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81.
H Kobayashi H Morita M Yamauchi R Ikeda H Kitagawa Y Kubota K Kato M Takata S Toh S Matsumura 《Journal of the American Chemical Society》2012,134(30):12390-12393
We have synthesized and characterized homogeneous solid-solution alloy nanoparticles of Pd and Rh, which are immiscible with each other in the equilibrium bulk state at around room temperature. The Pd-Rh alloy nanoparticles can absorb hydrogen at ambient pressure and the hydrogen pressure of Pd-Rh alloys for hydrogen storage is dramatically decreased by more than 4 orders of magnitude from the corresponding pressure in the metastable bulk state. The solid-solution state is still maintained in the nanoparticles even after hydrogen absorption/desorption, in contrast to the metastable bulks which are separated into Pd and Rh during the process. 相似文献
82.
Suzuki S Ishiwari F Nakazono K Takata T 《Chemical communications (Cambridge, England)》2012,48(52):6478-6480
Pendant rotaxane switch-tethering poly(m-phenylene diethynylene) was synthesized by the polyoxidative coupling of a rotaxane containing an axle-terminal m-diethynylbenzene group and an optically active crown ether. The reversible helix-random coil transition of the polymer was successfully performed by the positional switching of the rotaxane wheel. 相似文献
83.
Seiya Tanaka Tsuneaki Sakurai Yoshihito Honsho Dr. Akinori Saeki Prof. Dr. Shu Seki Dr. Kenichi Kato Prof. Dr. Masaki Takata Prof. Dr. Atsuhiro Osuka Prof. Dr. Takuzo Aida 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(34):10554-10561
In contrast with their dimeric homologue, triply fused zinc porphyrin trimer–pentamer, as extra‐large π‐extended mesogens, assemble into columnar liquid crystals (LCs) when combined with 3,4,5‐tri(dodecyloxy)phenyl side groups ( 3 PZn – 5 PZn , Figure 1 ). Their LC mesophases develop over a wide temperature range, namely, 41–280 °C (on heating) for 5 PZn , and all adopt an oblique columnar geometry, typically seen in columnar LC materials involving strong mesogenic interactions. These LC materials are characterized by their wide light‐absorption windows from the entire visible region up to a near infrared (NIR) region. Such ultralow‐bandgap LC materials are chemically stable and serve as hole transporters, in which 5 PZn gives the largest charge carrier mobility (2.4×10?2 cm V?1 s?1) among the series. Despite a big dimensional difference, they coassemble without phase separation, in which the resultant LC materials display essentially no deterioration of the intrinsic conducting properties. 相似文献
84.
85.
Eiji Nishibori Masaki Takata Makoto Sakata Hiroshi Tanaka Masaki Hasegawa Hisanori Shinohara 《Chemical physics letters》2000,330(5-6):497-502
An anomalous charge density distribution of La atom encapsulated in a C82 cage has been revealed for La@C82 by the maximum entropy method (MEM)/Rietveld analysis using synchrotron powder diffraction data. The obtained La atom charge density shows a feature almost like a bowl or a hemisphere, suggesting that the La atom has a giant motion (large amplitude motion) inside the C82 cage at room temperature. From the obtained MEM charge density, the main results are (1) the cage structure of La@C82 (I) has C2V symmetry; (2) La atom locates at an off-centered position adjacent to a six-membered ring of the carbon cage; (3) the nearest La–C distance is 2.55(8)
and (4) the amount of charge transfer from the La atom to the carbon cage is about 3.2 e, which corresponds to the nominal electronic structure, La3+@C823−. 相似文献
86.
Jun Zhang Dr. Wataru Kosaka Prof. Dr. Susumu Kitagawa Prof. Dr. Masaki Takata Prof. Dr. Hitoshi Miyasaka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(12):3020-3031
Optimal control of gas adsorption properties in metal–organic frameworks (MOFs) or porous coordination polymers (PCPs) remains a great challenge in the field of materials science. An efficient strategy to capture electron-acceptor-type gas molecules such as nitrogen monooxide (NO) is to use host–guest interactions by utilizing electron-donor-type MOFs/PCPs as host frameworks. Herein, we focus on a highly electron-donating chain compound by using the paddlewheel-type [Ru2II,II] complex [Ru2(2,4,5-Me3PhCO2)4] (2,4,5-Me3PhCO2−=2,4,5-trimethylbenzoate) with the phenazine (phz) linker: [Ru2(2,4,5-Me3PhCO2)4(phz)] ( 1 ). Compound 1 exhibited a specific gated adsorption for NO under gas pressures greater than 60 kPa at 121 K, which finally resulted in approximately seven molar equivalents being taken up at 100 kPa followed by four molar equivalents remaining under vacuum at 121 K; its Rh isomorph ( 2 ) with weaker donation ability was inactive for NO. When the sample of 1 ⊃4 NO was heated to room temperature, the compound underwent a crystal-to-crystal phase transition to give [Ru2(2,4,5-Me3PhCO2)4(NO)2](phz) ( 1 -NO), involving a post-synthetic nitrosylation on the [Ru2] unit, accompanied by an eventful site-exchange with phz. This drastic event, which is dependent on the NO pressure, temperature, and time, was coherently monitored by using several different in situ techniques, revealing that the stabilization of NO molecules in nanosized pores dynamically and stepwisely occurred with the support of strong electronic/magnetic host–guest interactions. 相似文献
87.
Germanium quantum dots (QDs) were extracted from ultrathin SixGe1−x oxide films using scanning tunneling microscope (STM) tips. The extraction was most efficiently performed at a positive sample bias voltage of +5.0 V. The tunneling current dependence of the extraction efficiency was explained by the electric field evaporation transfer mechanism for positive Ge ions from QDs to STM tips. Ge QDs (∼7 nm) were formed and isolated spatially by extracting the surrounding Ge QDs with an ultrahigh density of >1012 cm−2. Scanning tunneling spectroscopy of the spatially-isolated QDs revealed that QDs with an ultrahigh density are electrically-isolated from the adjacent dots. 相似文献
88.
89.
TPP-Sensitized photooxidation of five-membered ring sulfides in aprotic solvent afforded C-S bond cleavage products, unlike six- and seven-membered ring sulfides which gave only S-oxidation products. The products as well as substitution and concentration effects suggest that C-S bond cleavage depends upon acidity of α-proton of persulfoxide intermediate. 相似文献
90.
Photocatalytic overall water splitting under visible light by TaON and WO3 with an IO3-/I- shuttle redox mediator 总被引:2,自引:0,他引:2
Photocatalytic water splitting into H2 and O2 under visible-light irradiation (lambda > 420 nm) is demonstrated using the oxynitride Pt-TaON for H2 evolution and a Pt-WO3 catalyst for O2 evolution in an IO3-/I- shuttle redox-mediated system. 相似文献