Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
van cham » van chat, van tham, va cham
toan tai » toan tap, doanh tai, toan ban
sach ky » sac ky, sach y, sach ty
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
thuc va » thuc vat, thuc dan, thuc day
xuc va » tuc va, luc va, xac va
tai va » thai va, mai va, tri va
thiet » thieu

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 lang xa hoi. hieu van cham ((((xuc va) or (thuc va))) or (duc va)) toan tai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky lang xa hoi. hieu van cham ((((xuc va) OR (thuc va))) OR (duc va)) toan tai va thiet.
• Adding a wildcard symbol may retrieve word variants: thu sach ky lang xa hoi. hieu van cham ((((xuc va) or (thuc va))) or (duc va)) toan tai va thiet*.