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121.
4H-SiC金属-半导体-金属结构紫外探测器的模拟与分析 总被引:3,自引:0,他引:3
用MEDICI软件对金属-半导体-金属(MSM)结构4H-SiC紫外(UV)探测器的I-V特性以及光谱响应等特性进行了模拟与分析,并探讨了金属电极的宽度、电极间距以及外延层厚度对探测器响应度的影响.结果表明,室温下该探测器的暗电流线性密度达到10-13A/μm,且在不同电压下光电流至少比暗电流大两个数量级;探测器的光谱响应范围为200~400 nm,在347 nm处响应度达到极大值;增大指宽或者减小指间距可以提高探测器的响应度;当波长小于峰值波长时外延层厚度对探测器的响应度基本没影响,而当波长大于峰值波长时随着外延层厚度的增大探测器的响应度有所增大. 相似文献
122.
使用水热法KTP晶体实现了355nm紫外激光输出。实验中采用声光调Q技术,选用模体值大的V形谐振腔结构,对激光二极管(LD)侧抽运Nd…YAG模块产生的基波,分别利用水热法KTP晶体二倍频、LBO晶体三倍频,获得了高功率、高光束质量的355nm紫外激光输出。当抽运功率为93.09W,重复频率为4.9kHz时,获得4.133W的紫外355nm激光输出,光-光转换效率为4.44%。 相似文献
123.
为了航行安全远洋船舶需要注入和排放压载水。压载水中的有害水生物和病原体同时也被搬运,并导致海洋水域环境的污染。控制该污染的核心措施之一是在船上增添压载水处理设备。紫外线激光二极管可以制造产生紫外线的辐射,能穿透细菌、病毒的细胞膜,破坏核酸结构,使之失去繁殖和自我复制能力,达到快速杀菌的效果。紫外激光压载水处理设备杀菌快速,无二次污染,使用安全,占地小,可操作性强,尤其适用于中小型船舶压载水处理系统。 相似文献
124.
高质量AlN薄膜对制造高性能深紫外器件非常重要,但是目前还很难使用大型工业MOCVD生长出高质量的AlN薄膜.采用磁控溅射制备了不同厚度的用作成核层的AlN薄膜,使用大型工业MOCVD直接在成核层上高温生长AlN外延层,研究了不同成核层对AlN外延层质量的影响.通过扫描电子显微镜和原子力显微镜对成核层AlN薄膜的表面形貌进行表征;使用高分辨X射线衍射仪对AlN外延层晶体质量进行表征,结果表明:在溅射成核层上生长的AlN外延层的晶体质量有显著提高.使用大型工业MOCVD在蓝宝石衬底上成功制备出中心波长为282 nm的可商用深紫外LED,在注入电流为20 mA时,单颗深紫外LED芯片的光输出功率达到了1.65 mW,对应的外量子效率为1.87%,饱和光输出功率达到4.31 mW. 相似文献
125.
XiaoBo Chen ZengFu Song JinGuang Wu N. Sawanoboi M. Ohtsuka YongLiang Li Jing Zhou Ce Wang JinYing Liu Qiang Tian Ping Sun HongMei Jing 《中国科学G辑(英文版)》2008,51(12):1868-1876
The ultraviolet upconversion luminescence of Tm3+ ions sensitized by Yb3+ ions in oxyfluoride nanophase vitroceramics when excited by a 975 nm diode laser was studied. An ultraviolet upconversion
luminescence line positioned at 363.6 nm was found. It was attributed to the fluorescence transition of 1D2→3H6 of Tm3+ ion. Several visible upconversion luminescence lines at 450.7 nm, (477.0 nm, 462.5 nm), 648.5 nm, (680.5 nm, 699.5 nm) and
(777.2 nm, 800.7 nm) were also found, which result respectively from the fluorescence transitions of 1D2→3F4, 1G4→3H6, 1G4→3F4, 3F3→3H6 and 3H4→3H6 of Tm3+ ion. The careful measurement and analysis of the variation of upconversion luminescence intensity F as a function of the 975 nm pumping laser power P prove that the upconversion luminescence of 1D2 state is partly a five-photon upconversion luminescence, and the upconversion luminescence of 1G4 state and 3H4 state are respectively the three-photon and two-photon upconversion luminescence. The theoretical analysis suggested that
the upconversion mechanism of the 363.6 nm 1D2→3H6 upconversion luminescence is partly the cross energy transfer of {3H4(Tm3+), 3F4(Tm3+), 1G4(Tm3+)→1D2(Tm3+)} and {1G4(Tm3+)→3F4(Tm3+), 3H4(Tm3+)→1D2(Tm3+)} between Tm3+ ions. In addition, the upconversion luminescence of 1G4 and 3H4 state results respectively from the sequential energy transfer {2F5/2(Yb3+)→2F7/2(Yb3+), 3H4(Tm3+)→1G4(Tm3+)} and {2F5/2(Yb3+) →2F7/2(Yb3+), 3F4(Tm3+)→3F2(Tm3+)} from Yb3+ ions to Tm3+ ions.
Supported by the National Natural Science Foundation of China (Grant No. 10674019) 相似文献
126.
Wang X. Yang S. Wang J. Li M. Jiang X. Du G. Liu X. Chang R.P.H. 《Optical and Quantum Electronics》2002,34(9):883-891
High quality ZnO film was deposited by plasma-assisted metal-organic chemical vapor deposition (MOCVD). We observed a dominant peak at 34.6° due to (0 0 2) ZnO, which indicated that the growth of ZnO film was strongly C-oriented. The full-width at half-maximum (FWHM) of the -rocking curve was 0.56° indicating relatively small mosaicity. Photoluminescence (PL) measurement was performed at both room temperature and low temperature. Ultraviolet (UV) emission at 3.30 eV was found with high intensity at room temperature while the deep level transition was weakly observed at 2.513 eV. The ratio of the intensity of UV emission to that of deep level emission was as high as 193, which implied high quality of ZnO film. From PL spectrum at 10 K, we observed A-exciton emission at 3.377 eV and D°X bound exciton transition at 3.370 eV. The donor–acceptor transition and LO phonon replicas were observed at 3.333 and 3.241 eV respectively. Raman scattering was performed in back scattering at room temperature. The E2, A1(LO) and A1(TO) mode was seen at 437.6, 575.8 and 380 cm–1 respectively. In comparison with Raman spectrum of ZnO powder, we found that ZnO film was nearly free of strain, which indicated high crystal quality. 相似文献
127.
128.
P. Billaud J.-R. Huntzinger E. Cottancin J. Lermé M. Pellarin L. Arnaud M. Broyer N. Del Fatti F. Vallée 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,43(1-3):271-274
The extinction spectrum of single silver nanoparticles
with size ranging from 20 to 80 nm is investigated with the spatial
modulation spectroscopy technique using either a tunable laser or a white
lamp as the broadband source. Results are in good agreement with the
prediction of the Mie theory, permitting to extract the nanoparticle size
from the measured absolute value of the optical extinction cross-section. In
contrast, the deduced refractive index of the nanoparticle environment and
the reduction of the electron mean free path show a large dependence on the
precise value of the bulk silver dielectric function. 相似文献
129.
C. Labaune K. Lewis H. Bandulet S. Depierreux S. Hüller P. E. Masson-Laborde D. Pesme P. Loiseau 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,44(2):283-288
Many nonlinear processes may affect the laser beam propagation and the laser
energy deposition in the underdense plasma surrounding the pellet. These
processes, associated with anomalous and nonlinear absorption mechanisms,
are fundamental issues in the context of Inertial Confinement Fusion. The
work presented in this article refers to laser-plasma interaction
experiments which were conducted under well-controlled conditions, and to
their theoretical and numerical modeling. Thanks to important diagnostics
improvements, the plasma and laser parameters were sufficiently
characterized in these experiments to make it possible to carry out
numerical simulations modeling the laser plasma interaction in which the
hydrodynamics conditions were very close to the experimental ones. Two sets
of experiments were carried out with the LULI 2000 and the six beam LULI
laser facilities. In the first series of experiments, the interaction
between two single hot spots was studied as a function of their distance,
intensity and light polarization. In the second series, the intensity
distribution of stimulated Brillouin scattering (SBS) inside the plasma was
studied by means of a new temporally resolved imaging system.
Two-dimensional (2D) simulations were carried out with our code Harmony2D in
order to model these experiments. For both series of experiments, the
numerical results show a very good agreement with the experimental ones for
what concerns the main SBS features, namely the spatial and temporal
behavior of the SBS-driven acoustic waves, as well as the average SBS
reflectivities. Thus, these well diagnosed experiments, carried out with
well defined conditions, make it possible to benchmark our theoretical and
numerical modelings and, hence, to improve our predictive capabilities for
future experiments. 相似文献
130.