Perhaps you should try some spelling variations:
dang xay » dang van, van xay
cham hoc » cham soc, chat hoc, cham hoi
va cham » va chat, va tham
hieu va » lieu va, hieu qua
dang xa » lang xa, dang ha, dang va
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va
vi cua » vai cua, di cua

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 y) or (sac ky)) ((dang xa) or (dang xay)) hoi. hieu va cham hoc va dan vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach y) OR (sac ky)) ((dang xa) OR (dang xay)) hoi. hieu va cham hoc va dan vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach y) or (sac ky)) ((dang xa) or (dang xay)) hoi. hieu va cham hoc va dan vi cua tre*.