全文获取类型
收费全文 | 59614篇 |
免费 | 5428篇 |
国内免费 | 3073篇 |
专业分类
电工技术 | 4217篇 |
技术理论 | 5篇 |
综合类 | 4186篇 |
化学工业 | 9181篇 |
金属工艺 | 3555篇 |
机械仪表 | 3495篇 |
建筑科学 | 5192篇 |
矿业工程 | 1527篇 |
能源动力 | 1773篇 |
轻工业 | 3746篇 |
水利工程 | 1063篇 |
石油天然气 | 3174篇 |
武器工业 | 511篇 |
无线电 | 7328篇 |
一般工业技术 | 7357篇 |
冶金工业 | 2566篇 |
原子能技术 | 763篇 |
自动化技术 | 8476篇 |
出版年
2024年 | 317篇 |
2023年 | 1094篇 |
2022年 | 1765篇 |
2021年 | 2572篇 |
2020年 | 1835篇 |
2019年 | 1529篇 |
2018年 | 1730篇 |
2017年 | 1930篇 |
2016年 | 1718篇 |
2015年 | 2341篇 |
2014年 | 2829篇 |
2013年 | 3472篇 |
2012年 | 3755篇 |
2011年 | 3991篇 |
2010年 | 3617篇 |
2009年 | 3355篇 |
2008年 | 3480篇 |
2007年 | 3321篇 |
2006年 | 3339篇 |
2005年 | 2824篇 |
2004年 | 2006篇 |
2003年 | 1809篇 |
2002年 | 1902篇 |
2001年 | 1693篇 |
2000年 | 1466篇 |
1999年 | 1577篇 |
1998年 | 1159篇 |
1997年 | 1020篇 |
1996年 | 1000篇 |
1995年 | 809篇 |
1994年 | 672篇 |
1993年 | 492篇 |
1992年 | 437篇 |
1991年 | 329篇 |
1990年 | 220篇 |
1989年 | 185篇 |
1988年 | 158篇 |
1987年 | 100篇 |
1986年 | 66篇 |
1985年 | 56篇 |
1984年 | 35篇 |
1983年 | 23篇 |
1982年 | 32篇 |
1981年 | 18篇 |
1980年 | 19篇 |
1979年 | 8篇 |
1978年 | 2篇 |
1959年 | 2篇 |
1951年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
891.
论述了合成孔径雷达(Synthetic Aperture Radar,SAR)实时成像处理转置存储器(Corner Turning Memory,CTM)的功能和原理,提出了一种基于SDRAM的星载SAR星上实时成像处理CTM系统实现方案。考虑到星上环境对器件的抗辐照要求,系统选用一片XQB2V500 FPGA做控制器,主存储器选用三片Micron公司的MT48LC16A2 SDRAM。系统采用三页式结构,输入输出并行处理。文章分析了系统输入、输出接口时序,给出了详细的硬件实现和测试结果。实验结果表明该CTM系统方案可行,能够应用在星上实时成像处理器中。 相似文献
892.
893.
894.
HE Shi-ya DENG Yan-hao YU Yang HU Shu-yang GUAN Zheng 《光电子快报》2007,3(3):219-221
In this paper,a two-function light source is recommended. It can both amplify the light power and demodulate the wave-length signal. Its output power is 1000 times as high as traditional broadband light source(BBS) and it can demodulate the signal by scanning wavelength in 30 nm of bandwidth range in the situation of 1550 nm central wavelength. This kind of light source effectively solves the problem of light energy supply in more-point measurement of FBG and simplifies the structure of sensing measurement. 相似文献
895.
896.
Chengyun Zhang Min Ji Xilin Zhou Xiaohu Mi Huan Chen Baobao Zhang Zhengkun Fu Zhenglong Zhang Hairong Zheng 《Advanced functional materials》2023,33(2):2208561
All-optical responsive nanomaterials, which can rapidly switch between two stable states, have been regarded as the next-generation memories due to their potential to realize binary information storage and implement on-chip, integrated photonic neuromorphic systems. Rare earth oxides are preeminent candidates owing to their extraordinary luminescent stability and narrow optical transitions. However, due to the lack of simple and effective optical switches, it is difficult to realize all-optical data storage, encoding, and retrieval by pure rare earth-doped luminescent nanoparticles. Here, a rapid and high-contrast of 104 luminescent switching of Y2O3:Eu3+ nanoparticle between the enhancement and quenching states is achieved by employing the strong light confinement and ultrafast thermal response of localized surface plasmon resonance. A self-encrypted all-optical memory is presented with optical information writing, encryption, reading, and re-writing, and a high-sensitivity synaptic response of emitters to frequency and light intensity flux, which can be harnessed to encrypt information flows and promote convenient and high-security information encryption. Such a convenient and secure plasmonic thermally assisted self-encrypting luminescent switch paves the way for constructing high-performance stimuli-responsive rare earth oxide crystals on demand and expanding their applications in various data encryption, anti-counterfeiting, and rewritable colouration devices. 相似文献
897.
The pentacene-based organic field effect transistor (OFET) with a thin transition metal oxide (WO3) layer between pentacene and metal (AI) source/drain electrodes was fabricated. Compared with conventional OFET with only metal AI source/drain electrodes, the introduction of the WO3 buffer layer leads to the device performance enhancement. The effective field-effect mobility and threshold voltage are improved to 1.90 em2/(V.s) and 13 V, respectively. The performance improvements are attributed to the decrease of the interface energy barrier and the contact resistance. The results indicate that it is an effective approach to improve the OFET performance by using a WO3 buffer layer. 相似文献
898.
Xiangqian Jia Hang Chen Mengling Wu Luyao Wang Tiantian Li Jing Ma Xueqing Yi Pengcheng Tan Peiyuan Zheng Juanjuan Du 《Advanced functional materials》2023,33(10):2212085
Materials-based antigen delivery systems can augment the immune response by improving antigen uptake in antigen-presenting cells, targeting lymph nodes, prolonging antigen exposure, enhancing cross-presentation, etc. Recent research revealed that some antigen carriers activate the innate immune pathways without additional adjuvant. Here, a vaccine delivery platform (antigen nanocapsules) constructed by a one-step in situ polymerization is reported, weaving a biodegradable polymer network around the antigen surface. This simple technology allowed us to study the immunomodulatory effect of various antigen carriers. An antigen nanocapsule (NC7) capable of inducing dendritic cell activation and cross-presentation is identified. Further mechanistic studies revealed that NC7 activated the cGAS-STING pathway in a cGAS-dependent manner. Moreover, the subcutaneously injected NC7 accumulated in the lymph nodes and elicited strong cytotoxic T cell immunity and T cell memory against established cancer. Collectively, the often-neglected immunomodulatory effect of various cationic antigen carriers, enabling potential application in cancer vaccines, is uncovered. 相似文献
899.
Zhuoran Lv Baixin Peng Ximeng Lv Yusha Gao Keyan Hu Wujie Dong Gengfeng Zheng Fuqiang Huang 《Advanced functional materials》2023,33(16):2214370
Alloying-type metal sulfides with high theoretical capacities are promising anodes for sodium-ion batteries, but suffer from sluggish sodiation kinetics and huge volume expansion. Introducing intercalative motifs into alloying-type metal sulfides is an efficient strategy to solve the above issues. Herein, robust intercalative In S motifs are grafted to high-capacity layered Bi2S3 to form a cation-disordered (BiIn)2S3, synergistically realizing high-rate and large-capacity sodium storage. The In S motif with strong bonding serves as a space-confinement unit to buffer the volume expansion, maintaining superior structural stability. Moreover, the grafted high-metallicity Indium increases the bonding covalency of Bi S, realizing controllable reconstruction of Bi S bond during cycling to effectively prevent the migration and aggregation of atomic Bi. The novel (BiIn)2S3 anode delivers a high capacity of 537 mAh g−1 at 0.4 C and a superior high-rate stability of 247 mAh g−1 at 40 C over 10000 cycles. Further in situ and ex situ characterizations reveal the in-depth reaction mechanism and the breakage and formation of reversible Bi S bonds. The proposed space confinement and bonding covalency enhancement strategy via grafting intercalative motifs can be conducive to developing novel high-rate and large-capacity anodes. 相似文献
900.