全文获取类型
收费全文 | 1439篇 |
免费 | 32篇 |
国内免费 | 7篇 |
专业分类
化学 | 1026篇 |
晶体学 | 13篇 |
力学 | 21篇 |
数学 | 97篇 |
物理学 | 238篇 |
无线电 | 83篇 |
出版年
2023年 | 9篇 |
2022年 | 19篇 |
2021年 | 11篇 |
2020年 | 11篇 |
2019年 | 20篇 |
2018年 | 13篇 |
2017年 | 11篇 |
2016年 | 20篇 |
2015年 | 21篇 |
2014年 | 27篇 |
2013年 | 77篇 |
2012年 | 77篇 |
2011年 | 74篇 |
2010年 | 48篇 |
2009年 | 37篇 |
2008年 | 79篇 |
2007年 | 107篇 |
2006年 | 95篇 |
2005年 | 92篇 |
2004年 | 74篇 |
2003年 | 79篇 |
2002年 | 66篇 |
2001年 | 26篇 |
2000年 | 28篇 |
1999年 | 24篇 |
1998年 | 16篇 |
1997年 | 21篇 |
1996年 | 21篇 |
1995年 | 11篇 |
1994年 | 17篇 |
1993年 | 12篇 |
1992年 | 11篇 |
1991年 | 10篇 |
1990年 | 6篇 |
1989年 | 10篇 |
1988年 | 8篇 |
1986年 | 9篇 |
1985年 | 17篇 |
1984年 | 30篇 |
1983年 | 14篇 |
1982年 | 18篇 |
1981年 | 23篇 |
1980年 | 16篇 |
1979年 | 14篇 |
1978年 | 7篇 |
1977年 | 8篇 |
1976年 | 6篇 |
1975年 | 5篇 |
1973年 | 4篇 |
1970年 | 4篇 |
排序方式: 共有1478条查询结果,搜索用时 15 毫秒
81.
Application of plug–plug technique to ACE experiments for discovery of peptides binding to a larger target protein: A model study of calmodulin‐binding fragments selected from a digested mixture of reduced BSA
下载免费PDF全文
![点击此处可从《Electrophoresis》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Kazuki Saito Mamiko Nakato Takaaki Mizuguchi Shinji Wada Hiromasa Uchimura Hiroshi Kataoka Shigeyuki Yokoyama Hiroshi Hirota Yoshiaki Kiso 《Electrophoresis》2014,35(6):846-854
To discover peptide ligands that bind to a target protein with a higher molecular mass, a concise screening methodology has been established, by applying a “plug–plug” technique to ACE experiments. Exploratory experiments using three mixed peptides, mastoparan‐X, β‐endorphin, and oxytocin, as candidates for calmodulin‐binding ligands, revealed that the technique not only reduces the consumption of the protein sample, but also increases the flexibility of the experimental conditions, by allowing the use of MS detection in the ACE experiments. With the plug–plug technique, the ACE–MS screening methodology successfully selected calmodulin‐binding peptides from a random library with diverse constituents, such as protease digests of BSA. Three peptides with Kd values between 8–147 μM for calmodulin were obtained from a Glu‐C endoprotease digest of reduced BSA, although the digest showed more than 70 peaks in its ACE–MS electropherogram. The method established here will be quite useful for the screening of peptide ligands, which have only low affinities due to their flexible chain structures but could potentially provide primary information for designing inhibitors against the target protein. 相似文献
82.
83.
Shimoda K Tobu Y Shimoikeda Y Nemoto T Saito K 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2007,186(1):156-159
We here show the (43)Ca 5QMAS NMR spectra at high field (16.4 T) and the first 7QMAS spectrum at ultra-high field (21.8 T) for geologically important Ca-containing glasses. The high-resolution MQMAS spectra present a clear evidence of multiple Ca sites in the amorphous structures that have never been identified by other analytical methods. The present study suggests that the Ca(2+) ions are mainly in 7- and 8-fold coordination sites. This will offer valuable insights for dynamic properties of magmatic liquids. The MQMAS NMR technique at high magnetic field is a unique tool to understand the detailed structural information on a specific element in solids including organic and inorganic compounds. 相似文献
84.
Visible‐Light‐Mediated Addition of α‐Aminoalkyl Radicals to [60]Fullerene by Using Photoredox Catalysts
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Yoshihiro Miyake Yuya Ashida Dr. Kazunari Nakajima Prof. Dr. Yoshiaki Nishibayashi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(20):6120-6125
The functionalization of fullerene has been extensively studied and various fullerene derivatives have been synthesized. We have succeeded in the functionalization of [60]fullerene by using α‐aminoalkyl radicals generated by visible‐light‐mediated single‐electron oxidation of α‐silylamines as synthetic intermediates. In these reactions, the introduction of diarylamino groups, which are useful electron donors, has been easily achieved. 相似文献
85.
Ryota Kudo Masahiro Sonobe Yoshiaki Chino Yu Kitazawa Mutsumi Kimura 《Molecules (Basel, Switzerland)》2020,25(23)
The synthesis and characterization of two phthalocyanine (Pc) structural isomers, 1 and 2, in which four 2,6-di(hexyloxy)phenyl units were attached directly to the 1,8,15,22- or 1,4,15,18-positions of the Pc rings, are described. Both Pcs 1 and 2 exhibited low melting points, i.e., 120 and 130 °C respectively, due to the reduction in intermolecular π-π interaction among the Pc rings caused by the steric hindrance of 2,6-dihexyloxybenzene units. The thermal behaviors were investigated with temperature-controlled polarizing optical microscopy, differential scanning calorimetry, powder X-ray diffraction, and absorption spectral analyses. Pc 1, having C4h molecular symmetry, organized into a lamellar structure containing lateral assemblies of Pc rings. In contrast, the other Pc 2 revealed the formation of metastable crystalline phases, including disordered stacks of Pcs due to rapid cooling from a melted liquid. 相似文献
86.
87.
Atsuya Muranaka Yoshiaki Asano Akihiko Tsuda Atsuhiro Osuka Nagao Kobayashi 《Chemphyschem》2006,7(6):1235-1240
The electronic excited states of a meso-meso beta-beta doubly linked bis-porphyrin are comprehensively investigated by measuring its circular dichroism (CD) and magnetic circular dichroism (MCD) spectra. The observed spectroscopic properties are rationalized by DFT calculations. The frontier molecular orbitals (MOs) are constructed by the linear combinations of the constituent monomers' four MOs. Comparison of a theoretical CD spectrum based on time-dependent DFT (TDDFT) with the experimental spectra resulted in the assignment of the helical conformation of the dimer. This assignment is contrary to the previous assignment based on the point-dipole approximation (exciton coupling theory). 相似文献
88.
Koji Nemoto 《Tetrahedron letters》2009,50(31):4512-7862
The Lewis acid-mediated carboxylation of arenes with CO2 has been successfully applied to 1-substituted indoles and pyrroles by using dialkylaluminum chlorides instead of aluminum trihalides. Thus, the carboxylation of 1-methylindoles, 1-benzyl-, and 1-phenylpyrroles proceeds regioselectively with the aid of an equimolar amount of Me2AlCl under CO2 pressure (3.0 MPa) at room temperature to afford the corresponding indole-3-carboxylic acids and pyrrole-2-carboxylic acids in 61-85% yields, while the same treatment of 1,2,5-trimethylpyrrole affords the 3-carboxylic acid in 52% yield. 相似文献
89.
In our previous paper Ohkuwa et al. (2016) corrigendum was found in Eqs. (3.4) and (3.6). However, conclusions of our previous paper are not changed. 相似文献