全文获取类型
收费全文 | 529321篇 |
免费 | 4680篇 |
国内免费 | 1284篇 |
专业分类
化学 | 269916篇 |
晶体学 | 7650篇 |
力学 | 26042篇 |
综合类 | 17篇 |
数学 | 67831篇 |
物理学 | 163829篇 |
出版年
2021年 | 5072篇 |
2020年 | 5507篇 |
2019年 | 6245篇 |
2018年 | 8432篇 |
2017年 | 8574篇 |
2016年 | 11659篇 |
2015年 | 6211篇 |
2014年 | 10491篇 |
2013年 | 23576篇 |
2012年 | 18422篇 |
2011年 | 21880篇 |
2010年 | 16480篇 |
2009年 | 16335篇 |
2008年 | 20733篇 |
2007年 | 20582篇 |
2006年 | 18678篇 |
2005年 | 16680篇 |
2004年 | 15522篇 |
2003年 | 13998篇 |
2002年 | 13896篇 |
2001年 | 14756篇 |
2000年 | 11368篇 |
1999年 | 8766篇 |
1998年 | 7609篇 |
1997年 | 7476篇 |
1996年 | 6939篇 |
1995年 | 6266篇 |
1994年 | 6270篇 |
1993年 | 6025篇 |
1992年 | 6381篇 |
1991年 | 6866篇 |
1990年 | 6580篇 |
1989年 | 6490篇 |
1988年 | 6324篇 |
1987年 | 6134篇 |
1986年 | 5873篇 |
1985年 | 7413篇 |
1984年 | 7771篇 |
1983年 | 6533篇 |
1982年 | 6817篇 |
1981年 | 6326篇 |
1980年 | 6004篇 |
1979年 | 6505篇 |
1978年 | 6741篇 |
1977年 | 6629篇 |
1976年 | 6586篇 |
1975年 | 6302篇 |
1974年 | 6129篇 |
1973年 | 6424篇 |
1972年 | 4706篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Kang Il Yoo Ji Yeong Jeon Su Jeong Ryu Giri Nam Hyewon Youn Eun Young Choi 《Experimental & molecular medicine》2015,47(2):e140
In allogeneic transplantation, including the B6 anti-BALB.B settings, H60 and H4 are two representative dominant minor histocompatibility antigens that induce strong CD8 T-cell responses. With different distribution patterns, H60 expression is restricted to hematopoietic cells, whereas H4 is ubiquitously expressed. H60-specific CD8 T-cell response has been known to be dominant in most cases of B6 anti-BALB.B allo-responses, except in the case of skin transplantation. To understand the mechanism underlying the subdominance of H60 during allogeneic skin transplantation, we investigated the dynamics of the H60-specific CD8 T cells in B6 mice transplanted with allogeneic BALB.B tail skin. Unexpectedly, longitudinal bioluminescence imaging and flow cytometric analyses revealed that H60-specific CD8 T cells were not always subdominant to H4-specific cells but instead showed a brief dominance before the H4 response became predominant. H60-specific CD8 T cells could expand in the draining lymph node and migrate to the BALB.B allografts, indicating their active participation in the anti-BALB.B allo-response. Enhancing the frequencies of H60-reactive CD8 T cells prior to skin transplantation reversed the immune hierarchy between H60 and H4. Additionally, H60 became predominant when antigen presentation was limited to the direct pathway. However, when antigen presentation was restricted to the indirect pathway, the expansion of H60-specific CD8 T cells was limited, whereas H4-specific CD8 T cells expanded significantly, suggesting that the temporary immunodominance and eventual subdominance of H60 could be due to their reliance on the direct antigen presentation pathway. These results enhance our understanding of the immunodominance phenomenon following allogeneic tissue transplantation. 相似文献
5.
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
6.
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
7.
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
8.
9.
Dr. Sabin Llona‐Minguez Dr. Matthieu Desroses Artin Ghassemian Dr. Sylvain A. Jacques Dr. Lars Eriksson Rebecka Isacksson Tobias Koolmeister Dr. Pål Stenmark Dr. Martin Scobie Prof. Thomas Helleday 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(20):7394-7398
A two‐step synthesis of structurally diverse pyrrole‐containing bicyclic systems is reported. ortho‐Nitro‐haloarenes coupled with vinylic N‐methyliminodiacetic acid (MIDA) boronates generate ortho‐vinyl‐nitroarenes, which undergo a “metal‐free” nitrene insertion, resulting in a new pyrrole ring. This novel synthetic approach has a wide substrate tolerance and it is applicable in the preparation of more complex “drug‐like” molecules. Interestingly, an ortho‐nitro‐allylarene derivative furnished a cyclic β‐aminophosphonate motif. 相似文献
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