全文获取类型
收费全文 | 535769篇 |
免费 | 5421篇 |
国内免费 | 1710篇 |
专业分类
化学 | 233004篇 |
晶体学 | 6879篇 |
力学 | 22298篇 |
综合类 | 8篇 |
数学 | 65082篇 |
物理学 | 144312篇 |
无线电 | 71317篇 |
出版年
2020年 | 3017篇 |
2019年 | 3271篇 |
2018年 | 12622篇 |
2017年 | 13437篇 |
2016年 | 10275篇 |
2015年 | 5261篇 |
2014年 | 6593篇 |
2013年 | 18699篇 |
2012年 | 17996篇 |
2011年 | 29239篇 |
2010年 | 18799篇 |
2009年 | 19444篇 |
2008年 | 27041篇 |
2007年 | 31053篇 |
2006年 | 16860篇 |
2005年 | 22702篇 |
2004年 | 17790篇 |
2003年 | 16115篇 |
2002年 | 13766篇 |
2001年 | 14228篇 |
2000年 | 11512篇 |
1999年 | 9114篇 |
1998年 | 7837篇 |
1997年 | 7714篇 |
1996年 | 7456篇 |
1995年 | 6895篇 |
1994年 | 6702篇 |
1993年 | 6699篇 |
1992年 | 6970篇 |
1991年 | 7008篇 |
1990年 | 6500篇 |
1989年 | 6312篇 |
1988年 | 6163篇 |
1987年 | 5356篇 |
1986年 | 5071篇 |
1985年 | 6940篇 |
1984年 | 7039篇 |
1983年 | 5867篇 |
1982年 | 6262篇 |
1981年 | 5992篇 |
1980年 | 5819篇 |
1979年 | 5784篇 |
1978年 | 6036篇 |
1977年 | 5716篇 |
1976年 | 5890篇 |
1975年 | 5445篇 |
1974年 | 5450篇 |
1973年 | 5845篇 |
1972年 | 3621篇 |
1971年 | 2769篇 |
排序方式: 共有10000条查询结果,搜索用时 443 毫秒
11.
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
12.
Telecommunication Systems - Energy saving in User Equipment (UE) is one of the important issues for limited sources of power in the device. It is critical for the UE to maximize its energy... 相似文献
13.
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
14.
M. Amar D. Andreucci R. Gianni C. Timofte 《Journal of Mathematical Analysis and Applications》2021,493(2):124533
We prove a well-posedness result for two pseudo-parabolic problems, which can be seen as two models for the same electrical conduction phenomenon in heterogeneous media, neglecting the magnetic field. One of the problems is the concentration limit of the other one, when the thickness of the dielectric inclusions goes to zero. The concentrated problem involves a transmission condition through interfaces, which is mediated by a suitable Laplace-Beltrami type equation. 相似文献
15.
16.
Zadeba E. A. Khokhlov S. S. Kokoulin R. P. Petrukhin A. A. Shulzhenko I. A. Yashin I. I. 《Physics of Atomic Nuclei》2022,85(1):86-91
Physics of Atomic Nuclei - The muon puzzle is an excess of muon bundles generated by primary cosmic rays (PCR) at energies above 10 $${}^{17}$$ eV compared to estimations that assume even a heavy... 相似文献
17.
Mobile Networks and Applications - Blockchain applications have continuously improved ever since its first debut on cryptocurrency. From then on, its uses have branched out from the financial... 相似文献
18.
19.
Castro Mateus B. Souza Raphael R. N. Junior Agord M. P. Lima Eduardo R. Manera Leandro T. 《Analog Integrated Circuits and Signal Processing》2021,109(3):647-656
Analog Integrated Circuits and Signal Processing - This paper presents the complete design of a phase locked loop-based clock synthesizer for reconfigurable analog-to-digital converters. The... 相似文献
20.
Nonlinear Dynamics - In this article, the authors simulate and study dark and bright soliton solutions of 1D and 2D regularized long wave (RLW) models. The RLW model occurred in various fields such... 相似文献