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   234806篇
  免费   23864篇
  国内免费   9504篇
耳鼻咽喉   2705篇
儿科学   5522篇
妇产科学   3393篇
基础医学   35243篇
口腔科学   7118篇
临床医学   20665篇
内科学   34215篇
皮肤病学   5507篇
神经病学   13816篇
特种医学   4759篇
外国民族医学   126篇
外科学   20623篇
综合类   36984篇
现状与发展   55篇
一般理论   1篇
预防医学   15276篇
眼科学   4717篇
药学   18559篇
  88篇
中国医学   7796篇
肿瘤学   31006篇
  2024年   261篇
  2023年   3813篇
  2022年   5293篇
  2021年   9426篇
  2020年   9235篇
  2019年   8156篇
  2018年   8271篇
  2017年   8738篇
  2016年   9279篇
  2015年   9752篇
  2014年   15256篇
  2013年   17036篇
  2012年   14300篇
  2011年   15483篇
  2010年   12620篇
  2009年   11897篇
  2008年   12168篇
  2007年   12336篇
  2006年   11113篇
  2005年   10080篇
  2004年   8726篇
  2003年   7549篇
  2002年   6244篇
  2001年   5395篇
  2000年   4442篇
  1999年   3720篇
  1998年   3084篇
  1997年   2927篇
  1996年   2481篇
  1995年   2520篇
  1994年   2257篇
  1993年   1838篇
  1992年   1553篇
  1991年   1484篇
  1990年   1133篇
  1989年   1054篇
  1988年   967篇
  1987年   768篇
  1986年   720篇
  1985年   918篇
  1984年   814篇
  1983年   562篇
  1982年   600篇
  1981年   473篇
  1980年   399篇
  1979年   303篇
  1978年   208篇
  1977年   162篇
  1976年   139篇
  1975年   59篇
排序方式: 共有10000条查询结果,搜索用时 70 毫秒
991.
De-escalation of immunomodulators and biologic agents in inflammatory bowel disease is frequently discussed with patients and must weigh the risk of continued medical therapy with the risk of disease recurrence. Risk factors for disease flare after withdrawal of inflammatory bowel disease medications such as disease activity at de-escalation, disease prognostic features, and prior course of disease have been identified predominately in retrospective studies, allowing for risk stratification of patients. This review evaluates the published literature regarding therapeutic de-escalation and provides a framework for physicians to apply this to clinical practice. Prospective trials are underway and planned, which should provide further insight into this treatment paradigm and better inform patient selection for this strategy.  相似文献   
992.
《Vaccine》2016,34(24):2663-2670
Human metapneumovirus (HMPV) is a major cause of morbidity and mortality from acute lower respiratory tract illness, with most individuals seropositive by age five. Despite the presence of neutralizing antibodies, secondary infections are common and can be severe in young, elderly, and immunocompromised persons. Preclinical vaccine studies for HMPV have suggested a need for a balanced antibody and T cell immune response to enhance protection and avoid lung immunopathology. We infected transgenic mice expressing human HLA-A*0201 with HMPV and used ELISPOT to screen overlapping and predicted epitope peptides. We identified six novel HLA-A2 restricted CD8+ T cell (TCD8) epitopes, with M39–47 (M39) immunodominant. Tetramer staining detected M39-specific TCD8 in lungs and spleen of HMPV-immune mice. Immunization with adjuvant-formulated M39 peptide reduced lung virus titers upon challenge. Finally, we show that TCD8 from HLA-A*0201 positive humans recognize M39 by IFNγ ELISPOT and tetramer staining. These results will facilitate HMPV vaccine development and human studies.  相似文献   
993.
目的:探究G蛋白信号调节因子-13(RGS13)在结直肠癌(CRC)进展中的作用。方法:使用TCGA数据库和实时荧光定量聚合酶链反应(RT-qPCR)在mRNA水平分析CRC组织和细胞中RGS13 的表达量,使用免疫组织化学染色(IHC)和蛋白质印迹法(Western blot)在蛋白水平进一步分析。用ATP细胞活力检测实验、软琼脂克隆集落形成实验和细胞迁移侵袭实验检测RGS13对CRC细胞增殖、迁移和侵袭的影响,并通过Western blot、RT-qPCR等实验探究其下游分子机制。结果:RGS13在CRC组织与细胞系中低表达(P <0.01),RGS13 表达越低,患者的无病生存期越短(P =0.017)。RGS13 的下调可显著促进CRC细胞的增殖、迁移与侵袭(P <0.01),表明RGS13在CRC进展中发挥抑癌作用。机制上,RGS13通过下调Wnt/β-catenin信号通路中β-catenin的蛋白水平,进而降低癌基因c-Myc、MMP7 和CCND1等的表达水平(P <0.01),发挥对CRC的抑制作用。结论:RGS13可能通过下调β-catenin发挥抑制CRC进展的重要作用。  相似文献   
994.
The primary care literature lacks information on mast cell activation disease (MCAD) and, more specifically, mast cell activation syndrome, yet it affects approximately 17% of the population. Because many providers remain unaware of MCAD, this article provides a primer on mast cell diseases, including triggers, signs and symptoms, diagnosis, treatment, and resources for patients and providers. Primary care nurse practitioners are uniquely positioned and qualified to identify patients with multiple, diffuse complaints and chronic, multisystem symptoms—the hallmark of MCAD—and refer them for further diagnosis and treatment to reduce debilitating symptoms.  相似文献   
995.
《Cancer cell》2021,39(11):1479-1496.e18
  1. Download : Download high-res image (290KB)
  2. Download : Download full-size image
  相似文献   
996.
《Journal of thoracic oncology》2021,16(11):1909-1924
IntroductionWe report the final overall survival (OS) analyses of atezolizumab-carboplatin-paclitaxel (ACP [experimental arm]) and OS data with approximately 39.8 months of median follow-up with atezolizumab-bevacizumab-carboplatin-paclitaxel (ABCP) versus bevacizumab-carboplatin-paclitaxel (BCP) in chemotherapy-naive patients with metastatic nonsquamous NSCLC in the phase 3 IMpower150 study (NCT02366143).MethodsIn this randomized, open-label study (N = 1202), coprimary end points included investigator-assessed progression-free survival and OS in intention-to-treat (ITT) wild-type (WT; no EGFR or ALK alterations) patients. Secondary and exploratory end points included OS in ITT and programmed death-ligand 1 (PD-L1) subgroups defined by the VENTANA SP142 and SP263 immunohistochemistry assays.ResultsAt the final analysis with ACP versus BCP (data cutoff: September 13, 2019; minimum follow-up: 32.4 mo), ACP had numerical, but not statistically significant, improvements in OS (ITT-WT: median OS = 19.0 versus 14.7 mo; hazard ratio = 0.84; 95% confidence interval: 0.71–1.00). OS benefit was sustained with ABCP versus BCP (ITT-WT: 19.5 versus 14.7 mo; hazard ratio = 0.80; 95% confidence interval: 0.67–0.95). Exploratory analyses in the SP142-defined PD-L1 subgroups revealed longer median OS with ABCP and ACP versus BCP in PD-L1–high and PD-L1–positive subgroups; in the PD-L1–negative subgroups, median OS was similar with ACP and ABCP versus BCP. Safety was consistent with that in earlier analyses (data cutoff: January 22, 2018).ConclusionsAt the final IMpower150 OS analysis, ACP had numerical, but not statistically significant, OS improvement versus BCP. Updated data with an additional 20 months of follow-up revealed continued OS improvement with ABCP versus BCP in all patients.  相似文献   
997.
目的调查本科实习护生的患者安全态度现状,并分析影响因素,为开展患者安全教育提供参考。方法采用中文版安全态度问卷(C-SAQ)对重庆市某医学院校的225名本科实习护生进行问卷调查,采用SPSS 20.0软件进行数据分析。结果实习护生患者安全态度总均分为(3.75±0.54)分,安全态度6个维度的平均分由高到低依次为管理感知、工作满意、压力感知、团队合作、安全氛围和工作条件。多元线性回归分析结果表明,每周工作时间短、接受过患者安全教育、实习期间未发生过护理差错的本科实习护生患者安全态度更积极(P<0.05)。结论本科实习护生的患者安全态度处于中等水平。实习医院应将患者安全教育融入并贯穿于临床护理实践培养过程中,减轻实习护生的工作压力,重点关注经历过护理差错的护生,进而提高实习护生的患者安全态度。  相似文献   
998.
PurposeTo evaluate the radiation dose differences for intraprocedural computed tomography (CT) imaging between cone-beam CT and angio-CT acquired during transarterial radioembolization (TARE) therapies for hepatocellular carcinoma.Materials and MethodsA retrospective cohort of 22 patients who underwent 23 TARE procedures were selected. Patients were imaged in both cone-beam CT and angio-CT rooms as a part of their conventional treatment plan. Effective dose contributions from individual CT acquisitions as well as the cumulative dose contributions from procedural 3D imaging were evaluated. Angiography dose contributions were omitted. Cone-beam CT images were acquired on a C-arm Philips Allura system. Effective doses were evaluated by coupling previously published conversion factors (effective dose per dose-area product) to patient’s dose-area product meter readings after the procedure. Angio-CT images were acquired on a hybrid Canon Infinix-i Aquilion PRIME system. Effective doses from angio-CT scans were estimated using Radimetrics. Comparisons of a single patient’s dose differential between the 2 technologies were made.ResultsThe mean effective dose from a single CT scan was 6.42 mSv and 5.99 mSv in the cone-beam CT room and the angio-CT room, respectively (P = .3224), despite the greater field of view and average craniocaudal scan coverage in angio-CT. The mean effective dose summed across all CTs in a procedure was 12.89 mSv and 34.35 mSv in the cone-beam CT room and the angio-CT room, respectively (P = .0018).ConclusionsThe mean effective dose per CT scan is comparable between cone-beam CT and angio-CT when considered in direct comparison for a single patient.  相似文献   
999.
1000.

Background

Immune checkpoint inhibitors (ICIs) are an important treatment for metastatic renal cell carcinoma (mRCC). These agents may cause immune-related adverse events (irAEs), and the relationship between irAEs and outcomes is poorly understood. We investigated the association between irAEs and clinical outcomes in patients with mRCC treated with ICIs.

Methods

We performed a retrospective study of 200 patients with mRCC treated with ICIs at Winship Cancer Institute from 2015 to 2020. Data on irAEs were collected from clinic notes and laboratory values and grades were determined using Common Terminology Criteria in Adverse Events version 5.0. The association with overall survival (OS) and progression-free survival (PFS) was modeled by Cox proportional hazards model. Logistic regression models were used to define odds ratios (ORs) for clinical benefit (CB). Landmark analysis and extended Cox models were used to mitigate lead-time bias by treating irAEs as a time-varying covariate.

Results

Most patients (71.0%) were male, and one-third of patients (33.0%) experienced at least one irAE, most commonly involving the endocrine glands (13.0%), gastrointestinal tract (10.5%), or skin (10.0%). Patients who experienced irAEs had significantly longer OS (hazard ratio [HR], 0.52; p = .013), higher chance of CB (OR, 2.10; p = .023) and showed a trend toward longer PFS (HR, 0.71; p = .065) in multivariate analysis. Patients who had endocrine irAEs, particularly thyroid irAEs, had significantly longer OS and PFS and higher chance of CB. In a 14-week landmark analysis, irAEs were significantly associated with prolonged OS (p = .045). Patients who experienced irAEs had significantly longer median OS (44.5 vs. 18.2 months, p = .005) and PFS (7.5 vs. 3.6 months, p = .003) without landmark compared with patients who did not.

Conclusion

We found that patients with mRCC treated with ICIs who experienced irAEs, particularly thyroid irAEs, had significantly improved clinical outcomes compared with patients who did not have irAEs. This suggests that irAEs may be effective clinical biomarkers in patients with mRCC treated with ICIs. Future prospective studies are warranted to validate these findings.

Implications for Practice

This study found that early onset immune-related adverse events (irAEs) are associated with significantly improved clinical outcomes in patients with metastatic renal cell carcinoma (mRCC) treated with immune checkpoint inhibitors (ICIs). In this site-specific irAE analysis, endocrine irAEs, particularly thyroid irAEs, were significantly associated with improved clinical outcomes. These results have implications for practicing medical oncologists given the increasing use of ICIs for the treatment of mRCC. Importantly, these results suggest that early irAEs and thyroid irAEs at any time on treatment with ICIs may be clinical biomarkers of clinical outcomes in patients with mRCC treated with ICIs.
  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