Perhaps you should try some spelling variations:
nhan trong » nhuan trong, nhat trong, nhin trong
khoa sach » hoc sach
manh tung » manh hung, thanh tung
trong van » trong cac
khi sach » khi sac, khau sach, khoe sach
tung cac » dung cac, vung cac, cung cac
cac nhan » ca nhan, cac nha, cam nhan
ban cao » bao cao, ban can, ban co

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi ((khi sach) or (khoa sach)) - manh tung cac nhan trong van ban cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi ((khi sach) OR (khoa sach)) - manh tung cac nhan trong van ban cao.
• Adding a wildcard symbol may retrieve word variants: doi ((khi sach) or (khoa sach)) - manh tung cac nhan trong van ban cao*.