全文获取类型
收费全文 | 25628篇 |
免费 | 1826篇 |
国内免费 | 61篇 |
学科分类
医药卫生 | 27515篇 |
出版年
2023年 | 247篇 |
2022年 | 187篇 |
2021年 | 1061篇 |
2020年 | 553篇 |
2019年 | 931篇 |
2018年 | 1032篇 |
2017年 | 743篇 |
2016年 | 781篇 |
2015年 | 876篇 |
2014年 | 1317篇 |
2013年 | 1478篇 |
2012年 | 2438篇 |
2011年 | 2468篇 |
2010年 | 1268篇 |
2009年 | 1187篇 |
2008年 | 1777篇 |
2007年 | 1746篇 |
2006年 | 1545篇 |
2005年 | 1438篇 |
2004年 | 1236篇 |
2003年 | 1099篇 |
2002年 | 881篇 |
2001年 | 156篇 |
2000年 | 125篇 |
1999年 | 105篇 |
1998年 | 106篇 |
1997年 | 75篇 |
1996年 | 46篇 |
1995年 | 36篇 |
1994年 | 37篇 |
1993年 | 25篇 |
1992年 | 36篇 |
1991年 | 34篇 |
1990年 | 32篇 |
1989年 | 38篇 |
1988年 | 35篇 |
1987年 | 34篇 |
1986年 | 32篇 |
1985年 | 33篇 |
1984年 | 23篇 |
1983年 | 31篇 |
1982年 | 12篇 |
1981年 | 11篇 |
1980年 | 13篇 |
1979年 | 21篇 |
1978年 | 10篇 |
1975年 | 9篇 |
1974年 | 12篇 |
1973年 | 12篇 |
1971年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Rajiv V. Dave Baek Kim Alona Courtney Rachel OConnell Tim Rattay Vicky P. Taxiarchi Jamie J. Kirkham Elizabeth M. Camacho Patricia Fairbrother Nisha Sharma Christopher W. J. Cartlidge Kieran Horgan Stuart A. McIntosh Daniel R. Leff Raghavan Vidya Shelley Potter Chris Holcombe Ellen Copson Charlotte E. Coles Ramsey I. Cutress Ashu Gandhi Cliona C. Kirwan 《British journal of cancer》2021,124(11):1785
Background The B-MaP-C study aimed to determine alterations to breast cancer (BC) management during the peak transmission period of the UK COVID-19 pandemic and the potential impact of these treatment decisions.Methods This was a national cohort study of patients with early BC undergoing multidisciplinary team (MDT)-guided treatment recommendations during the pandemic, designated ‘standard’ or ‘COVID-altered’, in the preoperative, operative and post-operative setting.Findings Of 3776 patients (from 64 UK units) in the study, 2246 (59%) had ‘COVID-altered’ management. ‘Bridging’ endocrine therapy was used (n = 951) where theatre capacity was reduced. There was increasing access to COVID-19 low-risk theatres during the study period (59%). In line with national guidance, immediate breast reconstruction was avoided (n = 299). Where adjuvant chemotherapy was omitted (n = 81), the median benefit was only 3% (IQR 2–9%) using ‘NHS Predict’. There was the rapid adoption of new evidence-based hypofractionated radiotherapy (n = 781, from 46 units). Only 14 patients (1%) tested positive for SARS-CoV-2 during their treatment journey.Conclusions The majority of ‘COVID-altered’ management decisions were largely in line with pre-COVID evidence-based guidelines, implying that breast cancer survival outcomes are unlikely to be negatively impacted by the pandemic. However, in this study, the potential impact of delays to BC presentation or diagnosis remains unknown.Subject terms: Breast cancer, Surgical oncology, Health care economics, Quality of life, Health policy 相似文献
4.
Patrick W. Keeley Mikayla C. Lebo Jordan D. Vieler Jason J. Kim Ace J. St. John Benjamin E. Reese 《The Journal of neuroscience》2021,41(1):103
Amacrine cells of the retina are conspicuously variable in their morphologies, their population demographics, and their ensuing functions. Vesicular glutamate transporter 3 (VGluT3) amacrine cells are a recently characterized type of amacrine cell exhibiting local dendritic autonomy. The present analysis has examined three features of this VGluT3 population, including their density, local distribution, and dendritic spread, to discern the extent to which these are interrelated, using male and female mice. We first demonstrate that Bax-mediated cell death transforms the mosaic of VGluT3 cells from a random distribution into a regular mosaic. We subsequently examine the relationship between cell density and mosaic regularity across recombinant inbred strains of mice, finding that, although both traits vary across the strains, they exhibit minimal covariation. Other genetic determinants must therefore contribute independently to final cell number and to mosaic order. Using a conditional KO approach, we further demonstrate that Bax acts via the bipolar cell population, rather than cell-intrinsically, to control VGluT3 cell number. Finally, we consider the relationship between the dendritic arbors of single VGluT3 cells and the distribution of their homotypic neighbors. Dendritic field area was found to be independent of Voronoi domain area, while dendritic coverage of single cells was not conserved, simply increasing with the size of the dendritic field. Bax-KO retinas exhibited a threefold increase in dendritic coverage. Each cell, however, contributed less dendrites at each depth within the plexus, intermingling their processes with those of neighboring cells to approximate a constant volumetric density, yielding a uniformity in process coverage across the population.SIGNIFICANCE STATEMENT Different types of retinal neuron spread their processes across the surface of the retina to achieve a degree of dendritic coverage that is characteristic of each type. Many of these types achieve a constant coverage by varying their dendritic field area inversely with the local density of like-type neighbors. Here we report a population of retinal amacrine cells that do not develop dendritic arbors in relation to the spatial positioning of such homotypic neighbors; rather, this cell type modulates the extent of its dendritic branching when faced with a variable number of overlapping dendritic fields to approximate a uniformity in dendritic density across the retina. 相似文献
5.
Sarah J. Schrauben Haochang Shou Xiaoming Zhang Amanda Hyre Anderson Joseph V. Bonventre Jing Chen Steven Coca Susan L. Furth Jason H. Greenberg Orlando M. Gutierrez Joachim H. Ix James P. Lash Chirag R. Parikh Casey M. Rebholz Venkata Sabbisetti Mark J. Sarnak Michael G. Shlipak Sushrut S. Waikar Paul L. Kimmel Ramachandran S. Vasan Harold I. Feldman Jeffrey R. Schelling 《Journal of the American Society of Nephrology : JASN》2021,32(1):115
6.
7.
Love Patel Darshan Gandhi Emily Westergard Michael Ornes Matthew Lillyblad Nedaa Skeik 《World journal of radiology》2021,13(3):64-74
As we continue to fight against the current coronavirus disease-2019 (COVID-19) pandemic, healthcare professionals across the globe are trying to answer questions surrounding how to best help patients with the up-to-date available science while awaiting the development of new therapies and mass vaccination. Since early in the pandemic, studies indicated a heightened risk of venous thromboembolism (VTE) in COVID-19 infected patients. There have been differing expert opinions about how to assess pretest probability of VTE in this patient population. This has been partly due to the high prevalence of respiratory failure in this patient population and the use of D-dimer as a prognostic test which is also frequently elevated in patients with COVID-19 in absence of VTE. Some experts have argued for an approach similar to usual care with testing if clinical suspicion is high enough. Some have argued for more routine screening at different points of care. Others have even suggested empiric therapeutic anti-coagulation in moderate to severely ill COVID-19 patients. In the following article, we review and summarize the most current literature in hopes of assisting clinicians in decision making and guidance for when to be concerned for VTE in COVID-19 patients. We also discuss research gaps and share pathways currently being used within our institution. 相似文献
8.
Improving hyperpolarized 129Xe ADC mapping in pediatric and adult lungs with uncertainty propagation
9.
Loren Saulsberry PhD Ankur Bhargava MD MPH Sharon Zeng BA Jason B. Gibbons PhD Cody Brannan MS Diane S. Lauderdale PhD Robert D. Gibbons PhD 《Health services research》2023,58(4):873-881
Objective
To derive and validate a new ecological measure of the social determinants of health (SDoH), calculable at the zip code or county level.Data Sources and Study Setting
The most recent releases of secondary, publicly available data were collected from national U.S. health agencies as well as state and city public health departments.Study Design
The Social Vulnerability Metric (SVM) was constructed from U.S. zip-code level measures (2018) from survey data using multidimensional Item Response Theory and validated using outcomes including all-cause mortality (2016), COVID-19 vaccination (2021), and emergency department visits for asthma (2018). The SVM was also compared with the existing Centers for Disease Control and Prevention's Social Vulnerability Index (SVI) to determine convergent validity and differential predictive validity.Data Collection/Extraction Methods
The data were collected directly from published files available to the public online from national U.S. health agencies as well as state and city public health departments.Principal Findings
The correlation between SVM scores and national age-adjusted county all-cause mortality was r = 0.68. This correlation demonstrated the SVM's robust validity and outperformed the SVI with an almost four-fold increase in explained variance (46% vs. 12%). The SVM was also highly correlated (r ≥ 0.60) to zip-code level health outcomes for the state of California and city of Chicago.Conclusions
The SVM offers a measurement tool improving upon the performance of existing SDoH composite measures and has broad applicability to public health that may help in directing future policies and interventions. The SVM provides a single measure of SDoH that better quantifies associations with health outcomes. 相似文献10.