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   1454823篇
  免费   115224篇
  国内免费   13075篇
耳鼻咽喉   17777篇
儿科学   45292篇
妇产科学   37721篇
基础医学   208645篇
口腔科学   38383篇
临床医学   146856篇
内科学   270910篇
皮肤病学   27906篇
神经病学   115700篇
特种医学   52590篇
外国民族医学   410篇
外科学   193470篇
综合类   57545篇
现状与发展   41篇
一般理论   468篇
预防医学   125497篇
眼科学   32475篇
药学   113630篇
  237篇
中国医学   13732篇
肿瘤学   83837篇
  2021年   16547篇
  2020年   12086篇
  2019年   15513篇
  2018年   20217篇
  2017年   16714篇
  2016年   16935篇
  2015年   21389篇
  2014年   28396篇
  2013年   39853篇
  2012年   55834篇
  2011年   59173篇
  2010年   36556篇
  2009年   32790篇
  2008年   51332篇
  2007年   53303篇
  2006年   52446篇
  2005年   50068篇
  2004年   45866篇
  2003年   43479篇
  2002年   41555篇
  2001年   63343篇
  2000年   64591篇
  1999年   53842篇
  1998年   15509篇
  1997年   13213篇
  1996年   12875篇
  1995年   12976篇
  1994年   12141篇
  1993年   11160篇
  1992年   41762篇
  1991年   41015篇
  1990年   39671篇
  1989年   37505篇
  1988年   34722篇
  1987年   33821篇
  1986年   32217篇
  1985年   30694篇
  1984年   23027篇
  1983年   19558篇
  1982年   11701篇
  1979年   20770篇
  1978年   14770篇
  1977年   12015篇
  1976年   11834篇
  1975年   12085篇
  1974年   14775篇
  1973年   14456篇
  1972年   13349篇
  1971年   12408篇
  1970年   11472篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.

Objective

The aim of the study was to estimate the effect of the state-based reinsurance programs through the section 1332 State Innovation Waivers on health insurance marketplace premiums and insurer participation.

Data Source

2015 to 2022 Robert Wood Johnson Foundation Health Insurance Exchange Compare Datasets.

Study Design

An event study difference-in-differences (DD) model separately for each year of implementation and a synthetic control method (SCM) are used to estimate year-by-year effects following program implementation.

Data Collection/Extraction Methods

Not applicable.

Principal Findings

Reinsurance programs were associated with a decline in premiums in the first year of implementation by 10%–13%, 5%–19%, and 11%–17% for bronze, silver, and gold plans (p < 0.05). There is a trend of sustained declines especially for states that implemented their programs in 2019 and 2020. The SCM analyses suggest some effect heterogeneity across states but also premium declines across most states. There is no evidence that reinsurance programs affected insurer participation.

Conclusion

State-based reinsurance programs have the potential to improve the affordability of health insurance coverage. However, reinsurance programs do not appear to have had an effect on insurer participation, highlighting the need for policy makers to consider complementary strategies to encourage insurer participation.  相似文献   
2.
Kinase alterations are increasingly recognised as oncogenic drivers in mesenchymal tumours. Infantile fibrosarcoma and the related renal tumour, congenital mesoblastic nephroma, were among the first solid tumours shown to harbour recurrent tyrosine kinase fusions, with the canonical ETV6::NTRK3 fusion identified more than 20 years ago. Although targeted testing has long been used in diagnosis, the advent of more robust sequencing techniques has driven the discovery of kinase alterations in an array of mesenchymal tumours. As our ability to identify these genetic alterations has improved, as has our recognition and understanding of the tumours that harbour these alterations. Specifically, this study will focus upon mesenchymal tumours harbouring NTRK or other kinase alterations, including tumours with an infantile fibrosarcoma-like appearance, spindle cell tumours resembling lipofibromatosis or peripheral nerve sheath tumours and those occurring in adults with a fibrosarcoma-like appearance. As publications describing the histology of these tumours increase so, too, do the variety kinase alterations reported, now including NTRK1/2/3, RET, MET, RAF1, BRAF, ALK, EGFR and ABL1 fusions or alterations. To date, these tumours appear locally aggressive and rarely metastatic, without a clear link between traditional features used in histological grading (e.g. mitotic activity, necrosis) and outcome. However, most of these tumours are amenable to new targeted therapies, making their recognition of both diagnostic and therapeutic import. The goal of this study is to review the clinicopathological features of tumours with NTRK and other tyrosine kinase alterations, discuss the most common differential diagnoses and provide recommendations for molecular confirmation with associated treatment implications.  相似文献   
3.
综述了脑血管介入术穿刺点压迫方法(包括人工压迫、弹力带加压、压迫器加压、血管闭合装置压迫、止血敷料压迫、气囊加压6种)、止血压力以及压迫时间,提出由于穿刺点和压迫方法的不同,其压迫时间、减压时间和压力大小等需要进一步探讨,为脑血管介入术后患者穿刺点的临床护理提供参考。  相似文献   
4.
目的 了解我国老年人中医证候分布特征,为中医药辨治老年人提供参考依据。方法 系统检索中国知识基础设施(CNKI)、中文科技期刊数据库(CCD)、万方数据资源系统数据库(CSPD),纳入研究对象为老年人的临床流行病学调查研究文献,对其调查目的、调查疾病及调查结果等进行描述统计。结果 ①最终纳入168篇文献,其中2010至2020年之间发表138篇(82.14%);调查地区涵盖全国28个省市自治区,共纳入43948例老年人,累计覆盖340个研究中心;②主要研究结果显示,老年人中医证候阴虚阳亢证(10.05%)>血瘀证(9.5%)>痰浊(湿)证(8.91%)>阴阳两虚证(4.98%)>痰瘀互结证(4.96%);单元证分布阴虚证(14.70%)>痰证(11.22%)>气虚证(7.15%)>肾虚证(4.72%)>血瘀证(4.18%);涉及病变脏腑肾>肝>脾>肺>心。结论 根据统计结果,可以看出老年人证候分布虚证多于实证,虚证中又以阴虚证、气虚证最为多见,实证常见血瘀证、痰浊(湿)证等,且多见痰瘀互结证;老年人五脏皆损,其中又以肾、肝、脾功能失调最为突出。  相似文献   
5.
孔慧  崔彦 《眼科新进展》2022,(9):753-756
视网膜内皮细胞(REC)是参与糖尿病视网膜病变和许多眼部疾病的主要细胞类型之一。视网膜微血管系统有助于血-视网膜屏障的维持,这对正常的视功能至关重要。REC的改变在视网膜疾病的发生发展中起着关键作用。高血糖是糖尿病微血管损伤的重要原因,通过不同的机制导致REC功能障碍,包括向衰老表型改变、迁移和增殖能力增强、炎性凋亡等,最终导致无细胞毛细血管及病理性新生血管形成。本文对糖尿病视网膜病变中REC的功能障碍作一综述。  相似文献   
6.

Interstitial lung disease (ILD) represents a significant cause of morbidity and mortality in systemic sclerosis (SSc). The purpose of this study was to examine recirculating lymphocytes from SSc patients for potential biomarkers of interstitial lung disease (ILD). Peripheral blood mononuclear cells (PBMCs) were isolated from patients with SSc and healthy controls enrolled in the Vanderbilt University Myositis and Scleroderma Treatment Initiative Center cohort between 9/2017–6/2019. Clinical phenotyping was performed by chart abstraction. Immunophenotyping was performed using both mass cytometry and fluorescence cytometry combined with t-distributed stochastic neighbor embedding analysis and traditional biaxial gating. This study included 34 patients with SSc-ILD, 14 patients without SSc-ILD, and 25 healthy controls. CD21lo/neg cells are significantly increased in SSc-ILD but not in SSc without ILD (15.4 ± 13.3% vs. 5.8 ± 0.9%, p = 0.002) or healthy controls (5.0 ± 0.5%, p < 0.0001). While CD21lo/neg B cells can be identified from a single biaxial gate, tSNE analysis reveals that the biaxial gate is comprised of multiple distinct subsets, all of which are increased in SSc-ILD. CD21lo/neg cells in both healthy controls and SSc-ILD are predominantly tBET positive and do not have intracellular CD21. Immunohistochemistry staining demonstrated that CD21lo/neg B cells diffusely infiltrate the lung parenchyma of an SSc-ILD patient. Additional work is needed to validate this biomarker in larger cohorts and longitudinal studies and to understand the role of these cells in SSc-ILD.

  相似文献   
7.
8.
9.
目的 探究高密度多孔聚乙烯植入体在鼻整形中的应用价值方法 选取2019年5月-2021年8月我院接受综合鼻整形手术的106例患者为研究对象,采用照随机数字表法分为对照组和观察组,各53例。 对照组采用自体肋骨植入术,观察组采用高密度多孔聚乙烯植入体植入治疗,比较两组临床手术指标(手术时间、恢复时间)、整形优良率、鼻指标(鼻高度/鼻长度比例、鼻唇角)、并发症发生率以及疼痛评分结果 观察组手术时间、术后恢复时间均短于对照组(P<0.05);观察组整形优良率为94.34%,高于对照组的86.79%,差异有统计学意义(P<0.05);观察组鼻高度/鼻长度比例高于对照组,鼻唇角小于对照组,差异有统计学意义(P<0.05);观察组并发症发生率为5.66%,低于对照组的15.09%,差异有统计学意义(P<0.05);观察组疼痛评分低于对照组,差异有统计学意义(P<0.05);观察组治疗满意度为 96.23%,高于对照组的84.91%,差异有统计学意义(P<0.05)结论 高密度多孔聚乙烯植入体在鼻整形中的应用效果理想,可减轻患者疼痛度,缩短手术和恢复时间,降低并发症发生率,改善鼻高度/鼻长度比例和鼻唇角,实现理想的整形效果。  相似文献   
10.
Neoadjuvant programmed cell death protein 1 (PD-1) blockade exhibits promising efficacy in patients with mismatch repair deficient (dMMR) colorectal cancer (CRC). However, discrepancies between radiological and histological findings have been reported in the PICC phase II trial (NCT 03926338). Therefore, we strived to discern radiological features associated with pathological complete response (pCR) based on computed tomography (CT) images. Data were obtained from the PICC trial that included 36 tumors from 34 locally advanced dMMR CRC patients, who received neoadjuvant PD-1 blockade for 3 months. Among the 36 tumors, 28 (77.8%) tumors achieved pCR. There were no statistically significant differences in tumor longitudinal diameter, the percentage change in tumor longitudinal diameter from baseline, primary tumor sidedness, clinical stage, extramural venous invasion status, intratumoral calcification, peritumoral fat infiltration, intestinal fistula and tumor necrosis between the pCR and non-pCR tumors. Otherwise, tumors with pCR had smaller posttreatment tumor maximum thickness (median: 10 mm vs 13 mm, P = .004) and higher percentage decrease in tumor maximum thickness from baseline (52.9% vs 21.6%, P = .005) compared to non-pCR tumors. Additionally, a higher proportion of the absence of vascular sign (P = .003, odds ratio [OR] = 25.870 [95% CI, 1.357-493.110]), nodular sign (P < .001, OR = 189.000 [95% CI, 10.464-3413.803]) and extramural enhancement sign (P = .003, OR = 21.667 [2.848-164.830]) was observed in tumors with pCR. In conclusion, these CT-defined radiological features may have the potential to serve as valuable tools for clinicians in identifying patients who have achieved pCR after neoadjuvant PD-1 blockade, particularly in individuals who are willing to adopt a watch-and-wait strategy.  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