全文获取类型
收费全文 | 11787篇 |
免费 | 1961篇 |
国内免费 | 1319篇 |
专业分类
电工技术 | 560篇 |
技术理论 | 1篇 |
综合类 | 571篇 |
化学工业 | 1261篇 |
金属工艺 | 320篇 |
机械仪表 | 1876篇 |
建筑科学 | 169篇 |
矿业工程 | 125篇 |
能源动力 | 153篇 |
轻工业 | 755篇 |
水利工程 | 44篇 |
石油天然气 | 723篇 |
武器工业 | 161篇 |
无线电 | 3786篇 |
一般工业技术 | 2160篇 |
冶金工业 | 265篇 |
原子能技术 | 779篇 |
自动化技术 | 1358篇 |
出版年
2024年 | 73篇 |
2023年 | 325篇 |
2022年 | 489篇 |
2021年 | 585篇 |
2020年 | 617篇 |
2019年 | 541篇 |
2018年 | 594篇 |
2017年 | 627篇 |
2016年 | 676篇 |
2015年 | 684篇 |
2014年 | 814篇 |
2013年 | 771篇 |
2012年 | 908篇 |
2011年 | 925篇 |
2010年 | 650篇 |
2009年 | 626篇 |
2008年 | 620篇 |
2007年 | 647篇 |
2006年 | 548篇 |
2005年 | 421篇 |
2004年 | 441篇 |
2003年 | 350篇 |
2002年 | 299篇 |
2001年 | 234篇 |
2000年 | 238篇 |
1999年 | 214篇 |
1998年 | 166篇 |
1997年 | 196篇 |
1996年 | 165篇 |
1995年 | 101篇 |
1994年 | 107篇 |
1993年 | 89篇 |
1992年 | 64篇 |
1991年 | 51篇 |
1990年 | 49篇 |
1989年 | 38篇 |
1988年 | 23篇 |
1987年 | 21篇 |
1986年 | 20篇 |
1985年 | 15篇 |
1984年 | 14篇 |
1983年 | 9篇 |
1982年 | 3篇 |
1981年 | 13篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1959年 | 2篇 |
1951年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Higher resolution can be achieved in lithography by decreasing the wavelength of the exposure source. However, resist material
and their processing are also important when we move to a shorter wavelength lithography technology. This paper reviews the
recent development and challenges of deep-UV photoresists and their processing technology. 相似文献
32.
本文介绍红外热象技术在工程热物理研究中某些应用的探索。作为实例,通过热象技术,实验研究了具有水平凸台离散热源的倾斜板的散热,在研究它的自然对流换热部份结合利用激光全息干涉技术。此间着重于分析倾斜角对散热的影响。 相似文献
33.
34.
35.
Roy S. Berns 《Color research and application》2007,32(4):334-335
The term “color gamut” historically has been associated with color output such as optimal color stimuli and additive and subtractive imaging systems. Recently, this term has been used with input devices such as scanners and digital cameras. It is proposed that the term “color‐gamut rendering” should be used instead of input devices. This clarifies the distinction between input (analysis) and output (synthesis) color systems in terms of the effect of an input system on defining the colorimetric properties of an output system. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 334–335, 2007 相似文献
36.
介绍了ICP等离子体光谱仪的原理及测定高纯氧化铁中铝、钙、硫、钾、镁、锰、钠和钛等8种杂质元素的分析方法,考察了样品的溶解方案及工作曲线的选择,确定了仪器最佳工作条件和方法检出限。 相似文献
37.
Eva M. Valero Juan L. Nieves Sérgio M. C. Nascimento Kinjiro Amano David H. Foster 《Color research and application》2007,32(5):352-360
Many spectral‐recovery methods using RGB digital cameras assume the underlying smoothness of illuminant and reflectance spectra, and apply low‐dimensional linear models. The aim of the present work was to test whether a direct‐mapping method could be used instead of a linear‐models approach to recover spectral radiances and reflectances from natural scenes with an RGB digital camera and colored filters. In computer simulations, a conventional RGB digital camera with up to three colored filters was used to image scenes drawn from a hyperspectral image database. Three measures were used to evaluate recovery with the direct‐mapping method: goodness‐of‐fit, root‐mean‐square error, and a color‐difference metric. It was found that with two and three filters both spectral radiances and reflectances could be recovered sufficiently accurately for many practical applications. With little increase in computational complexity, an RGB camera and a few colored filters can provide significantly better recovery of natural scenes than an RGB camera alone. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 352–360, 2007 相似文献
38.
39.
Xiao-Ying Wang Jonathan M. Garibaldi Benjamin Bird Michael W. George 《Applied Intelligence》2007,27(3):237-248
Recently Fourier Transform Infrared (FTIR) spectroscopic imaging has been used as a tool to detect the changes in cellular
composition that may reflect the onset of a disease. This approach has been investigated as a mean of monitoring the change
of the biochemical composition of cells and providing a diagnostic tool for various human cancers and other diseases. The
discrimination between different types of tissue based upon spectroscopic data is often achieved using various multivariate
clustering techniques. However, the number of clusters is a common unknown feature for the clustering methods, such as hierarchical
cluster analysis, k-means and fuzzy c-means. In this study, we apply a FCM based clustering algorithm to obtain the best number
of clusters as given by the minimum validity index value. This often results in an excessive number of clusters being created
due to the complexity of this biochemical system. A novel method to automatically merge clusters was developed to try to address
this problem. Three lymph node tissue sections were examined to evaluate our new method. These results showed that this approach
can merge the clusters which have similar biochemistry. Consequently, the overall algorithm automatically identifies clusters
that accurately match the main tissue types that are independently determined by the clinician. 相似文献
40.
The exact magnetization pattern of magnetic films close to a spin-reorientation transition is difficult to analyze due to the intrinsically three-dimensional (3d) variation of the orientation of the local magnetization. We present a technique how this can be performed, based on the analysis of high quality 2d polarization maps from a single scanning electron microscope with polarization analysis (SEMPA) measurement with tilted sample. The key tool is the statistical distribution of all occurring polarization doublets, visualized in a 2d histogram plot. From the shape of the distribution the type of transition—canted-phase, or coexisting phases—can be inferred. For the canted-phase state, the canting angle can be accurately determined from geometrical considerations. With help of the histogram the image data can be analyzed and the three components of the magnetization can be calculated for most points of the image. For a Co/Pt multilayer film we found a cone state. The magnetization forms a complex pattern consisting of out-of-plane domains while the in-plane magnetization shows a maze pattern. 相似文献