Perhaps you should try some spelling variations:
dan thiet » luan thiet, toan thiet, doan thien
van thiet » va thiet, can thiet, van thien
han thai » han tai, ban thai, van thai
thu sach » tu sach, thuat sach, thuoc sach
van cham » van chat, van tham, va cham
hieu van » hieu va, thien van, lieu va
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
xuc va » duc va, luc va, xac va
tuc va » thuc va, truc va, tuc xa

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 (tuc va)) han thai ((van thiet) OR (dan 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 (tuc va)) han thai ((van thiet) OR (dan thiet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky lang xa hoi. hieu van cham ((xuc va) or (tuc va)) han thai ((van thiet) OR (dan thiet))".
• Adding a wildcard symbol may retrieve word variants: thu sach ky lang xa hoi. hieu van cham ((xuc va) or (tuc va)) han thai ((van thiet) OR (dan thiet))*.