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   8687篇
  免费   355篇
  国内免费   34篇
耳鼻咽喉   142篇
儿科学   201篇
妇产科学   181篇
基础医学   1357篇
口腔科学   195篇
临床医学   875篇
内科学   1701篇
皮肤病学   249篇
神经病学   754篇
特种医学   445篇
外国民族医学   3篇
外科学   1231篇
综合类   71篇
一般理论   3篇
预防医学   376篇
眼科学   253篇
药学   660篇
中国医学   27篇
肿瘤学   352篇
  2022年   59篇
  2021年   97篇
  2020年   93篇
  2019年   111篇
  2018年   148篇
  2017年   114篇
  2016年   158篇
  2015年   191篇
  2014年   224篇
  2013年   300篇
  2012年   402篇
  2011年   423篇
  2010年   281篇
  2009年   285篇
  2008年   420篇
  2007年   463篇
  2006年   418篇
  2005年   406篇
  2004年   388篇
  2003年   404篇
  2002年   375篇
  2001年   153篇
  2000年   117篇
  1999年   110篇
  1998年   74篇
  1997年   86篇
  1996年   67篇
  1995年   74篇
  1994年   68篇
  1993年   65篇
  1992年   88篇
  1991年   81篇
  1990年   60篇
  1989年   59篇
  1988年   68篇
  1987年   68篇
  1986年   60篇
  1985年   41篇
  1984年   58篇
  1983年   66篇
  1982年   43篇
  1981年   40篇
  1940年   43篇
  1937年   39篇
  1933年   55篇
  1932年   45篇
  1931年   47篇
  1928年   40篇
  1927年   45篇
  1926年   56篇
排序方式: 共有9076条查询结果,搜索用时 15 毫秒
11.
The cytologic diagnosis of malignancy is frequently straightforward. For difficult cases, multiple immunostains and immunostain panels have been investigated without consensus. beta-human chorionic gonadotropin (hCG) has been reportedly expressed in malignancies, but not in normal tissue. HCG also has been reported as a specific marker of metastases in serous fluids when detected with laboratory assays. We investigated the clinical utility of hCG in this cytologic setting. A total of 97 cases of benign and malignant effusions were studied. Each case was immunostained with monoclonal hCG using the avidin-biotin technique and diaminobenzidine as a chromogen. Additionally, a mucicarmine stain was performed on most cases. Cases were evaluated for hCG expression and mucin in a blinded fashion. After the cases were reviewed, the diagnoses were unblinded and staining patterns were evaluated. Of the 47 benign cases studied, 23 (49%) exhibited immunoreactivity to hCG in at least 5% of mesothelial cells present. In contrast, 28 of 44 (64%) adenocarcionomas exhibited a similar degree of immunostaining. In all, 21 (48%) of the adenocarcinomas were also positive for mucin; five of these mucin-positive cases were negative for hCG. The combination of mucin and hCG detected 33 of 44 (75%) adenocarcinomas. We conclude that hCG lacks the specificity for malignant cells to be of clinical use in effusion cytology.  相似文献   
12.
In the century or so since the birth of the research-based pharmaceutical industry, there has never been a more demanding time. The most pressing issue facing virtually all big pharmaceutical companies today is research and development productivity. Despite huge investments in research and development, the number of new medicines cleared for market has declined. On the other hand, there has never been a more exciting time to do healthcare research. New sciences and technologies are opening up radically new perspectives and opportunities for the future. Medical practice is undergoing a historic shift towards more personalized medicine. Over the next 10 years we can expect significant progress in the treatment of major diseases.  相似文献   
13.
Summary Sixteen patients with symptoms typical for Ockelbo disease (rash, arthralgia, fever) were enrolled in a 2 1/2 year study, during which clinical symptoms were recorded and ELISA was employed to study specific IgM, IgG and IgG subclass development. Initially, all patients presented with rash and arthralgia, and five patients still suffered from joint symptoms at the end of the study period. Ockelbo virus specific IgM was detected during the first week post onset in 6 patients and in 15 patients by day 14. One patient failed to develop specific IgM and was later diagnosed with a human parvovirus B 19 infection. All patients were IgM-negative 2 1/2 years post onset. Seroconversions or significant titer rises for specific total IgG were seen in 15 patients. IgG titers generally peaked within one year but in two patients maximum titers were seen 2 1/2 years post onset. Development of IgG1 followed that of total IgG, while IgG3, after an initial increase in all Ockelbo disease patients, remained at peak levels for one year in four patients, three of whom still had detectable IgG3 at the end of the study period. Ockelbo virus specific IgG2 or IgG4 was not detected in any of the patients.  相似文献   
14.
Sporadic amyotrophic lateral sclerosis is an idiopathic human degenerative disease of spinal cord and brain motor neurons. Prior studies demonstrated that most patients with amyotrophic lateral sclerosis posses immunoglobulins that bind to purified L-type voltage-gated calcium channels, that titers of anti–voltage-gated calcium channel antibodies correlate with disease progression rates, and that amyotrophic lateral sclerosis patient-derived antibodies (ALS IgG) produce electrophysiological changes in the function of voltage-gated calcium channels. Using Western transfer immunoblots and enzyme-linked immunosorbent assays, the calcium ionophore–forming α1 subunig of the voltage-gated calcium channel is now identified as the major voltage-gated calcium channel antigen to which ALS IgG binds. Additionally, the binding of an L-type voltage-gated calcium channel α1 subunit–directed monoclonal antibody, which itself mimics the effects of ALS IgG on skeletal muscle voltage-gated calcium channel currents, is selectively prevented by preaddition of ALS IgG. Voltage-gated calcium channel–binding IgG from patients with Lambert-Eaton myasthenic syndrome appears to be differentiated from ALS IgG by the reactivity of the former to both α1 and β subunits of the calcium channel. These assays provide further evidence linking amyotrophic lateral sclerosis to an autoimmune process, and suggest one means to differentiate immunoglobulins from patients with amyotrophic lateral sclerosis from those of patients with another autoimmune disease expressing calcium channel antibodies.  相似文献   
15.
16.
17.
18.
19.
20.
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