Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
ban hanh » ban hang
sach ky » sac ky, sach y, sach ty
luc ban » duc ban, cuc ban, luc bat
ve cau » ke cau, va cau, le cau
ve cua » le cua, de cua, ve cum
te cua » tue cua, le cua, de cua
ve cac » va cac, vien cac
x hoi » xa hoi, o hoi, x ho

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 nang x hoi. hieu ((ve cau) or (ve cac)) luc ban hanh ((ve cua) or (te cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ky nang x hoi. hieu ((ve cau) OR (ve cac)) luc ban hanh ((ve cua) OR (te cua)) tre.
• Adding a wildcard symbol may retrieve word variants: doc sach ky nang x hoi. hieu ((ve cau) or (ve cac)) luc ban hanh ((ve cua) or (te cua)) tre*.