Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
dang xay » dang van, van xay
dai truc » dai thuc, doan truc, dai trung
hai truc » hai trac, hang truc, thai thuc
va hanh » van hanh, va thanh, va danh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
tang ma » mang may, tang van
cua tre » cua te, cuu tre, cua triet
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: su sach ky ((dang xay) or (tang ma)) hoi. hieu van ((hai truc) or (dai truc)) va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((dang xay) OR (tang ma)) hoi. hieu van ((hai truc) OR (dai truc)) va hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ky ((dang xay) or (tang ma)) hoi. hieu van ((hai truc) or (dai truc)) va hanh vi cua tre*.