全文获取类型
收费全文 | 5442篇 |
免费 | 167篇 |
国内免费 | 16篇 |
专业分类
化学 | 3641篇 |
晶体学 | 19篇 |
力学 | 142篇 |
数学 | 1050篇 |
物理学 | 773篇 |
出版年
2021年 | 50篇 |
2020年 | 66篇 |
2019年 | 75篇 |
2018年 | 42篇 |
2017年 | 40篇 |
2016年 | 112篇 |
2015年 | 118篇 |
2014年 | 132篇 |
2013年 | 230篇 |
2012年 | 222篇 |
2011年 | 283篇 |
2010年 | 151篇 |
2009年 | 134篇 |
2008年 | 235篇 |
2007年 | 225篇 |
2006年 | 201篇 |
2005年 | 200篇 |
2004年 | 189篇 |
2003年 | 128篇 |
2002年 | 144篇 |
2001年 | 86篇 |
2000年 | 90篇 |
1999年 | 101篇 |
1998年 | 76篇 |
1997年 | 83篇 |
1996年 | 66篇 |
1995年 | 60篇 |
1994年 | 69篇 |
1993年 | 63篇 |
1992年 | 53篇 |
1991年 | 47篇 |
1990年 | 45篇 |
1989年 | 47篇 |
1988年 | 54篇 |
1987年 | 60篇 |
1986年 | 68篇 |
1985年 | 93篇 |
1984年 | 81篇 |
1983年 | 63篇 |
1982年 | 69篇 |
1981年 | 62篇 |
1980年 | 75篇 |
1979年 | 71篇 |
1978年 | 51篇 |
1977年 | 73篇 |
1976年 | 55篇 |
1975年 | 36篇 |
1974年 | 35篇 |
1972年 | 33篇 |
1971年 | 36篇 |
排序方式: 共有5625条查询结果,搜索用时 15 毫秒
1.
Dr. Jun Zeng Dr. Zhichao Wang Dr. Xin Huang Dr. Sabine S. Eckstein Prof. Dr. Xiaohui Lin Prof. Dr. Hailong Piao Prof. Dr. Cora Weigert Dr. Peiyuan Yin Prof. Dr. Rainer Lehmann Prof. Dr. Guowang Xu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(21):5427-5432
Mass spectrometry (MS) driven metabolomics is a frequently used tool in various areas of life sciences; however, the analysis of polar metabolites is less commonly included. In general, metabolomic analyses lead to the detection of the total amount of all covered metabolites. This is currently a major limitation with respect to metabolites showing high turnover rates, but no changes in their concentration. Such metabolites and pathways could be crucial metabolic nodes (e.g., potential drug targets in cancer metabolism). A stable-isotope tracing capillary electrophoresis–mass spectrometry (CE-MS) metabolomic approach was developed to cover both polar metabolites and isotopologues in a non-targeted way. An in-house developed software enables high throughput processing of complex multidimensional data. The practicability is demonstrated analyzing [U-13C]-glucose exposed prostate cancer and non-cancer cells. This CE-MS-driven analytical strategy complements polar metabolite profiles through isotopologue labeling patterns, thereby improving not only the metabolomic coverage, but also the understanding of metabolism. 相似文献
2.
3.
4.
Kinetics and Catalysis - Boron and barium were employed as dopants for the VMgO system. The catalysts were characterized by ICP-OES, BET, IR, powder XRD, EDX, TPR-H2, TPD-NH3, XPS, and 51V MAS NMR.... 相似文献
5.
Rainer Löwen 《Journal of Geometry》1989,36(1-2):110-116
We prove that a spread S over a locally compact nondlscrete field F defines a topological translation plane if and only if the spread is compact. For F=R, this is implicit in Breuning's thesis [Bre], cf. [B 2]. For the proof, we describe the point set of the projective translation plane as a quotient space of some projective space, with identifications taking place in one hyperplane. This is new even for F=R. 相似文献
6.
We relate the Schramm–Loewner Evolution processes (SLE) to highest-weight representations of the Virasoro Algebra. The restriction properties of SLE that have been recently derived in [19] play a crucial role. In this setup, various considerations from conformal field theory can be interpreted and reformulated via SLE. This enables one to make a concrete link between the two-dimensional discrete critical systems from statistical physics and conformal field theory. To cite this article: R. Friedrich, W. Werner, C. R. Acad. Sci. Paris, Ser. I 335 (2002) 947–952. 相似文献
7.
8.
Johannes Elschner Rainer Hinder Gunther Schmidt 《Advances in Computational Mathematics》2002,16(2-3):139-156
This paper is devoted to the numerical study of diffraction by periodic structures of plane waves under oblique incidence. For this situation Maxwell's equations can be reduced to a system of two Helmholtz equations in R
2 coupled via quasiperiodic transmission conditions on the piecewise smooth interfaces between different materials. The numerical analysis is based on a strongly elliptic variational formulation of the differential problem in a bounded periodic cell involving nonlocal boundary operators. We obtain existence and uniqueness results for discrete solutions and provide the corresponding error analysis. 相似文献
9.
Ohne Zusammenfassung 相似文献
10.
Christian J. -F. Dupraz Patrick Nickels Udo Beierlein Wendy U. Huynh Friedrich C. Simmel 《Superlattices and Microstructures》2003,33(5-6):369
This paper provides an overview of recent research developments in the field of nanoelectronics with organic materials such as carbon nanotubes and DNA-templated nanowires. Carbon nanotubes and gold electrodes are chemically functionalized in order to contact carbon nanotubes by self-assembly. The transport properties of these nanotubes are dominated by charging effects and display clear Coulomb blockade behaviour. A different approach towards nanoscale electronics is based on the molecular recognition properties of biomolecules such as DNA. As an example, DNA is stretched between electrodes using a molecular combing technique. A two-step metallization procedure leads to the formation of highly conductive gold nanowires. 相似文献