全文获取类型
收费全文 | 1805篇 |
免费 | 40篇 |
国内免费 | 3篇 |
专业分类
化学 | 1289篇 |
晶体学 | 3篇 |
力学 | 58篇 |
数学 | 245篇 |
物理学 | 253篇 |
出版年
2021年 | 11篇 |
2020年 | 26篇 |
2019年 | 19篇 |
2018年 | 16篇 |
2017年 | 16篇 |
2016年 | 35篇 |
2015年 | 27篇 |
2014年 | 30篇 |
2013年 | 50篇 |
2012年 | 89篇 |
2011年 | 86篇 |
2010年 | 47篇 |
2009年 | 50篇 |
2008年 | 64篇 |
2007年 | 66篇 |
2006年 | 60篇 |
2005年 | 62篇 |
2004年 | 63篇 |
2003年 | 45篇 |
2002年 | 41篇 |
2001年 | 26篇 |
2000年 | 27篇 |
1999年 | 20篇 |
1998年 | 17篇 |
1997年 | 22篇 |
1996年 | 26篇 |
1995年 | 27篇 |
1994年 | 25篇 |
1993年 | 12篇 |
1992年 | 22篇 |
1991年 | 22篇 |
1990年 | 14篇 |
1989年 | 12篇 |
1988年 | 11篇 |
1987年 | 18篇 |
1986年 | 9篇 |
1985年 | 16篇 |
1984年 | 14篇 |
1982年 | 12篇 |
1980年 | 10篇 |
1979年 | 18篇 |
1978年 | 13篇 |
1977年 | 13篇 |
1976年 | 14篇 |
1975年 | 16篇 |
1974年 | 22篇 |
1973年 | 8篇 |
1972年 | 11篇 |
1968年 | 290篇 |
1967年 | 89篇 |
排序方式: 共有1848条查询结果,搜索用时 15 毫秒
71.
Schulte RF Henning A Tsao J Boesiger P Pruessmann KP 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2007,186(2):167-175
The achievable bandwidth of common linear-phase RF pulses is limited by the maximum feasible B1 amplitude of the MR system. It has been shown previously, that this limitation can be circumvented by overlaying a quadratic phase in the frequency domain, which spreads the power across the pulse duration. Quadratic-phase RF pulses are near optimal in terms of achieving minimal B1max. In this work, it is demonstrated that further B1max reduction can be achieved by combining quadratic with higher-order polynomial-phase functions. RF pulses with a phase response up to tenth order were designed using the Shinnar-Le Roux transformation, yielding considerable increases in bandwidth and selectivity as compared to pure quadratic-phase pulses. These benefits are studied for a range of pulse specifications and demonstrated experimentally. For B1max = 20 microT and a pulse duration of 2.1 ms, it was possible to increase the bandwidth from 3.1 kHz for linear and 3.8 kHz for a quadratic to 9.9 kHz for a polynomial-phase pulse. 相似文献
72.
Click‐Tag and Amine‐Tag: Chemical Tag Approaches for Efficient Protein Labeling In Vitro and on Live Cells using the Naturally Split Npu DnaE Intein
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Vivien Schütz Prof. Dr. Henning D. Mootz 《Angewandte Chemie (International ed. in English)》2014,53(16):4113-4117
Protein labeling with synthetic moieties remains in many cases a technically challenging or unresolved task. Two new and simple concepts are presented. In both approaches, a very short tag of only a few amino acids is prepared with the desired chemical modification and, in a second step, it is transferred to the protein of interest by protein trans‐splicing. For the amine‐tag, a recombinant intein fragment free of lysine residues was generated such that the amine group of the N terminus could be selectively modified with regular amine‐reactive reagents. Thus, standard bioconjugation procedures without any chemical synthesis could be applied without modification of lysines in the protein of interest. For the click‐tag, protein trans‐splicing was combined with unnatural amino acid mutagenesis and subsequent bioorthogonal side chain modification, as demonstrated for click chemistry using p‐azidophenylalanine. By the two‐step strategy, exposure of the protein of interest to the copper catalyst was avoided. 相似文献
73.
Benedikt Jedlitzke Zahide Yilmaz Wolfgang Drner Henning D. Mootz 《Angewandte Chemie (International ed. in English)》2020,59(4):1506-1510
Photocaged antibody fragments, termed photobodies, have been developed that are impaired in their antigen‐binding capacity and can be activated by irradiation with UV light (365 nm). This rational design concept builds on the selective photocaging of a single tyrosine in a nanobody (a single‐domain antibody fragment). Tyrosine is a frequently occurring residue in central positions of the paratope region. o‐Nitrobenzyl‐protected tyrosine variants were incorporated into four nanobodies, including examples directed against EGFR and HER2, and photodeprotection restores the native sequence. An anti‐GFP photobody exhibited an at least 10 000‐fold impaired binding affinity before photodeprotection compared with the parent nanobody. A bispecific nanobody–photobody fusion protein was generated to trigger protein heterodimerization by light. Photoactivatable antibodies are expected to become versatile protein reagents and to enable novel approaches in diagnostic and therapeutic applications. 相似文献
74.
75.
76.
77.
In this review on polymer crazing and fatigue three aspects have been treated more explicitely: the molecular rearrangements preceding and provoking craze initiation, the competition between disentanglement and chain scission during lateral craze growth, and the distinct fatigue failure mechanism occurring in cyclically loaded PET and PA fibers. An overview on other aspects is given including references to work in progress. 相似文献
78.
Henning Osholm Srensen Magnus Magnussen Nicolai Stuhr‐Hansen 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(8):o503-o505
The first crystal structure of a three‐terminal sulfur end‐capped oligophenylenevinylene, C36H30O3S3·0.5C7H8, has been determined at 122 (1) K. The molecular threefold symmetry is not utilized in the crystal structure. It is confirmed that the double bonds have been fully transformed into a trans configuration by iodine treatment. 相似文献
79.
80.