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   231篇
  免费   3篇
电工技术   1篇
化学工业   38篇
金属工艺   4篇
机械仪表   6篇
建筑科学   13篇
能源动力   5篇
轻工业   30篇
石油天然气   1篇
无线电   13篇
一般工业技术   57篇
冶金工业   37篇
原子能技术   2篇
自动化技术   27篇
  2022年   2篇
  2021年   3篇
  2019年   1篇
  2018年   3篇
  2016年   4篇
  2015年   4篇
  2014年   7篇
  2013年   15篇
  2012年   8篇
  2011年   16篇
  2010年   12篇
  2009年   12篇
  2008年   22篇
  2007年   11篇
  2006年   8篇
  2005年   7篇
  2004年   5篇
  2003年   3篇
  2002年   3篇
  2001年   3篇
  2000年   2篇
  1999年   1篇
  1998年   14篇
  1997年   11篇
  1996年   10篇
  1995年   2篇
  1994年   8篇
  1993年   4篇
  1992年   4篇
  1991年   1篇
  1989年   2篇
  1988年   2篇
  1987年   1篇
  1986年   2篇
  1985年   3篇
  1984年   2篇
  1983年   1篇
  1981年   2篇
  1980年   4篇
  1976年   5篇
  1974年   2篇
  1970年   1篇
  1969年   1篇
排序方式: 共有234条查询结果,搜索用时 15 毫秒
1.
The effect of serotonin and the serotonin antagonists ketanserin, methiotepine and ICS-205-930 on the migration of leucocytes was studied by using the sealed capillary migration technique. The migration of mononuclear leucocytes was inhibited by serotonin at 10(-4) and 10(-6)-10(-10)mol/l. An inhibition of the mononuclear leucocyte migration was also caused by ICS-205-930 at 10(-4)mol/l, ketanserin at 10(-4) and 10(-8)-10(-10)mol/l and methiotepine at 10(-4) and 10(-6)-10(-8)mol/l. No inhibiting effects of serotonin or the serotonin antagonists were found on the migration of polymorphonuclear leucocytes. Thus, both serotonin and serotonin antagonists may inhibit mononuclear leucocyte migration.  相似文献   
2.
This paper presents a general framework for analysing condition based replacement policies for stochastically failing units. The framework is based on the theory of counting processes. A replacement policy minimizing the long run expected cost is determined. The paper discusses both non-repairable and repairable units. Two examples are analysed in detail: shock models and monotone (coherent) systems.  相似文献   
3.
A national multicentre study was performed to investigate the prevalent use of "alternative medicine", here called "non-proven therapies (NPT)", applied among Norwegian cancer patients. Of 911 patients invited to take part in the study, 642 were included in the analysis. Demographic characteristics were collected for all patients. The participating physicians gave information about the patients' clinical characteristics. Among 630 evaluable patients, 20% had been or were present users of NPTs for their oncological disease. The preferred methods were healing by hand and faith healing. Herbs, vitamins, diets and Iscador were other popular methods. As many as 40% of the users of NPTs had used NPTs earlier for non-malignant diseases. Elderly patients were less likely to use NPTs. Use was high in the northern part of Norway.  相似文献   
4.
The present paper evaluates the use of software agents to identify relevance of information, called awareness. This evaluation is based on existing policies and scenarios in the context of wireless communication of a hospital in Norway. The study is to address the lack of literature for experimental studies on a method to employ software agents for awareness identification. Research in computer supported cooperative work indicates the significant contributions of software agents to assist individuals. There are bodies of work that show awareness provides the means for software agents in which effective cooperation can take place. In addition, the role of the methods to identify awareness is emphasized in the literature of both computer supported cooperative work and software agents. This paper explains a step-wise process, called Policy-based Awareness Management, which allows agents to use policies as a source to identify awareness and thus change their behaviors accordingly. The contribution of this method is based on the concepts proposed by the logic of general awareness. The present study applies Directory Enabled Networks-next generation as the policy structure for the method. The paper evaluates the process via its application to identify the relevance of information in wireless communication scenarios in a hospital. The present study conducts observations, interviews and discussions on the wireless communication system of the hospital to identify the different scenarios happening in the system. The paper presents a set of simulations on these scenarios and concludes that the method is effective and cost-efficient.  相似文献   
5.
A versatile apparatus to measure the cross-plane Seebeck coefficient and the resistivity of bulk samples shaped as disks or thin plates, over a temperature range of 300 K-620 K with possible extension to higher temperatures, is presented. It is constructed from readily available equipment and instrumentation with parts that are easily manufactured. The Seebeck coefficient is measured over an average region of the sample under steady-state conditions. The sample resistance is measured using a four-point alternating current method and scaled to room temperature measurements with known geometry to calculate resistivity. A variety of sample shapes are supported. Most importantly, the support of the thin disk geometry allows for the very same samples to be used in a laser flash instrument. The design allows for rough vacuum, high vacuum, or purging with inert gases in the sample chamber. Measurements on thermoelectric ZnSb and a Ni reference material are presented.  相似文献   
6.
The field of computer supported cooperative work aims at providing information technology models, methods, and tools that assist individuals to cooperate. The presented paper is based on three main observations from literature. First, one of the problems in utilizing information technology for cooperation is to identify the relevance of information, called awareness. Second, research in computer supported cooperative work proposes the use of agent technologies to aid individuals to maintain their awareness. Third, literature lacks the formalized methods on how software agents can identify awareness. This paper addresses the problem of awareness identification. The main contribution of this paper is to propose and evaluate a formalized structure, called Policy-based Awareness Management (PAM). PAM extends the logic of general awareness in order to identify relevance of information. PAM formalizes existing policies into Directory Enabled Networks-next generation structure and uses them as a source for awareness identification. The formalism is demonstrated by applying PAM to the space shuttle Columbia disaster occurred in 2003. The paper also argues that efficacy and cost-efficiency of the logic of general awareness will be increased by PAM. This is evaluated by simulation of hypothetical scenarios as well as a case study.  相似文献   
7.
A semi-climatized zone in the shape of a glazed space is heated to some degree by solar radiation and to some degree by excess heat or heat loss from the main and fully insulated part of the building. Such a space will not offer full thermal comfort for permanent occupancy during the winter season, but it is useful for secondary functions such as circulation, storage, physical activities, etc. During the summer season glazed spaces will also be very attractive for ordinary occupancy.

A condition for energy conservation is that these spaces are not heated directly but utilize heat loss and possibly excess heat from the adjoining buildings. If they are properly positioned and constructed, they will also function as solar collectors.

The energy reduction potential will vary greatly with the relative size of the spaces, with the system installed, and with possibilities for long term storage. If the glazed space covers relatively large parts of the adjoining buildings, the reduced heat loss from these may be considerable. If in addition a certain minimum temperature can be kept in the glazed space, the need for heating in the adjoining buildings may be minimal.

Abroad such spaces are often used consciously as architectural elements due to their special spatial character. In countries like Norway they may in addition serve several needs resulting from the special climatic conditions.

SINTEF has developed energy conservation systems based on this concept and has tested them in experimental buildings. One example is the three solar energy houses in the Heimdal low energy dwellings project which totals 14 houses. Another example is a day care centre now under development for the local student union.  相似文献   
8.
Oil from the marine copepod, Calanus finmarchicus, which contains >86 % of fatty acids present as wax esters, is a novel source of n‐3 fatty acids for human consumption. In a randomized, two‐period crossover study, 18 healthy adults consumed 8 capsules providing 4 g of Calanus® Oil supplying a total of 260 mg EPA and 156 mg DHA primarily as wax esters, or 1 capsule of Lovaza® providing 465 mg EPA and 375 mg DHA as ethyl esters, each with an EPA‐ and DHA‐free breakfast. Plasma EPA and DHA were measured over a 72 h period (t = 1, 2, 4, 6, 8, 10, 12, 24, 48, and 72 h). The positive incremental area under the curve over the 72 h test period (iAUC0‐72 h) for both EPA and DHA was significantly different from zero (p < 0.0001) in both test conditions, with similar findings for the iAUC0–24 h and iAUC0–48 h, indicating the fatty acids were absorbed. There was no difference in the plasma iAUC0–72 h for EPA + DHA, or DHA individually, in response to Calanus Oil vs the ethyl ester condition; however, the iAUC0–48 h and iAUC0–72 h for plasma EPA in response to Calanus Oil were both significantly increased relative to the ethyl ester condition (iAUC0–48 h: 381 ± 31 vs 259 ± 39 μg*h/mL, p = 0.026; iAUC0‐72 h: 514 ± 47 vs 313 ± 49 μg*h/mL, p = 0.009). These data demonstrate a novel wax ester rich marine oil is a suitable alternative source of EPA and DHA for human consumption.  相似文献   
9.
10.
This article investigates the relationship between food chains and the production of consumer trust through cases drawn from the introduction of frozen fish fillets in Norway. Specifically, it will discuss how the frozen fish industry worked to create consumer trust in this new food product despite initial skepticism. Conventional ways of building trust such as quality control systems, branding, and marketing are investigated, but in addition to these mechanisms, the article discusses how the frozen fish industry utilized a range of more mundane technologies as trust-producing technologies. By investigating this effort, the article argues that technology is a valuable lens for understanding how consumers are familiarized with new foods.  相似文献   
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