Perhaps you should try some spelling variations:
trinh dai » trinh tai, trinh di, trinh da
thu sach » tu sach, thuat sach, thuoc sach
chat huu » pham huu
dua tren » dung tren
tinh dai » tinh da, tinh hai, tinh doi
van chat » cao chat
hieu van » hieu va, thien van, lieu va
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
cuu tre » cua tre, cau tren, cau treo
huu va » cuu va, tuu va

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky nang xa hoi. hieu van chat huu va ((tinh dai) or (trinh dai)) ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang xa hoi. hieu van chat huu va ((tinh dai) OR (trinh dai)) ((dua tren) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang xa hoi. hieu van chat huu va ((tinh dai) or (trinh dai)) ((dua tren) or (cuu tre))*.