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991.
Charge separation in a novel artificial photosynthetic reaction center lives 380 ms. 总被引:3,自引:0,他引:3
H Imahori D M Guldi K Tamaki Y Yoshida C Luo Y Sakata S Fukuzumi 《Journal of the American Chemical Society》2001,123(27):6617-6628
An extremely long-lived charge-separated state has been achieved successfully using a ferrocene-zincporphyrin-freebaseporphyrin-fullerene tetrad which reveals a cascade of photoinduced energy transfer and multistep electron transfer within a molecule in frozen media as well as in solutions. The lifetime of the resulting charge-separated state (i.e., ferricenium ion-C(60) radical anion pair) in a frozen benzonitrile is determined as 0.38 s, which is more than one order of magnitude longer than any other intramolecular charge recombination processes of synthetic systems, and is comparable to that observed for the bacterial photosynthetic reaction center. Such an extremely long lifetime of the tetrad system has been well correlated with the charge-separated lifetimes of two homologous series of porphyrin-fullerene dyad and triad systems. 相似文献
992.
Summary: Self‐oscillating polymers and nano‐gel particles consisting of N‐isopropylacrylamide and the ruthenium catalyst of the Belousov‐Zhabotinsky reaction have been prepared. In order to clarify the crosslinking effect on the self‐oscillating behavior, the phase transition behaviors were investigated by measuring the transmittance and the fluorescence intensity of the polymer solution and the gel bead suspension. Cooperative effects due to crosslinking will play an important role for the design of nanoactuators.
993.
H. Yamazaki T. Yorita T. Kinoshita T. Okuda H. Matsui T. Maruyama J. Kasagi T. Suda K. Itoh T. Miyakawa H. Okuno H. Shimizu H. Y. Yoshida T. Kinashi 《Nuclear Physics A》2000,670(1-4):202-205
In order to study the S11(1535) resonance in the nuclear medium, total cross sections of the (γ, η) reactions on C, Al and Cu have been measured for photon energies between 680 and 1000 MeV. A broad resonance due to the excitation and decay of the S11 resonance in the nucleus has been clearly observed for the first time. The apparent energy and width of the resonance are 900 and 300 MeV, respectively. Model calculations based on the quantum molecular dynamics have been performed. A comparison of the calculations with the data indicates that the S11 resonance in nuclei should have a larger width; the width of about 250 MeV is required while the elementary one is about 150 MeV. 相似文献
994.
Experimental results are reported which demonstrate that submicroscopic changes occur in metal specimens electron-irradiated in a high-voltage electron microscope at high temperatures where no visible damage is produced. These changes give rise to drastic effects on the visible radiation damage created during a later re-irradiation of the specimen at lower temperatures. The observations made on copper are explained by the formation of small vacancy aggregates. The results obtained for aluminium are explained in terms of specimen purification by radiation-induced segregation of impurity atoms to the specimen surfaces. In the two other metals investigated, molybdenum and nickel, high-temperature irradiation leads to submicroscopic changes which can also be attributed to impurity effects. 相似文献
995.
Electrochemical Determination of D‐Glucose Using Nortropine‐N‐oxyl under Physiological Conditions 下载免费PDF全文
Katsuhiko Sato Tetsuya Ono Kentaro Yoshida Toshinori Ito Yoshitomo Kashiwagi 《Electroanalysis》2015,27(10):2272-2274
Nortropine‐N‐oxyl (NNO) was synthesized in a single step from nortropine. The electrocatalytical activity of NNO was evaluated by cyclic voltammetry in pH7.0 phosphate buffer solution. The anodic peak current for ethanol, isopropanol and glucose was enhanced, showing these alcohols were oxidized by electrocatalytic effect of NNO. On the other hand, TEMPO derivative (4‐hydroxy‐2,2,6,6,‐terramethylpiperidine N‐oxyl free radical) could not oxidize the alcohols under the same condition. The electrochemical response of the NNO to glucose was investigated. The anodic peak current increased with an increase in the concentration of glucose. A linear response to the glucose concentration ranging from 0.1 to 10 mM was obtained. 相似文献
996.
Eri Yoshida 《Colloid and polymer science》2014,292(6):1463-1468
In order to clarify the formation mechanisms of micrometer-sized spherical vesicles through the polymerization-induced self-assembly of amphiphilic poly(methacrylic acid)-block-poly(methyl methacrylate-random-methacrylic acid), PMAA-b-P(MMA-r-MAA), the nitroxide-mediated photocontrolled/living radical polymerization initiated by a PMAA end-capped with 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl was performed in an aqueous methanol solution. The polymerization proceeded in a living manner during the self-assembly. The vesicles produced during the early stage of the polymerization were not completely spherical and had dents and very small holes on their surface. As the hydrophobic P(MMA-r-MAA) block chains grew by the polymerization, the contorted vesicles were changed into half-sized elliptical vesicles accompanied by enlargement of the dents and holes. The vesicles were finally transformed into much smaller spherical vesicles by further growth of the hydrophobic chains. The mechanisms of the vesicles by fission involved the outside separation by the expansion of the dents and holes on the surface and the inside separation by budding. 相似文献
997.
998.
Wilkins RC Romm H Oestreicher U Marro L Yoshida MA Suto Y Prasanna PG 《Radiation measurements》2011,46(9):923-928
Biological dosimetry is an essential tool for estimating radiation doses received to personnel when physical dosimetry is not available or inadequate. The current preferred biodosimetry method is based on the measurement of radiation-specific dicentric chromosomes in exposed individuals' peripheral blood lymphocytes. However, this method is labour-, time- and expertise-demanding. Consequently, for mass casualty applications, strategies have been developed to increase its throughput. One such strategy is to develop validated cytogenetic biodosimetry laboratory networks, both national and international. In a previous study, the dicentric chromosome assay (DCA) was validated in our cytogenetic biodosimetry network involving five geographically dispersed laboratories. A complementary strategy to further enhance the throughput of the DCA among inter-laboratory networks is to use a triage DCA where dose assessments are made by truncating the labour-demanding and time-consuming metaphase-spread analysis to 20 to 50 metaphase spreads instead of routine 500 to 1000 metaphase spread analysis. Our laboratory network also validated this triage DCA, however, these dose estimates were made using calibration curves generated in each laboratory from the blood samples irradiated in a single laboratory. In an emergency situation, dose estimates made using pre-existing calibration curves which may vary according to radiation type and dose rate and therefore influence the assessed dose. Here, we analyze the effect of using a pre-existing calibration curve on assessed dose among our network laboratories. The dose estimates were made by analyzing 1000 metaphase spreads as well as triage quality scoring and compared to actual physical doses applied to the samples for validation. The dose estimates in the laboratory partners were in good agreement with the applied physical doses and determined to be adequate for guidance in the treatment of acute radiation syndrome. 相似文献
999.
1000.