Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
toc sach » hoc sach, doc sach, thuoc sach
cac vuc » cac nuoc, cac vung, cac cuoc
vai cua » hai cua, lai cua, bai cua
vuc van » duc van, luc van, thuc van
hieu ve » hieu va, hieu van
cho hoc » co hoc, khoa hoc
ty hang » ly hang, thi hang, thu hang
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ((ty hang) or (ty xang)) cho hoc. hieu ve cac vuc van thanh ((vai cua) OR (dai cua)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ty hang) OR (ty xang)) cho hoc. hieu ve cac vuc van thanh ((vai cua) OR (dai cua)) cau*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ty hang) or (ty xang)) cho hoc. hieu ve cac vuc van thanh ((vai cua) OR (dai cua)) cau*".