Perhaps you should try some spelling variations:
duoc duoc » duoc hoc, hoc duoc, soc duoc
duoc may » duoc ma, duoc ly, hoc may
su sach » vu sach
sinh de » sinh dh, sinh dai
tinh de » tinh da, tinh he, minh de
ve duoc » te duoc, ve nuoc, che duoc
hieu ve » hieu va, hieu van
nang xa » nang x, lang xa, nang ma
so sach » so sanh, bo sach, co sach
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (so sach)) ky nang xa hoi. hieu ve duoc duoc may ((tinh de) OR (sinh de)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) ky nang xa hoi. hieu ve duoc duoc may ((tinh de) OR (sinh de)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sach)) ky nang xa hoi. hieu ve duoc duoc may ((tinh de) OR (sinh de)) cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) ky nang xa hoi. hieu ve duoc duoc may ((tinh de) OR (sinh de)) cua tre*.