Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
cau tren » cu tren, dau tren, ca tren
ky lang » ky nang, ky dang, tay lang
ky tang » ky nang, ky dang, kho tang
va dinh » van dinh, va kinh, va tinh
van cau » van dau, van hau, van chat
va cam » va cham, va cao, va cai
o va » do va, so va, co 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 lang) OR (ky tang)) xa hoi. hieu ((va cam) or (va cac)) o va dinh van cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((ky lang) OR (ky tang)) xa hoi. hieu ((va cam) OR (va cac)) o va dinh van cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((ky lang) OR (ky tang)) xa hoi. hieu ((va cam) or (va cac)) o va dinh van cau tren".
• Adding a wildcard symbol may retrieve word variants: thu sach ((ky lang) OR (ky tang)) xa hoi. hieu ((va cam) or (va cac)) o va dinh van cau tren*.