全文获取类型
收费全文 | 2206679篇 |
免费 | 170160篇 |
国内免费 | 7331篇 |
专业分类
耳鼻咽喉 | 29662篇 |
儿科学 | 71044篇 |
妇产科学 | 59976篇 |
基础医学 | 306373篇 |
口腔科学 | 61977篇 |
临床医学 | 198419篇 |
内科学 | 437592篇 |
皮肤病学 | 52118篇 |
神经病学 | 175902篇 |
特种医学 | 90321篇 |
外国民族医学 | 472篇 |
外科学 | 342610篇 |
综合类 | 49304篇 |
现状与发展 | 3篇 |
一般理论 | 657篇 |
预防医学 | 167611篇 |
眼科学 | 48597篇 |
药学 | 164638篇 |
10篇 | |
中国医学 | 4397篇 |
肿瘤学 | 122487篇 |
出版年
2018年 | 22480篇 |
2017年 | 17784篇 |
2016年 | 20951篇 |
2015年 | 23338篇 |
2014年 | 32260篇 |
2013年 | 47934篇 |
2012年 | 61192篇 |
2011年 | 65356篇 |
2010年 | 39948篇 |
2009年 | 38499篇 |
2008年 | 61019篇 |
2007年 | 65139篇 |
2006年 | 66603篇 |
2005年 | 63912篇 |
2004年 | 61133篇 |
2003年 | 59211篇 |
2002年 | 56744篇 |
2001年 | 112213篇 |
2000年 | 115468篇 |
1999年 | 96117篇 |
1998年 | 25601篇 |
1997年 | 22572篇 |
1996年 | 23320篇 |
1995年 | 24147篇 |
1994年 | 22355篇 |
1993年 | 21017篇 |
1992年 | 77096篇 |
1991年 | 74818篇 |
1990年 | 72607篇 |
1989年 | 69697篇 |
1988年 | 63858篇 |
1987年 | 62578篇 |
1986年 | 59002篇 |
1985年 | 56399篇 |
1984年 | 42024篇 |
1983年 | 35319篇 |
1982年 | 21003篇 |
1981年 | 18581篇 |
1980年 | 17567篇 |
1979年 | 37758篇 |
1978年 | 26533篇 |
1977年 | 22927篇 |
1976年 | 20595篇 |
1975年 | 22268篇 |
1974年 | 26062篇 |
1973年 | 25062篇 |
1972年 | 23477篇 |
1971年 | 21817篇 |
1970年 | 19973篇 |
1969年 | 18973篇 |
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
1.
2.
3.
Jayaraman Chandrasekaran Embry Kyle R. Mummidisetty Chaithanya K. Moon Yaejin Giffhorn Matt Prokup Sara Lim Bokman Lee Jusuk Lee Younbaek Lee Minhyung Jayaraman Arun 《Journal of neuroengineering and rehabilitation》2022,19(1):1-13
Numerous studies showed that postural balance improves through light touch on a stable surface highlighting the importance of haptic information, seemingly downplaying the mechanical contributions of the support. The present study examined the mechanical effects of canes for assisting balance in healthy individuals challenged by standing on a beam. Sixteen participants supported themselves with two canes, one in each hand, and applied minimal, preferred, or maximum force onto the canes. They positioned the canes in the frontal plane or in a tripod configuration. Statistical analysis used a linear mixed model to evaluate the effects on the center of pressure and the center of mass. The canes significantly reduced the variability of the center of pressure and the center of mass to the same level as when standing on the ground. Increasing the exerted force beyond the preferred level yielded no further benefits, although in the preferred force condition, participants exploited the altered mechanics by resting their arms on the canes. The tripod configuration allowed for larger variability of the center of pressure in the task-irrelevant anterior–posterior dimension. High forces had a destabilizing effect on the canes: the displacement of the hand on the cane handle increased with the force. Given this static instability, these results show that using canes can provide not only mechanical benefits but also challenges. From a control perspective, effort can be reduced by resting the arms on the canes and by channeling noise in the task-irrelevant dimensions. However, larger forces exerted onto the canes can also have destabilizing effects and the instability of the canes needs to be counteracted, possibly by arm and shoulder stiffness. Insights into the variety of mechanical effects is important for the design of canes and the instructions of how to use them. 相似文献
4.
S. M. White C. L. Shelton A. W. Gelb C. Lawson F. McGain J. Muret J. D. Sherman representing the World Federation of Societies of Anaesthesiologists Global Working Group on Environmental Sustainability in Anaesthesia 《Anaesthesia》2022,77(2):201-212
The Earth’s mean surface temperature is already approximately 1.1°C higher than pre-industrial levels. Exceeding a mean 1.5°C rise by 2050 will make global adaptation to the consequences of climate change less possible. To protect public health, anaesthesia providers need to reduce the contribution their practice makes to global warming. We convened a Working Group of 45 anaesthesia providers with a recognised interest in sustainability, and used a three-stage modified Delphi consensus process to agree on principles of environmentally sustainable anaesthesia that are achievable worldwide. The Working Group agreed on the following three important underlying statements: patient safety should not be compromised by sustainable anaesthetic practices; high-, middle- and low-income countries should support each other appropriately in delivering sustainable healthcare (including anaesthesia); and healthcare systems should be mandated to reduce their contribution to global warming. We set out seven fundamental principles to guide anaesthesia providers in the move to environmentally sustainable practice, including: choice of medications and equipment; minimising waste and overuse of resources; and addressing environmental sustainability in anaesthetists’ education, research, quality improvement and local healthcare leadership activities. These changes are achievable with minimal material resource and financial investment, and should undergo re-evaluation and updates as better evidence is published. This paper discusses each principle individually, and directs readers towards further important references. 相似文献
5.
6.
7.
8.
Moskaleva P. V. Shnayder N. A. Dmitrenko D. V. Shilkina O. S. Neznanov N. G. Nasyrova R. F. 《Neuroscience and behavioral physiology》2022,52(3):462-469
Neuroscience and Behavioral Physiology - The question of the involvement of impairments to the metabolism of melatonin and its precursors (tryptophan and serotonin) in the development of... 相似文献
9.
Andreas Lundin Martin Annborn Ola Borgquist Joachim Düring Johan Undén Christian Rylander 《Acta anaesthesiologica Scandinavica》2023,67(5):655-662
Patients admitted to intensive care after cardiac arrest are at risk of circulatory shock and early mortality due to cardiovascular failure. The aim of this study was to evaluate the ability of the veno-arterial pCO2 difference (∆pCO2; central venous CO2 – arterial CO2) and lactate to predict early mortality in postcardiac arrest patients. This was a pre-planned prospective observational sub-study of the target temperature management 2 trial. The sub-study patients were included at five Swedish sites. Repeated measurements of ∆pCO2 and lactate were conducted at 4, 8, 12, 16, 24, 48, and 72 h after randomization. We assessed the association between each marker and 96-h mortality and their prognostic value for 96-h mortality. One hundred sixty-three patients were included in the analysis. Mortality at 96 h was 17%. During the initial 24 h, there was no difference in ∆pCO2 levels between 96-h survivors and non-survivors. ∆pCO2 measured at 4 h was associated with an increased risk of death within 96 h (adjusted odds ratio: 1.15; 95% confidence interval [CI]: 1.02–1.29; p = .018). Lactate levels were associated with poor outcome over multiple measurements. The area under the receiving operating curve to predict death within 96 h was 0.59 (95% CI: 0.48–0.74) and 0.82 (95% CI: 0.72–0.92) for ∆pCO2 and lactate, respectively. Our results do not support the use of ∆pCO2 to identify patients with early mortality in the postresuscitation phase. In contrast, non-survivors demonstrated higher lactate levels in the initial phase and lactate identified patients with early mortality with moderate accuracy. 相似文献
10.