全文获取类型
收费全文 | 589篇 |
免费 | 20篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 9篇 |
综合类 | 7篇 |
化学工业 | 152篇 |
金属工艺 | 6篇 |
机械仪表 | 3篇 |
建筑科学 | 65篇 |
能源动力 | 17篇 |
轻工业 | 107篇 |
水利工程 | 3篇 |
无线电 | 20篇 |
一般工业技术 | 88篇 |
冶金工业 | 33篇 |
原子能技术 | 3篇 |
自动化技术 | 97篇 |
出版年
2023年 | 8篇 |
2022年 | 21篇 |
2021年 | 24篇 |
2020年 | 9篇 |
2019年 | 16篇 |
2018年 | 21篇 |
2017年 | 19篇 |
2016年 | 19篇 |
2015年 | 23篇 |
2014年 | 34篇 |
2013年 | 40篇 |
2012年 | 41篇 |
2011年 | 45篇 |
2010年 | 36篇 |
2009年 | 36篇 |
2008年 | 31篇 |
2007年 | 32篇 |
2006年 | 29篇 |
2005年 | 16篇 |
2004年 | 20篇 |
2003年 | 11篇 |
2002年 | 10篇 |
2001年 | 5篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 5篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1975年 | 2篇 |
排序方式: 共有610条查询结果,搜索用时 62 毫秒
1.
2.
3.
Oxidative Stress Imaging: Visualizing Oxidative Cellular Stress Induced by Nanoparticles in the Subcytotoxic Range Using Fluorescence Lifetime Imaging (Small 23/2018)
下载免费PDF全文
![点击此处可从《Small (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
4.
Graph constraints were introduced in the area of graph transformation, in connection with the notion of (negative) application conditions, as a form to limit the applicability of transformation rules. However, we believe that graph constraints may also play a significant role in the area of visual software modelling or in the specification and verification of semi-structured documents or websites (i.e. HTML or XML sets of documents). In this sense, after some discussion on these application areas, we concentrate on the problem of how to prove the consistency of specifications based on this kind of constraints. In particular, we present proof rules for two classes of graph constraints and show that our proof rules are sound and (refutationally) complete for each class. In addition, we study clause subsumption in this context as a form to speed up refutation. 相似文献
5.
Joachim Kimmerle Ulrike Cress 《International Journal of Computer-Supported Collaborative Learning》2008,3(1):85-97
A common challenge in many situations of computer-supported collaborative learning is increasing the willingness of those
involved to share their knowledge with other group members. As a prototypical situation of computer-supported information
exchange, a shared-database setting was chosen for the current study. This information-exchange situation represented a social
dilemma: while the contribution of information to a shared database induced costs and provided no benefit for the individual,
the entire group suffered when all members decided to withhold information. In order to alleviate the information-exchange
dilemma, a group-awareness tool was employed. It was hypothesized that participants would use group awareness for self-presentational
purposes. For the examination of this assumption, the personality variable ‘protective self-presentation’ (PSP) was measured.
An interaction effect of group awareness and PSP was found: when an awareness tool provided information concerning the contribution
behavior of each individual, this tool was used as a self-presentation opportunity. In order to understand this effect in
more detail, single items of the PSP-scale were analyzed. 相似文献
6.
Per definition, CSCL research deals with the data of individuals nested in groups, and the influence of a specific learning
setting on the collaborative process of learning. Most well-established statistical methods are not able to analyze such nested
data adequately. This article describes the problems which arise when standard methods are applied and introduces multilevel
modelling (MLM) as an alternative and adequate statistical approach in CSCL research. MLM enables testing interactional effects
of predictor variables varying within groups (for example, the activity of group members in a chat) and predictors varying
between groups (for example, the group homogeneity created by group members’ prior knowledge). So it allows taking into account
that an instruction, tool or learning environment has different but systematic effects on the members within the groups on
the one hand and on the groups on the other hand. The underlying statistical model of MLM is described using an example from
CSCL. Attention is drawn to the fact that MLM requires large sample sizes which are not provided in most CSCL research. A
proposal is made for the use of some analyses which are useful. 相似文献
7.
8.
Gadolinium-enhanced magnetic resonance angiography of the pelvis in patients with erectile impotence
Michael K. Stehling Libin Liu Gerhard Laub Kurt Fleischmann Ulrike Rohde 《Magma (New York, N.Y.)》1997,5(3):247-254
This study evaluted the potential of contrast-enhanced digital-subtraction magnetic resonance angiography (CE-DS-MRA) for
noninvasive angiographic delineation of the arterial supply of the penis in patients with erectile dysfunction. After induction
of an erection with prostaglandin E, a three-dimensional fast imaging with steady-state precision (FISP) sequence with TE
of 1.8–2 milliseconds, TR of 4.4–5 milliseconds, and flip angle of 40°–60° was used to obtain high-resolution angiograms of
the pelvis and penis during the injection of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) 0.3 mmol/kg body weight,
within 30–50 seconds. DS maximum intensity projections (MIPs) and multiplanar reconstructions (MPRs) were compared with clinical
work-up and directional Doppler ultrasound in 11 patients. In all 11 patients (100%), the arterial supply of the penis could
be delineated from the aortic bifurcation via the iliac and internal pudendal arteries to the dorsal and deep penile arteries.
Of the 22 internal pudendal arteries, 6 (27%) were occluded on CE-DS-MRA and 5 (23%) had stenoses, of which 4 (18%) were greater
than 50%. In 7 patients (64%) good correlation between CE-DS-MRA and clinical findings and/or Doppler ultrasound was found;
in 2 patients (18%), the correlation was moderate, and in 2 patients (18%) results were discrepant. In 6 patients (55%), MRA
provided additional information to the clinical and Doppler ultrasound work-up. CE-DS-MRA can delineate small sessels such
as the internal pudendal and penile arteries and thus has the potential to become a noninvasive angiography method in the
work-up of erectile impotence.
Supported by Siemens Medical Systems, Erlangen; Schering AG, Berlin; and Agfa-Gevaert AG, Leverkusen. 相似文献
9.
Pia Fahlbusch Aleksandra Nikolic Sonja Hartwig Sylvia Jacob Ulrike Kettel Cornelia Kllmer Hadi Al-Hasani Stefan Lehr Dirk Müller-Wieland Birgit Knebel Jrg Kotzka 《International journal of molecular sciences》2022,23(12)
Alterations in mitochondrial function are an important control variable in the progression of metabolic dysfunction-associated fatty liver disease (MAFLD), while also noted by increased de novo lipogenesis (DNL) and hepatic insulin resistance. We hypothesized that the organization and function of a mitochondrial electron transport chain (ETC) in this pathologic condition is a consequence of shifted substrate availability. We addressed this question using a transgenic mouse model with increased hepatic insulin resistance and DNL due to constitutively active human SREBP-1c. The abundance of ETC complex subunits and components of key metabolic pathways are regulated in the liver of these animals. Further omics approaches combined with functional assays in isolated liver mitochondria and primary hepatocytes revealed that the SREBP-1c-forced fatty liver induced a substrate limitation for oxidative phosphorylation, inducing enhanced complex II activity. The observed increased expression of mitochondrial genes may have indicated a counteraction. In conclusion, a shift of available substrates directed toward activated DNL results in increased electron flows, mainly through complex II, to compensate for the increased energy demand of the cell. The reorganization of key compounds in energy metabolism observed in the SREBP-1c animal model might explain the initial increase in mitochondrial function observed in the early stages of human MAFLD. 相似文献
10.
Gen Li Ulrike K. Müller Johan L. van Leeuwen Hao Liu 《Journal of the Royal Society Interface》2014,11(101)
Fish larvae may intercept their own wake during sharp turns, which might affect their escape performance. We analysed C-starts of larval zebrafish (Danio rerio, Hamilton, 1822) using a computational fluid dynamics approach that simulates free swimming (swimming trajectory is determined by fluid forces) by coupling hydrodynamics and body dynamics. The simulations show that fish may intercept their own wake when they turn by 100–180°. During stage 1 of a C-start, the fish generates a strong jet at the tail that is shed into the wake. During stage 2, the fish intercepts this wake. Counterfactual simulations showed that wake interception increased the lateral force on the fish and reduced the fish''s turning angle by more than 5°. Wake interception caused no significant acceleration tangential to the trajectory of the fish and did not affect total power output. While experimental and simulation evidence suggests that fish larvae can either undershoot or intercept but not overshoot their wake, our simulations show that larger fish might be able to avoid intercepting their wake by either under- or overshooting. As intercepting its own wake modifies the fish''s escape trajectory, fish should account for this effect when planning their escape route. 相似文献