Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
van cac » van cau, van bac, dan cac
van hac » van hoc, van ha, van hai
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
va dan » va dao, va dau, va dap
ca dan » cac dan, ca dao
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky nang xa hoi. hieu ((van cac) OR (van hac)) trung ((va dan) or (ca dan)) di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang xa hoi. hieu ((van cac) OR (van hac)) trung ((va dan) OR (ca dan)) di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang xa hoi. hieu ((van cac) OR (van hac)) trung ((va dan) or (ca dan)) di cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang xa hoi. hieu ((van cac) OR (van hac)) trung ((va dan) or (ca dan)) di cua tre*.