The main manifestations of lung cancer are as follows: 1. Cough: Cough is often a common symptom in early stage, which may be irritating dry cough or accompanied by a small amount of white mucus sputum, and the cough is often high-pitched and progressively aggravated. The cough is often high-pitched and progressively aggravated. It cannot be completely relieved by general anti-infection treatment. The main reason is that the tumor grows in the bronchial tube, blocking part of the bronchial lumen and narrowing the distal bronchial tube, which causes persistent persistent cough with or without wheezing, chest tightness, shortness of breath, etc. 2. Haemoptysis or blood in sputum: It is often an accompanying symptom of lung cancer. As the blood supply of cancer tissues is very rich, the growth of tumor cells depends on blood supply, and it is very easy to erode blood vessels in the process of growth, which may cause hemoptysis or sputum with dark-red blood in varying degrees.3. Fever: Generally, tumor may cause fever due to cell necrosis. Most patients have fever because the tumor blocks the lumen and the mucus is not easy to be discharged, which causes secondary obstructive pneumonia, and the symptoms are sometimes reduced after treatment with anti-infective drugs, but the shadow of lungs can not be completely absorbed by X-ray examination.4. Chest tightness and shortness of breath: the tumor growing in the lumen of the bronchial tubes causes partial narrowing of the lumen, or the tumor metastasizes to the hilar lymph nodes, which compresses the bronchial tubes, or it metastasizes to the pleura and pericardium, and a large amount of pleural effusion, shortness of breath occurs. Large amount of pleural effusion and pericardial effusion can cause impaired lung function and chest tightness and shortness of breath; if combined with chronic bronchitis and emphysema, the chest tightness and shortness of breath will be more serious.5. Chest pain: about 30% of the patients can feel chest pain, which is an irregular dull pain or hidden pain due to the direct invasion of tumor on the pleura, ribs and chest wall. If the tumor is located near the pleura, the chest pain will be aggravated when breathing or coughing. The pain will be aggravated if the invaded ribs and chest wall are touched by hand.6. Weight loss: weight loss is one of the common symptoms of malignant tumors, and when the tumor develops to the late stage, due to the tumor toxin and consumed raw material, accompanied by the loss of appetite caused by infection and pain, it can be manifested as wasting, and in the late stage, there will be malignant fluid.7. Difficulty of respiratory disease: if the tumor itself presses on the large trachea, it can appear inspiratory dyspnea and accompanied by chest tightness and shortness of breath. Difficulty in swallowing and hoarseness: when the cancer invades or compresses the esophagus, it may cause difficulty in swallowing and discomfort in swallowing, similar to the symptoms of esophageal cancer; if the tumor is large, it may directly compress or metastasize to the mediastinal lymph nodes, and hoarseness may occur when the laryngeal nerve is compressed by enlarged lymph nodes. 9. Headache, dizziness or dizziness: due to edema of the head, face, neck and upper limbs, as well as bruising in the anterior part of the chest and varicose veins, the flow of the superior vena cava is obstructed, and the blood flow of the superior vena cava is obstructed, and the blood flow of the upper vena cava is obstructed. Obstruction of blood flow of superior vena cava can cause headache, dizziness and vertigo. In conclusion, when cancer cells metastasize to distant organs, it can cause functional impairment of corresponding organs. For example, when cancer cells metastasize to the brain, headache, dizziness, vomiting, diplopia, weakness of half limbs or even hemiplegia may appear, and in serious cases, intracranial hypertension may appear, causing brain hernia, i.e. sudden unconsciousness and respiratory arrest; if cancer cells metastasize to bones, local pain and pressure pain may appear; if cancer cells metastasize to the liver, anorexia, ergonomics, pain in the liver area, enlargement of the liver, jaundice and accumulation of fluid in the peritoneal cavity may appear; if cancer cells metastasize to the pleural cavity, headache, dizziness and dizziness may occur. If the cancer cells have metastasized to pleura and pericardium, pleural and pericardial effusion will occur, and when the amount of fluid is large, secondary dyspnea, chest tightness, shortness of breath, panic, palpitation and other discomforts will occur.10. The discomforts that the patients feel are called clinical symptoms, while the physical signs are the positive results collected by doctors after detailed examination of the patients through looking, touching, knocking, listening, etc. Generally speaking, the confirmation of each disease is made through the examination of the patients' physical signs. Generally speaking, the diagnosis of each disease is made after comprehensive analysis of clinical symptoms, physical signs and some auxiliary examination results. In general, peripheral lung cancer has no obvious special positive signs in lungs, while central lung cancer has more prominent signs, especially when combined with obstructive pneumonia or atelectasis, the palpable trembling of diseased lung field is weaker than that of the opposite side, turbid tone can be seen on percussion of lungs, respiratory tone on auscultation is lower than that of the opposite side, and wet rosette can be smelled in case of obvious infections; and in case of combined with pleural metastasis, the palpable trembling is weakened obviously, and turbid tone is detected on percussion with reduced respiratory tone. In conclusion, patients with simple lung cancer generally have fewer positive signs, and positive signs are more prominent in the presence of comorbidities.