thrombosis       
noun [ C or U ] uk/θrɒmˈbəʊ.sɪs/ us/θrɑːmˈboʊ.sɪs/  thromboses /θrɒmˈbəʊ.siːz/ /θrɑːmˈboʊ.siːz/
 血栓形成
a medical condition in which the flow of blood in the body is blocked by a clot (= partly solid mass) of blood
  Maintaining whatever mobility is possible can prevent thrombosis.
 Travellers risk deep vein thromboses if they sit in cramped seats for too long.
  - More examples
 - A blood test is performed in the laboratory to diagnose thrombosis.
 - He gave the cause of death as coronary thrombosis.
 - Arterial and venous thromboses can occur in a number of organs.