Perhaps you should try some spelling variations:
thieu hach » chieu sach, hieu cach, thieu cac
thien hach » thien thanh, hien hanh
thanh tung » thanh cong
thong cong » tong cong, thong thong, phong chong
tung quan » tuong quan, trung quan, dung quan
dan chan » dan gian, dan ca, van chat
chan cau » phan cau, can cau, chinh cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((thieu hach) OR (thien hach)) - thanh tung quan ((thong cong) or (trong cong)) dan chan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu hach) OR (thien hach)) - thanh tung quan ((thong cong) OR (trong cong)) dan chan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu hach) OR (thien hach)) - thanh tung quan ((thong cong) or (trong cong)) dan chan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu hach) OR (thien hach)) - thanh tung quan ((thong cong) or (trong cong)) dan chan cau*.