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   2390839篇
  免费   190839篇
  国内免费   9759篇
耳鼻咽喉   30661篇
儿科学   78295篇
妇产科学   65511篇
基础医学   339802篇
口腔科学   66005篇
临床医学   225729篇
内科学   474267篇
皮肤病学   52849篇
神经病学   198820篇
特种医学   92391篇
外国民族医学   623篇
外科学   352588篇
综合类   55614篇
现状与发展   3篇
一般理论   841篇
预防医学   200622篇
眼科学   51865篇
药学   172432篇
  11篇
中国医学   4915篇
肿瘤学   127593篇
  2018年   26478篇
  2017年   20423篇
  2016年   23304篇
  2015年   26391篇
  2014年   36653篇
  2013年   56087篇
  2012年   72348篇
  2011年   77422篇
  2010年   46626篇
  2009年   44335篇
  2008年   71371篇
  2007年   75705篇
  2006年   76993篇
  2005年   74442篇
  2004年   70933篇
  2003年   68279篇
  2002年   65495篇
  2001年   109689篇
  2000年   112790篇
  1999年   94672篇
  1998年   28247篇
  1997年   25379篇
  1996年   25980篇
  1995年   25572篇
  1994年   23957篇
  1993年   22454篇
  1992年   77430篇
  1991年   75588篇
  1990年   72932篇
  1989年   69326篇
  1988年   64410篇
  1987年   63181篇
  1986年   60001篇
  1985年   57689篇
  1984年   43969篇
  1983年   37088篇
  1982年   22965篇
  1981年   20526篇
  1980年   19224篇
  1979年   39755篇
  1978年   28803篇
  1977年   23939篇
  1976年   22766篇
  1975年   23500篇
  1974年   28147篇
  1973年   27202篇
  1972年   25170篇
  1971年   23311篇
  1970年   21422篇
  1969年   19827篇
排序方式: 共有10000条查询结果,搜索用时 496 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.
Die Anaesthesiologie - Phantomschmerzen haben eine hohe Prävalenz nach Majoramputationen und sind mit einer zusätzlichen Einschränkung der Lebensqualität verbunden....  相似文献   
4.

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   
5.
6.
7.

The exercise pressor reflex is a feedback mechanism engaged upon stimulation of mechano- and metabosensitive skeletal muscle afferents. Activation of these afferents elicits a reflex increase in heart rate, blood pressure, and ventilation in an intensity-dependent manner. Consequently, the exercise pressor reflex has been postulated to be one of the principal mediators of the cardiorespiratory responses to exercise. In this updated review, we will discuss classical and recent advancements in our understating of the exercise pressor reflex function in both human and animal models. Particular attention will be paid to the afferent mechanisms and pathways involved during its activation, its effects on different target organs, its potential role in the abnormal cardiovascular response to exercise in diseased states, and the impact of age and biological sex on these responses. Finally, we will highlight some unanswered questions in the literature that may inspire future investigations in the field.

  相似文献   
8.
9.
Journal of Behavioral Medicine - Evidence supports the use of graphic warnings to educate the public about the health harms of smoking and suggests warnings eliciting negative emotional responses...  相似文献   
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