Perhaps you should try some spelling variations:
van thanh » ban thanh
thu sach » tu sach, thuat sach, thuoc sach
van tuan » van quan, van ban, anh tuan
hieu van » hieu va, thien van, lieu va
su triet » su viet, su tien, ve triet
cac lop » cac hop, cac loai
ky tang » ky nang, ky dang, kho tang
ky lang » ky nang, ky dang, tay lang
van cac » van hac, van cau, van bac
ha hoi » hoa hoi, ha noi, xa hoi
via su » va su, gia su

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)) ha hoi. hieu van cac lop ((van thanh) or (van tuan)) via su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((ky lang) OR (ky tang)) ha hoi. hieu van cac lop ((van thanh) OR (van tuan)) via su triet.
• Adding a wildcard symbol may retrieve word variants: thu sach ((ky lang) or (ky tang)) ha hoi. hieu van cac lop ((van thanh) or (van tuan)) via su triet*.