Perhaps you should try some spelling variations:
duoc chat » doc chat, duoc pham, hoc chat
ninh viet » sinh vien, anh viet
viet cua » viec cua, viet ca, viet qua
van ninh » van minh, van dinh, van binh
tu cach » tu cac
xuc van » duc van, luc van, vuc van
cua tre » cua te, cuu tre, cua triet
du chat » dung chat, doc chat, cuu chat
bo sach » co sach, hoc sach
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: ((tu cach) or (bo sach)) ky nang x hoi. hien ((du chat) OR (duoc chat)) xuc van ninh viet cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu cach) OR (bo sach)) ky nang x hoi. hien ((du chat) OR (duoc chat)) xuc van ninh viet cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu cach) or (bo sach)) ky nang x hoi. hien ((du chat) OR (duoc chat)) xuc van ninh viet cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu cach) or (bo sach)) ky nang x hoi. hien ((du chat) OR (duoc chat)) xuc van ninh viet cua tre*.