Perhaps you should try some spelling variations:
trinh vatn » trinh van, trinh han, trinh san
nhung cong » dung cong, thong cong, hang cong
dieu danh » dieu hanh, tieu danh, dia danh
trinh vat » trinh van, trinh luat, sinh vat
van chinh » va chinh, lan chinh, van thinh
chinh cau » chinh chau, chinh ca, chinh can
dieu dan » dien dan, dieu can, dieu ban
cong van » cong vang, cong san, song van

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((dieu dan) OR (dieu danh)) - hanh ((trinh vat) or (trinh vatn)) nhung cong van chinh cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((dieu dan) OR (dieu danh)) - hanh ((trinh vat) OR (trinh vatn)) nhung cong van chinh cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((dieu dan) OR (dieu danh)) - hanh ((trinh vat) or (trinh vatn)) nhung cong van chinh cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((dieu dan) OR (dieu danh)) - hanh ((trinh vat) or (trinh vatn)) nhung cong van chinh cau*.