Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
sach ty » sach y, sach tu, sach thu
ty lang » tay lang, ty xang, ty hang
lang xa » lang ha, dang xay, lang van
va hanh » va thanh, va danh, dao hanh
su tien » su kien, su hien, tu tieng
va cau » van cau, va cac, va dau
ki su » ky su

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 lang xa hoi. lieu va cau truc ((((va hanh) or (ban hanh))) or (van hanh)) ki su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty lang xa hoi. lieu va cau truc ((((va hanh) OR (ban hanh))) OR (van hanh)) ki su tien.
• Adding a wildcard symbol may retrieve word variants: toc sach ty lang xa hoi. lieu va cau truc ((((va hanh) or (ban hanh))) or (van hanh)) ki su tien*.