Perhaps you should try some spelling variations:
dua tren » dung tren
hanh lai » hanh lam, hanh tai, thanh lap
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
xuc van » duc van, luc van, xuc ban
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
nang ma » tang ma, nang cao, mang may
sang ma » tang ma, sang tao, mang may
ve cam » ve cham, ve cac, va cam
cua tu » cua tuc, cua su, cua cu

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 ky ((sang ma) or (nang ma)) hoi. hieu ve cam xuc van hanh lai ((dua tren) or (cua tu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((sang ma) OR (nang ma)) hoi. hieu ve cam xuc van hanh lai ((dua tren) OR (cua tu)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((sang ma) or (nang ma)) hoi. hieu ve cam xuc van hanh lai ((dua tren) or (cua tu))*.