Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
thiet tach » chiet tach, thien hach, thuat tach
hoc thiet » hoc thieu, hoc thuyet, hoc hien
nang cua » mang cua, hang cua, tang cua
nang dua » nang du, nang suat, nang quan
van than » van thanh, van thang, van phan
van tuan » van quan, van ban, anh tuan

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 tach - anh ((nang cua) OR (nang dua)) nhung cong ((van than) or (van tuan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thiet tach - anh ((nang cua) OR (nang dua)) nhung cong ((van than) OR (van tuan)) cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thiet tach - anh ((nang cua) OR (nang dua)) nhung cong ((van than) or (van tuan)) cau".
• Adding a wildcard symbol may retrieve word variants: hoc thiet tach - anh ((nang cua) OR (nang dua)) nhung cong ((van than) or (van tuan)) cau*.