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   12489篇
  免费   1412篇
  国内免费   22篇
耳鼻咽喉   157篇
儿科学   352篇
妇产科学   300篇
基础医学   1606篇
口腔科学   352篇
临床医学   1934篇
内科学   2477篇
皮肤病学   242篇
神经病学   1332篇
特种医学   335篇
外国民族医学   1篇
外科学   2114篇
综合类   355篇
一般理论   17篇
预防医学   965篇
眼科学   178篇
药学   608篇
中国医学   5篇
肿瘤学   593篇
  2023年   96篇
  2022年   90篇
  2021年   182篇
  2020年   172篇
  2019年   198篇
  2018年   281篇
  2017年   251篇
  2016年   254篇
  2015年   277篇
  2014年   364篇
  2013年   523篇
  2012年   684篇
  2011年   695篇
  2010年   448篇
  2009年   418篇
  2008年   625篇
  2007年   581篇
  2006年   548篇
  2005年   575篇
  2004年   531篇
  2003年   483篇
  2002年   419篇
  2001年   462篇
  2000年   490篇
  1999年   393篇
  1998年   180篇
  1997年   152篇
  1996年   148篇
  1995年   135篇
  1994年   110篇
  1993年   103篇
  1992年   265篇
  1991年   254篇
  1990年   232篇
  1989年   245篇
  1988年   195篇
  1987年   194篇
  1986年   181篇
  1985年   170篇
  1984年   145篇
  1983年   104篇
  1982年   71篇
  1981年   63篇
  1979年   94篇
  1978年   56篇
  1977年   50篇
  1976年   62篇
  1975年   52篇
  1974年   66篇
  1972年   65篇
排序方式: 共有10000条查询结果,搜索用时 20 毫秒
71.
The traditional method of establishing a pneumoperitoneum before laparoscopic surgery is via a Verres needle inserted in the midline below the umbilicus while tenting the abdominal wall with the hand. A new approach is described in which preliminary surgical exposure and tenting of the linea alba immediately above the umbilicus is achieved before needle insertion through the superior margin of the umbilical ring. The advantages of this new technique over the conventional method are discussed. Further technical features important in the safe formation of the pneumoperitoneum are emphasized.  相似文献   
72.
73.
74.
75.
76.
D A Walsh  J R Govan 《Thorax》1990,45(6):478-481
Long term continuous oxygen therapy improves prognosis in patients with hypoxaemic chronic airflow limitation. Transtracheal delivery of oxygen permits adequate oxygenation of such patients at lower flow rates than are required for delivery by nasal cannulas, thus increasing the time for which portable oxygen cylinders can be used and improving the efficacy of domiciliary oxygen concentrators in patients with refractory hypoxaemia. In a study of the long term acceptability and risks of transtracheal oxygen in 37 patients, with a total follow up of 595 patient-months, most patients reported symptomatic benefit and four have used transtracheal oxygen successfully for more than four years. Problems have included surgical emphysema (4 patients), catheter fracture (9), local infection (34), and catheter dislodgement (21); but these have been relatively infrequent and in general have not caused important clinical problems. Transtracheal oxygen therapy was discontinued in 10 patients before death for various reasons, including infection (2 patients), catheter fracture (1), and surgical emphysema (1). Accumulation of mucus balls has not been a problem. It is concluded that transtracheal oxygen therapy is a safe and acceptable alternative to nasal cannulas in well motivated patients with hypoxaemia due to chronic airflow limitation who are keen to pursue an active life.  相似文献   
77.
78.
79.
Despite improved resolution with new imaging techniques, surgical confirmation of mediastinal lymph node status is often required for reliable staging of patients with non-small cell lung cancer. Recent scintigraphic studies suggest that s.c. administration of radiolabeled antibodies can be more efficient than the i.v. route for targeting regional lymph nodes in animals and humans. To determine if this approach could be applied to the lymphatics of the lung, we injected both specific and irrelevant radiolabeled monoclonal antibodies via a flexible fiberoptic bronchoscope through the mucosa of lobar bronchi in normal dogs. The injected antibodies were expected to drain by way of local lymphatic vessels toward the central lymph nodes, in effect following the same pathway as do cells metastasizing to these nodes during early regional tumor dissemination. To accomplish this, anesthetized dogs were intubated and then coinjected with the two labeled antibodies [600 microCi/100 micrograms (total)] through a fiberoptic bronchoscope. The animals were serially imaged and then autopsied 14-36 h after injection. Individual hilar and carinal nodes contained over 1% of the injected 131I-labeled specific antibody dose and the average selectivity was 2.5:1 with respect to a coinjected irrelevant IgG. Distant organs (mesenteric lymph node, liver, spleen, bone marrow, and lung parenchyma other than the injection site) contained much less radioactivity, and those sites accumulated a greater fraction of the non-specific labeled antibody. The ratio of iodine-131 to iodine-125 counts between hilar/carinal lymph nodes and abdominal lymph nodes ranged from 15:1 to 100:1. These initial studies indicate efficient delivery of antibody to a subset of the regional nodes via pulmonary lymphatics. They suggest the feasibility of this technique which may be of use in the detection and perhaps therapy of human lung cancer metastases in regional lymph nodes.  相似文献   
80.
The effect of lithium administration (800 mg daily for 7 days) on the neuroendocrine and temperature responses to the 5-HT1A receptor agonist, gepirone, was studied in eight healthy male volunteers. Gepirone (20 mg orally) significantly increased plasma levels of prolactin, growth hormone, corticotropin and cortisol, and lowered oral temperature. None of these responses was significantly altered by lithium treatment. The results suggest that the ability of short-term lithium treatment to increase 5-HT-mediated neuroendocrine responses in humans is unlikely to be related to changes in the sensitivity of pre- or post-synaptic 5-HT1A receptors.  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