全文获取类型
收费全文 | 321942篇 |
免费 | 4475篇 |
国内免费 | 1136篇 |
专业分类
化学 | 175896篇 |
晶体学 | 4567篇 |
力学 | 13307篇 |
综合类 | 7篇 |
数学 | 37565篇 |
物理学 | 96211篇 |
出版年
2020年 | 2040篇 |
2019年 | 2039篇 |
2018年 | 2043篇 |
2017年 | 1936篇 |
2016年 | 4007篇 |
2015年 | 3382篇 |
2014年 | 4559篇 |
2013年 | 14428篇 |
2012年 | 11057篇 |
2011年 | 13750篇 |
2010年 | 8475篇 |
2009年 | 8452篇 |
2008年 | 12669篇 |
2007年 | 12953篇 |
2006年 | 12561篇 |
2005年 | 11488篇 |
2004年 | 10325篇 |
2003年 | 9126篇 |
2002年 | 8962篇 |
2001年 | 10253篇 |
2000年 | 7852篇 |
1999年 | 6246篇 |
1998年 | 4997篇 |
1997年 | 4876篇 |
1996年 | 4948篇 |
1995年 | 4507篇 |
1994年 | 4267篇 |
1993年 | 4102篇 |
1992年 | 4557篇 |
1991年 | 4385篇 |
1990年 | 4090篇 |
1989年 | 3934篇 |
1988年 | 4233篇 |
1987年 | 3887篇 |
1986年 | 3769篇 |
1985年 | 5442篇 |
1984年 | 5544篇 |
1983年 | 4493篇 |
1982年 | 4872篇 |
1981年 | 4925篇 |
1980年 | 4670篇 |
1979年 | 4771篇 |
1978年 | 4781篇 |
1977年 | 4749篇 |
1976年 | 4688篇 |
1975年 | 4601篇 |
1974年 | 4438篇 |
1973年 | 4583篇 |
1972年 | 2608篇 |
1971年 | 1908篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Yang T. L. Kao C. L. Kuo C. E. Yeh H. C. Li W. J. Li H. T. Chen C. Y. 《Chemistry of Natural Compounds》2022,58(5):825-827
Chemistry of Natural Compounds - A novel bibenzyl derivative, hydrangchinenin (1), was isolated from the stems of Hydrangea chinensis Maxim. (Hydrangeaceae). Its structure was determined on the... 相似文献
2.
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
3.
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
4.
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
5.
Kobayashi M. Zhang Y. Ishikawa H. Sun J. Oddershede J. Juul Jensen D. Miura H. 《Experimental Mechanics》2021,61(5):817-828
Experimental Mechanics - The internal strain distribution developing during plastic deformation is important for understanding the mechanical properties of polycrystalline materials. Such... 相似文献
6.
Laguel Yassine Pillutla Krishna Malick Jérôme Harchaoui Zaid 《Set-Valued and Variational Analysis》2021,29(4):967-996
Set-Valued and Variational Analysis - R. Tyrell Rockafellar and his collaborators introduced, in a series of works, new regression modeling methods based on the notion of superquantile (or... 相似文献
7.
8.
Li Y. Shi W. H. Dong L. M. Xu S. X. Huang H. J. Yin J. R. 《Journal of Applied Spectroscopy》2022,89(3):534-541
Journal of Applied Spectroscopy - Sr3B2O6:Dy3+, Eu3+ single-matrix white-light-emitting materials are prepared using the high-temperature solid-state method. The microstructure, emission spectrum,... 相似文献
9.
10.
Restricted testing conditions were considered recently. For the maximal operator, Hytönen, Li and Sawyer [8] first obtained parental testing condition. Later, they [9] showed that it suffices to restrict testing to doubling cubes. Chen and Lacey [3] gave a similar restricted testing condition. In our paper, we discuss a version of the latter in the multilinear setting.
相似文献