全文获取类型
收费全文 | 14934篇 |
免费 | 187篇 |
国内免费 | 18篇 |
专业分类
电工技术 | 269篇 |
综合类 | 6篇 |
化学工业 | 1332篇 |
金属工艺 | 424篇 |
机械仪表 | 145篇 |
建筑科学 | 178篇 |
矿业工程 | 25篇 |
能源动力 | 336篇 |
轻工业 | 333篇 |
水利工程 | 21篇 |
石油天然气 | 15篇 |
无线电 | 1058篇 |
一般工业技术 | 1269篇 |
冶金工业 | 931篇 |
原子能技术 | 127篇 |
自动化技术 | 8670篇 |
出版年
2023年 | 58篇 |
2022年 | 59篇 |
2021年 | 134篇 |
2020年 | 126篇 |
2019年 | 122篇 |
2018年 | 157篇 |
2017年 | 159篇 |
2016年 | 140篇 |
2015年 | 110篇 |
2014年 | 359篇 |
2013年 | 560篇 |
2012年 | 983篇 |
2011年 | 2554篇 |
2010年 | 1334篇 |
2009年 | 1185篇 |
2008年 | 909篇 |
2007年 | 791篇 |
2006年 | 645篇 |
2005年 | 759篇 |
2004年 | 664篇 |
2003年 | 703篇 |
2002年 | 381篇 |
2001年 | 118篇 |
2000年 | 80篇 |
1999年 | 91篇 |
1998年 | 218篇 |
1997年 | 157篇 |
1996年 | 109篇 |
1995年 | 85篇 |
1994年 | 115篇 |
1993年 | 107篇 |
1992年 | 87篇 |
1991年 | 69篇 |
1990年 | 61篇 |
1989年 | 48篇 |
1988年 | 60篇 |
1987年 | 57篇 |
1986年 | 50篇 |
1985年 | 82篇 |
1984年 | 61篇 |
1983年 | 50篇 |
1982年 | 48篇 |
1981年 | 63篇 |
1980年 | 48篇 |
1979年 | 43篇 |
1978年 | 37篇 |
1977年 | 47篇 |
1976年 | 48篇 |
1974年 | 32篇 |
1973年 | 34篇 |
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
1.
Vilde Yuli Stenberg Roy Hartvig Larsen Li-Wei Ma Qian Peng Petras Juzenas
yvind Sverre Bruland Asta Juzeniene 《International journal of molecular sciences》2021,22(9)
Radioligand therapy targeting the prostate-specific membrane antigen (PSMA) is rapidly evolving as a promising treatment for metastatic castration-resistant prostate cancer. The PSMA-targeting ligand p-SCN-Bn-TCMC-PSMA (NG001) labelled with 212Pb efficiently targets PSMA-positive cells in vitro and in vivo. The aim of this preclinical study was to evaluate the therapeutic potential of 212Pb-NG001 in multicellular tumour spheroid and mouse models of prostate cancer. The cytotoxic effect of 212Pb-NG001 was tested in human prostate C4-2 spheroids. Biodistribution at various time points and therapeutic effects of different activities of the radioligand were investigated in male athymic nude mice bearing C4-2 tumours, while long-term toxicity was studied in immunocompetent BALB/c mice. The radioligand induced a selective cytotoxic effect in spheroids at activity concentrations of 3–10 kBq/mL. In mice, the radioligand accumulated rapidly in tumours and was retained over 24 h, while it rapidly cleared from nontargeted tissues. Treatment with 0.25, 0.30 or 0.40 MBq of 212Pb-NG001 significantly inhibited tumour growth and improved median survival with therapeutic indexes of 1.5, 2.3 and 2.7, respectively. In BALB/c mice, no signs of long-term radiation toxicity were observed at activities of 0.05 and 0.33 MBq. The obtained results warrant clinical studies to evaluate the biodistribution, therapeutic efficacy and toxicity of 212Pb-NG001. 相似文献
2.
Wireless Personal Communications - The paper reports the performance of an energy harvesting cognitive radio network under primary user emulation (PUE) attack. A secondary user (SU) can harvest... 相似文献
3.
Roy Swalpa Kumar Chanda Bhabatosh Chaudhuri Bidyut B. Ghosh Dipak Kumar Dubey Shiv Ram 《Multimedia Tools and Applications》2020,79(7-8):4783-4809
Multimedia Tools and Applications - Methods based on locally encoded image features have recently become popular for texture classification tasks, particularly in the existence of large intra-class... 相似文献
4.
5.
Kihong Lee Sebastian F. Maehrlein Xinjue Zhong Daniele Meggiolaro Jake C. Russell Douglas A. Reed Bonnie Choi Filippo De Angelis Xavier Roy Xiaoyang Zhu 《Advanced materials (Deerfield Beach, Fla.)》2019,31(36)
The coupling of phonons to electrons and other phonons plays a defining role in material properties, such as charge and energy transport, light emission, and superconductivity. In atomic solids, phonons are delocalized over the 3D lattice, in contrast to molecular solids where localized vibrations dominate. Here, a hierarchical semiconductor that expands the phonon space by combining localized 0D modes with delocalized 2D and 3D modes is described. This material consists of superatomic building blocks (Re6Se8) covalently linked into 2D sheets that are stacked into a layered van der Waals lattice. Using transient reflectance spectroscopy, three types of coherent phonons are identified: localized 0D breathing modes of isolated superatom, 2D synchronized twisting of superatoms in layers, and 3D acoustic interlayer deformation. These phonons are coupled to the electronic degrees of freedom to varying extents. The presence of local phonon modes in an extended crystal opens the door to controlling material properties from hierarchical phonon engineering. 相似文献
6.
A. K. Roy 《Journal of Modern Optics》2019,66(4):448-454
Two ways of constructing analytic phase function for a polydispersion of small spherical non-absorbing particles have been investigated. First one is a straightforward procedure emanating from the implementation of single particle scattering input into the defined polydisperse phase function. This results in an analytic phase function in terms of moments of the distribution. The second approach is a new strategy, based on the Lagrange mean value theorem. A clear understanding of the relationship between these two approaches has been developed. The efficacy and accuracy of the scattering phase functions is illustrated by applying it to a power-law size distributed sphere ensemble. 相似文献
7.
8.
9.
In the past decade, remarkable progress has been made in the domain of augmented reality/virtual reality (AR/VR). The need for realistic and immersive augmentation has propelled the development of haptics interfaces-enabled AR/VR. The haptics interfaces facilitate direct interaction and manipulation with both real and virtual objects, thus augmenting the perception and experiences of the users. The level of augmentation can be significantly improved by thermal stimulation or sensing, which facilitates a higher degree of object identification and discrimination. This review discusses the thermal technology-enabled augmented reality and summarizes the recent progress in the development of different thermal technology such as thermal haptics including thermo-resistive heater and Peltier devices, thermal sensors including resistive, pyroelectric, and thermoelectric sensors, which can be utilized to improve the realism of augmentation. The fundamental mechanism, design strategies, and the rational guidelines for the adoption of these technologies in AR/VR is explicitly discussed. The conclusion provides an outlook on the existing challenges and outlines the future roadmap for the realization of next-generation thermo-haptics enabled augmented reality. 相似文献
10.
Santanu Mandal Vijay Kishore Madhuparna Bose Samit Kumar Nandi Mangal Roy 《材料科学技术学报》2021,84(25):159-172
In recent years,iron(Fe)based degradable metal is explored as an alternative to permanent fracture fixation devices.In the present work,copper(Cu)is added in Fe-Mn system to enhance the degradation rate and antimicrobial properties.Fe-Mn-xCu(x=0.9,5 and 10 wt.%)alloys are prepared by the melting-casting-forging route.XRD analysis confirms austenite phase stabilization due to the presence of Mn and Cu.As predicted by Thermo-Calc calculations,Cu rich phase precipitations are noticed along the austen-ite grain boundaries.Degradation behaviours of Cu added Fe-Mn alloys are investigated through static immersion and electrochemical polarization where enhanced degradation is found for higher Cu added alloys.When challenged against E.Coli bacteria,the Fe-Mn-Cu alloy media extract shows a significant bac-tericidal effect compare to the base alloy.In vitro cytocompatibility studies,as determined using MG63 and MC3T3-E1 cell lines,indicate increased cell density as a function of time for all the alloys.When implanted in rabbit femur,the newly developed alloy does not show any kind of tissue necrosis around the implants.Better osteogenesis and higher new bone formation are observed with Fe-Mn-10Cu alloy as evident from micro-computed tomography(μ-CT)and fluorochrome labelling. 相似文献