Perhaps you should try some spelling variations:
khien tu » dien tu
thanh va » thanh van, hanh va, thanh ha
khoa hoi » khoan hoi, khoa hoc, khoa doi
duc van » duc va, duc tan, duc manh
xuc van » luc van, vuc van, xuc ban
so sach » so sanh, bo sach, co sach
tu cham » toc cham, thi cham
sach ky » sac ky, sach y, sach ty
hoa hoi » hoa hoc, hoa doi, hoc hoi
ky cong » ke cong, ly cong, khu cong
va cua » va chua, via cua, ca cua
cua tu » cua tuc, cua su, cua cu

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 cong ((hoa hoi) OR (khoa hoi)). khien tu cham ((xuc van) or (duc van)) thanh va cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky cong ((hoa hoi) OR (khoa hoi)). khien tu cham ((xuc van) OR (duc van)) thanh va cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky cong ((hoa hoi) OR (khoa hoi)). khien tu cham ((xuc van) or (duc van)) thanh va cua tu".
• Adding a wildcard symbol may retrieve word variants: so sach ky cong ((hoa hoi) OR (khoa hoi)). khien tu cham ((xuc van) or (duc van)) thanh va cua tu*.