Perhaps you should try some spelling variations:
dong hoa » dong hoc, dong co
hanh tai » thanh tai, hang tai, han tai
van hanh » van thanh, ban hanh, van anh
so sach » so sanh, bo sach, co sach
kham oc » kham cuoc
vu kham » vu khanh
hieu vu » hieu va, hieu ve, hieu su
sach ty » sach y, sach tu, sach thu
lang ha » long ha
nang ma » tang ma, sang ma, nang cao
cuc tre » duc tre, cua tre, cuu tre
oc van » hoc van, luoc van, quoc van

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ty ((nang ma) or (((lang ha) or (dong hoa)))) hoi. hieu vu kham oc van hanh tai cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty ((nang ma) OR (((lang ha) OR (dong hoa)))) hoi. hieu vu kham oc van hanh tai cuc tre.
• Adding a wildcard symbol may retrieve word variants: so sach ty ((nang ma) or (((lang ha) or (dong hoa)))) hoi. hieu vu kham oc van hanh tai cuc tre*.