全文获取类型
收费全文 | 282972篇 |
免费 | 19667篇 |
国内免费 | 924篇 |
专业分类
化学 | 182358篇 |
晶体学 | 3729篇 |
力学 | 11714篇 |
综合类 | 2篇 |
数学 | 29585篇 |
物理学 | 76175篇 |
出版年
2023年 | 4304篇 |
2021年 | 3898篇 |
2020年 | 6097篇 |
2019年 | 4220篇 |
2018年 | 4615篇 |
2017年 | 2960篇 |
2016年 | 9040篇 |
2015年 | 7733篇 |
2014年 | 8498篇 |
2013年 | 15924篇 |
2012年 | 11068篇 |
2011年 | 11012篇 |
2010年 | 9745篇 |
2009年 | 9627篇 |
2008年 | 9959篇 |
2007年 | 9860篇 |
2006年 | 8501篇 |
2005年 | 7926篇 |
2004年 | 7066篇 |
2003年 | 6266篇 |
2002年 | 6186篇 |
2001年 | 7237篇 |
2000年 | 5383篇 |
1999年 | 4246篇 |
1998年 | 3571篇 |
1997年 | 3654篇 |
1996年 | 3363篇 |
1995年 | 3257篇 |
1994年 | 3015篇 |
1993年 | 3194篇 |
1992年 | 3386篇 |
1991年 | 3389篇 |
1990年 | 3192篇 |
1989年 | 3167篇 |
1988年 | 3266篇 |
1987年 | 3120篇 |
1986年 | 2996篇 |
1985年 | 4072篇 |
1984年 | 4240篇 |
1983年 | 3489篇 |
1982年 | 3867篇 |
1981年 | 3786篇 |
1980年 | 3690篇 |
1979年 | 3722篇 |
1978年 | 3951篇 |
1977年 | 3889篇 |
1976年 | 4148篇 |
1975年 | 3813篇 |
1974年 | 3939篇 |
1973年 | 4087篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Bazarra Noelia Castejón Alberto Fernández José R. Quintanilla Ramón 《Meccanica》2021,56(12):3025-3037
Meccanica - In this work we study, from the numerical point of view, a one-dimensional thermoelastic problem where the thermal law is of type III. Quasi-static microvoids are also assumed within... 相似文献
12.
Aequationes mathematicae - In this paper, we establish a new class of dynamic inequalities of Hardy’s type which generalize and improve some recent results given in the literature. More... 相似文献
13.
Yuki Shintani Taku Ohtomi Dr. Aya Shibata Dr. Yoshiaki Kitamura Koichiro M. Hirosawa Prof. Kenichi G. N. Suzuki Prof. Masato Ikeda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(8):e202104421
Aqueous self-assembly of short peptides has attracted growing attention for the construction of supramolecular materials for various bioapplications. Herein, we describe how the thermolysin-assisted biocatalytic construction of a dipeptide hydrazide from an N-protected amino acid and an amino acid hydrazide leads to the formation of thermally stable supramolecular hydrogels. In addition, we demonstrate the post-assembly modification of the supramolecular architectures constructed in situ tethering hydrazide groups as a chemical handle by means of fluorescence imaging. 相似文献
14.
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
15.
Prof. Dr. Peter Hess 《Chemphyschem》2022,23(6):e202100880
In the periodic table the position of each atom follows the ‘aufbau’ principle of the individual electron shells. The resulting intrinsic periodicity of atomic properties determines the overall behavior of atoms in two-dimensional (2D) bonding and structure formation. Insight into the type and strength of bonding is the key in the discovery of innovative 2D materials. The primary features of 2D bonding and the ensuing monolayer structures of the main-group II–VI elements result from the number of valence electrons and the change of atom size, which determine the type of hybridization. The results reveal the tight connection between strength of bonding and bond length in 2D networks. The predictive power of the periodic table reveals general rules of bonding, the bonding-structure relationship, and allows an assessment of published data of 2D materials. 相似文献
16.
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
17.
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
18.
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
19.
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
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