全文获取类型
收费全文 | 1588篇 |
免费 | 73篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 19篇 |
综合类 | 2篇 |
化学工业 | 287篇 |
金属工艺 | 33篇 |
机械仪表 | 41篇 |
建筑科学 | 82篇 |
矿业工程 | 1篇 |
能源动力 | 48篇 |
轻工业 | 110篇 |
水利工程 | 15篇 |
石油天然气 | 2篇 |
无线电 | 80篇 |
一般工业技术 | 421篇 |
冶金工业 | 254篇 |
原子能技术 | 15篇 |
自动化技术 | 254篇 |
出版年
2024年 | 2篇 |
2023年 | 10篇 |
2022年 | 25篇 |
2021年 | 41篇 |
2020年 | 21篇 |
2019年 | 27篇 |
2018年 | 33篇 |
2017年 | 30篇 |
2016年 | 40篇 |
2015年 | 44篇 |
2014年 | 70篇 |
2013年 | 87篇 |
2012年 | 91篇 |
2011年 | 137篇 |
2010年 | 93篇 |
2009年 | 83篇 |
2008年 | 102篇 |
2007年 | 116篇 |
2006年 | 89篇 |
2005年 | 89篇 |
2004年 | 54篇 |
2003年 | 53篇 |
2002年 | 43篇 |
2001年 | 28篇 |
2000年 | 18篇 |
1999年 | 18篇 |
1998年 | 20篇 |
1997年 | 21篇 |
1996年 | 15篇 |
1995年 | 13篇 |
1994年 | 10篇 |
1993年 | 11篇 |
1992年 | 9篇 |
1991年 | 9篇 |
1990年 | 13篇 |
1989年 | 11篇 |
1988年 | 10篇 |
1987年 | 16篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 12篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1975年 | 2篇 |
排序方式: 共有1664条查询结果,搜索用时 15 毫秒
961.
In general, the shared family environment appears to play a negligible role in determining individual differences in personality and interests. Nevertheless, scattered reports of significant shared environmental influence on such variables appear in the literature. Using data from the Texas Adoption Project (TAP), the current study attempted to replicate twin study findings of significant shared environmental variance on four of nine Minnesota Multiphasic Personality Inventory (MMPI) factor scales (Rose, 1988). Conventional behavioral genetic analyses of the adoption data agreed in affirming a significant shared environmental influence on individual differences in Religious Orthodoxy only. Subsequent simultaneous modeling of Rose's twin data and TAP adoption data resulted in three scales (Extraversion, Inadequacy, and Religious Orthodoxy) showing significant shared environmental influence. Again, effects were most substantial for Religious Orthodoxy, where the shared environment accounted for nearly 50% of the variance. It is argued that assortative mating cannot explain this finding. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
962.
963.
Nazar Almeida Valrie Meyer Auphlia Burnet Jeremy Boucher David Talens-Perales Susana Pereira Petri Ihalainen Thomas Leve Julio Polaina Michel Petit-Conil Susana Camarero Paula Pinto 《International journal of molecular sciences》2022,23(21)
Xylanases can boost pulp bleachability in Elemental Chlorine Free (ECF) processes, but their industrial implementation for producing bleached kraft pulps is not straightforward. It requires enzymes to be active and stable at the extreme conditions of alkalinity and high temperature typical of this industrial process; most commercial enzymes are unable to withstand these conditions. In this work, a novel highly thermo and alkaline-tolerant xylanase from Pseudothermotoga thermarum was overproduced in E. coli and tested as a bleaching booster of hardwood kraft pulps to save chlorine dioxide (ClO2) during ECF bleaching. The extremozyme-stage (EXZ) was carried out at 90 °C and pH 10.5 and optimised at lab scale on an industrial oxygen-delignified eucalyptus pulp, enabling us to save 15% ClO2 to reach the mill brightness, and with no detrimental effect on paper properties. Then, the EXZ-assisted bleaching sequence was validated at pilot scale under industrial conditions, achieving 25% ClO2 savings and reducing the generation of organochlorinated compounds (AOX) by 18%, while maintaining pulp quality and papermaking properties. Technology reproducibility was confirmed with another industrial kraft pulp from a mix of hardwoods. The new enzymatic technology constitutes a realistic step towards environmentally friendly production of kraft pulps through industrial integration of biotechnology. 相似文献
964.
Seifollah Jalili Elham Moharramzadeh Goliaei Jeremy Schofield 《International Journal of Hydrogen Energy》2017,42(21):14522-14533
An Ag8 cluster deposited on three different types of nitrogen (N)-doped graphene was studied using density functional theory calculations with empirical pair potentials (DFT-D). Among the different kinds of N-doped graphene, the pyridinic-N3 (P-N3) type can act as the best anchor position to stabilize Ag8. In addition, it is found that supported Ag8 clusters show higher activity in oxygen reduction reaction compared to unsupported clusters due to significant decrease in O2 adsorption energy and higher charge transfer to O2. Electron transfer from Ag to O2 leads to the elongation of the OO bond, which facilitates the breaking of this bond in the oxygen reduction reaction. All results suggest that N-doped graphene support can play a significant role in the chemical reactivity of a Ag8 cluster in oxygen reduction reaction. 相似文献
965.
Jeremy 《中国眼镜科技杂志》2022,(2):46-47
近两年,虽然实体经济不断走低,但在疫情得以逐步控制的当下,不少眼镜连锁企业开始调整业务结构,再次将拓展计划加入年度规划中.那么,连锁企业的拓展计划该如何做?是否有基础数据作为支撑? 相似文献
966.
967.
Annika Traa Emily Machiela Paige D. Rudich Sonja K. Soo Megan M. Senchuk Jeremy M. Van Raamsdonk 《International journal of molecular sciences》2021,22(24)
Huntington’s disease (HD) is one of at least nine polyglutamine diseases caused by a trinucleotide CAG repeat expansion, all of which lead to age-onset neurodegeneration. Mitochondrial dynamics and function are disrupted in HD and other polyglutamine diseases. While multiple studies have found beneficial effects from decreasing mitochondrial fragmentation in HD models by disrupting the mitochondrial fission protein DRP1, disrupting DRP1 can also have detrimental consequences in wild-type animals and HD models. In this work, we examine the effect of decreasing mitochondrial fragmentation in a neuronal C. elegans model of polyglutamine toxicity called Neur-67Q. We find that Neur-67Q worms exhibit mitochondrial fragmentation in GABAergic neurons and decreased mitochondrial function. Disruption of drp-1 eliminates differences in mitochondrial morphology and rescues deficits in both movement and longevity in Neur-67Q worms. In testing twenty-four RNA interference (RNAi) clones that decrease mitochondrial fragmentation, we identified eleven clones—each targeting a different gene—that increase movement and extend lifespan in Neur-67Q worms. Overall, we show that decreasing mitochondrial fragmentation may be an effective approach to treating polyglutamine diseases and we identify multiple novel genetic targets that circumvent the potential negative side effects of disrupting the primary mitochondrial fission gene drp-1. 相似文献
968.
Scanning electron microscopy (SEM) has been used to classify and quantify the types of damage evident in a population potato starch granules following ball milling. Whilst the majority of granules remained undamaged, a significant (p<0.01) increase in the number of granules with localized damage was observed (1.6% to 15.1%). A variety fo types of localised damage were discernable, ranging from areas where small amounts of granule surface material had been removed, to large areas possessing coarse surfaces caused by extensive removal of material. The generation of this latter category termed ‘rough faces’, was the most significant and predominant change following ball milling (p <0.05). Ball-milling was therefore attributed to the penetration of an outer granule layer, via the removal of surface material at existing points of weakness. This produced rough, disrupted areas of the granule surface, which are more likely to be susceptible to hydration and enzyme attack. 相似文献
969.
970.
Jennifer R. Mawdsley J. David Carter A. Jeremy Kropf Bilge Yildiz Victor A. Maroni 《International Journal of Hydrogen Energy》2009,34(9):4198-4207
The oxygen electrodes from two solid oxide electrolysis stacks that performed high-temperature steam electrolysis (HTSE) and produced hydrogen for 1000 and 2000 h, respectively, were examined using X-ray fluorescence, X-ray absorption near edge structure (XANES), four-point resistivity, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction and Raman micro-spectroscopy to determine possible causes for the degradation in stack performance over the test periods. These techniques yielded information such as elemental distribution, oxidation state, phases present, electrode delamination, and porosity within the electrode layers. From these studies, we found two phenomena that were likely the cause of increasingly poor oxygen electrode performance over time. The first source of degradation was chromium substitution into the oxygen electrode bond layer, which serves to bond the cell to the flow field and interconnect. This is caused by migration of a chromium species from the bipolar plate. The effect of this is a significant increase in the electrical resistance of the bond layer material. The other source of degradation identified was oxygen electrode delamination. The cause of electrode delamination, which is locally catastrophic to the operation of the cell, is unclear; however, we will discuss two possible mechanisms that might cause this phenomenon. 相似文献