Perhaps you should try some spelling variations:
thiet tach » chiet tach, thien hach, thuat tach
nhung cong » dung cong, thong cong, hang cong
hoc thiet » hoc thieu, hoc thuyet, hoc hien
tuong vao » tuong va, tuong vo, tuong dao
thanh cad » thanh ca, thanh cac, thanh cham
tung vap » tung va, trung van, dung va
cong ban » cong bang, cong san, cong tan
hanh cad » hanh cac, hanh cat, hanh cap

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 ((tung vap) OR (tuong vao)) nhung cong ban ((thanh cad) or (hanh cad))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thiet tach - thanh ((tung vap) OR (tuong vao)) nhung cong ban ((thanh cad) OR (hanh cad)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thiet tach - thanh ((tung vap) OR (tuong vao)) nhung cong ban ((thanh cad) or (hanh cad))".
• Adding a wildcard symbol may retrieve word variants: hoc thiet tach - thanh ((tung vap) OR (tuong vao)) nhung cong ban ((thanh cad) or (hanh cad))*.