Perhaps you should try some spelling variations:
lang khoa » hang khoa, dang khoa, long khoa
su triet » su viet, su tien, ve triet
hanh vai » hanh vi, hanh va, hanh tai
khoa hoi » khoan hoi, khoa hoc, khoa doi
thuc va » thuc dan, thuc day
hieu ve » hieu va, hieu van
bai ky » ban ky, bac ky, dai ky
ve nam » he nam, va nam, le nam
sai ky » sac ky
vai su » va su, van su, lai su

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

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