首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   52170篇
  免费   3590篇
  国内免费   1139篇
耳鼻咽喉   93篇
儿科学   1224篇
妇产科学   648篇
基础医学   2319篇
口腔科学   492篇
临床医学   7123篇
内科学   18121篇
皮肤病学   169篇
神经病学   626篇
特种医学   801篇
外国民族医学   1篇
外科学   6600篇
综合类   8402篇
现状与发展   3篇
预防医学   2170篇
眼科学   81篇
药学   4845篇
  46篇
中国医学   2607篇
肿瘤学   528篇
  2024年   73篇
  2023年   853篇
  2022年   1210篇
  2021年   2195篇
  2020年   2113篇
  2019年   1872篇
  2018年   1820篇
  2017年   1666篇
  2016年   1715篇
  2015年   1805篇
  2014年   3770篇
  2013年   4023篇
  2012年   2938篇
  2011年   3450篇
  2010年   2718篇
  2009年   2721篇
  2008年   2623篇
  2007年   2659篇
  2006年   2375篇
  2005年   2208篇
  2004年   1693篇
  2003年   1427篇
  2002年   1198篇
  2001年   1125篇
  2000年   812篇
  1999年   715篇
  1998年   585篇
  1997年   534篇
  1996年   508篇
  1995年   442篇
  1994年   437篇
  1993年   313篇
  1992年   280篇
  1991年   275篇
  1990年   239篇
  1989年   239篇
  1988年   223篇
  1987年   162篇
  1986年   138篇
  1985年   139篇
  1984年   115篇
  1983年   65篇
  1982年   77篇
  1981年   70篇
  1980年   57篇
  1979年   58篇
  1978年   44篇
  1977年   31篇
  1976年   35篇
  1974年   15篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Patients with multiple system atrophy (MSA) present large changes in blood pressure (BP) due to autonomic disturbances. We analyzed how this change may influence dynamic cerebral autoregulation (DCA). Simultaneous recordings of arterial BP (Finapres) and middle cerebral artery (MCA) blood flow velocity (BFV) (transcranial Doppler) were performed in 10 patients with MSA (61 +/- 12 yr of age) and 12 healthy volunteers (61 +/- 11 yr of age): cerebral BFV response to oscillations in mean BP was studied in the supine position by cross-spectral analysis of mean BP and mean MCA BFV. The DCA was also studied during the decrease in BP the first seconds when standing up from a sitting position by the assessment of the cerebrovascular resistance index (CR; mean BP/mean MCA BFV ratio). The MCA BFV/BP cross-spectral analysis showed a phase for the mid-frequency band (0.07-0.2 Hz) significantly larger in MSA, suggesting more active autoregulation in response to larger changes in BP. Changes in CR reflecting the rate of autoregulation, when standing did not differ between the two groups. These data suggest that dynamic cerebral autoregulation is preserved in MSA.  相似文献   
62.
目的比较伊贝沙坦与雷米普利对充血性心力衰竭(CHF)的临床疗效及安全性。方法72例CHF患者在常规治疗基础上随机分为2组。伊贝沙坦组(36例)口服伊贝沙坦150 mg.d-1;雷米普利组(36例)口服雷米普利2.5 mg.d-1。治疗前与治疗6 mo后分别用超声心动图测量左室射血分数(LVEF)、左室短轴缩短分数(LVFS)、每搏输出量(SV)、心排量(CO)、心脏指数(CI)评估心功能。结果治疗6 mo后,2组心功能较治疗前非常明显改善(P<0.01),2组之间比较差异无统计学意义(P>0.05)。结论伊贝沙坦与雷米普利治疗CHF均有效,且疗效相当。  相似文献   
63.
甘草酸及肾十方治疗慢性马兜铃酸肾病26例疗效观察   总被引:3,自引:0,他引:3  
目的观察甘草酸及复方中药肾十方对慢性马兜铃酸肾病的疗效。方法26例符合慢性马兜铃酸肾病的患者,给予甘草酸二铵150mg加中药复方汤剂肾十方治疗3个疗程。观察治疗前后尿素氮(BUN)、血肌酐(SCr)、尿酶及24h尿蛋白排泄量,血红蛋白、红细胞压积。结果治疗后患者临床症状有显著改善,总有效率80.76%;BUN、SCr、尿N-乙酰葡萄胺酶(NAG)、β2-微球蛋白(β2-MG)均显著下降(P〈0.05),血红蛋白、红细胞压积较治疗前升高(P〈0.05)。结论甘草酸及复方中药肾十方对慢性马兜铃酸肾病有确切的疗效。  相似文献   
64.
目的 研究天文潮汐对心脏病患者发生心衰的影响。方法 分析 118例心脏病患者发生心衰在各潮汐期的分布。结果 在强天文潮汐期内心脏病患者发生心衰显著多于其余时期 ,而且在朔、望期发生的人数多于上、下弦期。结论 护理人员要了解天文潮汐的变化规律 ,教育心脏病患者在强天文潮汐期内要保持情绪稳定 ,必要时在强天文潮汐期内可给予心脏病患者适量的镇静剂和安眠药。  相似文献   
65.
慢性肾衰竭急性加重的临床特征及相关因素分析   总被引:2,自引:0,他引:2  
目的:探讨慢性肾衰竭(CRF)急性加重因素及其治疗措施对预后的影响。方法:对2001年1月~2005年6月住院治疗的CRF急性加重患者42例,按其加重原因、基础疾病、治疗方式和疗效进行回顾性总结。结果:CRF急性加重因素依次为各种感染(45.2%)、原发病加重(19.0%)、高血压未控制(14.3%)、水电解质紊乱(11.9%)、肾毒性药物(11.9%)、心功能不全(9.5%)、尿路梗阻(4.8%)、血高粘滞状态(2.4%),7例同时存在≥2种上述病因(16.7%)。CRF急性加重原发病以慢性肾小球肾炎(52.4%)和糖尿病肾病(11.9%)为主。积极治疗后肾功能恢复达到或接近原来水平者40例,死亡2例,死亡2例的年龄均在60岁以上。结论:对于CRF肾功能急剧恶化的患者,应积极寻找其加重因素,并采取非透析和透析相结合治疗,改善肾功能,降低病死率,延长患者生命。  相似文献   
66.
BACKGROUND AND AIM: Severe dysautonomia may be secondary to viral infections, resulting in impaired autoimmune, cardiovascular, urinary and digestive dysfunction. Herein, we present a case of a 31-year-old white female patient who had severe gastroparesis related to autonomic failure following an episode of acute gastroenteritis. This seems to be the first report providing thorough assessment of the enteric and autonomic nervous system by analysis of full-thickness small intestinal biopsies, cardiovagal testing and autopsy. HOSPITAL COURSE: This patient affected by a severe gastroparesis was treated with antiemetics, prokinetics, analgesics and gastric electrical stimulation to control symptoms. Nutritional support was made using jejunal feeding tube and, in the final stage of disease, with total parenteral nutrition. Autonomic studies revealed minimal heart rate variability and a disordered Valsalva manoeuvre although the enteric nervous system and the smooth muscle layer showed a normal appearance. Hospital courses were complicated by episodes of bacteraemia and fungemia. Serum antiphospholipid antibodies were noted but despite anticoagulation, she developed a pulmonary embolism and shortly thereafter the patient died. Autopsy revealed acute haemorrhagic Candida pneumonia with left main pulmonary artery thrombus. Sympathetic chain analysis revealed decreased myelinated axons with vacuolar degeneration and patchy inflammation consistent with Guillain-Barre syndrome. The evaluation of the enteric nervous system in the stomach and small bowel revealed no evidence of enteric neuropathy or myopathy. CONCLUSION: A Guillain-Barre-like disease with gastroparesis following acute gastroenteritis is supported by physiological and autonomic studies with histological findings.  相似文献   
67.
Objective: Descending and ascending aortomyoplasty are two surgical procedures intended to induce hemodynamic benefits similar to those of the intra-aortic-balloon-pump (IABP). To date, there have been no studies comparing the two surgical techniques. The objective of this study was to compare coronary blood flow augmentation and afterload reduction as produced by descending and ascending aortomyoplasty counterpulsation Methods: Twenty-two mongrel dogs (18–35 kg) underwent IABP application (n=7), descending (n=8), or ascending (n=7) aortomyoplasty. Left anterior descending (LAD) coronary artery blood flow was measured using a Transonic Doppler flow probe. Left ventricular pressure as well as aortic pressures proximal and distal to either the aortomyoplasty site or the IABP position were monitored continuously. Results: Descending aortomyoplasty induced higher elevation in the LAD blood flow during assisted beats (27% from 10.8±4 to 13.8±6 ml/min, P<0.001) than that induced by either ascending aortomyoplasty (19% from 11.7±5 to 14±5 ml/min, P<0.001) or IABP counterpulsation (18% from 8.6±3 to 10.2±4 ml/min, P<0.001). Conversely, while ascending aortomyoplasty reduced the left ventricular end-diastolic pressure by 16% (from 60±18 to 50±22 mmHg, P<0.001), similar to the 16% after load reduction achieved by the IABP counterpulsation, descending aortomyoplasty failed to induce afterload reduction. Conclusions: Descending aortomyoplasty produces higher coronary blood flow augmentation than either ascending aortomyoplasty or IABP. However, afterload reduction comparable to that achieved by IABP was observed only with ascending aortomyoplasty and not with descending aortomyoplasty.  相似文献   
68.
Acute renal failure (ARF) developed in a 7-week-old infant due to bilateral candidal bezoars (fungal balls) causing obstruction at the pelviureteric junction. The baby was born at term with an appropriate birthweight, and had been treated with broad-spectrum antibiotics for respiratory distress and septicemia during the 1st week of life. Recovery from ARF followed renal decompression with bilateral nephrostomy tube placement and parenteral administration of amphotericin B and 5-flucytosine. Received August 21, 1996; received in revised form and accepted January 3, 1997  相似文献   
69.
To date, only 10 cases of distal penile gangrene in patients with chronic renal failure have been reported. This rare condition is believed to result from progressive vascular calcification due to secondary hyperparathyroidism in patients with chronic renal failure. We report an additional case of distal penile gangrene in a 41-year-old man who presented with chronic renal disease and pulmonary tuberculosis. Since some authors have emphasized that aggressive surgical treatment in such cases has a significant mortality rate, we took a more conservative approach to treatment.  相似文献   
70.
A 69-year-old man was admitted to our kidney center with endstage renal failure. We started intermittent peritoneal dialysis immediately because of severe azotemia, hyperkalemia, and metabolic acidosis. Two weeks after admission, he developed uremic pericarditis with frequent ventricular premature contractions and supraventricular premature contractions. The intermittent peritoneal dialysis was then replaced by intensive hemodialysis, and oral administration of 300 mg/d of cibenzoline was started. Four days later, he developed thirst, weakness, and dyspnea due to respiratory muscular paralysis. We initiated respiratory support with a respirator because analysis of his blood gases revealed marked hypercapnia and hypoxia. He also developed hypoglycemia and prolonged PQ and QRS intervals on the electrocardiogram, which we believed were due to cibenzoline intoxication; we discontinued the cibenzoline immediately. All symptoms improved, and he was extubated 5 days later. After 2 months, his pericardial effusion disappeared. He now continues maintenance hemodialysis as an outpatient. We suspect that the cibenzoline induced the respiratory muscular paralysis for 2 reasons: 1) the patient experienced the respiratory muscular paralysis, at the same time he also experienced thirst, weakness, hypoglycemia, and prolonged PQ and QRS intervals on electrocardiogram, and all of these symptoms improved after the discontinuation of cibenzoline, and 2) his plasma concentration of cibenzoline became remarkably elevated, to 20 times above the standard therapeutic level. This patient's clinical course indicates that hemodialysis might be superior to intermittent peritoneal dialysis for treatment of cibenzoline intoxication.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号