Perhaps you should try some spelling variations:
thien van » thi van
gianh lai » gian lan
nang cau » nang cao, hang cau, nang dau
van cham » van chat, van tham, va cham
cua viet » hoa viet, cua vat, cua dieu
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
ca viet » va viet, co viet, hoa viet
soc va » loc va, doc va, goc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky nang cau hoi. thien van cham ((soc va) OR (hoc va)) gianh lai ((cua viet) or (ca viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang cau hoi. thien van cham ((soc va) OR (hoc va)) gianh lai ((cua viet) OR (ca viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky nang cau hoi. thien van cham ((soc va) OR (hoc va)) gianh lai ((cua viet) or (ca viet))".
• Adding a wildcard symbol may retrieve word variants: so sach ky nang cau hoi. thien van cham ((soc va) OR (hoc va)) gianh lai ((cua viet) or (ca viet))*.