Perhaps you should try some spelling variations:
dai khoa » da khoa, dac khoa, dai hoa
hanh day » hanh may, han day, hanh dao
tai khoa » da khoa, noi khoa
bo sach » co sach, hoc sach
ve chat » va chat, van chat
day cuu » day cua, day chu, day cuon
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau tren, cau treo
sach ky » sac ky, sach y, sach ty
ky lang » ky nang, ky dang, ky tang
luc va » duc va, tuc va, loc va
va cam » va cham, va cac, va cao

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

• Performing a fuzzy search may retrieve terms with similar spellings: bo sach ky lang ((dai khoa) or (tai khoa)). hieu ((va cam) or (ve chat)) luc va hanh day cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: bo sach ky lang ((dai khoa) OR (tai khoa)). hieu ((va cam) OR (ve chat)) luc va hanh day cuu tre.
• Adding a wildcard symbol may retrieve word variants: bo sach ky lang ((dai khoa) or (tai khoa)). hieu ((va cam) or (ve chat)) luc va hanh day cuu tre*.