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   206049篇
  免费   18668篇
  国内免费   4306篇
耳鼻咽喉   3239篇
儿科学   4018篇
妇产科学   3564篇
基础医学   16419篇
口腔科学   7201篇
临床医学   19071篇
内科学   19195篇
皮肤病学   2389篇
神经病学   10220篇
特种医学   5667篇
外国民族医学   11篇
外科学   20019篇
综合类   33382篇
现状与发展   9篇
一般理论   24篇
预防医学   27198篇
眼科学   1976篇
药学   20030篇
  331篇
中国医学   26197篇
肿瘤学   8863篇
  2023年   3969篇
  2022年   6213篇
  2021年   9805篇
  2020年   9973篇
  2019年   11345篇
  2018年   10050篇
  2017年   8653篇
  2016年   7710篇
  2015年   7172篇
  2014年   14222篇
  2013年   14419篇
  2012年   12712篇
  2011年   13609篇
  2010年   10963篇
  2009年   9420篇
  2008年   8728篇
  2007年   8805篇
  2006年   7511篇
  2005年   6335篇
  2004年   5259篇
  2003年   4669篇
  2002年   3603篇
  2001年   2988篇
  2000年   2654篇
  1999年   2135篇
  1998年   1590篇
  1997年   1437篇
  1996年   1150篇
  1995年   1205篇
  1994年   1099篇
  1993年   974篇
  1992年   880篇
  1991年   812篇
  1990年   707篇
  1989年   689篇
  1988年   632篇
  1987年   569篇
  1986年   524篇
  1985年   1783篇
  1984年   2053篇
  1983年   1286篇
  1982年   1707篇
  1981年   1182篇
  1980年   1011篇
  1979年   902篇
  1978年   736篇
  1977年   553篇
  1976年   693篇
  1975年   477篇
  1974年   406篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
ObjectiveThe Improving Medicare Post-Acute Care Transformation Act of 2014 mandates using standardized patient functional data across post-acute settings. This study characterized similarities and differences in clinician-observed scores of self-care and transfer items for the standardized section GG functional domain and the functional independent measure (FIM) at inpatient rehabilitation facilities.DesignWe conducted secondary analyses of 2017 Uniform Data System for Medical Rehabilitation national data. Patients were assessed by clinicians on both section GG and FIM at admission and discharge. We identified 7 self-care items and 6 transfer items in section GG conceptually equivalent with FIM. Clinician-assessed scores for each pair of items were examined using score distributions, Bland-Altman plot, correlation (Pearson coefficients), and agreement (kappa and weighted kappa) analyses.Setting and ParticipantsIn all, 408,491 patients were admitted to Uniform Data System for Medical Rehabilitation-affiliated inpatient rehabilitation facilities with one of the following impairments: stroke, brain dysfunction, neurologic condition, orthopedic disorders, and debility.MeasuresSection GG and FIM.ResultsPatients were scored as more functionally independent in section GG compared with FIM, but change score distributions and score orders within impairment groups were similar. Total scores in section GG had strong positive correlations (self-care: r = 0.87 and 0.95; transfer: r = 0.82 and 0.90 at admission and discharge, respectively) with total FIM scores. Weak to moderate ranking agreements with total FIM scores were observed (self-care: kappa = 0.49 and 0.60; transfers: kappa = 0.43 and 0.52 at admission and discharge, respectively). Lower agreements were observed for less able patients at admission and for higher ability patients of their change scores.Conclusions and ImplicationsOverall, response patterns were similar in section GG and FIM across impairments. However, variations exist in score distributions and ranking agreement. Future research should examine the use of GG codes to maintain effective care, outcomes, and unbiased reimbursement across post-acute settings.  相似文献   
63.
在过去的近40年里,直肠癌的治疗方案逐渐标准化。大多数早期直肠癌患者仅通过手术即可得到充分的治疗。然而,相当比例的直肠癌患者处于局部进展期,此类患者需要行新辅助治疗。直肠癌的新辅助放射治疗已被证明能有效地降低患者术前肿瘤分期、改善患者生存以及降低直肠癌局部复发率等,随之而来的是患者放疗后出现的不同程度的放疗不良反应,但随着放射治疗规范化、放射治疗技术及设备的改进,放疗不良反应严重程度在逐渐降低。本文就新辅助放疗中的放疗方案的选择、放射治疗技术、放疗不良反应、放疗后的手术时间以及放疗后的观察与等待等问题的最新研究进展进行了系统性的综述,从而为临床直肠癌新辅助治疗提供有力依据。  相似文献   
64.
65.
《Vaccine》2022,40(6):934-944
Respiratory Syncytial Virus (RSV) remains a leading cause of severe respiratory disease for which no licensed vaccine is available. We have previously described the derivation of an RSV Fusion protein (F) stabilized in its prefusion conformation (preF) as vaccine immunogen and demonstrated superior immunogenicity in naive mice of preF versus wild type RSV F protein, both as protein and when expressed from an Ad26 vaccine vector. Here we address the question if there are qualitative differences between the two vaccine platforms for induction of protective immunity. In naïve mice, both Ad26.RSV.preF and preF protein induced humoral responses, whereas cellular responses were only elicited by Ad26.RSV.preF. In RSV pre-exposed mice, a single dose of either vaccine induced cellular responses and strong humoral responses. Ad26-induced RSV-specific cellular immune responses were detected systemically and locally in the lungs. Both vaccines showed protective efficacy in the cotton rat model, but Ad26.RSV.preF conferred protection at lower virus neutralizing titers in comparison to RSV preF protein. Factors that may contribute to the protective capacity of Ad26.RSV.preF elicited immunity are the induced IgG2a antibodies that are able to engage Fcγ receptors mediating Antibody Dependent Cellular Cytotoxicity (ADCC), and the induction of systemic and lung resident RSV specific CD8 + T cells. These data demonstrate qualitative improvement of immune responses elicited by an adenoviral vector based vaccine encoding the RSV preF antigen compared to the subunit vaccine in small animal models which may inform RSV vaccine development.  相似文献   
66.
67.
68.
BackgroundChyle leak (CL) is a clinically relevant complication after pancreatectomy. Its incidence and the associated risk factors are ill defined, and various treatments options have been described. There is no consensus, however, regarding optimal management. The present study aims to systematically review the literature on CL after pancreatectomy.MethodsA systematic review from PubMed, Scopus and Embase database was performed. Studies using a clear definition for CL and published from January 2000 to January 2021 were included. The PRISMA guidelines were followed during all stages of this systematic review. The MINORS score was used to assess methodological quality.ResultsLiterature search found 361 reports, 99 of which were duplicates. The titles and abstracts of 262 articles were finally screened. The references from the remaining 181 articles were manually assessed. After the exclusions, 43 articles were thoroughly assessed. A total of 23 articles were ultimately included for this review. The number of patients varied from 54 to 3532. Incidence of post pancreatectomy CL varied from 1.3% to 22.1%. Main risk factors were the extent of the surgery and early oral or enteral feeding. CL dried up spontaneously or after conservative management within 14 days in 53% to 100% of the cases.ConclusionsThe extent of surgery is the most common predictor of risk of CL. Conservative treatment has been shown to be effective in most cases and can be considered the treatment of choice. We propose a management algorithm based on the current available evidence.  相似文献   
69.
70.
ObjectivesDonor-specific cell-free DNA shows promise as a noninvasive marker for allograft rejection, but as yet has not been validated in both adult and pediatric recipients. The study objective was to validate donor fraction cell-free DNA as a noninvasive test to assess for risk of acute cellular rejection and antibody-mediated rejection after heart transplantation in pediatric and adult recipients.MethodsPediatric and adult heart transplant recipients were enrolled from 7 participating sites and followed for 12 months or more with plasma samples collected immediately before all endomyocardial biopsies. Donor fraction cell-free DNA was extracted, and quantitative genotyping was performed. Blinded donor fraction cell-free DNA and clinical data were analyzed and compared with a previously determined threshold of 0.14%. Sensitivity, specificity, negative predictive value, positive predictive value, and receiver operating characteristic curves were calculated.ResultsA total of 987 samples from 144 subjects were collected. After applying predefined clinical and technical exclusions, 745 samples from 130 subjects produced 54 rejection samples associated with the composite outcome of acute cellular rejection grade 2R or greater and pathologic antibody-mediated rejection 2 or greater and 323 healthy samples. For all participants, donor fraction cell-free DNA at a threshold of 0.14% had a sensitivity of 67%, a specificity of 79%, a positive predictive value of 34%, and a negative predictive value of 94% with an area under the curve of 0.78 for detecting rejection. When analyzed independently, these results held true for both pediatric and adult cohorts at the same threshold of 0.14% (negative predictive value 92% and 95%, respectively).ConclusionsDonor fraction cell-free DNA at a threshold of 0.14% can be used to assess for risk of rejection after heart transplantation in both pediatric and adult patients with excellent negative predictive value.  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