全文获取类型
收费全文 | 2563篇 |
免费 | 106篇 |
国内免费 | 315篇 |
专业分类
电工技术 | 88篇 |
综合类 | 166篇 |
化学工业 | 403篇 |
金属工艺 | 188篇 |
机械仪表 | 124篇 |
建筑科学 | 108篇 |
矿业工程 | 33篇 |
能源动力 | 52篇 |
轻工业 | 167篇 |
水利工程 | 82篇 |
石油天然气 | 110篇 |
武器工业 | 5篇 |
无线电 | 278篇 |
一般工业技术 | 726篇 |
冶金工业 | 120篇 |
原子能技术 | 65篇 |
自动化技术 | 269篇 |
出版年
2024年 | 47篇 |
2023年 | 185篇 |
2022年 | 213篇 |
2021年 | 211篇 |
2020年 | 91篇 |
2019年 | 70篇 |
2018年 | 79篇 |
2017年 | 44篇 |
2016年 | 45篇 |
2015年 | 68篇 |
2014年 | 79篇 |
2013年 | 101篇 |
2012年 | 236篇 |
2011年 | 273篇 |
2010年 | 80篇 |
2009年 | 59篇 |
2008年 | 189篇 |
2007年 | 154篇 |
2006年 | 167篇 |
2005年 | 128篇 |
2004年 | 59篇 |
2003年 | 45篇 |
2002年 | 49篇 |
2001年 | 36篇 |
2000年 | 36篇 |
1999年 | 35篇 |
1998年 | 34篇 |
1997年 | 26篇 |
1996年 | 42篇 |
1995年 | 20篇 |
1994年 | 15篇 |
1993年 | 14篇 |
1992年 | 11篇 |
1991年 | 12篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1982年 | 12篇 |
1980年 | 1篇 |
排序方式: 共有2984条查询结果,搜索用时 12 毫秒
11.
Pei Han Li-Sha Li Zi-Xi Wang Lin Xi Hang Yu Lin Cong Zheng-Wei Zhang Jie Fu Ran Peng Li-Bin Pan Shu-Rong Ma Xue-Yan Wang Hong-Tian Wang Xiang-Dong Wang Yan Wang Jin-Lyu Sun Jian-Dong Jiang 《工程(英文)》2022,(8):115-125
Due to the worldwide epidemic of allergic disease and a cure nowhere in sight, there is a crucial need to explore its pathophysiological mechanisms. As allergic disease has been associated with gut dysbiosis, we searched for a possible mechanism from the perspective of the molecular interface between host and microbiota with concurrent metabolomics and microbiome composition analysis. Sprague-Dawley rats were injected with Artemisia pollen extract to stimulate a hyper reaction to pollen. This hy... 相似文献
12.
Formationcrossectionsofnucleiwith(n,2n)reactionsChenXueShi,XieKuanZhong,ZhouShengMo,YanQingQuan(ShanghaiInstituteofNucle... 相似文献
13.
Chen Hui Yan Jiasong Su Youyou Wei Xueer Li Rui Wang Peng Yu Shanqing Dai Zhenyu 《中国炼油与石油化工》2022,(4):12-20
Although naphthenes have long been identified as important feedstock components for the production of light olefins and aromatics in fluid catalytic cracking units, their cacking mechanism and microscopic reaction networks, such as activation modes, ring-opening paths, and the production of aromatics, remain debated. In this context, we reported experimental and computational work aimed at elucidating the reaction network of naphthenes in fluid catalytic cracking using cyclohexane as the model n... 相似文献
14.
Yan-Fang Zhang Jinbo Pan Huta Banjade Jie Yu Hsin Lin Arun Bansil Shixuan Du Qimin Yan 《Nano Research》2021,(3):584-589
We propose a novel class of two-dimensional(2D)Dirac materials in the MX family(M=Be,Mg,Zn and Cd,X=Cl,Br and I),which exhibit graphene-like band structures with linearly-dispersing Dirac-cone states over large energy scales(0.8–1.8 eV)and ultra-high Fermi velocities comparable to graphene.Spin-orbit coupling opens sizable topological band gaps so that these compounds can be effectively classified as quantum spin Hall insulators.The electronic and topological properties are found to be highly tunable and amenable to modulation via anion-layer substitution and vertical electric field.Electronic structures of several members of the family are shown to host a Van-Hove singularity(VHS)close to the energy of the Dirac node.The enhanced density-of-states associated with these VHSs could provide a mechanism for inducing topological superconductivity.The presence of sizable band gaps,ultra-high carrier mobilities,and small effective masses makes the MX family promising for electronics and spintronics applications. 相似文献
15.
随着清洁能源的广泛应用,提高输气管道的输送效率成为热点问题,其中降低管输过程中的摩擦阻力至关重要。为探究三角形肋条在输气管道减阻中的应用效果,利用ANSYS-FLUENT软件对光滑管道和肋条管道中的湍流流动进行了数值模拟。结果表明,在近壁区域,肋条管道与光滑管道的速度剖面相差较大,主流区域相差较小,肋条结构的减阻效果主要基于近壁面;肋条结构将漩涡推离壁面,使肋底充满低速流体,降低近壁面处动量交换,减小摩擦阻力;与光滑壁面相比,尺寸为s=h=0.516 5 mm的肋条具有4.38%的减阻效果。 相似文献
16.
In the multi-target localization based on Compressed Sensing(CS), the sensing matrix’s characteristic is significant to the localization accuracy.To improve the CS-based localization approach’s performance, we propose a sensing matrix optimization method in this paper, which considers the optimization under the guidance of the t%-averaged mutual coherence. First, we study sensing matrix optimization and model it as a constrained combinatorial optimization problem. Second, the t%-averaged mutual ... 相似文献
17.
A two-step high-precision Time-to-Digital Converter(TDC), integrated with a Single-Photon Avalanche Diode(SPAD), used for Time-Of-Flight(TOF) application, has been developed and tested. Time interval measurement is performed by the coarse counter and fine interpolator, which are utilized to measure the total periods and the residue time of the reference clock, respectively. Following a detail analysis of time precision and clock jitter in the two-step structure, the prototype TDC fabricated in GSMC 1P6M 0.18 μm CMOS Image Sensor(CIS) technology exhibits a Single-Shot Precision(SSP) of 11.415 ps and a dynamic range of 216.7 ns. In addition, a pixel of the chip occupies 100 μm×100 μm, and the measured Integral Nonlinearity(INL) and Differential Nonlinearity(DNL) are better than ±0.88 LSB and ±0.67 LSB, respectively. Meanwhile, the overall power consumption of the chip is 35 mW at 1.8 V power supply. Combined with these characteristics, the designed chip is suitable for TOF-based ranging applications. 相似文献
18.
Yuanhao Mao Dong Zhao Shen Yan Hongjia Zhang Juan Li Kai Han Xiaojun Xu Chuan Guo Lexian Yang Chaofan Zhang Kun Huang Yulin Chen 《光:科学与应用(英文版)》2021,10(3):371-378
Vacuum ultraviolet(VUV)lasers have demonstrated great potential as the light source for various spectroscopies,which,if they can be focused into a small beam spot,will not only allow investigation of mesoscopic materials and structures but also find application in the manufacture of nano-objects with excellent precision.In this work,we report the construction of a 177 nm VUV laser that can achieve a record-small(〜0.76 μm)focal spot at a long focal length(~45 mm)by using a flat lens without spherical aberration.The size of the beam spot of this VUV laser was tested using a metal grating and exfoliated graphene flakes,and we demonstrated its application in a fluorescence spectroscopy study on pure and Tm3+-doped NaYF4 microcrystals,revealing a new emission band that cannot be observed in the traditional up-conversion process.In addition,this laser system would be an ideal light source for spatially and angleresolved photoemission spectroscopy. 相似文献
19.
交口地区低品位铝土矿石泥化严重,有用矿物嵌布粒度极细,浮选给料-10μm占56.16%。山西道尔铝业现场不仅药剂消耗量大,而且精矿产率低。针对该极微细粒难选矿石,采用EFD空腔谐振式浮选柱开展了一系列小试、中试及扩大连选试验。在半工业试验取得理想指标的基础上,采用6台EFD?5.0 m×8.5 m型空腔谐振式浮选柱扩建一条年处理50万t低品位铝土矿石的生产线。新建生产线采用1粗1精1扫流程取代原系统的2粗1精2扫流程。在精矿铝硅比相当的情况下,精矿产率比原系统提高了3.36个百分点、Al2O3回收率提高了3.68个百分点。浮选药剂消耗比原系统的1 600 g/t降低了509 g/t,年经济效益超过1 000万元。空腔谐振式浮选柱在超细粒铝土矿行业的成功应用,为具有超细粒嵌布特征的金属、非金属矿石的高效浮选开辟出了新思路,具有广阔的应用前景和推广价值。 相似文献
20.
以城市森林建设项目监理管控技术为研究对象,通过对城市森林建设项目的理解,分析监理管控的难点,并提出针对性的管控要点及方式。同时,提出监理对“双碳”和绿色绩效的监管方式和手段。 相似文献