Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
dau truc » cau truc, dai truc, doan truc
van hanh » van thanh, ban hanh, van ban
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
van anh » van thanh, tuan anh, van minh
cuc tre » duc tre, cua tre, cuu tre
va dau » va dao

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ky) or (sach thu)) nang xa hoi. lieu va dau truc ((van hanh) OR (van anh)) tai cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach thu)) nang xa hoi. lieu va dau truc ((van hanh) OR (van anh)) tai cuc tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sach thu)) nang xa hoi. lieu va dau truc ((van hanh) OR (van anh)) tai cuc tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach thu)) nang xa hoi. lieu va dau truc ((van hanh) OR (van anh)) tai cuc tre*.