全文获取类型
收费全文 | 817708篇 |
免费 | 10212篇 |
国内免费 | 2619篇 |
专业分类
化学 | 438815篇 |
晶体学 | 11791篇 |
力学 | 36854篇 |
综合类 | 26篇 |
数学 | 103723篇 |
物理学 | 239330篇 |
出版年
2021年 | 6031篇 |
2020年 | 6924篇 |
2019年 | 7364篇 |
2018年 | 9215篇 |
2017年 | 8958篇 |
2016年 | 14358篇 |
2015年 | 9547篇 |
2014年 | 14226篇 |
2013年 | 36770篇 |
2012年 | 27715篇 |
2011年 | 34134篇 |
2010年 | 23431篇 |
2009年 | 22983篇 |
2008年 | 31287篇 |
2007年 | 31513篇 |
2006年 | 29574篇 |
2005年 | 26753篇 |
2004年 | 24491篇 |
2003年 | 21866篇 |
2002年 | 21473篇 |
2001年 | 23170篇 |
2000年 | 17999篇 |
1999年 | 14281篇 |
1998年 | 11993篇 |
1997年 | 11669篇 |
1996年 | 11535篇 |
1995年 | 10416篇 |
1994年 | 10314篇 |
1993年 | 9866篇 |
1992年 | 11065篇 |
1991年 | 10942篇 |
1990年 | 10488篇 |
1989年 | 10170篇 |
1988年 | 10389篇 |
1987年 | 10079篇 |
1986年 | 9605篇 |
1985年 | 12909篇 |
1984年 | 13222篇 |
1983年 | 10876篇 |
1982年 | 11341篇 |
1981年 | 11219篇 |
1980年 | 10781篇 |
1979年 | 11188篇 |
1978年 | 11568篇 |
1977年 | 11452篇 |
1976年 | 11415篇 |
1975年 | 10687篇 |
1974年 | 10670篇 |
1973年 | 10957篇 |
1972年 | 7455篇 |
排序方式: 共有10000条查询结果,搜索用时 7 毫秒
1.
2.
3.
Paired single residue‐transposed Lys‐N and Lys‐C digestions for label‐free identification of N‐terminal and C‐terminal MS/MS peptide product ions: ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry and tandem mass spectrometry for peptide de novo sequencing 下载免费PDF全文
4.
The influence of different referencing methods on the accuracy of δ13C value measurement of ethanol fuel by gas chromatography/combustion/isotope ratio mass spectrometry 下载免费PDF全文
5.
ABSTRACTThe Coupled-Cluster (CC) theory is one of the most successful high precision methods used to solve the stationary Schrödinger equation. In this article, we address the mathematical foundation of this theory with focus on the advances made in the past decade. Rather than solely relying on spectral gap assumptions (non-degeneracy of the ground state), we highlight the importance of coercivity assumptions – Gårding type inequalities – for the local uniqueness of the CC solution. Based on local strong monotonicity, different sufficient conditions for a local unique solution are suggested. One of the criteria assumes the relative smallness of the total cluster amplitudes (after possibly removing the single amplitudes) compared to the Gårding constants. In the extended CC theory the Lagrange multipliers are wave function parameters and, by means of the bivariational principle, we here derive a connection between the exact cluster amplitudes and the Lagrange multipliers. This relation might prove useful when determining the quality of a CC solution. Furthermore, the use of an Aubin–Nitsche duality type method in different CC approaches is discussed and contrasted with the bivariational principle. 相似文献
6.
Dr. Yulia Y. Enakieva Dr. Anna A. Sinelshchikova Prof. Mikhail S. Grigoriev Prof. Vladimir V. Chernyshev Dr. Konstantin A. Kovalenko Prof. Irina A. Stenina Prof. Andrey B. Yaroslavtsev Prof. Yulia G. Gorbunova Prof. Aslan Y. Tsivadze 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(45):10552-10556
The design of new solid-state proton-conducting materials is a great challenge for chemistry and materials science. Herein, a new anionic porphyrinylphosphonate-based MOF ( IPCE-1Ni ), which involves dimethylammonium (DMA) cations for charge compensation, is reported. As a result of its unique structure, IPCE-1Ni exhibits one of the highest value of the proton conductivity among reported proton-conducting MOF materials based on porphyrins (1.55×10−3 S cm−1 at 75 °C and 80 % relative humidity). 相似文献
7.
Cavitation erosion is caused in solids exposed to strong pressure waves developing in an adjacent fluid field. The knowledge of the transient distribution of stresses in the solid is important to understand the cause of damaging by comparisons with breaking points of the material. The modeling of this problem requires the coupling of the models for the fluid and the solid. For this purpose, we use a strategy based on the solution of coupled Riemann problems that has been originally developed for the coupling of 2 fluids. This concept is exemplified for the coupling of a linear elastic structure with an ideal gas. The coupling procedure relies on the solution of a nonlinear equation. Existence and uniqueness of the solution is proven. The coupling conditions are validated by means of quasi‐1D problems for which an explicit solution can be determined. For a more realistic scenario, a 2D application is considered where in a compressible single fluid, a hot gas bubble at low pressure collapses in a cold gas at high pressure near an adjacent structure. 相似文献
8.
9.
10.
Knyazev A. A. Karyakin M. E. Krupin A. S. Galyametdinov Yu. G. 《Russian Journal of General Chemistry》2015,85(12):2806-2812
Russian Journal of General Chemistry - Hybrid liquid crystal systems with different ratios of the components have been prepared on the basis of 5,5′-di(heptadecyl)-2,2′-bipyridine... 相似文献