Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
tao khoi » tao hoi, thao khoa, lao khoa
va thanh » gia thanh, ban thanh, va tinh
ky sang » ky nang, ky tang, duy sang
ky dang » ky nang, ky danh
hieu vi » hieu voi, hieu va, hien vi
hieu ve » hieu va, hieu van
san cua » sang cua, ban cua, dan cua
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ((ky sang) or (ky dang)) tao khoi. ((hieu vi) OR (hieu ve)) pham duc va thanh san cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ((ky sang) OR (ky dang)) tao khoi. ((hieu vi) OR (hieu ve)) pham duc va thanh san cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ((ky sang) or (ky dang)) tao khoi. ((hieu vi) OR (hieu ve)) pham duc va thanh san cua te".
• Adding a wildcard symbol may retrieve word variants: doc sach ((ky sang) or (ky dang)) tao khoi. ((hieu vi) OR (hieu ve)) pham duc va thanh san cua te*.