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   564篇
  免费   36篇
电工技术   6篇
化学工业   136篇
金属工艺   9篇
机械仪表   8篇
建筑科学   20篇
矿业工程   2篇
能源动力   25篇
轻工业   87篇
水利工程   6篇
无线电   35篇
一般工业技术   89篇
冶金工业   98篇
原子能技术   1篇
自动化技术   78篇
  2022年   15篇
  2021年   20篇
  2020年   9篇
  2019年   10篇
  2018年   20篇
  2017年   11篇
  2016年   15篇
  2015年   16篇
  2014年   24篇
  2013年   32篇
  2012年   28篇
  2011年   37篇
  2010年   29篇
  2009年   21篇
  2008年   26篇
  2007年   24篇
  2006年   18篇
  2005年   23篇
  2004年   12篇
  2003年   13篇
  2002年   9篇
  2001年   6篇
  2000年   7篇
  1999年   14篇
  1998年   26篇
  1997年   23篇
  1996年   18篇
  1995年   13篇
  1994年   15篇
  1993年   7篇
  1992年   4篇
  1991年   2篇
  1990年   7篇
  1989年   5篇
  1988年   7篇
  1987年   3篇
  1986年   3篇
  1985年   4篇
  1984年   4篇
  1982年   3篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
  1977年   1篇
  1976年   6篇
  1972年   1篇
  1970年   2篇
  1964年   1篇
  1956年   1篇
  1934年   1篇
排序方式: 共有600条查询结果,搜索用时 15 毫秒
71.
Technical-term translation represents one of the most difficult tasks for human translators since (1) most translators are not familiar with terms and domain-specific terminology and (2) such terms are not adequately covered by printed dictionaries. This paper describes an algorithm for translating technical words and terms from noisy parallel corpora across language groups. Given any word which is part of a technical term in the source language, the algorithm produces a ranked candidate match for it in the target language. Potential translations for the term are compiled from the matched words and are also ranked. We show how this ranked list helps translators in technical-term translation. Most algorithms for lexical and term translation focus on Indo-European language pairs, and most use a sentence-aligned clean parallel corpus without insertion, deletion or OCR noise. Our algorithm is language- and character-set-independent, and is robust to noise in the corpus. We show how our algorithm requires minimum preprocessing and is able to obtain technical-word translations without sentence-boundary identification or sentence alignment, from the English–Japanese awk manual corpus with noise arising from text insertions or deletions and on the English–Chinese HKUST bilingual corpus. We obtain a precision of 55.35% from the awk corpus for word translation including rare words, counting only the best candidate and direct translations. Translation precision of the best-candidate translation is 89.93% from the HKUST corpus. Potential term translations produced by the program help bilingual speakers to get a 47% improvement in translating technical terms.  相似文献   
72.
Many river rehabilitation projects to enhance the aquatic habitat focus on the creation of pool and riffle habitat by the implementation of flow deflectors, with various degrees of successes and failures. A more comprehensive understanding of the complex three‐dimensional flow dynamics that induces scour around instream structures is required for a more effective design. The objective of this study is to examine the three‐dimensional mean and turbulent flow characteristics around paired flow deflectors for various types of deflector design in a laboratory flume. Three deflector angles (45°, 90° and 135°) and two deflector heights (with flow under and over the deflector height) were tested over a smooth (plexiglas) bed and a sand bed. Three‐dimensional velocity measurements were taken with an acoustic Doppler velocimeter at several planform positions at two heights above the bed. Results show that the 90° deflectors create the most important disturbance in the mean flow field, in turbulence intensity and bed shear stress. There is, however, a marked difference in the spatial distribution of the mean and turbulent parameters over a mobile bed and over a smooth, fixed bed. This stresses the importance of understanding the feedback between bed topography and flow dynamics and limits the applicability of conclusions drawn from plane bed experiments to natural rivers. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   
73.
Experimental study of heat transfer in oscillating flow   总被引:2,自引:0,他引:2  
This paper describes an experimental study of heat transfer in oscillating flow inside a cylindrical tube. Profiles of temperature are taken inside the wall and in the fluid from an instrumented test rig, in different conditions of oscillating flow. Profiles obtained allow the observation of the wall effect on heat transfer. A method using the inverse heat conduction principle allows the characterization of local heat transfers at the fluid-solid interface. Finally, a comparison between global and local approaches of heat transfer shows the difficulty of defining a dimensionless heat flux density to model local heat transfer in oscillating flow.  相似文献   
74.
75.
76.
The treatment of a 12-year-old girl with a lifelone history of recurrent infections and aphthous stomatitis is reported. A profound neutropenis, first noted at the age of 2 years, occurring at least every month was observed together with multiple mouth ulcers a sore throat and swelling of the jugular glands. Levamisole, originally described as an anthelmintic, has a beneficial effect on the symptoms of recurrent aphthous stomatitis. After levamisole treatment aphthous stomatitis was milder and in the 1-year follow-up period the patient was asymptomatic several times during a phase of obvious neutrophil depression. The child no longer complained of a sore throat with swelling of the jugular glands and the recurrent staphylococcal infections of the skin disappeared. After therapy a marked increase in monocytes at the moment of neutropenia was observed.  相似文献   
77.
This article aims to clarify why, and by which mechanisms, exercise may influence the normal menstrual cycle. Therefore, the vast amount of literature on this subject is reviewed and a critical appraisal of the most widespread hypotheses if offered. The strikingly low body mass which frequently accompanies exercise-related menstrual irregularities (ERMI) has led some authors to develop a hypothesis which postulates that a critical percentage of body fat is essential to trigger normal menstruation. The relevance of any reference to anorexia nervosa to support this view lacks consistency: female athletes differ in many ways from patients with anorexia nervosa, not least in their excellent physical status which is essential to deliver first-class performances. ERMI is not identical to the so-called female athlete triad, a complicated pathology that involves ERMI, premature osteoporosis and disordered eating. ERMI itself does not seem to have any substantial pathological effects as long as attention is paid to preventing osteoporosis or stress fractures which may result from prolonged hypo-estrogenaemia. In the female athlete with ERMI who wishes to conceive, the accompanying subfertility may necessitate a response other than a prompt reduction in training intensity, as this is hardly a first choice for any top athlete. During recent years, a number of prospective studies have greatly contributed to our understanding of the complexity of the mechanisms involved in ERMI. Older hypotheses, such as those considering hyperprolactinaemia as the cornerstone of ERMI, have now been firmly rejected. The present hypotheses emphasise the importance of caloric deficiency and limited energy availability, although they still fail to identify the actual mechanism that causes ERMI. There is, however, evidence that ERMI is produced by a disturbance of the hypothalamic gonadotrophin-releasing hormone oscillator. This disturbance is caused by either an insufficient estrogen or progesterone feedback or by an imbalance of local opioid peptide and catecholamine activities mediated by gamma-aminobutyric acid (GABA), corticotrophin-releasing hormone and insulin-like growth factor-1. More recent experiments have also linked ERMI with changes in steroid metabolism, in particular, an increasing activity of catecholestrogens possibly leading to enhanced intracerebral noradrenaline (norepinephrine) levels that may interfere with normal gonadotrophin release. This article demonstrates that the outcome of the many studies of ERMI is characterised by much controversy and numerous methodological flaws. The importance and complexity of some recent findings necessitate a comprehensive study which links older and newer findings within a critical perspective.  相似文献   
78.
In order to check its possible acute toxicity, C60 was incorporated into living human phagocytes. It was observed that C60 has no influence on the survival of human leukocytes.  相似文献   
79.
198 men and 413 women responded to random telephone surveys in Fargo, North Dakota and Memphis, Tennessee. Each S was given the Smoking Attitudes Survey, which assesses generalized health beliefs and health-related problems associated with smoking. Ss' knowledge of smoking-associated diseases and diseases not associated with smoking was also assessed. Stepwise regression analysis of composite knowledge scores revealed 4 predictors of the health consequences of smoking: education, race, smoking status, and income. Smokers reported less knowledge and less concern about health consequences of smoking, were more likely to be male, and were more concerned about health consequences of cholesterol. The best predictor of smokers who had never attempted cessation was their greater concern over weight control, compared with smokers with a history of smoking-cessation attempts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
80.
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