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   1853028篇
  免费   145425篇
  国内免费   2920篇
耳鼻咽喉   25330篇
儿科学   61722篇
妇产科学   53477篇
基础医学   265828篇
口腔科学   53672篇
临床医学   162681篇
内科学   361074篇
皮肤病学   39669篇
神经病学   148061篇
特种医学   74379篇
外国民族医学   516篇
外科学   282649篇
综合类   45985篇
现状与发展   4篇
一般理论   706篇
预防医学   140951篇
眼科学   42428篇
药学   139328篇
  3篇
中国医学   3619篇
肿瘤学   99291篇
  2018年   18326篇
  2016年   16034篇
  2015年   18299篇
  2014年   24792篇
  2013年   38291篇
  2012年   51213篇
  2011年   53905篇
  2010年   31988篇
  2009年   30028篇
  2008年   51220篇
  2007年   54226篇
  2006年   54770篇
  2005年   52984篇
  2004年   52081篇
  2003年   49735篇
  2002年   48501篇
  2001年   85940篇
  2000年   88944篇
  1999年   75096篇
  1998年   20210篇
  1997年   18539篇
  1996年   18382篇
  1995年   18018篇
  1994年   16921篇
  1993年   15969篇
  1992年   61641篇
  1991年   60226篇
  1990年   58902篇
  1989年   57120篇
  1988年   52915篇
  1987年   52095篇
  1986年   49532篇
  1985年   47989篇
  1984年   35828篇
  1983年   30820篇
  1982年   18129篇
  1981年   16078篇
  1980年   15173篇
  1979年   33896篇
  1978年   23545篇
  1977年   19968篇
  1976年   18637篇
  1975年   19860篇
  1974年   24135篇
  1973年   23383篇
  1972年   21381篇
  1971年   20149篇
  1970年   18582篇
  1969年   17357篇
  1968年   15933篇
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
991.
As the fields of astronomy, cosmology, and space travel move rapidly forward, so must space medicine. The manned space program and medical knowledge and support have developed in tandem. Dermatology will play a fundamental role in survival during space flight. This paper reviews past, present, and future accomplishments of the space program as they relate to medicine and characterizes some of dermatology's multiple roles in the future. It further explores the immunologic alterations noted during space flight and the attendant implications for health and well-being both in flight and on return to Earth, or to an Earthlike environment.  相似文献   
992.
993.
Histological sections of brain from patients showing evidence of advanced pathology of Alzheimer disease (AD) were examined for the presence of herpes simplex type-1 (HSV-1) nucleic acids by a sensitive in-situ hybridization technique. Samples from neurologically normal patients were examined in parallel. Sensitivity of the assay was verified by the detection of HSV-1 nucleic acids in neurons of trigeminal ganglia taken from cases of AD and normal controls. This indicated that the hybridization reaction was sufficiently sensitive to detect latent HSV-1 infections. Positive hybridization in the brain was only detected in a confirmed case of herpes simplex virus encephalitis. These results appear to confirm previous reports that HSV-1 infection is not directly involved in the pathology associated with AD.  相似文献   
994.
995.
Apexcardiography was employed to make a noninvasive assessment of left ventricular diastolic function in 80 patients with extensive myocardial infarction. In half the patients, there were impairments in cardiac diastole as manifested by its altered phase structure and some changed parameters indirectly indicating a rise in left ventricular end diastolic pressure and a fall in myocardial relation rates and diastolic compliance. Prior 10-day administration of tocopherol and nicotinamide to 45 patients caused a decrease in the severity of diastolic abnormalities in those in whom the latter had been abnormal. The use of membrane protectors resulted in lower incidence of complications and improved outcome of the disease.  相似文献   
996.
Despite extensive investigation, the pathogenesis of the adult respiratory distress syndrome (ARDS) remains uncertain. As yet, there is no clear explanation of why some patients at risk for ARDS develop the syndrome, whereas others do not. Neutrophils and complement fragments have been implicated in the acute lung injury, but it is clear from published data that evidence of complement activation alone predicts neither the development nor the severity of ARDS. We investigated whether the combination of endotoxin, a leukocyte-priming agent, and complement fragments, leukocyte-stimulating agents, was associated with the development of ARDS. Ninety-eight patients were identified as being either at risk for the development of ARDS or having ARDS, and serial blood samples were obtained. There was no correlation between C5 fragments and the development of ARDS. C3 fragment levels were increased in 89% of the patients with ARDS, but they were also increased in 62% of patients at risk. Endotoxin was detected in 74% of the plasma samples obtained from patients at risk who subsequent developed ARDS and in 64% of the plasma samples obtained from the patients with ARDS. In contrast, only 22% of the plasma samples obtained from the patients at risk who did not develop ARDS had measurable endotoxin. We suggest that the combination of endotoxin and complement fragments may be one mechanism involved in the development of ARDS.  相似文献   
997.
Enoximone is a positive inotropic agent belonging to the group of phosphodiesterase F-III inhibitors. The drug was tested in 34 patients uncontrolled by sympathomimetic drugs and referred to our department for urgent heart transplantation or circulatory assistance. After insertion of a Swan-Ganzgatheter and a radial artery catheter for haemodynamic monitoring, enoximone was administered as a 15-minute intravenous bolus injection of 1 to 2.5 mg/kf every 8 hours, in addition to sympathomimetic agents. Clinical and haemodynamic improvement was observed after thirty minutes in 30 patients. The cardiac index rose from 1.82 to 2.67 l/min/m2 and the pulmonary wedge pressure fell from 30.8 to 18.9 mmHg. Systemic arterial resistance decreased from 2170 to 1520 dyn. s. cm-5, and pulmonary resistance from 5.5 to 4.6 Wood units (p less than 0.01 for all values). Four patients had no haemodynamic improvement and were put on circulatory assistance, using a Jarvik 7 total artificial heart in 3 of them and heterotopic circulatory assistance in one. After clinical investigation for contra-indication to heart transplantation, and as their improved haemodynamic status permitted, 12 of the 30 patients were considered suitable (group B) for heart transplantation. Transplantation was performed within a week of admission in 11 patients without any need for mechanical assistance. One of the group B patients who required implantation of a Jarvik 7 artificial heart died after 12 hours of assistance. Eighteen patients were considered unsuitable for transplantation (group A) and treated medically.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
998.
In 422 patients admitted from the emergency department (ED) for suspected acute myocardial infarction, the hypothesis that chest pain that persists on arrival in the ED or recurs during the initial ED evaluation is a useful predictor of acute myocardial infarction (AMI) and complications of coronary ischemia was tested. Compared with patients whose chest pain spontaneously ceased before arrival in the ED, patients whose chest pain persisted or recurred during the initial ED evaluation had a 2.3 times greater risk of interventions (P less than .001), a 1.7 times greater risk of complications (P = .045), a 3.8 times greater risk of life-threatening complications (P = .04), and a 2.4 times greater risk of AMI (P = .005). A third group of patients with suspected AMI never experienced chest pain. This group of patients who never experienced chest pain had a three times higher risk of death (P = .02) compared with patients whose chest pain persisted or recurred in the ED, and a 2.1 times greater risk of intervention (P = .01), a 5.2 times greater risk of life-threatening complication (P = .015), and a 7.9 times greater risk of death (P = .025) compared with patients whose chest pain resolved before arrival in the ED. It was concluded that patients with chest pain that resolves spontaneously before arrival to the ED have a better in-hospital prognosis than any other group.  相似文献   
999.
1000.
G Rao  H R Madoff 《Chest》1989,95(1):244-245
A 64-year-old woman presented in shock. The computed tomography (CT) scan confirmed rupture of the left diaphragm with strangulation. Three days after surgery, the patient developed herniation of abdominal contents on the right side with cardiorespiratory collapse. Marlex mesh was used to repair on the right side. Postoperatively, she needed partial gastrectomy for massive duodenal ulcer bleeding. A dual chamber pacemaker was used to correct the complete heart block.  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