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   238552篇
  免费   4134篇
  国内免费   280篇
耳鼻咽喉   1960篇
儿科学   8356篇
妇产科学   4505篇
基础医学   24860篇
口腔科学   3159篇
临床医学   17146篇
内科学   46634篇
皮肤病学   2031篇
神经病学   22094篇
特种医学   11028篇
外国民族医学   6篇
外科学   36563篇
综合类   2644篇
一般理论   20篇
预防医学   24251篇
眼科学   3792篇
药学   13611篇
中国医学   818篇
肿瘤学   19488篇
  2023年   471篇
  2022年   919篇
  2021年   1929篇
  2020年   1065篇
  2019年   1633篇
  2018年   25157篇
  2017年   19323篇
  2016年   20850篇
  2015年   2390篇
  2014年   2891篇
  2013年   3738篇
  2012年   11115篇
  2011年   25163篇
  2010年   21109篇
  2009年   13574篇
  2008年   22781篇
  2007年   25019篇
  2006年   3864篇
  2005年   5484篇
  2004年   6442篇
  2003年   7215篇
  2002年   5200篇
  2001年   1730篇
  2000年   1951篇
  1999年   1437篇
  1998年   739篇
  1997年   572篇
  1996年   450篇
  1995年   413篇
  1994年   370篇
  1993年   310篇
  1992年   652篇
  1991年   584篇
  1990年   627篇
  1989年   508篇
  1988年   445篇
  1987年   450篇
  1986年   375篇
  1985年   347篇
  1984年   259篇
  1983年   213篇
  1982年   153篇
  1980年   153篇
  1979年   177篇
  1978年   170篇
  1977年   145篇
  1975年   151篇
  1974年   159篇
  1973年   151篇
  1972年   146篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
International Journal of Clinical Oncology - Immune-checkpoint inhibitors (ICIs) are standard treatments for metastatic non-small cell lung cancer (NSCLC). Patients with poor performance status...  相似文献   
3.
4.
Magnetic field generated by neuronal activity could alter magnetic resonance imaging (MRI) signals but detection of such signal is under debate. Previous researches proposed that magnitude signal change is below current detectable level, but phase signal change (PSC) may be measurable with current MRI systems. Optimal imaging parameters like echo time, voxel size and external field direction, could increase the probability of detection of this small signal change. We simulate a voxel of cortical column to determine effect of such parameters on PSC signal. We extended a laminar network model for somatosensory cortex to find neuronal current in each segment of pyramidal neurons (PN). 60,000 PNs of simulated network were positioned randomly in a voxel. Biot–savart law applied to calculate neuronal magnetic field and additional phase. The procedure repeated for eleven neuronal arrangements in the voxel. PSC signal variation with the echo time and voxel size was assessed. The simulated results show that PSC signal increases with echo time, especially 100/80 ms after stimulus for gradient echo/spin echo sequence. It can be up to 0.1 mrad for echo time = 175 ms and voxel size = 1.48 × 1.48 × 2.18 mm3. With echo time less than 25 ms after stimulus, it was just acquired effects of physiological noise on PSC signal. The absolute value of the signal increased with decrease of voxel size, but its components had complex variation. External field orthogonal to local surface of cortex maximizes the signal. Expected PSC signal for tactile detection in the somatosensory cortex increase with echo time and have no oscillation.  相似文献   
5.
In the current immunosuppressive therapy era, vessel thrombosis is the most common cause of early graft loss after renal transplantation. The prevalence of IgA anti–β2-glycoprotein I antibodies (IgA-aB2GPI-ab) in patients on dialysis is elevated (>30%), and these antibodies correlate with mortality and cardiovascular morbidity. To evaluate the effect of IgA-aB2GPI-ab in patients with transplants, we followed all patients transplanted from 2000 to 2002 in the Hospital 12 de Octubre prospectively for 10 years. Presence of IgA-aB2GPI-ab in pretransplant serum was examined retrospectively. Of 269 patients, 89 patients were positive for IgA-aB2GPI-ab (33%; group 1), and the remaining patients were negative (67%; group 2). Graft loss at 6 months post-transplant was significantly higher in group 1 (10 of 89 versus 3 of 180 patients in group 2; P=0.002). The most frequent cause of graft loss was thrombosis of the vessels, which was observed only in group 1 (8 of 10 versus 0 of 3 patients in group 2; P=0.04). Multivariate analysis showed that the presence of IgA-aB2GPI-ab was an independent risk factor for early graft loss (P=0.04) and delayed graft function (P=0.04). There were no significant differences regarding patient survival between the two groups. Graft survival was similar in both groups after 6 months. In conclusion, patients with pretransplant IgA-aB2GPI-ab have a high risk of early graft loss caused by thrombosis and a high risk of delayed graft function. Therefore, pretransplant IgA-aB2GPI-ab may have a detrimental effect on early clinical outcomes after renal transplantation.  相似文献   
6.
7.
8.
Annals of Nuclear Medicine - The Response Evaluation Criteria In Solid Tumors (RECIST) is the most used radiological method for evaluating response after peptide receptor radionuclide therapy...  相似文献   
9.
10.
We present a 6‐year‐old girl with skin hyperpigmentation, leukoplakia, and onychodystrophy, the classic mucocutaneous triad usually associated with dyskeratosis congenita. The patient also had premature graying of the hair, bone marrow failure, hepatitis, exudative retinopathy, osteopenia with multiple long bone fractures, and intracranial calcifications and brain cysts. Coats plus syndrome is a rare disease with a clinical and genetic overlap with dyskeratosis congenita. This disease is reviewed, with a focus on the pathogenesis of the genetic anomalies and its background as a telomere biology disorder.  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