Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hieu van » hieu va, thien van, lieu va
cuu tre » cua tre, cau treo
tinh di » tinh doi, trinh di, tinh da
va tinh » may tinh
nam xuc » cam xuc, nam xua, nam thuc
sach ty » sach y, sach tu, sach thu
sac ky » cac ky, sai ky
xuc va » duc va, tuc va, luc va
x hoi » xa hoi, o hoi, x ho

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

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