Perhaps you should try some spelling variations:
trinh vatn » trinh van, trinh han, trinh san
trinh vat » trinh van, trinh luat, sinh vat
chinh cau » chinh chau, chinh ca, chinh can
hoc dieu » hoc thieu, hoc hien
dieu can » dieu hanh, tiep can, dieu cua
cong tan » cong san, cong thanh, cong ty
cong tac » cong ty

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 can - hanh ((trinh vat) or (trinh vatn)) thong ((cong tan) OR (cong tac)) chinh cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc dieu can - hanh ((trinh vat) OR (trinh vatn)) thong ((cong tan) OR (cong tac)) chinh cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc dieu can - hanh ((trinh vat) or (trinh vatn)) thong ((cong tan) OR (cong tac)) chinh cau".
• Adding a wildcard symbol may retrieve word variants: hoc dieu can - hanh ((trinh vat) or (trinh vatn)) thong ((cong tan) OR (cong tac)) chinh cau*.