Perhaps you should try some spelling variations:
dang khoa » dung khoa, hang khoa, dang khoi
hoc sach » hoc sinh, hoc cac, hoc anh
vat hanh » vat thanh, van hanh, va hanh
nam thuc » nam thuoc, am thuc, nam tu
khoa hoi » khoan hoi, khoa hoc, khoa doi
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
ky dang » ky nang, ky danh

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 ky dang khoa hoi. hieu ve ((nam thuc) or (nam thu)) vat hanh ((ve su) OR (va su)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ky dang khoa hoi. hieu ve ((nam thuc) OR (nam thu)) vat hanh ((ve su) OR (va su)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ky dang khoa hoi. hieu ve ((nam thuc) or (nam thu)) vat hanh ((ve su) OR (va su)) triet".
• Adding a wildcard symbol may retrieve word variants: hoc sach ky dang khoa hoi. hieu ve ((nam thuc) or (nam thu)) vat hanh ((ve su) OR (va su)) triet*.