Perhaps you should try some spelling variations:
duoc tren » nuoc tren, thuoc tren, dung tren
duc tien » duc thien, luc tieng, thuc tien
dang cau » hang cau, bang cau, dang mau
hanh tai » thanh tai, hang tai, han tai
van hanh » van thanh, ban hanh, van anh
xuc van » duc van, luc van, vuc van
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
hieu ve » hieu va, hieu van
cau hoa » cau hoi
ty dang » ty xang, ky dang, ty hang
cac xuc » cam xuc, cac nuoc, chat xuc
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: tu sach ty dang cau hoa. hieu ve cac xuc van hanh tai ((duc tien) or (duoc tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty dang cau hoa. hieu ve cac xuc van hanh tai ((duc tien) OR (duoc tren)).
• Adding a wildcard symbol may retrieve word variants: tu sach ty dang cau hoa. hieu ve cac xuc van hanh tai ((duc tien) or (duoc tren))*.