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91.
This work is concerned with the development of a technique to observe the onset of corrosion as it occurs beneath a temporary
protective layer. Such temporary protectives include paints, varnishes, greases and oils that are applied to metal surfaces
to give short-term protection from corrosion. The objective of this project was to develop a technique that could be used
to evaluate the effectiveness of various temporary protectives in different environments, without the need to remove the protective
layer, thus eliminating the possibility of any chemical changes or loss of corrosion products occurring as a result of removal.
The temporary protective layers are typically 25Μm for paints and 15Μm per layer for varnishes. The 6.3 keV fluorescence X-ray is able to penetrate such layers, but the large escape depth (∼10Μm) of the X-rays means that for a thin protective layer a large proportion of the X-rays detected will originate from deep
within the substrate and the resultant spectrum will be representative of the bulk rather than the surface. To enhance the
surface sensitivity of the CXMS technique, the near surface region must be enriched in the isotope Fe-57. To achieve this,
Fe-57 was vacuum evaporated onto the surface of mild steel substrates and subsequently diffused into the near surface region.
An approximate 20 nm Fe-57 layer was deposited onto mild steel samples. The surface enriched samples were then annealed to
allow the Fe-57 to diffuse into the near surface region of the mild steel substrate, and also to allow back diffusion of the
substrate. A diffusion model was developed to predict the surface distribution of Fe-57 as a function of annealing parameters.
The computer diffusion model allowed the ideal annealing conditions to be estimated to obtain a required near surface environment.
It was essential that the annealing conditions did not result in any surface oxidation, and did result in a surface that was
characteristic of mild steel. CEMS and CXMS spectra were recorded of samples before and after annealing, and also dynamic
Secondary Ion Mass Spectrometry (SIMS) was used to monitor the enrichment and diffusion process. Energy Dispersive X-ray Analysis
(EDXA) was also used to characterize the surface. A number of enriched samples were prepared and treated with a variety of
surface temporary protectives. The CXMS spectra were recorded before and after exposure of the coated samples to various aggressive
environments. 相似文献
92.
93.
94.
Joshua L. Brooks Phil Olsen Lijian Chen Andrew A. Rodriguez 《Tetrahedron letters》2017,58(11):1050-1052
Herein, we describe the isolation and characterization of a UnyLinker dimer which, if left uncontrolled, can become incorporated in oligonucleotide products. The dimer is formed as a result of an unusual intermolecular osmium-catalyzed etherification. We demonstrate that by simply replacing H2O2 as the co-oxidant with NMO, none of the UnyLinker dimer impurity is formed. 相似文献
95.
Larkin JD Fossey JS James TD Brooks BR Bock CW 《The journal of physical chemistry. A》2010,114(47):12531-12539
o-(N,N-Dialkylaminomethyl)arylboronate systems are an important class of compounds in diol-sensor development. We report results from a computational investigation of fourteen o-(N,N-dialkylaminomethyl)arylboronates using second-order M?ller-Plesset (MP2) perturbation theory. Geometry optimizations were performed at the MP2/cc-pVDZ level and followed by single-point calculations at the MP2/aug-cc-pVDZ(cc-pVTZ) levels. These results are compared to those from density functional theory (DFT) at the PBE1PBE(PBE1PBE-D)/6-311++G(d,p)(aug-cc-pVDZ) levels, as well as to experiment. Results from continuum PCM and CPCM solvation models were employed to assess the effects of a bulk aqueous environment. Although the behavior of o-(N,N-dialkylaminomethyl) free acid and ester proved to be complicated, we were able to extract some important trends from our calculations: (1) for the free acids the intramolecular hydrogen-bonded B-O-H···N seven-membered ring conformers 12 and 16 are found to be slightly lower in energy than the dative-bonded N→B five-membered ring conformers 10 and 14 while conformers 13 and 17, with no direct boron-nitrogen interaction, are significantly higher in energy than 12 and 16; (2) for the esters where no intramolecular B-O-H···N bonded form is possible, the N→B conformers 18 and 21 are significantly lower in energy than the no-interaction forms 20 and 23; (3) H(2)O insertion reactions into the N→B structures 10, 14, 18, and 21 leading to the seven-membered intermolecular hydrogen-bonded B···OH(2)···N ring structures 11, 15, 19, and 22 are all energetically favorable. 相似文献
96.
Adare A Afanasiev S Aidala C Ajitanand NN Akiba Y Al-Bataineh H Alexander J Angerami A Aoki K Apadula N Aphecetche L Aramaki Y Asai J Atomssa ET Averbeck R Awes TC Azmoun B Babintsev V Bai M Baksay G Baksay L Baldisseri A Barish KN Barnes PD Bassalleck B Basye AT Bathe S Batsouli S Baublis V Baumann C Bazilevsky A Belikov S Belmont R Bennett R Berdnikov A Berdnikov Y Bhom JH Bickley AA Blau DS Boissevain JG Bok JS Borel H Boyle K Brooks ML Buesching H Bumazhnov V Bunce G Butsyk S Camacho CM 《Physical review letters》2011,107(14):142301
We present measurements of J/ψ yields in d+Au collisions at sqrt[s(NN)]=200 GeV recorded by the PHENIX experiment and compare them with yields in p+p collisions at the same energy per nucleon-nucleon collision. The measurements cover a large kinematic range in J/ψ rapidity (-2.2相似文献
97.
Terpenoid phytoalexins. 总被引:2,自引:0,他引:2
98.
Gregory Fridman Alexey Shereshevsky Monika M. Jost Ari D. Brooks Alexander Fridman Alexander Gutsol Victor Vasilets Gary Friedman 《Plasma Chemistry and Plasma Processing》2007,27(2):163-176
Initiation of apoptosis, or programmed cell death, is an important issue in cancer treatment as cancer cells frequently have
acquired the ability to block apoptosis and thus are more resistant to chemotherapeutic drugs. Targeted and perhaps selective
destruction of cancerous tissue is desirable for many reasons, ranging from the enhancement of or aid to current medical methods
to problems currently lacking a solution, i.e., lung cancer. Demonstrated in this publication is the inactivation (killing)
of human Melanoma skin cancer cell lines, in vitro, by Floating Electrode Dielectric Barrier Discharge (FE-DBD) plasma. Not
only are these cells shown to be killed immediately by high doses of plasma treatment, but low doses are shown to promote
apoptotic behavior as detected by TUNEL staining and subsequent flow cytometry. It is shown that plasma acts on the cells directly and not by
“poisoning” the solution surrounding the cells, even through a layer of such solution. Potential mechanisms of interaction
of plasma with cells are discussed and further steps are proposed to develop an understanding of such systems. 相似文献
99.
Adare A Adler SS Afanasiev S Aidala C Ajitanand NN Akiba Y Al-Bataineh H Alexander J Al-Jamel A Aoki K Aphecetche L Armendariz R Aronson SH Asai J Atomssa ET Averbeck R Awes TC Azmoun B Babintsev V Baksay G Baksay L Baldisseri A Barish KN Barnes PD Bassalleck B Bathe S Batsouli S Baublis V Bauer F Bazilevsky A Belikov S Bennett R Berdnikov Y Bickley AA Bjorndal MT Boissevain JG Borel H Boyle K Brooks ML Brown DS Bruner N Bucher D Buesching H Bumazhnov V Bunce G Burward-Hoy JM Butsyk S Camard X 《Physical review letters》2007,98(23):232302
We present azimuthal angle correlations of intermediate transverse momentum (1-4 GeV/c) hadrons from dijets in Cu+Cu and Au+Au collisions at square root sNN=62.4 and 200 GeV. The away-side dijet induced azimuthal correlation is broadened, non-Gaussian, and peaked away from Delta phi=pi in central and semicentral collisions in all the systems. The broadening and peak location are found to depend upon the number of participants in the collision, but not on the collision energy or beam nuclei. These results are consistent with sound or shock wave models, but pose challenges to Cherenkov gluon radiation models. 相似文献
100.
Adare A Afanasiev S Aidala C Ajitanand NN Akiba Y Al-Bataineh H Alexander J Al-Jamel A Aoki K Aphecetche L Armendariz R Aronson SH Asai J Atomssa ET Averbeck R Awes TC Azmoun B Babintsev V Baksay G Baksay L Baldisseri A Barish KN Barnes PD Bassalleck B Bathe S Batsouli S Baublis V Bauer F Bazilevsky A Belikov S Bennett R Berdnikov Y Bickley AA Bjorndal MT Boissevain JG Borel H Boyle K Brooks ML Brown DS Bucher D Buesching H Bumazhnov V Bunce G Burward-Hoy JM Butsyk S Campbell S Chai JS Chang BS 《Physical review letters》2007,98(23):232301
The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) has measured J/psi production for rapidities -2.2相似文献