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排序方式: 共有542条查询结果,搜索用时 140 毫秒
1.
Whittum D.H. Ebihara K. Hiramatsu S. Kishiro J.-i. Monaka T. Ozaki T. Takayama K. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1993,21(1):136-141
Studies of microwave amplification with an in-focused electron beam drawn from an induction injector are reported. A free-electron laser (FEL) operating at 9.4 GHz and employing ion-focusing within the interaction region has achieved power in excess of 30 MW at 9.4 GHz, with a beam energy of 0.8 MeV and current of 0.7 kA. Peak gain is 20 dB/m, with no saturation after 15 wiggler periods. Also reported are the first evolution and detuning data for an ion-channel laser/maser (ICL). Two shortcomings of the prematurely halted ICL studies are poor frequency discrimination and a large axial plasma gradient. Prospects for operation with an upgraded 1.6 MeV accelerator are discussed 相似文献
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3.
A special poster session was run during the 18th International Symposium on Shock Waves, held on July 21 – 26, 1991, in Sendai, Japan. The purpose of this session was to compare various CFD schemes which are useful for simulating shock wave phenomena. A 2-D planar shock wave diffraction over a 90 degree sharp corner was selected as a bench mark problem. The problem specification and the output format are described below. Experimental outputs for the close flow conditions to the computational ones were also called for. Twenty six poster presentations were made at this session and the majority of the posters reflected a standard of excellence that warrants publication in the Shock Waves journal. Therefore these results are reproduced here. However, since there is a limit on the available page numbers, it was not possible to publish all the posters that were presented at the special poster session. We express our sincere thanks to all the participants in this session. 相似文献
4.
The influence of the acidic and basic characters of constituent amino acid residues on the peptide fragment ions produced by in-source decay under matrix assisted laser desorption/ionization (MALDI) conditions has been studied using positive- and negative-ion experiments. Whereas the in-source decay spectra of peptides containing basic Arg and/or Lys residues near the N-terminus showed so-called cn- and an-series ions in positive-ion mode, a peptide that has an acidic amino acid cluster near the N-terminus and a basic residue near the C-terminus characteristically formed yn- and zn-series ions in the positive-ion in-source decay spectrum. These results indicated that fragment ion series produced by in-source decay depend strongly upon the acidic and basic characters of the constituent amino acid residues and the near N- and C-termini. It was suggested that in-source decay processes occur intrinsically at NH–Cα and CO–NH bonds independent of the formation of molecular-related ions, and that the cleavages at the NH–Cα and CO–NH bonds occurred independently and were dependent on the matrix used. 相似文献
5.
Y Watanabe M Suda Y Matsumoto K Takayama M Matsumoto W Zhao 《Chemical & pharmaceutical bulletin》1991,39(9):2391-2394
The dissolution behavior of the aspirin enteric granule prepared using acylglycerols, glyceryl monostearate (GMS) and glyceryl trilaurate (GTL), was investigated in vitro and in human subjects in a fasting or non-fasting state. Aspirin was slowly released from the granule in vitro at pH 1.2. No acceleration of the aspirin dissolution rate in the medium without lipase and cholic acid was observed when the pH level of the medium increased to a neutral region (pH 6.4). However, the dissolution of aspirin was significantly increased by increasing the concentrations of lipase and cholic acid in the medium. Lipase appears to play an essential role in the dissolution process of aspirin granules. In human subjects, the average levels of the cumulative amount of total salicylate excreted in a urine-time curve, and the mean residence time (MRT) obtained after oral administration of a granule in the fasting state were markedly delayed in comparison with the results observed using an aqueous solution and a crystalline form of aspirin. In comparing the fasting condition with the non-fasting condition (after food ingestion), no significant difference was recognized in the total amount of salicylate excreted in urine to an infinite time (Ae(infinity)), whether the MRT was obtained by granule, crystalline form or aqueous solution. It can be concluded that aspirin granule prepared by GMS and GTL has a property of pancreatic lipase-sensitive dissolution, and its bioavailability is unaffected by food intake. 相似文献
6.
The amounts of d-limonene, ethanol and indomethacin (IMC) which were transferred from aqueous gel ointments to the skin were determined in rats. The concentration of IMC in the skin correlated well with the plasma concentration of IMC percutaneously absorbed from the gel ointment. The increase of d-limonene concentration in the gel ointments was directly proportional to the accumulation of ethanol in the skin. The amount of ethanol in the skin was closely associated with the percutaneous absorption of IMC. As a possible mechanism for enhancement action of d-limonene and ethanol, it was considered that, at first, d-limonene penetrates into the skin under coexistence with ethanol and may change the barrier structure of the stratum corneum. The transfer of ethanol to the skin is thereby enhanced under the coexistence of d-limonene in the skin. Thus, the permeation of IMC can be promoted due to its affinity with ethanol. 相似文献
7.
Alexei A. Belik Andrei V. Mironov Roman V. Shpanchenko Eiji Takayama‐Muromachi 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(7):i37-i39
The crystal structure of a new high‐pressure modification of cadmium divanadium hexaoxide, CdV2O6, was refined from X‐ray single‐crystal data. It contains zigzag chains of edge‐sharing VO6 octahedra. Octahedra in adjacent chains share corners and form corrugated layers. Octahedrally coordinated Cd atoms, which lie on twofold axes, are situated between the layers. The columbite‐like structure results in a strong distortion of the CdO6 octahedra which may be stabilized only at high pressure. 相似文献
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9.
Chang-Kyu Kim A. Takaku M. Yamamoto H. Kawamura K. Shiraishi Y. Igarashi S. Igarashi H. Takayama N. Ikeda 《Journal of Radioanalytical and Nuclear Chemistry》1989,131(1):131-137
Ammonium uranates (AU) obtained by the addition of aqueous NH4 OH to a solution of UO2 (NO3)2 or the equilibrium reaction of UO3 · 2H2 O with the vapour over concentrated NH4 OH have been studied by X-ray diffraction (XRD) analysis, diffuse reflectance Fourier transform infrared spectrometry (DR-FTIR) and chemical analysis. Ammonia can be present as either NH3 or NH
4
+
. For precipitates obtained at a pH of 3.7, ammonia in the form of NH3 is predominant. For ammonium uranate obtained by reaction over concentrated NH4OH, most of the ammonia is bonded as NH
4
+
. The reaction mechanism and structures of the products are also discussed. 相似文献
10.