Perhaps you should try some spelling variations:
trinh vietn » trinh dien, trinh bien, tinh viet
trinh viet » ninh viet, trinh vat
thong cong » trong cong, tong cong, thong thong
dieu tinh » diep tinh, lieu tinh, dien tinh
cong van » cong vang, cong san, song van
so dieu » bo dieu, hoc dieu
tao cao » bao cao, toan cao
tan ca » tan cua, tang ca, dan ca

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

• Performing a fuzzy search may retrieve terms with similar spellings: so dieu tinh - canh ((trinh viet) or (trinh vietn)) thong cong van ((tan ca) or (tao cao))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so dieu tinh - canh ((trinh viet) OR (trinh vietn)) thong cong van ((tan ca) OR (tao cao)).
• Adding a wildcard symbol may retrieve word variants: so dieu tinh - canh ((trinh viet) or (trinh vietn)) thong cong van ((tan ca) or (tao cao))*.