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991.
Research on planar-to-stereo image conversion has significant theoretical and practical implications for image processing. In this paper we use a method which segments an image into sub-blocks to perform this kind of conversion; parameters such as random variables are used for conversion control. We use two quantitative criteria, cross-entropy and root-mean-square error, to evaluate the stereo effect. Furthermore, the stereo effect that the random variables create is discussed. The results of the experiment show that, (i) when all random variables have the same distribution, different values of these random variables only slightly affect the stereo effect; and (ii) when different distributions are applied to the random variables, the cross-entropies or root-mean-square errors are slightly different, which indicates different distributions have a small influence on the stereo effect. Generally, we recommend normal distribution for better stereo effect in most cases. 相似文献
992.
Kaizhi Zhang Haidong Yu Zhongpo Liu Xinmin Lai 《Simulation Modelling Practice and Theory》2010,18(7):1019-1031
In this paper, by taking into account the periodically varying mesh stiffness in multiple pinions transmission and the speed–torque characteristics of variable frequency motor drives, the dynamic model for the revolving system of tunnel boring machine (TBM) has been established. Based on the soft ground/hard rock assumption of mixed-face conditions and the analysis of cutting force on each disc cutter and each drag bit, the time-varying excavation torque on the TBM cutterhead in mixed-face tunnelling is obtained. The dynamic excavation torque and cutterhead rotation speed are discussed and compared for TBM tunnelling in several typical mixed-face conditions, which are characterized by the area percentage of soft ground on the excavation face and the uniaxial compressive strength (UCS) of rock. The results show that the excavation torque may run up to a critical value and fluctuate greatly in extremely adverse excavation environments, which may lead to an unexpected TBM stoppage and even a catastrophic failure of the drive motor. To decrease the penetration per revolution in time through applying a lower advance velocity and a higher cutterhead revolution will significantly reduce the excavation torque and effectively avoid such situations. 相似文献
993.
Linux防火墙Netfilter-iptables扩展机制及应用研究 总被引:2,自引:0,他引:2
分析了Linux2.4内核的Netfilter在IP协议栈的位置和结构,介绍了应用patch-o-matic结构扩展Netfilter-iptables目标(target)选项的机制和方法。以实例说明如何通过自定义的target选项分析输出网络堆栈,实现在不同网络节点分析观察网络数据包。 相似文献
994.
一种障碍环境下机器人路径规划的蚁群粒子群算法 总被引:5,自引:3,他引:5
针对机器人在障碍环境下寻找最优路径问题, 提出了一种障碍环境下机器人路径规划的蚁群粒子群算法.该方法有效地结合了粒子群算法和蚁群算法的优点, 采用栅格法进行环境建模, 利用粒子群算法的快速简洁等特点得到蚁群算法初始信息素分布, 以减少迭代次数, 加快算法的收敛速度; 同时利用蚁群算法之间的可并行性, 采用分布式技术实现蚂蚁之间的并行搜索, 求解精度高等优点, 求精确解. 仿真实验结果证明了该方法的有效性, 是机器人路径规划的一种较好的方法. 相似文献
995.
无线电信号的模拟调制参数测量在无线电检测定位、通信发射机测试校准,民用船舶的导航通信等领域都有广泛应 用。设计实现了一种基于超外差结构的无线电信号模拟调制参数的测量系统,以STM32F4 系列单片机作为控制核心,包括 的主要硬件电路模块有本振信号源、混频器、LC无源滤波器、锁相环、低噪声放大器、包络检波电路、鉴频电路等。系统可自 动识别普通调幅波、调频波、未调制的单频载波等模拟调制类型,完成无线电信号解调输出的同时自动测量出载波频率、调制 信号频率、调幅指数、调频指数等主要调制参数。实测结果表明,系统对调制类型识别正确,调幅或调频信号的解调波形信噪 比高、无明显失真,载波频率测量的相对误差小于10-5,主要调制参数测量的相对误差均小于5%。 相似文献
996.
997.
Huaying Ren Huan Wang Li Lin Miao Tang Shuli Zhao Bing Deng Manish Kumar Priydarshi Jincan Zhang Hailin Peng Zhongfan Liu 《Nano Research》2017,10(4):1189-1199
In the chemical vapor deposition growth of large-area graphene polycrystalline thin films,the coalescence of randomly oriented graphene domains results in a high density of uncertain grain boundaries (GBs).The structures and properties of various GBs are highly dependent on the misorientation angles between the graphene domains,which can significantly affect the performance of the graphene films and impede their industrial applications.Graphene bicrystals with a specific type of GB can be synthesized via the controllable growth of graphene domains with a predefined lattice orientation.Although the bicrystal has been widely investigated for traditional bulk materials,no successful synthesis strategy has been presented for growing two-dimensional graphene bicrystals.In this study, we demonstrate a simple approach for growing well-aligned large-domain graphene bicrystals with a confined tilt angle of 30° on a facilely recrystallized single-crystal Cu (100) substrate.Control of the density of the GBs with a misorientation angle of 30° was realized via the controllable rapid growth of subcentimeter graphene domains with the assistance of a cooperative catalytic surface-passivation treatment.The large-area production of graphene bicrystals consisting of the sole specific GBs with a tunable density provides a new material platform for fundamental studies and practical applications. 相似文献
998.
999.
Zi Yang Qiang Li Yuanyuan Li Shaofeng Zhang Lin Wang 《Journal of Materials Science》2012,47(23):8007-8012
Single crystals of Pb0.97La0.02(Zr0.66Sn0.27Ti0.07)O3 (PLZST) with the composition near the morphotropic phase boundary were grown by the flux method. The PbO–PbF2–B2O3 system was used as a solvent. PLZST single crystals with the size of 4–6 mm are obtained and these crystals are slightly translucent after polishing. The splitting of (200) reflection peak indicates that the obtained crystals are of a single phase with tetragonal perovskite structure. The element contents of the grown crystals were measured by inductively coupled plasma atomic emission spectrometry. The chemical composition of the crystals is Pb0.979La0.014(Zr0.666Sn0.285Ti0.049)O3. Thermal properties and dielectric properties of PLZST single crystals were studied. The results show that flux-grown PLZST single crystals exhibit obvious endothermic processes and relaxor behaviors near the phase transition temperatures. 相似文献
1000.
研究以壳聚糖(Cs)作为高分子金属催化剂载体,制得负载稀土金属化合物的高分子金属催化剂,应用于环氧乙烷(BO)和环氧丙烷(PO)的共聚合反应.研究发现以三异丁基铝(Al(i-Bu)3)为助催化剂,乙酰丙酮(Acac)为第三组分时,该体系的催化活性高达192 kg*copolymer/mol*Y,比非负载型稀土催化体系活性提高1个数量级以上.环氧乙烷和环氧丙烷的竞聚率r 1(EO)、r 2(PO)分别为2.75±0.02和0.55±0.01;并用13C-NMR谱和DSC谱对共聚物结构进行了表征. 相似文献