全文获取类型
收费全文 | 570篇 |
免费 | 18篇 |
国内免费 | 1篇 |
专业分类
化学 | 445篇 |
晶体学 | 4篇 |
力学 | 13篇 |
数学 | 55篇 |
物理学 | 72篇 |
出版年
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 15篇 |
2019年 | 9篇 |
2018年 | 4篇 |
2017年 | 7篇 |
2016年 | 9篇 |
2015年 | 9篇 |
2014年 | 13篇 |
2013年 | 25篇 |
2012年 | 33篇 |
2011年 | 33篇 |
2010年 | 16篇 |
2009年 | 23篇 |
2008年 | 43篇 |
2007年 | 38篇 |
2006年 | 38篇 |
2005年 | 27篇 |
2004年 | 27篇 |
2003年 | 14篇 |
2002年 | 27篇 |
2001年 | 7篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 8篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1989年 | 5篇 |
1988年 | 5篇 |
1987年 | 8篇 |
1986年 | 4篇 |
1985年 | 12篇 |
1984年 | 13篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 2篇 |
1979年 | 5篇 |
1978年 | 8篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1974年 | 6篇 |
1973年 | 4篇 |
1968年 | 2篇 |
1964年 | 2篇 |
排序方式: 共有589条查询结果,搜索用时 15 毫秒
31.
Self‐Assembled Fibers Containing Stable Organic Radical Moieties: Alignment and Magnetic Properties in Liquid Crystals
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)
Hiroki Eimura Yoshikazu Umeta Prof. Dr. Hiroko Tokoro Prof. Dr. Masafumi Yoshio Prof. Dr. Shin‐ichi Ohkoshi Prof. Dr. Takashi Kato 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(26):8872-8878
Macroscopically oriented stable organic radicals have been obtained by using a liquid–crystalline (LC) gel composed of an l ‐isoleucine‐based low molecular weight gelator containing a 2,2,6,6‐tetramethylpiperidine 1‐oxyl moiety. The LC gel has allowed magnetic measurements of the oriented organic radical. The gelator has formed fibrous aggregates in liquid crystals via intermolecular hydrogen bonds. The fibrous aggregates of the radical gelator are formed and oriented on cooling by applying a magnetic field to the mixture of liquid crystals and the gelator. Superconducting quantum interference device (SQUID) measurements have revealed that both oriented and nonoriented fibrous aggregates exhibited antiferromagnetic interactions, in which super‐exchange interaction constant J is estimated as ?0.89 cm?1. 相似文献
32.
Naoyuki Toriumi Atsuya Muranaka Daisuke Hashizume Masanobu Uchiyama 《Tetrahedron letters》2017,58(23):2267-2271
Methylene-bridged benziphthalocyanine dimer 2 was unexpectedly generated by the reaction of dihydroxybenziphthalocyanine 1 and formaldehyde in the presence of a catalytic amount of a base at room temperature. Single-crystal X-ray diffraction analysis of 2 revealed a V-shaped structure. Dimer 2 exhibited longer-wavelength absorption and fluorescence bands than monomer 1 in the near-IR region. 相似文献
33.
Sun-Chan Jeong Ichiro Katayama Hirokane Kawakami Yutaka Watanabe Hironobu Ishiyama Nobuaki Imai Yoshikazu Hirayama Hiroari Miyatake Masao Sataka Hiroyuki Sugai Satoru Okayasu Shin-Ichi Ichikawa Katsuhisa Nishio Shinichi Mitsuoka Takamitsu Nakanoya Takashi Hashimoto Takanori Hashimoto Masahito Yahagi 《Solid State Ionics》2009,180(6-8):626-630
The diffusion coefficients of Li in the NaTl-type Li intermetallic compound of β-LiGa have been measured by using a short-lived radioactive diffusion tracer. As the tracer, the α-emitting radioisotope of 8Li delivered as the energetic and pulsed beam from Tokai Radioactive Ion Accelerator Complex (TRIAC) was implanted into the β-LiGa compounds with the composition in the range of about 43 to 54 at.% Li. By analyzing the time-dependent yields of the α-particles measured according to the repetition cycle of the beam, the tracer diffusion coefficients were extracted over the wide range of Li composition. Abnormal composition-dependence of Li diffusion coefficients in β-LiGa was observed; the stoichiometric β-LiGa showed the highest diffusivity of Li. By referring to the composition-dependent diffusivity of Li in the iso-structural β-LiAl and β-LiIn, we could identify the abnormal diffusion of Li in very Li-poor composition of β-LiGa. The anomaly has been discussed qualitatively in terms of the formation of defect complex and the interaction between the constitutional defects. 相似文献
34.
Kô Takehara Takao Fujimori Kei Inagi Mari Kajiwara Yoshikazu Harata Kazuhisa Yoshimura 《Electroanalysis》2013,25(2):387-393
A square‐wave voltammetric method for the determination of boric acid in water has been described based on the new understanding of the electrochemical behavior of boric acid‐Azomethine H complexation. Salicylaldehyde and H‐acid were used as the starting materials of boric acid‐Azomethine H complex and their concentrations were optimized for boric acid determination in water. A glassy carbon electrode, instead of a conventional mercury electrode, was used in the measurement. The detection limit of the proposed method was 0.10 mg B dm?3. The proposed method was successfully used for boric acid determination in the water from a seawater desalination RO plant. 相似文献
35.
Masaru Asari Kumiko Oka Tomohiro Omura Chikatoshi Maseda Yoshikazu Tasaki Hiroshi Shiono Kazuo Matsubara Mitsuyoshi Matsuda Keiko Shimizu 《Electrophoresis》2013,34(3):448-455
Amplification/hybridization‐based genetic analyses using primers containing locked nucleic acids (LNAs) present many benefits. Here, we developed a novel design for universal fluorescent PCR using LNAs. Universal fluorescent PCR generates intermediate nonlabeled fragments and final fluorescent fragments in a two‐step amplification process that uses locus‐specific primers with universal tails and universal fluorescent primers. In this study, a few standard nucleotides were replaced with LNAs only in the fluorescent universal primers. The sequence of the fluorescent universal primer significantly affected the amplification efficiency. For primers with three LNAs, the fluorescent primers with stable M13(‐47) sequences provided the most efficient signal (approximately tenfold higher than the primers with M13(‐21) sequences at lower Tm values). Moreover, AT‐rich LNA substitutions in the fluorescent primers produced much lower amplification efficiencies than GC‐rich substitutions. GC‐rich LNAs produced greater differences in Tm values among primers, and resulted in the preferential production of fluorescently labeled amplicons. The specificity and sensitivity of LNA‐containing fluorescent primers were assessed by genotyping eight STRs in Japanese individuals, and full STR profiles could be generated using as little as 0.25 ng of genomic DNA. The method permitted clear discrimination of alleles and represents sensitive STR genotyping at a reduced cost. 相似文献
36.
Prof. Dr. Hiromitsu Maeda Wataru Hane Dr. Yuya Bando Dr. Yoshitaka Terashima Dr. Yohei Haketa Hiroshi Shibaguchi Prof. Dr. Tsuyoshi Kawai Prof. Dr. Masanobu Naito Dr. Kazuto Takaishi Prof. Dr. Masanobu Uchiyama Dr. Atsuya Muranaka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(48):16263-16271
Anion‐responsive π‐conjugated compounds having chiral alkyl chains were synthesized. Circular dichroism (CD) and circularly polarized luminescence (CPL) were observed in the solution‐state assemblies of the chiral anion receptors and those of their anion complexes as salts of a planar triazatriangulenium cation. The CD and CPL spectral patterns of the ion‐pair‐based assemblies were completely opposite to those of the anion‐free assemblies, and this suggests that anion binding and subsequent ion pairing change the chirality of the assembly modes. 相似文献
37.
38.
Co–Pd bimetallic alloy nanoparticle catalysts were prepared from CoCl2, Pd(OAc)2 and several capping agents with Li(C2H5)3BH. The nanoparticle catalysts were applied to the aerobic oxidation of a variety of alcohols in water to give the corresponding carbonyl products. The catalyst was magnetically recovered and reused for further oxidation. The nanoparticle catalysts were characterized with TEM, ICP, and XPS analyses. 相似文献
39.
Dr. Yoshikazu Ito Dr. Yoichi Tanabe Dr. H.‐J. Qiu Dr. Katsuaki Sugawara Dr. Satoshi Heguri Dr. Ngoc Han Tu Dr. Khuong Kim Huynh Dr. Takeshi Fujita Prof. Takashi Takahashi Prof. Katsumi Tanigaki Prof. Mingwei Chen 《Angewandte Chemie (International ed. in English)》2014,53(19):4822-4826
We report three‐dimensional (3D) nanoporous graphene with preserved 2D electronic properties, tunable pore sizes, and high electron mobility for electronic applications. The complex 3D network comprised of interconnected graphene retains a 2D coherent electron system of massless Dirac fermions. The transport properties of the nanoporous graphene show a semiconducting behavior and strong pore‐size dependence, together with unique angular independence. The free‐standing, large‐scale nanoporous graphene with 2D electronic properties and high electron mobility holds great promise for practical applications in 3D electronic devices. 相似文献
40.
Suzuka Kinoshita Ryota Yamano Dr. Yu Shibata Yusuke Tanaka Kyoichi Hanada Dr. Takashi Matsumoto Prof. Dr. Kazunori Miyamoto Dr. Atsuya Muranaka Prof. Dr. Masanobu Uchiyama Prof. Dr. Ken Tanaka 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(27):11113-11120
An S-shaped double helicene-like molecule (>99 % ee), possessing stable helical chirality, has been synthesized by the rhodium(I)/difluorphos complex-catalyzed highly diastereo- and enantioselective intramolecular double [2+2+2] cycloaddition of a 2-naphthol- and benzene-linked hexayne. The collision between two terminal naphthalene rings destabilizes the helical chirality of the S-shaped double helicene-like molecule, but the introduction of two additional fused benzene rings significantly increases the configurational stability. Thus, no epimerization and racemization were observed even at 100 °C. The enantiopure S-shaped double helicene-like molecule forms a trimer through the multiple C−H⋅⋅⋅π and C−H⋅⋅⋅O interactions in the solid-state. The trimers stack to form columnar packing structures, in which neighboring stacks have opposite dipole directions. The accumulation of helical structures in the same direction in the S-shaped double helicene-like molecule enhanced the chiroptical properties. 相似文献