全文获取类型
收费全文 | 10555篇 |
免费 | 685篇 |
国内免费 | 18篇 |
专业分类
电工技术 | 127篇 |
综合类 | 20篇 |
化学工业 | 2480篇 |
金属工艺 | 268篇 |
机械仪表 | 207篇 |
建筑科学 | 387篇 |
矿业工程 | 30篇 |
能源动力 | 322篇 |
轻工业 | 1052篇 |
水利工程 | 129篇 |
石油天然气 | 33篇 |
无线电 | 733篇 |
一般工业技术 | 2154篇 |
冶金工业 | 1700篇 |
原子能技术 | 53篇 |
自动化技术 | 1563篇 |
出版年
2024年 | 15篇 |
2023年 | 87篇 |
2022年 | 174篇 |
2021年 | 277篇 |
2020年 | 218篇 |
2019年 | 244篇 |
2018年 | 303篇 |
2017年 | 285篇 |
2016年 | 315篇 |
2015年 | 239篇 |
2014年 | 426篇 |
2013年 | 763篇 |
2012年 | 576篇 |
2011年 | 843篇 |
2010年 | 566篇 |
2009年 | 589篇 |
2008年 | 617篇 |
2007年 | 541篇 |
2006年 | 466篇 |
2005年 | 410篇 |
2004年 | 347篇 |
2003年 | 312篇 |
2002年 | 293篇 |
2001年 | 168篇 |
2000年 | 158篇 |
1999年 | 166篇 |
1998年 | 240篇 |
1997年 | 208篇 |
1996年 | 155篇 |
1995年 | 135篇 |
1994年 | 128篇 |
1993年 | 97篇 |
1992年 | 93篇 |
1991年 | 44篇 |
1990年 | 55篇 |
1989年 | 58篇 |
1988年 | 60篇 |
1987年 | 55篇 |
1986年 | 54篇 |
1985年 | 71篇 |
1984年 | 57篇 |
1983年 | 52篇 |
1982年 | 55篇 |
1981年 | 45篇 |
1980年 | 38篇 |
1979年 | 26篇 |
1978年 | 23篇 |
1977年 | 28篇 |
1976年 | 34篇 |
1975年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Currently, the efficient detection of fingerprints is essential for the crime investigations. Revealing fingerprints is commonly achieved with fluorescent organic compounds but they are not efficient for fingerprint detection on porous or reflective surfaces. In order to solve the problem of collecting fingerprints on porous/reflective surfaces, inorganic phosphors have been employed, since they have characteristics of variable color emission, afterglow, high chemical stability and nano-size, which allow the fingerprint detection on any porous or non-porous surfaces. Due to these last properties, this review presents a summary about the use of phosphorescent and fluorescent phosphors for the detection of latent fingerprints. First, we discussed the main physical and chemical characteristics of the fingerprints which permit their detection and collection from any surface. After this, we presented the main morphological, structural and luminescent properties of the phosphorescent and fluorescent phosphors that allow their use for fingerprint detection. Later, we demonstrated with pictures of fingerprints (with and without light emission from the phosphors deposited on them) that both, phosphorescent and fluorescent phosphors can be used to visualize fingerprints with high resolution and high contrast without interference of the background surface, which is ideal for its collection and registration in the Automated Fingerprint Identification System (AFIS). We believe that this review could be useful to understand how to select an appropriate phosphorescent or fluorescent material for fingerprint detection depending on the type of surface (porous or non-porous, reflective or not reflective) where the fingerprint is deposited. 相似文献
2.
3.
Carolyn A. Grimley Stephen Funni Christopher Green Elizabeth C. Dickey 《Journal of the European Ceramic Society》2021,41(4):2807-2817
In flash sintering experiments, the thermal history of the sample is key to understanding the mechanisms underlying densification rate and final properties. By combining robust temperature measurements with current-ramp-rate control, this study examined the effects of the thermal profile on the flash sintering of yttria-stabilized zirconia, with experiments ranging from a few seconds to several hours. The final density was maximized at slower heating rates, although processes slower than a certain threshold led to grain growth. The amount of grain growth observed was comparable to a similar conventional thermal process. The bulk electrical conductivity correlated with the maximum temperature and cooling rate. The only property that exhibited behavior that could not be attributed to solely the thermal profile was the grain boundary conductivity, which was consistently higher than conventional in flash sintered samples. These results suggest that, during flash sintering, athermal electric field effects are relegated to the grain boundary. 相似文献
4.
5.
6.
7.
Daniela Frasca Maria Romero Alain Diaz Denisse Garcia Seth Thaller Bonnie B. Blomberg 《International journal of molecular sciences》2021,22(4)
Senescent cells accumulate in the adipose tissue (AT) of individuals with obesity and secrete multiple factors that constitute the senescence-associated secretory phenotype (SASP). This paper aimed at the identification of B cells with a SASP phenotype in the AT, as compared to the peripheral blood, of individuals with obesity. Our results show increased expression of SASP markers in AT versus blood B cells, a phenotype associated with a hyper-metabolic profile necessary to support the increased immune activation of AT-derived B cells as compared to blood-derived B cells. This hyper-metabolic profile is needed for the secretion of the pro-inflammatory mediators (cytokines, chemokines, micro-RNAs) that fuel local and systemic inflammation. 相似文献
8.
9.