Perhaps you should try some spelling variations:
"toc sach tranh tien" » "toc canh tranh tien", "toc sach thanh tien", "toc sach tran tien", "toc sach trinh tien", "hoc sach tranh tien", "doc sach tranh tien", "thuoc sach tranh tien"
"hoc cac doanh tri" » "hoc cac dan tri", "hoc cac dang tri", "hoc van doanh tri", "hoc cac doanh tai", "hoc cac doanh tren", "hoc cac dinh tri", "hoc cao doanh tri"
"hoc cac dinh tren" » "hoc cac dinh trong", "hoc cac dinh tri", "hoc cac dinh dien", "hoc xac dinh tren", "hoc cac tinh tren", "hoc cac hinh tren", "hoc cao dinh tren"

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (((("hoc cac doanh tri") or ("hoc cac dinh tren"))) or ("toc sach tranh tien"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("hoc cac doanh tri") OR ("hoc cac dinh tren"))) OR ("toc sach tranh tien")).
• Removing quotes may allow a broader search: (((( hoc cac doanh tri ) or ( hoc cac dinh tren ))) or ( toc sach tranh tien )).
• Adding a wildcard symbol may retrieve word variants: (((("hoc cac doanh tri") or ("hoc cac dinh tren"))) or ("toc sach tranh tien"))*.