Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
thanh lap » thanh san, phan lap, thanh hai
van pham » san pham, van phan, van phat
van chat » cao chat
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, su sach, te sach
duc van » duc va, duc tan, duc manh
lap cua » lai cua, tap cua, lam cua
y nang » ky nang, ly nang, v nang
x hoi » xa hoi, o hoi, x ho
o hai » co hai, so hai, o lai

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y nang ((x hoi) or (o hai)). hieu ((van pham) or (van chat)) duc van thanh lap cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((x hoi) OR (o hai)). hieu ((van pham) OR (van chat)) duc van thanh lap cua viet.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((x hoi) or (o hai)). hieu ((van pham) or (van chat)) duc van thanh lap cua viet*.