Perhaps you should try some spelling variations:
trinh thong » trinh thuong, trinh trong, trinh khong
thiet danh » thien danh, thien anh, thien dang
trinh tong » trinh trong, trinh cong, trinh bong
cong ngang » cong nhan, cong quang, cong lang
hoc thiet » hoc thieu, hoc thuyet, hoc hien
cong vang » cong lang, cong quang, cong san
phan cau » phan dau, phan cac, phan tu

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

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