)) hoi. lieu va ((tham hoc) OR (than hoc)) va danh vi su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((nang ma) or (tang ma)) hoi. lieu va ((tham hoc) OR (than hoc)) va danh vi su triet".
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang ma) or (tang ma)) hoi. lieu va ((tham hoc) OR (than hoc)) va danh vi su triet*.