全文获取类型
收费全文 | 265篇 |
免费 | 9篇 |
国内免费 | 1篇 |
专业分类
化学 | 239篇 |
晶体学 | 1篇 |
力学 | 5篇 |
数学 | 3篇 |
物理学 | 27篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 5篇 |
2015年 | 3篇 |
2014年 | 6篇 |
2013年 | 16篇 |
2012年 | 12篇 |
2011年 | 13篇 |
2010年 | 6篇 |
2009年 | 11篇 |
2008年 | 11篇 |
2007年 | 13篇 |
2006年 | 14篇 |
2005年 | 10篇 |
2004年 | 10篇 |
2003年 | 13篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 7篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 7篇 |
1987年 | 1篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1984年 | 8篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 7篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 7篇 |
1972年 | 1篇 |
排序方式: 共有275条查询结果,搜索用时 406 毫秒
101.
Hiromichi Egami Taiki Rouno Tomoki Niwa Kousuke Masuda Kenji Yamashita Yoshitaka Hamashima 《Angewandte Chemie (International ed. in English)》2020,59(33):14101-14105
A linked dicarboxylate phase‐transfer catalyst enables smooth asymmetric dearomative fluorination of 2‐naphthols with Selectfluor under mild conditions to give the corresponding 1‐fluoronaphthalenone derivatives in a highly enantioselective manner. This reaction, which is compatible with a range of functional groups, is the first example of catalytic asymmetric fluorination of 2‐naphthols, and is expected to be useful in the synthesis of bioactive molecules. 相似文献
102.
103.
Tomoaki Hino Zhijun Yang Hirofumi Takeuchi Toshiyuki Niwa Toshiyuki Tanaka Yoshiaki Kawashima Hiroyuki Kojima 《Journal of colloid and interface science》1993,160(2)
Baicalein is the flavonoid contained in the root of Scutellaria baicalensis Georgi. X-ray diffraction patterns of the dried baicalein-intermixed phosphatidylcholine films and 1H NMR spectra in d6-acetone solutions were investigated to clarify the interaction of the flavonoid and phosphatidylcholine molecules in the liposomal membranes. It was found that baicalein molecules were entrapped in liposomal membranes by hydrogen bonding of the polar headgroups of phosphatidylcholine molecules with C5- and C6-hydroxyl groups of baicalein. 相似文献
104.
105.
Masatake Niwa Shigeki Ogiso Tetsuzi Endo Hideyuki Furukawa Shosuke Yamamura 《Tetrahedron letters》1980,21(46):4481-4482
Citreopyrone isolated from the mycelium of B. has been found to be 5-crotonoyl-4-methoxy-6-methyl-2-pyrone. This is the first naturally occurring pyrone with an acyl group at C5-position. 相似文献
106.
Hideo Kigoshi Yoshikazu Shizuri Haruki Niwa Kiyoyuki Yamada 《Tetrahedron letters》1981,22(47):4729-4732
Structural elucidation of two new acetylenic polyenes, laurencenyne and neolaurencenyne isolated from , together with their syntheses, was achieved, suggesting that laurencenyne was a possible precursor of various nonterpenoid C15-compounds in the marine red algae of the genus . 相似文献
107.
ABSTRACTWe report a single-shot nanosecond time-resolved dispersive XAFS measurement of copper foil under laser-induced shock compression. Obtained EXAFS results indicated clearly the structural evolution, though XANES spectra showed that the laser irradiation does not affect the copper electronic state. The nearest (ca. 0.22 nm) and longer (ca. 0.44 nm) Cu–Cu distances are changed at 4 and 200 ns, respectively, in the radial structure functions (RSFs). It was revealed that an average compression of 2% occurs at 4 ns and is released within 200?ns. It was found that the fragmentation of the copper begins at around 200 ns according to the increase in distance of the RSF. 相似文献
108.
Kato D Sekioka N Ueda A Kurita R Hirono S Suzuki K Niwa O 《Journal of the American Chemical Society》2008,130(12):3716-3717
We describe the quantitative nonlabel electrochemical detection of both cytosine (C) and methylcytosine (mC) in oligonucleotides using newly developed nanocarbon film electrodes. The film consists of nanocrystalline sp2 and sp3 mixed bonds formed by employing the electron cyclotron resonance (ECR) sputtering method. We successfully used this film to develop a simple electrochemical DNA methylation analysis technique based on the measurement of the differences between the oxidation currents of C and mC since our ECR nanocarbon film electrode can directly measure all DNA bases more quantitatively than conventional glassy carbon or boron-doped diamond electrodes. The excellent properties of ECR nanocarbon film electrodes result from the fact that they have a wide potential window while maintaining the high electrode activity needed to oxidize oligonucleotides electrochemically. Proof-of-concept experiments were performed with synthetic oligonucleotides including different numbers of C and mC. This film allowed us to perform both C- and mC-positive assays solely by using the electrochemical oxidation of oligonucleotides without bisulfite or labeling processes. 相似文献
109.
Aki Honda Hirokazu Komatsu Dai Kato Akio Ueda Kenichi Maruyama Yuzuru Iwasaki Takeshi Ito Osamu Niwa Koji Suzuki 《Analytical sciences》2008,24(1):55-66
A cellular analyzing system including a "real-time cellular imaging system" and a "comprehensive analyzing system for cellular responses" was developed. A "real-time cellular imaging system" is a system used to measure real-time imaging of multiple phenomena of a single cell with high special and temporal resolutions for the purpose to understand the pathology and physiology in a single cell and realize to single cell level diagnosis. A "real-time cellular imaging system" includes multi-probe imaging with AFM (atomic force microscopy), optical and SECM (scanning electrochemical microscopy) modes, which provides us with topological information and biochemical reactions at the local area of the interior and exterior of a cell. Scanning electrochemical/optical microscopy was applied to image PC12 cells. On the other hand, cells respond to their specific substances via their ligands. Therefore, the comprehensive analysis of protein-protein interaction is the important issue to determine the functions of cells. For this purpose, a "comprehensive analysis system for cellular responses" was developed. This system is based on SPR (surface plasmon resonance) and MS (mass spectrometry) using a nano-fabricated substrate. The interaction between IL-1 beta and anti-IL-1 beta antibodies was detected. 相似文献
110.
This paper reports results obtained when comparing an electrochemical enzyme immunosensor and a surface plasmon resonance (SPR) based immunosensor on the same gold surface installed in an electrochemical SPR flow cell. Simultaneous electrochemical and SPR measurements were performed on a gold surface modified with multilayers of poly‐L ‐lysine and poly‐styrenesulfonate assembled with the layer‐by‐layer method. First, we obtained the SPR response induced by the formation of an immunocomplex from the shift in the SPR angle by injecting an anti tumor necrosis factor‐α antibody solution labeled with alkaline phosphatase into the flow cell containing the multilayer modified with tumor necrosis factor‐α. Then we compared this SPR result with that obtained for the electrochemical oxidation current of p‐aminophenol catalyzed by alkaline phosphatase from p‐aminophenolphosphate on the same gold film. We compared the two immunosensor responses obtained using the different measurement principles and found that there was a high correlation efficient of 0.973 between them. This was because we were able to immobilize the immunoreagents with good stability and without losing the transport of the enzyme product in the multilayer whose thickness we easily controlled with nanometer scale accuracy. We also report that the detection limit of our electrochemical immunosensor after optimization was around 100 pg/mL (0.4 pM), which is one of the lowest values yet reported for an electrochemical immunosensor. 相似文献