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   530篇
  免费   22篇
电工技术   10篇
综合类   1篇
化学工业   158篇
金属工艺   7篇
机械仪表   6篇
建筑科学   30篇
矿业工程   7篇
能源动力   7篇
轻工业   37篇
水利工程   6篇
石油天然气   1篇
无线电   36篇
一般工业技术   89篇
冶金工业   69篇
原子能技术   3篇
自动化技术   85篇
  2023年   3篇
  2022年   23篇
  2021年   32篇
  2020年   14篇
  2019年   10篇
  2018年   13篇
  2017年   15篇
  2016年   19篇
  2015年   7篇
  2014年   23篇
  2013年   33篇
  2012年   36篇
  2011年   37篇
  2010年   22篇
  2009年   21篇
  2008年   34篇
  2007年   26篇
  2006年   12篇
  2005年   13篇
  2004年   12篇
  2003年   12篇
  2002年   8篇
  2001年   5篇
  2000年   6篇
  1999年   6篇
  1998年   10篇
  1997年   8篇
  1996年   5篇
  1995年   7篇
  1994年   4篇
  1993年   9篇
  1992年   4篇
  1991年   2篇
  1990年   8篇
  1989年   5篇
  1987年   4篇
  1986年   2篇
  1984年   3篇
  1981年   3篇
  1980年   6篇
  1979年   3篇
  1976年   3篇
  1974年   3篇
  1972年   2篇
  1970年   4篇
  1969年   3篇
  1967年   2篇
  1964年   1篇
  1963年   1篇
  1961年   2篇
排序方式: 共有552条查询结果,搜索用时 15 毫秒
1.
This article depicts some features of the geography of science and technology outputs in the EU, with a particular attention to regional “co-location” of these two pillars of the “knowledge-based society”. Economists have, for a decade, paid great attention to local “spillovers” stating that industrial firms often draw advantages from the presence of nearby academic centres. The presence in the same areas of strong academic and technological resources is both a condition and a result of science-technology interactions. Concentrating on publications and patents as proxies of the science and technology level in regions, we built a typology of regions according to their commitment to the two knowledge-base activities and then analysed the co-locations of science and technology from several points of view. A fine-grain lattice, mainly based on standard Nuts3 level, was used. Co-location, at the EU level, is not a general rule. A strong potential for spillover/ interaction does exist in the top-class regions which concentrate a high proportion of European S and T output. But for regions with a small/medium level of S&T activity, a divergence of orientations appears between a science-oriented family and a technology-oriented family, indicating an imbalance between local S and T resources. If we look at the S-oriented regions, whilst controlling for underlying factors, such as population and regional economic product, a significant geographic linkage between T and S appears. This suggests a trajectory of science-based technological development. A careful examination of S&T thematic alignments and specialisation is necessary to develop the hypothesis that fostering academic resources could increase the technological power along a growth path. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
2.
The limited effect of current medications on neuropathic pain (NP) has initiated large efforts to develop effective treatments. Animal studies showed that glycine transporter (GlyT) inhibitors are promising analgesics in NP, though concerns regarding adverse effects were raised. We aimed to study NFPS and Org-25543, GlyT-1 and GlyT-2 inhibitors, respectively and their combination in rat mononeuropathic pain evoked by partial sciatic nerve ligation. Cerebrospinal fluid (CSF) glycine content was also determined by capillary electrophoresis. Subcutaneous (s.c.) 4 mg/kg NFPS or Org-25543 showed analgesia following acute administration (30–60 min). Small doses of each compound failed to produce antiallodynia up to 180 min after the acute administration. However, NFPS (1 mg/kg) produced antiallodynia after four days of treatment. Co-treatment with subanalgesic doses of NFPS (1 mg/kg) and Org-25543 (2 mg/kg) produced analgesia at 60 min and thereafter meanwhile increased significantly the CSF glycine content. This combination alleviated NP without affecting motor function. Test compounds failed to activate G-proteins in spinal cord. To the best of our knowledge for the first time we demonstrated augmented analgesia by combining GlyT-1 and 2 inhibitors. Increased CSF glycine content supports involvement of glycinergic system. Combining selective GlyT inhibitors or developing non-selective GlyT inhibitors might have therapeutic value in NP.  相似文献   
3.
With current digital technologies, people have large archives of digital media, such as images and audio files, but there are only limited means to include these media in creative practices of crafting and making. Nevertheless, studies have shown that crafting with digital media often makes these media more cherished and that people enjoy being creative with their digital media. This paper aims to open up the way for novel means for crafting, which include digital media in integrations with physical construction, here called ‘hybrid crafting’. Notions of hybrid crafting were explored to inform the design of products or systems that may support these new crafting practices. We designed ‘Materialise’—a building set that allows for the inclusion of digital images and audio files in physical constructions by using tangible building blocks that can display images or play audio files, alongside a variety of other physical components—and used this set in four hands-on creative workshops to gain insight into how people go about doing hybrid crafting; whether hybrid crafting is desirable; what the characteristics of hybrid crafting are; and how we may design to support these practices. By reflecting on the findings from these workshops, we provide concrete guidelines for the design of novel hybrid crafting products or systems that address craft context, process and result. We aim to open up the design space to designing for hybrid crafting because these new practices provide interesting new challenges and opportunities for future crafting that can lead to novel forms of creative expression.  相似文献   
4.
To determine antioxidative effects of ferulic acid and esterified ferulic acids, these compounds were added to soybean oils (SBO), which were evaluated for oxidative stability and frying stability. Additives included feruloylated MAG and DAG (FMG/FDG), ferulic acid, ethyl ferulate, and TBHQ. After frying tests with potato chips, oils were analyzed for retention of additives and polar compounds. Chips were evaluated for hexanal and rancid odor. After 15 h frying, 71% of FMG/FDG was retained, whereas 55% of ethyl ferulate was retained. TBHQ and ferulic acid levels were 6% and <1%, respectively. Frying oils with ethyl ferulate or TBHQ produced significantly less polar compounds than SBO with no additives. Chips fried in SBO with TBHQ or ferulic acid had significantly lower amounts of hexanal and significantly less rancid odor after 8 d at 60°C than other samples. Oils were also aged at 60°C, and stability was analyzed by PV, hexanal, and rancid odor. Oils with TBHQ or FMG/FDG had significantly less peroxides and hexanal, and a lower rancid odor intensity than the control. FMG/FDG inhibited deterioration at 60°C, whereas ethyl ferulate inhibited the formation of polar compounds in frying oil. Ferulic acid acted as an antioxidant in aged fried food. TBHQ inhibited oil degradation at both temperatures. Presented at the 94th AOCS Meeting & Expo, Kansas City, MO, May 4–7, 2003.  相似文献   
5.
This exploratory study aims to achieve a better understanding of the users-related factors that affect the choice of routes in public transport (PT). We also look at what can motivate route and modes changes towards alternatives in a real situation. We investigated the experience of 19 users of PTs, using the critical incident technique (Flanagan in Psychol Bull 51(4):327, 1954). We asked participants to report incidents (i.e. situations) in cases they were very satisfied or dissatisfied with their choice. For both situations, the case of their usual route and case of an alternative were considered. A total of 91 incidents were collected and analysed using a multiple correspondences analysis. Additionally, users’ profiles were characterized and superposed to the analysis of incidents content. The main results are as follows. First, the user’s choice of PT route depends on the context (i.e. aim of the travel, time of day). Second, taking an alternative to the usual PT route or using a route combining different transport modes is determined by the context and by factors related to the pleasantness of the travel (e.g. to accompany a friend along the travel). Finally, depending on the user’s profile (i.e. combination of attitude towards PT and demographic variables), the factors taken into account to make the choice of a PT route are related to the efficiency or the pleasantness of the trip. These results show the importance of the contextual factors and the users’ profiles in route choice. They suggest that these factors should be further taken into account in new tools and services for mobility.  相似文献   
6.
In our global village, distance is not a barrier anymore for traveling. People experience new cultures and face accompanying difficulties in order to live anywhere. Social support can help these sojourners to cope with difficulties, such as culture shock. In this paper, we investigate how computer-mediated communication (CMC) tools can facilitate social support when living physically separated from loved-ones in different cultures. The goal is to understand the design considerations necessary to design new CMC tools. We studied communication practices of Chinese sojourners living in the Netherlands and the use of a technology probe with a novel video communication system. These results led to recommendations which can help designers to design interactive communication tools that facilitate communication across cultures. We conclude the paper with an interactive communication device called Circadian, which was designed based on these recommendations. We experienced the design recommendations to be abstract enough to leave space for creativity while providing a set of clear requirements which we used to base design decisions upon.  相似文献   
7.
The NP-hard microaggregation problem seeks a partition of data points into groups of minimum specified size k, so as to minimize the sum of the squared euclidean distances of every point to its group's centroid. One recent heuristic provides an O(k3) guarantee for this objective function and an O(k2) guarantee for a version of the problem that seeks to minimize the sum of the distances of the points to its group's centroid. This paper establishes approximation bounds for another microaggregation heuristic, providing better approximation guarantees of O(k2) for the squared distance measure and O(k) for the distance measure.  相似文献   
8.
When meeting someone new, the first impression is often influenced by someone’s physical appearance and other types of prejudice. In this paper, we present TouchMeDare, an interactive canvas, which aims to provide an experience when meeting new people, while preventing visual prejudice and lowering potential thresholds. The focus of the designed experience was to stimulate people to get acquainted through the interactive canvas. TouchMeDare consists of a flexible, opaque canvas, which plays music when touched simultaneously from both sides. Dynamic variation of this bodily contact is reflected through real-time adaptations of the musical compositions. Two redesigns were qualitatively and quantitatively evaluated and a final version was placed in the Lowlands Festival as a case study. Evaluation results showed that some explanation was needed for the initial interaction with the installation. On the other hand, after this initial unfamiliarity passed, results showed that making bodily contact through the installation did help people to get acquainted with each other and increased their social interaction.  相似文献   
9.
Magnetic Resonance Materials in Physics, Biology and Medicine - Signal intensity normalization is necessary to reduce heterogeneity in T2-weighted (T2W) magnetic resonance imaging (MRI) for...  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