Perhaps you should try some spelling variations:
vat thanh » dat thanh, gat thanh, tat thanh
hieu viec » nhieu viec, hieu ve, sieu viet
viec cac » vien cac, viec cua, viec lam
cac thuc » cach thuc, cac thu, can thuc
thanh vi » hanh vi, thanh va, thanh ve
su triet » su viet, su tien, ve triet
sach ty » sach y, sach thu, xach tay
sach tu » sach thu, cach tu, sach uu
5 hoi » o hoi
vi su » va su, ve su, ki su

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 ty) OR (sach tu)) xang ((5 hoi) or (x ho)). hieu viec cac thuc vat thanh vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ty) OR (sach tu)) xang ((5 hoi) OR (x ho)). hieu viec cac thuc vat thanh vi su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ty) OR (sach tu)) xang ((5 hoi) or (x ho)). hieu viec cac thuc vat thanh vi su triet".
• Adding a wildcard symbol may retrieve word variants: su ((sach ty) OR (sach tu)) xang ((5 hoi) or (x ho)). hieu viec cac thuc vat thanh vi su triet*.