全文获取类型
收费全文 | 7240篇 |
免费 | 628篇 |
国内免费 | 250篇 |
专业分类
电工技术 | 248篇 |
综合类 | 332篇 |
化学工业 | 2184篇 |
金属工艺 | 165篇 |
机械仪表 | 175篇 |
建筑科学 | 444篇 |
矿业工程 | 229篇 |
能源动力 | 357篇 |
轻工业 | 718篇 |
水利工程 | 195篇 |
石油天然气 | 127篇 |
武器工业 | 49篇 |
无线电 | 320篇 |
一般工业技术 | 1852篇 |
冶金工业 | 178篇 |
原子能技术 | 178篇 |
自动化技术 | 367篇 |
出版年
2024年 | 28篇 |
2023年 | 104篇 |
2022年 | 291篇 |
2021年 | 251篇 |
2020年 | 227篇 |
2019年 | 275篇 |
2018年 | 248篇 |
2017年 | 300篇 |
2016年 | 278篇 |
2015年 | 274篇 |
2014年 | 390篇 |
2013年 | 773篇 |
2012年 | 472篇 |
2011年 | 468篇 |
2010年 | 367篇 |
2009年 | 350篇 |
2008年 | 313篇 |
2007年 | 408篇 |
2006年 | 350篇 |
2005年 | 343篇 |
2004年 | 257篇 |
2003年 | 189篇 |
2002年 | 197篇 |
2001年 | 147篇 |
2000年 | 137篇 |
1999年 | 115篇 |
1998年 | 85篇 |
1997年 | 99篇 |
1996年 | 60篇 |
1995年 | 58篇 |
1994年 | 48篇 |
1993年 | 46篇 |
1992年 | 24篇 |
1991年 | 28篇 |
1990年 | 21篇 |
1989年 | 22篇 |
1988年 | 16篇 |
1987年 | 10篇 |
1986年 | 9篇 |
1985年 | 9篇 |
1984年 | 11篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 8篇 |
1978年 | 1篇 |
1965年 | 1篇 |
1951年 | 1篇 |
排序方式: 共有8118条查询结果,搜索用时 0 毫秒
81.
半纤维素基水凝胶是一种具有优异保水性、良好生物相容性和力学性能的三维网络状亲水聚合物,在软材料领域尤其是半纤维素基材料研究领域备受瞩目。本文综述了近年来半纤维素基水凝胶的研究进展,从化学交联和物理交联两个方面介绍了半纤维素基水凝胶的制备方法、形成机理和性能,比较了化学交联中光、酶、微波辐射和辉光放电电解等离子体等不同引发体系的差异,总结了半纤维素基水凝胶在药物控释、伤口敷料、高效吸附及3D打印等领域的最新应用和发展,并对半纤维素基水凝胶领域所面临的挑战进行了总结和展望,以期为新型半纤维素水凝胶的研究提供参考。 相似文献
82.
83.
介绍了柳州市柳石路鸡山工地复杂环境条件下高梯段深孔控制爆破技术。根据工程要求及环境特点,采用3~4排深孔及15排深孔一次起爆的爆破方案;通过选取合理的爆破参数,采用孔内孔外微差网格式闭合起爆网路,严格控制爆破飞石及爆破振动,使爆破工程取得了成功。 相似文献
84.
85.
The primary objective of this paper is to study the influence of the electroelastic interactions on the stress intensity factor
in bonded layers of piezoelectric and orthotropic materials containing a crack along the interface under antiplane shear.
Attention is given to a two-layer hybrid laminate formed by adding a layer of piezoelectric ceramic to a unidirectional graphite/epoxy
composite or an aluminum layer. Electric displacement or electric field is prescribed on the surfaces of the piezoelectric
layer. The problem is formulated in terms of a singular integral equation which is solved by using a relatively simple and
efficient technique. A number of examples are given for various material combinations. The results show that the effect of
the electroelastic interactions on the stress intensity factor and the energy release rate can be highly significant.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
86.
为了掌握环境温度和火灾强度对自然通风城市隧道温度场的影响,运用火灾模拟软件FDS,对在不同环境温度和火灾强度下自然通风隧道火灾进行模拟,得到各种火灾工况下的模拟结果,并对各种工况下的温度场进行对比分析。 相似文献
87.
88.
给出基于Matlab/Simulink三相无刷直流电机调速系统实用仿真模型,为系统中电机本体优化设计及电子器件参数合理选择提供重要依据。 相似文献
89.
Seo-Jun Kang Soo-Jeong Kim Hye Rin Noh Beom Jin Kim Jae-Bong Kim Uram Jin Sun Ah Park Sang Myun Park 《International journal of molecular sciences》2022,23(15)
The presence of protein inclusions, called Lewy bodies (LBs) and Lewy neurites (LNs), in the brain is the main feature of Parkinson’s disease (PD). Recent evidence that the prion-like propagation of α-synuclein (α-syn), as a major component of LBs and LNs, plays an important role in the progression of PD has gained much attention, although the molecular mechanism remains unclear. In this study, we evaluated whether neuronal ApoE regulates the cell-to-cell transmission of α-syn and explored its molecular mechanism using in vitro and in vivo model systems. We demonstrate that neuronal ApoE deficiency attenuates both α-syn uptake and release by downregulating LRP-1 and LDLR expression and enhancing chaperone-mediated autophagy activity, respectively, thereby contributing to α-syn propagation. In addition, we observed that α-syn propagation was attenuated in ApoE knockout mice injected with pre-formed mouse α-syn fibrils. This study will help our understanding of the molecular mechanisms underlying α-syn propagation. 相似文献
90.
Niuosha Sanaeifar Karsten Mder Dariush Hinderberger 《International journal of molecular sciences》2022,23(13)
We report extended ethanol-induced gelation procedures of bovine serum albumin (BSA) at 37 °C and investigate the release behavior of a spin-labeled naproxen derivative (SL-NPX) from these hydrogels. The macroscopic mechanical properties of these gels during formation were studied using rheology, while a nanoscopic, more molecular view was obtained by analyzing the secondary structure of the protein during gelation via infrared (ATR-IR) spectroscopy. To evaluate the potential use of BSA hydrogels in controlled drug delivery, SL-NPX-BSA interaction was investigated in detail by continuous-wave electron paramagnetic resonance (CW EPR) spectroscopy, which provides information on the interaction of the small drug molecules and the hydrogel. In addition to CW EPR spectroscopy, dynamic light scattering (DLS), which provides insight into the size and nature of released components, was applied to characterize the combined influence of incubation time, ethanol, SL-drug, and BSA concentration on release behavior. It was found that the alteration of initial drug loading percentage, hydrogel incubation time as well as BSA and alcohol concentrations affect and thus tune the release rate of SL-NPX from BSA hydrogels. These results lead to the conclusion that BSA hydrogels as controlled release systems offer a remarkable fine-tuning capability for pharmaceutical applications due to the variety of gelation parameters. 相似文献