Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
sach ty » sach y, sach tu, sach thu
nang xa » nang x, lang xa, nang ma
van cau » van dau, van hau, van chat
va tinh » may tinh
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
di cua » dai cua, doi cua, de 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 ((sac ky) or (sach ty)) nang xa hoi. hieu van cau truc ((va tinh) or (van hanh)) di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sac ky) OR (sach ty)) nang xa hoi. hieu van cau truc ((va tinh) OR (van hanh)) di cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sac ky) or (sach ty)) nang xa hoi. hieu van cau truc ((va tinh) or (van hanh)) di cua tre*.