Perhaps you should try some spelling variations:
sach duy » sach dung, sach duoc, sach dao
duy sang » duy van, duy can, duy anh
van hanh » van thanh, ban hanh, van anh
hanh dai » hanh tai, hanh dao, vanh dai
vu sach » vu bach, su sach, vu khach
sang ma » tang ma, nang ma, sang tao
luc van » luoc van, luu van, duc van
ma hoi » mai hoi, xa hoi, ma hoa
ve cac » va cac, vien cac
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: vu sach duy sang ma hoi. hieu ((ve cac) or (va cam)) luc van hanh dai cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach duy sang ma hoi. hieu ((ve cac) OR (va cam)) luc van hanh dai cua vat*.