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991.
Shen Ting-gen Zhou Yue-qun Ge Jun Yu Feng-chao Ji Pei-lai Wang Gang 《Journal of Russian Laser Research》2008,29(3):255-261
The method of finite-difference-time domain (FDTD) was used to study the characteristics of the patch antenna based on drilling
air holes in the PBG substrate. The results obtained show that the waves propagating along the substrate surface can be suppressed
by the drilled photonic crystal band gap (PBG) structure due to the influence of its forbidden band. The energy of the electromagnetic
waves is concentrated mainly in the substrate. As a result, patch antennas based on drilling air holes in the PBG substrate
have lower return losses (S11) in comparison with the conventional patch antennas; thus, a high gain is reached and the performance
is improved. Due to such the advantages, the use of patch antennas can be extended to such fields as mobile communication,
satellite communication, aviation, etc. 相似文献
992.
Xiaoli Li Guangmin Wu Jun Shen Fan Yang Jue Wang 《Journal of Sol-Gel Science and Technology》2002,25(3):235-242
When designing a cut-off interference filter, extra layers are needed to add on each side of periodic symmetrical multilayer to match the incident medium and the substrate. In this paper, we use sol-gel film with adjustable refractive index as the match layer. The influence of the refractive index and thickness of the match layer on the film system is discussed in detail. As an example, a special filter which is transparent (>80%) at the wavelength 3–5 m and high reflective (>90%) at the wavelength 1.3 m is designed. Finally a series of optimized film parameters are presented. The whole design process is a good reference to the other multilayer special filter made by sol-gel process. 相似文献
993.
Pasa-Tolić L Lipton MS Masselon CD Anderson GA Shen Y Tolić N Smith RD 《Journal of mass spectrometry : JMS》2002,37(12):1185-1198
In the era of systems biology, computational and high-throughput experimental biological approaches are increasingly being combined to provide global snapshots of entire genomes and proteomes under tissue- and disease-specific conditions. The aim is to identify proteins changing in concentration and/or post-translational state and/or location, and develop a better molecular level understanding of the operation of biological systems. Here we describe an approach for comparative proteomics that builds upon the combination of high-performance nano-scale separations with the high-mass measurement accuracy, mass-resolving power and sensitivity of Fourier transform ion cyclotron resonance mass spectrometry to provide broad dynamic range, comprehensive and quantitative proteome measurements. 相似文献
994.
The first synthesis of functionalized gem-difluoroallenes 4 served as platform for an unprecedented molybdenum-catalyzed intramolecular allene-alkyne [2 + 2]-cycloaddition that produced 6, a hitherto unknown class of bicyclo- and heterobicyclo-CF2-containing cyclobutenes. 相似文献
995.
Badro J Fiquet G Struzhkin VV Somayazulu M Mao HK Shen G Le Bihan T 《Physical review letters》2002,89(20):205504
We present a new method to separate the crystallographic and electronic phase transitions in hematite using x-ray emission spectroscopy and x-ray diffraction. Our observations, based on the behavior of a metastable high-pressure phase in the stability domain of the low-pressure phase, show that the electronic transition is preempted by the crystallographic transition. The former occurs only afterwards in the high-pressure phase, possibly as a result of a Mott transition. The idea that the electronic transition drives the transition in hematite is therefore invalidated. Such methods should help elucidate the mechanics and the driving forces behind a number of first-order high-pressure phase transitions. 相似文献
996.
Feng DL Damascelli A Shen KM Motoyama N Lu DH Eisaki H Shimizu K Shimoyama Ji JI Kishio K Kaneko N Greven M Gu GD Zhou XJ Kim C Ronning F Armitage NP Shen ZX 《Physical review letters》2002,88(10):107001
The low-energy electronic structure of the nearly optimally doped trilayer cuprate superconductor Bi(2)Sr(2)Ca(2)Cu(3)O(10+delta) is investigated by angle-resolved photoemission spectroscopy. The normal state quasiparticle dispersion and Fermi surface and the superconducting d-wave gap and coherence peak are observed and compared with those of single- and bilayer systems. We find that both the superconducting gap magnitude and the relative coherence-peak intensity scale linearly with T(c) for various optimally doped materials. 相似文献
997.
We report for what is believed to be the first time planar waveguide formation and propagation mode reduction in Nd:YVO(4) crystal, which were achieved by 3.0-MeV silicon-ion implantation followed by annealing under specific conditions. After the implantation, an enhanced refractive-index region was formed with a width of ~2microm beneath the sample surface to act as a waveguide structure. We found that there were four propagation modes for the as-implanted Nd:YVO(4) waveguide, whereas after annealing at 240-360 degrees C for several hours the number of modes could be reduced to three, two, and one. After annealing at 400 degrees C for 1 h the monomode waveguide was destroyed completely, and no mode was observed in the sample. 相似文献
998.
Poly (3-alkylthiophenes) (P3ATs) have made up of a family of conductive polymerswhich are soluble, fusible and processable, since the introduction of flexible alkyl sidechains"'. It is generally accepted that P3ATs can form similar layered structures. inwhich the thiophene rings possess planarity and the side chains act as spacers'-'. Whenthe number. of 'carbon atoms of alkyl side chains is more than 10, some orderlyarrangements will occur for side chains betWeen the' layers'. It has been w… 相似文献
999.
Low tropospheric wind measurement with Mie Doppler Lidar 总被引:3,自引:0,他引:3
A double edge Mie Doppler lidar at 1064 nm was developed in Hefei, China in 2005 for low tropospheric wind measurement. Intercomparison
experiments with a wind profiler and a wiresonde were held. Intercomparisons of concurrent lidar and other instrument observations
show good agreement with expected measurement accuracy. The examples of validated lidar wind profiles obtained during these
experiments as well as an example of continuous wind observations are presented. The instrument has demonstrated the capability
of atmospheric wind field measurement from 0.2 to 5 km altitude, achieving below 2 m/s accuracy with 1 min averaging and 21.2
m vertical resolution. 相似文献
1000.
In this paper, 3-glycidoxypropyltrimethoxysilane was used to produce diol-bonded capillaries at room temperature for capillary electrophoresis (CE). A variety of standard reference compounds and authentic biological samples including ribonucleotides, peptides and proteins were used to test the columns. It was found that greatly suppressed electroosmotic flow was measured over a pH range of 3–10. Lower than 1.6% relative standard deviation (>10 runs) in migration time was observed for the analysis of test proteins. For real samples of ribonucleotides in tumor cell extracts, 1 million theoretical plates and excellent peak shapes were obtained. The high column efficiency and symmetrical peaks allowed the separation of samples with only 0.6% maximum difference in migration times. The diol-bonded fused-silica capillary columns were stable when used in a pH range of 2–8 under typical CE conditions. The column preparation method involved a simple dynamic coating procedure at room temperature, greatly simplifying the more typical static coating methods that require vacuum pumps and ovens. 相似文献