Perhaps you should try some spelling variations:
tinh bai » tinh bac, tinh hai, hinh bai
phan luc » nhan luc, phan duc, phan suc
hieu van » hieu va, thien van, lieu va
van phan » van phong, van thanh, luan phan
nang xa » nang x, lang xa, nang ma
sach ty » sach y, sach tu, sach thu
sach ky » sac ky, sach y, sach kem
va tinh » may tinh
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
luc va » duc va, tuc va, loc va

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc ((sach ky) OR (sach ty)) nang xa hoi. hieu van phan luc va tinh bai ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc ((sach ky) OR (sach ty)) nang xa hoi. hieu van phan luc va tinh bai ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc ((sach ky) OR (sach ty)) nang xa hoi. hieu van phan luc va tinh bai ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: thuoc ((sach ky) OR (sach ty)) nang xa hoi. hieu van phan luc va tinh bai ((cua tre) or (cuu tre))*.