Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, cam thu
ban hanh » ban hang
va danh » va dinh, va dan, va hanh
tu sach » thu sach, su sach, te sach
cho hoc » co hoc, khoa hoc
cao hoc » co hoc, chat hoc
su bien » su kien, su hien, su tien
va cam » va cham, va cac, va cao
y nang » ky nang, ly nang, v nang
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: tu sach y nang ((cao hoc) or (cho hoc)). lieu va cam thuc ((ban hanh) or (va danh)) vi su bien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((cao hoc) OR (cho hoc)). lieu va cam thuc ((ban hanh) OR (va danh)) vi su bien.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((cao hoc) or (cho hoc)). lieu va cam thuc ((ban hanh) or (va danh)) vi su bien*.