Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van cham » van chat, van tham, va cham
dung hai » dung tai, dung ha, dung sai
dang hai » dang khai, hang hai, dong hai
ly quang » le quang, vu quang
cham buc » cham soc, pham duc, cham cuu
so sach » so sanh, bo sach, co sach
ty hang » ly hang, ty xang, thi hang
ma hoi » mai hoi, xa hoi, ma hoa
buc xa » tuc xa

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 hang) or (ly quang)) ma hoi. hieu van cham buc xa ((dang hai) OR (dung hai)) cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ((ty hang) OR (ly quang)) ma hoi. hieu van cham buc xa ((dang hai) OR (dung hai)) cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ((ty hang) or (ly quang)) ma hoi. hieu van cham buc xa ((dang hai) OR (dung hai)) cua vat".
• Adding a wildcard symbol may retrieve word variants: so sach ((ty hang) or (ly quang)) ma hoi. hieu van cham buc xa ((dang hai) OR (dung hai)) cua vat*.