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排序方式: 共有1143条查询结果,搜索用时 31 毫秒
141.
142.
Abstract High pressure X-ray studies on CuH up to 23 GPa have been performed at room temperature using a gasketed diamond anvil cell. The experimental data on the molar volume of CuH as a function of pressure have been fitted to Murnaghan's equation of state giving a bulk modulus: B0 = 72.5±2 GPa and B0 = 2.7 ± 0.3. By comparison with the equation of state for pure copper the effective additive volume of hydrogen has been evaluated as a function of pressure. It decreases from 3.2 cm3/mol H, at ambient pressure reaching a flattening value of 1.7cm3hol H at about 60 GPa. This suggests a continuous transition of CuH from ionic or covalent character at normal pressure to metallic hydride behavior at high pressure 相似文献
143.
Yutaka Udagawa Masatake Yamaguchi Tomohito Tsuru Hiroaki Abe Naoto Sekimura 《哲学杂志》2013,93(12):1665-1678
We have investigated the effects of Sn and Nb on dislocation properties in a Zr lattice to elucidate the role of these alloying elements in hydride nucleation processes. According to experimental observations, γ-hydride habit planes are close to the prismatic plane in pure Zr and close to the basal plane in Zircaloy. Dislocation loops are observed around hydride precipitates, implying they play a part in hydride formation. Our ab initio generalized stacking-fault energy calculations showed remarkable effects of Sn on unstable-stacking energy and stacking-fault energy: these parameters for basal slip were considerably reduced while those for prismatic slip were increased in the presence of Sn. These results suggest selective stabilization and enhancement of dislocation spreading in the basal plane, promoting possible elementary processes of hydride precipitation with basal habit plane, i.e. screw-dislocation spreading and edge-dislocation emission in the basal plane. 相似文献
144.
Systematic studies using density functional theory have shown that some hydrides possess the features of semiconductors. These features include larger fundamental band gap, well dispersed bottom-most conduction band and/or top-most valence band, small electron/hole effective masses and small intrinsic carrier concentration. It is demonstrated that depending upon the composition, hydrides possess a wide range of band gap values and hence they can be regarded as materials for narrow to wide band gap semiconducting applications. The possibility of designing hydride-based p–n junctions, and also their advantages as well as deficiencies compared to existing oxide semiconductors, are discussed. Replacing oxide-based semiconductors by hydrides can help to avoid problems such as formation of an oxide layer, band offsets, large concentration of defect states at the interface between the oxide and semiconductor, etc. Moreover, hydrides can be regarded as an alternative to conventional semiconductors and hence can be used in future-generation electronic devices called “hydride electronics”. 相似文献
145.
Kristina O. Kvashnina Anna Yu. Romanchuk Ivan Pidchenko Lucia Amidani Evgeny Gerber Alexander Trigub Andre Rossberg Stephan Weiss Karin Popa Olaf Walter Roberto Caciuffo Andreas C. Scheinost Sergei M. Butorin Stepan N. Kalmykov 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(49):18044-18044
146.
A. M. Shaikh 《Pramana》2008,71(4):663-672
Design and development of neutron detectors and R&D work in neutron radiography (NR) for non-destructive evaluation are important
parts of the neutron beam and allied research programme of Solid State Physics Division (SSPD) of Bhabha Atomic Research Centre
(BARC). The detectors fabricated in the division not only meet the in-house requirement of neutron spectrometers but also
the need of other divisions in BARC, Department of Atomic Energy units and some universities and research institutes in India
and abroad for a variety of applications. The NR facility set up by SSPD at Apsara reactor has been used for a variety of
applications in nuclear, aerospace, defense and metallurgical industries. The work done in the development of neutron detectors
and neutron radiography is reported in this article.
相似文献
147.
Dr. Felix Pape Lea T. Brechmann Jun.-Prof. Dr. Johannes F. Teichert 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(4):985-988
Copper(I)–N-heterocyclic-carbene (NHC) complexes enabled the catalytic generation of nucleophilic hydrides from dihydrogen (H2) and their subsequent transfer to allylic chlorides. The highly chemoselective catalyst displayed no concomitant hydrogenation reactivity; in fact, the terminal double bond formed in the hydride transfer remained intact. Switching to deuterium gas (D2) allowed for regioselective monodeuteration with excellent isotope incorporation. 相似文献
148.
Steffen Pospiech Dr. Michael Bolte Dr. Hans‐Wolfram Lerner Prof. Dr. Matthias Wagner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8229-8236
9,10‐(Bpin)2‐anthracene ( 3 , HBpin=pinacolborane) was synthesized from 9,10‐dibromoanthracene in a stepwise lithiation/borylation sequence. The reaction of 3 with highly activated magnesium furnished the diborylated magnesium anthracene 4 , which was quenched in situ with ethereal HCl to yield cis‐9,10‐(Bpin)2‐DHA (cis‐ 5 , DHA=9,10‐dihydroanthracene). Compound cis‐ 5 , in turn, can be reduced with Li[AlH4] in THF to give its diborate Li2[cis‐9,10‐(BH3)2‐DHA] (Li2[cis‐ 6 ]). In the crystal lattice, the THF solvate Li2[cis‐ 6 ] ? 3 THF establishes a dimeric structure with Li‐(μ‐H)‐B coordination modes. Hydride abstraction from Li2[cis‐ 6 ] with Me3SiCl yields the B?H?B‐bridged DHA Li[ 7 ]. This product can also be viewed as a unique cyclic B2H7? derivative with a hydrocarbon backbone. Treatment of Li2[cis‐ 6 ] with the stronger hydride abstracting agent Me3SiOTf (HOTf=trifluoromethanesulfonic acid) in THF affords the THF diadduct of cis‐9,10‐(BH(OTf))2‐DHA. 相似文献
149.
Blanca G. Beltrán Laura Ferrer Victor Cerdà 《International journal of environmental analytical chemistry》2015,95(11):1054-1065
Lead hydride or plumbane (PbH4) generation was optimised by exploiting a simple flow-injection method coupled to atomic fluorescence spectrometry (HG-AFS), and allowing ultra-trace lead determination. Plumbane was generated through two methods: (1) 5% (v/v) H2O2 was employed as oxidant with 1.5% (m/v) KBH4 as a reducing agent and 1.5% (v/v) HCl solution; (2) with 1.5% (m/v) K3[Fe(CN)6] as an oxidant/sensitiser, 1% (m/v) KBH4 as a reducing agent and 1.5% (v/v) HCl. Variables such as reagent concentrations, flow rates and sample and reagent volumes were tested and critically compared. The best results were obtained with potassium ferricyanide K3[Fe(CN)6], achieving a detection limit of 0.03 μg Pb L?1 and a relative standard deviation (RSD) of 1.1%. The selected method was validated by analysis of certified reference materials such as SRM-2976 (mussel tissue) and BCR-610 (groundwater), with good agreement with the certified values. The developed methodology was successfully applied to different environmental sample matrices, such as rain water, tap water, ground water, spring water and drinking water, and biological samples, i.e., human blood, plasma and serum. 相似文献
150.
Single‐Site Zeolite‐Anchored Organoiridium Carbonyl Complexes: Characterization of Structure and Reactivity by Spectroscopy and Computational Chemistry
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Claudia Martinez‐Macias Dr. Mingyang Chen Prof. David A. Dixon Prof. Bruce C. Gates 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(33):11825-11835
A family of HY zeolite‐supported cationic organoiridium carbonyl complexes was formed by reaction of Ir(CO)2(acac) (acac=acetylacetonate) to form supported Ir(CO)2 complexes, which were treated at 298 K and 1 atm with flowing gas‐phase reactants, including C2H4, H2, 12CO, 13CO, and D2O. Mass spectrometry was used to identify effluent gases, and infrared and X‐ray absorption spectroscopies were used to characterize the supported species, with the results bolstered by DFT calculations. Because the support is crystalline and presents a nearly uniform array of bonding sites for the iridium species, these were characterized by a high degree of uniformity, which allowed a precise determination of the species involved in the replacement, for example, of one CO ligand of each Ir(CO)2 complex with ethylene. The supported species include the following: Ir(CO)2, Ir(CO)(C2H4)2, Ir(CO)(C2H4), Ir(CO)(C2H5), and (tentatively) Ir(CO)(H). The data determine a reaction network involving all of these species. 相似文献