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   23623篇
  免费   1736篇
  国内免费   55篇
耳鼻咽喉   308篇
儿科学   448篇
妇产科学   510篇
基础医学   3079篇
口腔科学   396篇
临床医学   2801篇
内科学   4680篇
皮肤病学   343篇
神经病学   2029篇
特种医学   897篇
外国民族医学   2篇
外科学   4178篇
综合类   186篇
一般理论   50篇
预防医学   1763篇
眼科学   590篇
药学   1555篇
中国医学   22篇
肿瘤学   1577篇
  2024年   19篇
  2023年   225篇
  2022年   362篇
  2021年   1017篇
  2020年   509篇
  2019年   870篇
  2018年   941篇
  2017年   682篇
  2016年   730篇
  2015年   826篇
  2014年   1224篇
  2013年   1368篇
  2012年   2240篇
  2011年   2262篇
  2010年   1165篇
  2009年   1078篇
  2008年   1641篇
  2007年   1616篇
  2006年   1444篇
  2005年   1345篇
  2004年   1144篇
  2003年   1010篇
  2002年   835篇
  2001年   123篇
  2000年   81篇
  1999年   75篇
  1998年   109篇
  1997年   75篇
  1996年   44篇
  1995年   27篇
  1994年   34篇
  1993年   24篇
  1992年   21篇
  1991年   17篇
  1990年   9篇
  1989年   22篇
  1988年   19篇
  1987年   17篇
  1986年   16篇
  1985年   23篇
  1984年   12篇
  1983年   15篇
  1982年   12篇
  1981年   7篇
  1980年   10篇
  1979年   11篇
  1978年   6篇
  1977年   4篇
  1976年   4篇
  1968年   4篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
991.
The Standardizing Care to Improve Outcomes in Pediatric End Stage Renal Disease (SCOPE) Collaborative is a North American multi-center quality transformation effort whose primary aim is to minimize exit-site infection and peritonitis rates among pediatric chronic peritoneal dialysis patients. The project, developed by the quality improvement faculty and staff at the Children’s Hospital Association’s Quality Transformation Network (QTN) and content experts in pediatric nephrology and pediatric infectious diseases, is modeled after the QTN’s highly successful Pediatric Intensive Care Unit and Hematology-Oncology central line-associated blood-stream infection (CLABSI) Collaboratives. Like the Association’s other QTN efforts, the SCOPE Collaborative is part of a broader effort to assist pediatric nephrology teams in learning about and using quality improvement methods to develop and implement evidence-based practices. In addition, the design of this project allows for targeted research that builds on high-quality, ongoing data collection. Finally, the project, while focused on reducing peritoneal dialysis catheter-associated infections, will also serve as a model for future pediatric nephrology projects that could further improve the quality of care provided to children with end stage renal disease.  相似文献   
992.
Remoras are fishes that attach to a broad range of hosts using an adhesive disc on their head that is derived from dorsal fin elements. Research on the adhesive mechanism of remoras has focused primarily on the skeletal components of the disc and their contribution to generating suction and friction. However, the soft tissues of the disc, such as the soft lip surrounding the bony disc and the muscles that control the bony lamellae, have been largely ignored. To understand the sealing mechanism of the disc, it is imperative to understand the tissue morphology and material properties of the soft lip. Here, we show that the soft lip surrounding the remora disc is comprised of discrete multilayered collagen, fat, and elastic tissues which we hypothesize to have specific roles in the viscoelastic sealing mechanism of the remora disc. The central, heavily vascularized fat and collagen layer are infiltrated by strands of elastic tissue and surrounded by crossed-fiber collagen. A newly described jubilee muscle underneath the adhesive disc provides a mechanism for stopping venous return from the disc lip, thereby allowing it to become engorged and create a pressurized fit to the attachment substrate. Thus, the remora lip acts as a vascular hydrostat.  相似文献   
993.
Deep learning-based computer vision methods have recently made remarkable breakthroughs in the analysis and classification of cancer pathology images. However, there has been relatively little investigation of the utility of deep neural networks to synthesize medical images. In this study, we evaluated the efficacy of generative adversarial networks to synthesize high-resolution pathology images of 10 histological types of cancer, including five cancer types from The Cancer Genome Atlas and the five major histological subtypes of ovarian carcinoma. The quality of these images was assessed using a comprehensive survey of board-certified pathologists (n = 9) and pathology trainees (n = 6). Our results show that the real and synthetic images are classified by histotype with comparable accuracies and the synthetic images are visually indistinguishable from real images. Furthermore, we trained deep convolutional neural networks to diagnose the different cancer types and determined that the synthetic images perform as well as additional real images when used to supplement a small training set. These findings have important applications in proficiency testing of medical practitioners and quality assurance in clinical laboratories. Furthermore, training of computer-aided diagnostic systems can benefit from synthetic images where labeled datasets are limited (e.g. rare cancers). We have created a publicly available website where clinicians and researchers can attempt questions from the image survey ( http://gan.aimlab.ca/ ). © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.  相似文献   
994.
995.
Desmoplastic small round cell tumors (DSRCTs) are highly aggressive sarcomas that most commonly occur intra‐abdominally, and are defined by EWSR1WT1 gene fusion. Intracranial DSRCTs are exceptionally rare with only seven previously reported fusion‐positive cases. Herein, we evaluate the clinical, morphologic, immunohistochemical and molecular features of five additional examples. All patients were male (age range 6–25 years; median 11 years), with four tumors located supratentorially and one within the posterior fossa. The histologic features were highly variable including small cell, embryonal, clear cell, rhabdoid, anaplastic and glioma‐like appearances. A prominent desmoplastic stroma was seen in only two cases. The mitotic index ranged from <1 to 12/10 HPF (median 5). While all tumors showed strong desmin positivity, epithelial markers such as EMA, CAM 5.2 and other keratins were strongly positive in only one, focally positive in two and negative in two cases. EWSR1WT1 gene fusion was present in all cases, with accompanying mutations in the TERT promoter or STAG2 gene in individual cases. Given the significant histologic diversity, in the absence of genetic evaluation these cases could easily be misinterpreted as other entities. Desmin immunostaining is a useful initial screening method for consideration of a DSRCT diagnosis, prompting confirmatory molecular testing. Demonstrating the presence of an EWSR1WT1 fusion provides a definitive diagnosis of DSRCT. Genome‐wide methylation profiles of intracranial DSRCTs matched those of extracranial DSRCTs. Thus, despite the occasionally unusual histologic features and immunoprofile, intracranial DSRCTs likely represent a similar, if not the same, entity as their soft tissue counterpart based on the shared fusion and methylation profiles.  相似文献   
996.
997.
Circulating tumor cell (CTC) and cell‐free (cf) DNA‐based genomic alterations are increasingly being used for clinical decision‐making in oncology. However, the concordance and discordance between paired CTC and cfDNA genomic profiles remain largely unknown. We performed comparative genomic hybridization (CGH) on CTCs and cfDNA, and low‐pass whole genome sequencing (lpWGS) on cfDNA to characterize genomic alterations (CNA) and tumor content in two independent prospective studies of 93 men with mCRPC treated with enzalutamide/abiraterone, or radium‐223. Comprehensive analysis of 69 patient CTCs and 72 cfDNA samples from 93 men with mCRPC, including 64 paired samples, identified common concordant gains in FOXA1, AR, and MYC, and losses in BRCA1, PTEN, and RB1 between CTCs and cfDNA. Concordant PTEN loss and discordant BRCA2 gain were associated with significantly worse outcomes in Epic AR‐V7 negative men with mCRPC treated with abiraterone/enzalutamide. We identified and externally validated CTC‐specific genomic alternations that were discordant in paired cfDNA, even in samples with high tumor content. These CTC/cfDNA‐discordant regions included key genomic regulators of lineage plasticity, osteomimicry, and cellular differentiation, including MYCN gain in CTCs (31%) that was rarely detected in cfDNA. CTC MYCN gain was associated with poor clinical outcomes in AR‐V7 negative men and small cell transformation. In conclusion, we demonstrated concordance of multiple genomic alterations across CTC and cfDNA platforms; however, some genomic alterations displayed substantial discordance between CTC DNA and cfDNA despite the use of identical copy number analysis methods, suggesting tumor heterogeneity and divergent evolution associated with poor clinical outcomes.  相似文献   
998.
The World Health Organization declared COVID-19, the infectious disease caused by the coronavirus SARS-CoV-2, a pandemic on March 12, 2020. COVID-19 is causing massive health problems and economic suffering around the world. The European Association for the Study of Obesity (EASO) promptly recognised the impact that the outbreak could have on people with obesity. On one side, emerging data suggest that obesity represents a risk factor for a more serious and complicated course of COVID-19 in adults. On the other side, the health emergency caused by the outbreak diverts attention from the prevention and care of non-communicable chronic diseases to communicable diseases. This might be particularly true for obesity, a chronic and relapsing disease frequently neglected and linked to significant bias and stigmatization. The Obesity Management Task Force (OMTF) of EASO contributes in this paper to highlighting the key aspects of these two sides of the coin and suggests some specific actions.  相似文献   
999.
1000.
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