全文获取类型
收费全文 | 606401篇 |
免费 | 7699篇 |
国内免费 | 2228篇 |
专业分类
化学 | 326558篇 |
晶体学 | 9209篇 |
力学 | 25839篇 |
综合类 | 12篇 |
数学 | 75366篇 |
物理学 | 179344篇 |
出版年
2020年 | 4510篇 |
2019年 | 4861篇 |
2018年 | 5662篇 |
2017年 | 5550篇 |
2016年 | 9518篇 |
2015年 | 6714篇 |
2014年 | 9862篇 |
2013年 | 28010篇 |
2012年 | 20594篇 |
2011年 | 25500篇 |
2010年 | 16800篇 |
2009年 | 16675篇 |
2008年 | 23218篇 |
2007年 | 23291篇 |
2006年 | 22206篇 |
2005年 | 20262篇 |
2004年 | 18328篇 |
2003年 | 16347篇 |
2002年 | 16009篇 |
2001年 | 17651篇 |
2000年 | 13627篇 |
1999年 | 10835篇 |
1998年 | 8970篇 |
1997年 | 8730篇 |
1996年 | 8559篇 |
1995年 | 7844篇 |
1994年 | 7556篇 |
1993年 | 7425篇 |
1992年 | 8191篇 |
1991年 | 8057篇 |
1990年 | 7652篇 |
1989年 | 7485篇 |
1988年 | 7646篇 |
1987年 | 7369篇 |
1986年 | 7036篇 |
1985年 | 9899篇 |
1984年 | 10137篇 |
1983年 | 8425篇 |
1982年 | 9069篇 |
1981年 | 8821篇 |
1980年 | 8594篇 |
1979年 | 8789篇 |
1978年 | 9110篇 |
1977年 | 8897篇 |
1976年 | 8955篇 |
1975年 | 8500篇 |
1974年 | 8473篇 |
1973年 | 8914篇 |
1972年 | 5578篇 |
1971年 | 4319篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Tsyganova S. I. Fetisova O. Yu. Mazurova E. N. Taran O. P. Kuznetsov B. N. 《Russian Journal of Applied Chemistry》2022,95(3):408-416
Russian Journal of Applied Chemistry - A method for the disposal of hydrolysis lignin waste based on its modification with ZnCl2 and FeCl3 and subsequent carbonization at 800°C was proposed.... 相似文献
12.
Roopa K. P. Keshavamurthy K. Mahesh B. Veena K. P. Shankara B. S. Basavaiah K. 《Journal of Applied Spectroscopy》2022,89(4):809-818
Journal of Applied Spectroscopy - Three simple, sensitive, precise, and rapid spectrophotometric methods are developed and optimized for the assay of vardenafil in pharmaceutical formulations. The... 相似文献
13.
Low-flow chromatography has a rich history of innovation but has yet to reach widespread implementation in bioanalytical applications. Improvements in pump technology, microfluidic connections, and nano-electrospray sources for MS have laid the groundwork for broader application, and innovation in this space has accelerated in recent years. This article reviews the instrumentation used for nano-flow LC, the types of columns employed, and strategies for multidimensionality of separations, which are key to the future state of the technique to the high-throughput needs of modern bioanalysis. An update of the current applications where nano-LC is widely used, such as proteomics and metabolomics, is discussed. But the trend toward biopharmaceutical development of increasingly complex, targeted, and potent therapeutics for the safe treatment of disease drives the need for ultimate selectivity and sensitivity of our analytical platforms for targeted quantitation in a regulated space. The selectivity needs are best addressed by mass spectrometric detection, especially at high resolutions, and exquisite sensitivity is provided by nano-electrospray ionization as the technology continues to evolve into an accessible, robust, and easy-to-use platform. 相似文献
14.
Varfolomeev S. D. Panin A. A. Semenova N. A. Ublinskiy M. V. Akhadov T. A. Bykov V. I. Tsybenova S. B. 《Russian Chemical Bulletin》2022,71(3):591-594
A kinetic study of the effect of thermoheliox (inhalation of a helium and oxygen mixture, 70 °C) on the functional hemodynamics of the human brain by functional magnetic resonance imaging was carried out. The dynamic responses of the BOLD signal were found to be biphasic. An empirical equation describing the first phase of the hemodynamic response to visual stimulus was proposed. It was shown that preliminary inhalation of thermoheliox stimulates the hemodynamic responses by slowing down the vasoconstriction.
相似文献15.
Experimental Mechanics - Temperature gradients significantly affect the material fatigue process. A reliable and robust test procedure is needed for quantifying the effects of temperature gradients... 相似文献
16.
Schmalian Misha Suris Yuri B. Tumarkin Yuriy 《Mathematical Physics, Analysis and Geometry》2021,24(4):1-17
Mathematical Physics, Analysis and Geometry - In this paper, we develop the dressing method to study the modified Camassa-Holm equation with the help of reciprocal transformation and the associated... 相似文献
17.
18.
Machado J. A. Tenreiro Rocha-Neves J. M. Azevedo Filipe Andrade J. P. 《Nonlinear dynamics》2021,106(2):1525-1555
Nonlinear Dynamics - Given a data-set of Ribonucleic acid (RNA) sequences we can infer the phylogenetics of the samples and tackle the information for scientific purposes. Based on current data and... 相似文献
19.
Acta Mathematica Hungarica - Minkowski’s classical existence theorem provides necessary and sufficient conditions for a Borel measure on the unit sphere of Euclidean space to be the surface... 相似文献
20.
Karandashev S. A. Lukhmyrina T. S. Matveev B. A. Remennyi M. A. Usikova A. A. 《Optics and Spectroscopy》2021,129(11):1231-1235
Optics and Spectroscopy - The current–voltage characteristics and photocurrent of “monolithic” diode optical pairs optically coupled by a substrate made of InAs common for them... 相似文献