Perhaps you should try some spelling variations:
dai khoa » da khoa, tai khoa, dac khoa
hanh dao » lanh dao, thanh dat, thanh dam
noi khoa » ngoai khoa, hoc khoa, tai khoa
bo sach » co sach, hoc sach
ve chat » va chat, van chat
dao cuu » dao huu, dao cau, dao chu
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau tren, cau treo
sach ty » sach y, sach tu, sach thu
ty lang » tay lang, ty xang, ty hang
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 ty lang ((dai khoa) or (noi khoa)). hieu ((va cam) or (ve chat)) luc va hanh dao cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: bo sach ty lang ((dai khoa) OR (noi khoa)). hieu ((va cam) OR (ve chat)) luc va hanh dao cuu tre.
• Adding a wildcard symbol may retrieve word variants: bo sach ty lang ((dai khoa) or (noi khoa)). hieu ((va cam) or (ve chat)) luc va hanh dao cuu tre*.