Perhaps you should try some spelling variations:
thanh trung » thanh tung
thiet tach » chiet tach, thien hach, thuat tach
hoc thiet » hoc thieu, hoc thuyet, hoc hien
trung cua » truong cua, trung tuan, trung cap
cua nhung » va nhung
cong sat » cong suat, cong san, cong nhat
cong hat » cong nhat, cong chat, cong ha
phan dau » phan tu, hang dau

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 - thanh trung cua nhung ((cong sat) OR (cong hat)) phan dau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thiet tach - thanh trung cua nhung ((cong sat) OR (cong hat)) phan dau".
• Adding a wildcard symbol may retrieve word variants: hoc thiet tach - thanh trung cua nhung ((cong sat) OR (cong hat)) phan dau*.