Perhaps you should try some spelling variations:
lang khoa » hang khoa, dang khoa, long khoa
khoa hoi » khoan hoi, khoa hoc, khoa doi
dua tren » dung tren
ban hanh » ban hang
cuu tre » cua tre, cau tren, cau treo
hanh de » hanh ve, hanh kem
ky lang » ky nang, ky dang, ky tang
luc ban » duc ban, cuc ban, luc bat
tai ky » thai ky, trai ky, sai ky
ve cau » ke cau, va cau, le cau
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: te tai ky lang khoa hoi. hieu ((ve cau) or (ve cac)) luc ban hanh de ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te tai ky lang khoa hoi. hieu ((ve cau) OR (ve cac)) luc ban hanh de ((dua tren) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: te tai ky lang khoa hoi. hieu ((ve cau) or (ve cac)) luc ban hanh de ((dua tren) or (cuu tre))*.