首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   5356篇
  免费   346篇
  国内免费   8篇
电工技术   99篇
综合类   30篇
化学工业   1251篇
金属工艺   159篇
机械仪表   108篇
建筑科学   384篇
矿业工程   21篇
能源动力   124篇
轻工业   424篇
水利工程   38篇
石油天然气   3篇
无线电   425篇
一般工业技术   1122篇
冶金工业   611篇
原子能技术   41篇
自动化技术   870篇
  2023年   65篇
  2022年   113篇
  2021年   174篇
  2020年   125篇
  2019年   115篇
  2018年   154篇
  2017年   134篇
  2016年   183篇
  2015年   184篇
  2014年   226篇
  2013年   333篇
  2012年   308篇
  2011年   377篇
  2010年   293篇
  2009年   247篇
  2008年   269篇
  2007年   275篇
  2006年   213篇
  2005年   182篇
  2004年   128篇
  2003年   121篇
  2002年   130篇
  2001年   96篇
  2000年   81篇
  1999年   92篇
  1998年   161篇
  1997年   106篇
  1996年   99篇
  1995年   77篇
  1994年   53篇
  1993年   45篇
  1992年   30篇
  1991年   44篇
  1990年   27篇
  1989年   32篇
  1988年   30篇
  1987年   22篇
  1986年   25篇
  1985年   23篇
  1984年   25篇
  1983年   18篇
  1982年   17篇
  1981年   19篇
  1980年   14篇
  1979年   22篇
  1978年   14篇
  1977年   25篇
  1976年   39篇
  1975年   11篇
  1969年   11篇
排序方式: 共有5710条查询结果,搜索用时 15 毫秒
1.
Fullerenes are candidates for theranostic applications because of their high photodynamic activity and intrinsic multimodal imaging contrast. However, fullerenes suffer from low solubility in aqueous media, poor biocompatibility, cell toxicity, and a tendency to aggregate. C70@lysozyme is introduced herein as a novel bioconjugate that is harmless to a cellular environment, yet is also photoactive and has excellent optical and optoacoustic contrast for tracking cellular uptake and intracellular localization. The formation, water-solubility, photoactivity, and unperturbed structure of C70@lysozyme are confirmed using UV-visible and 2D 1H, 15N NMR spectroscopy. The excellent imaging contrast of C70@lysozyme in optoacoustic and third harmonic generation microscopy is exploited to monitor its uptake in HeLa cells and lysosomal trafficking. Last, the photoactivity of C70@lysozyme and its ability to initiate cell death by means of singlet oxygen (1O2) production upon exposure to low levels of white light irradiation is demonstrated. This study introduces C70@lysozyme and other fullerene-protein conjugates as potential candidates for theranostic applications.  相似文献   
2.
3.
4.
This paper presents an integrated passive damping approach in hybrid metal-CFRP parts for structural applications. In this concept a viscoelastic material is embedded in the joint zone of the hybrid component. To examine the connection strength single-lap-joint specimens were produced and tested and the influence of the used material combinations, different surface structures, and different process parameters i.e. the moment of cross-linking were evaluated. Afterwards, the metal-CFRP hybrids were tested in quasi-static tests to assess their connection strength and failure behaviour. Dynamic cyclic tensile tests with step-wise increased loading conditions were performed to determine the specimens damping behaviour and to estimate their fatigue performance. Finally, these results are compared to a state of the art metal-CFRP hybrid with rivets connecting both materials.  相似文献   
5.
6.
An addition of boron largely increases the ductility in polycrystalline high-temperature Co–Re alloys. Therefore, the effect of boron on the alloy structural characteristics is of high importance for the stability of the matrix at operational temperatures. Volume fractions of ε (hexagonal close-packed—hcp), γ (face-centered cubic—fcc) and σ (Cr2Re3 type) phases were measured at ambient and high temperatures (up to 1500 °C) for a boron-containing Co–17Re–23Cr alloy using neutron diffraction. The matrix phase undergoes an allotropic transformation from ε to γ structure at high temperatures, similar to pure cobalt and to the previously investigated, more complex Co–17Re–23Cr–1.2Ta–2.6C alloy. It was determined in this study that the transformation temperature depends on the boron content (0–1000 wt. ppm). Nevertheless, the transformation temperature did not change monotonically with the increase in the boron content but reached a minimum at approximately 200 ppm of boron. A probable reason is the interplay between the amount of boron in the matrix and the amount of σ phase, which binds hcp-stabilizing elements (Cr and Re). Moreover, borides were identified in alloys with high boron content.  相似文献   
7.
In advancement of Pyrosil®‐technology a new kind of precursor delivery was developed, build and tested on real substrates. A Lab‐demonstrator was build to demonstrate the resources of the technology.  相似文献   
8.
9.
The aim of this work was to determine the principal mechanical parameters of a thin film on a substrate, i.e. Young's modulus, Poisson's ratio, intrinsic stress, and coefficient of linear thermal expansion. First, standard experiments possibly suitable for this purpose were investigated theoretically. The margin of error of the mechanical parameters determined was estimated as dependent on the geometrical conditions, substrate properties, and error in the respective measurements. In addition, the homogeneity and stability of the parameters were taken into account, for instance inhomogeneity of the film thickness and possible modification of substrate parameters during film growth. To obtain meaningful results, the accuracy of the measurements as well as the homogeneity and stability of several geometrical and physical parameters in general must be extremely high. However, the experimental conditions were found to fulfill these requirements.  相似文献   
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号