全文获取类型
收费全文 | 758994篇 |
免费 | 8510篇 |
国内免费 | 2345篇 |
专业分类
化学 | 394901篇 |
晶体学 | 11082篇 |
力学 | 34998篇 |
综合类 | 18篇 |
数学 | 105242篇 |
物理学 | 223608篇 |
出版年
2020年 | 5222篇 |
2019年 | 5684篇 |
2018年 | 13298篇 |
2017年 | 13811篇 |
2016年 | 13970篇 |
2015年 | 8265篇 |
2014年 | 11239篇 |
2013年 | 31006篇 |
2012年 | 26113篇 |
2011年 | 37110篇 |
2010年 | 23993篇 |
2009年 | 23673篇 |
2008年 | 33240篇 |
2007年 | 35948篇 |
2006年 | 24850篇 |
2005年 | 27466篇 |
2004年 | 22871篇 |
2003年 | 20592篇 |
2002年 | 18819篇 |
2001年 | 19382篇 |
2000年 | 15148篇 |
1999年 | 11932篇 |
1998年 | 10072篇 |
1997年 | 9805篇 |
1996年 | 9745篇 |
1995年 | 8862篇 |
1994年 | 8748篇 |
1993年 | 8354篇 |
1992年 | 9274篇 |
1991年 | 9186篇 |
1990年 | 8786篇 |
1989年 | 8551篇 |
1988年 | 8805篇 |
1987年 | 8482篇 |
1986年 | 8103篇 |
1985年 | 11196篇 |
1984年 | 11671篇 |
1983年 | 9638篇 |
1982年 | 10303篇 |
1981年 | 10152篇 |
1980年 | 9926篇 |
1979年 | 9991篇 |
1978年 | 10393篇 |
1977年 | 10241篇 |
1976年 | 10347篇 |
1975年 | 9739篇 |
1974年 | 9681篇 |
1973年 | 10206篇 |
1972年 | 6594篇 |
1971年 | 5193篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
Knyazev Yu. V. Kazak N. V. Gavrichkov V. A. Polukeev S. I. Ovchinnikov S. G. 《JETP Letters》2022,116(8):567-573
JETP Letters - Changes in the magnetic properties of FeBO3 single crystals in the course of spin crossover occurring with increasing pressure up to 63 GPa are studied both experimentally and... 相似文献
22.
Chemistry of Heterocyclic Compounds - 2-Imino-2,5-dihydrofurans are a highly valuable class of heterocyclic compounds that show versatile biological activity and are used in diverse fields of... 相似文献
23.
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
24.
Siberian Mathematical Journal - Let $ \{(A_{i},B_{i})\}_{i=1}^{m} $ be a set pair system. Füredi, Gyárfás, and Király called it $ 1 $ -cross intersecting if $... 相似文献
25.
Edward G. Sheetz Zhao Zhang Alyssa Marogil Minwei Che Dr. Maren Pink Dr. Veronica Carta Prof. Dr. Krishnan Raghavachari Prof. Dr. Amar H. Flood 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(60):e202201584
The recognition of boron compounds is well developed as boronic acids but untapped as organotrifluoroborate anions (R−BF3−). We are exploring the development of these and other designer anions as anion-recognition motifs by considering them as substituted versions of the parent inorganic ion. To this end, we demonstrate strong and reliable binding of organic trifluoroborates, R−BF3−, by cyanostar macrocycles that are size-complementary to the inorganic BF4− progenitors. We find that recognition is modulated by the substituent's sterics and that the affinities are retained using the common K+ salts of R−BF3− anions. 相似文献
26.
27.
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
28.
Verdecho María-José Alarcón-Valero Faustino Pérez-Perales David Alfaro-Saiz Juan-José Rodríguez-Rodríguez Raúl 《Central European Journal of Operations Research》2021,29(4):1231-1251
Central European Journal of Operations Research - Sustainability practice within supply chains remains in an early development phase. Enterprises still need tools that support the integration of... 相似文献
29.
30.
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