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   683篇
  免费   58篇
  国内免费   2篇
耳鼻咽喉   4篇
儿科学   19篇
妇产科学   15篇
基础医学   53篇
口腔科学   6篇
临床医学   62篇
内科学   157篇
皮肤病学   7篇
神经病学   47篇
特种医学   8篇
外科学   182篇
综合类   12篇
一般理论   1篇
预防医学   37篇
眼科学   5篇
药学   67篇
中国医学   8篇
肿瘤学   53篇
  2024年   1篇
  2023年   10篇
  2022年   22篇
  2021年   29篇
  2020年   27篇
  2019年   31篇
  2018年   47篇
  2017年   26篇
  2016年   36篇
  2015年   28篇
  2014年   41篇
  2013年   41篇
  2012年   42篇
  2011年   43篇
  2010年   21篇
  2009年   25篇
  2008年   41篇
  2007年   40篇
  2006年   30篇
  2005年   22篇
  2004年   20篇
  2003年   18篇
  2002年   12篇
  2001年   8篇
  2000年   10篇
  1999年   6篇
  1997年   1篇
  1996年   5篇
  1995年   2篇
  1993年   2篇
  1992年   5篇
  1991年   3篇
  1990年   3篇
  1989年   5篇
  1988年   8篇
  1987年   3篇
  1986年   1篇
  1985年   2篇
  1983年   3篇
  1982年   1篇
  1981年   4篇
  1980年   4篇
  1979年   1篇
  1978年   5篇
  1977年   2篇
  1976年   2篇
  1975年   1篇
  1973年   1篇
  1969年   2篇
排序方式: 共有743条查询结果,搜索用时 15 毫秒
1.
2.
The findings of an extensive experimental research study on the usage of nano-sized cement powder and other additives combined to form cement–fine-aggregate matrices are discussed in this work. In the laboratory, dry and wet methods were used to create nano-sized cements. The influence of these nano-sized cements, nano-silica fumes, and nano-fly ash in different proportions was studied to the evaluate the engineering properties of the cement–fine-aggregate matrices concerning normal-sized, commercially available cement. The composites produced with modified cement–fine-aggregate matrices were subjected to microscopic-scale analyses using a petrographic microscope, a Scanning Electron Microscope (SEM), and a Transmission Electron Microscope (TEM). These studies unravelled the placement and behaviour of additives in controlling the engineering properties of the mix. The test results indicated that nano-cement and nano-sized particles improved the engineering properties of the hardened cement matrix. The wet-ground nano-cement showed the best result, 40 MPa 28th-day compressive strength, without mixing any additive compared with ordinary and dry-ground cements. The mix containing 50:50 normal and wet-ground cement exhibited 37.20 MPa 28th-day compressive strength. All other mixes with nano-sized dry cement, silica fume, and fly ash with different permutations and combinations gave better results than the normal-cement–fine-aggregate mix. The petrographic studies and the Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) analyses further validated the above findings. Statistical analyses and techniques such as correlation and stepwise multiple regression analysis were conducted to compose a predictive equation to calculate the 28th-day compressive strength. In addition to these methods, a repeated measures Analysis of Variance (ANOVA) was also implemented to analyse the statistically significant differences among three differently timed strength readings.  相似文献   
3.
Background Surgery for renal cell carcinoma (RCC) with venous tumour thrombus (VTT) extension into the renal vein (RV) and/or inferior vena cava (IVC) has high peri-surgical morbidity/mortality. NAXIVA assessed the response of VTT to axitinib, a potent tyrosine kinase inhibitor.Methods NAXIVA was a single-arm, multi-centre, Phase 2 study. In total, 20 patients with resectable clear cell RCC and VTT received upto 8 weeks of pre-surgical axitinib. The primary endpoint was percentage of evaluable patients with VTT improvement by Mayo level on MRI. Secondary endpoints were percentage change in surgical approach and VTT length, response rate (RECISTv1.1) and surgical morbidity.Results In all, 35% (7/20) patients with VTT had a reduction in Mayo level with axitinib: 37.5% (6/16) with IVC VTT and 25% (1/4) with RV-only VTT. No patients had an increase in Mayo level. In total, 75% (15/20) of patients had a reduction in VTT length. Overall, 41.2% (7/17) of patients who underwent surgery had less invasive surgery than originally planned. Non-responders exhibited lower baseline microvessel density (CD31), higher Ki67 and exhausted or regulatory T-cell phenotype.Conclusions NAXIVA provides the first Level II evidence that axitinib downstages VTT in a significant proportion of patients leading to reduction in the extent of surgery.Clinical trial registration NCT03494816.Subject terms: Surgical oncology, Renal cell carcinoma, Predictive markers  相似文献   
4.
5.
6.
Hematological malignancies express high levels of CD47 as a mechanism of immune evasion. CD47-SIRPα triggers a cascade of events that inhibit phagocytosis. Preclinical research supports several models of antibody-mediated blockade of CD47-SIRPα resulting in cell death signaling, phagocytosis of cells bearing stress signals, and priming of tumor-specific T cell responses. Four different antibody molecules designed to target the CD47-SIRPα interaction in malignancy are currently being studied in clinical trials: Hu5F9-G4, CC-90002, TTI-621, and ALX-148. Hu5F9-G4, a humanized anti-CD47 blocking antibody is currently being studied in four different Phase I trials. These studies may lay the groundwork for therapeutic bispecific antibodies. Bispecific antibody (CD20-CD47SL) fusion of anti-CD20 (Rituximab) and anti-CD47 also demonstrated a synergistic effect against lymphoma in preclinical models. This review summarizes the large body of preclinical evidence and emerging clinical data supporting the use of antibodies designed to target the CD47-SIRPα interaction in leukemia, lymphoma and multiple myeloma.  相似文献   
7.
Acetabular fractures are relatively uncommon and their definitive treatment tends to be focused on specialist major trauma centres. This can make both accurate diagnosis and management challenging, particularly in hospitals where they are rarely seen. Contemporary management of these injuries owes a lot to the work of Judet and Letournel undertaken in the 1970s. The key to understanding these injuries is to know the embryology and development of the pelvis and then be able to appreciate its three-dimensional structure from two-dimensional X-rays. This can then be overlaid with the Judet classification and the action of force vectors encountered in various mechanisms of injury. It is also important to realise the ageing demographics of this group of patients and the complexities this adds to classification and ultimately treatment. Finally, the presence of an acetabular fracture is often seen in association with a number of other injuries. It is imperative that these are appropriately and contemporaneously diagnosed so that a comprehensive management plan may be instituted to give the best outcomes. However, even with optimal management the prognosis is guarded with a majority of patients suffering some degree of functional loss and this must be made clear to the patient from the outset.  相似文献   
8.
9.
10.
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