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   670篇
  免费   65篇
  国内免费   3篇
电工技术   3篇
化学工业   252篇
金属工艺   8篇
机械仪表   13篇
建筑科学   26篇
矿业工程   1篇
能源动力   26篇
轻工业   152篇
水利工程   3篇
石油天然气   3篇
武器工业   1篇
无线电   29篇
一般工业技术   100篇
冶金工业   32篇
原子能技术   1篇
自动化技术   88篇
  2023年   11篇
  2022年   12篇
  2021年   71篇
  2020年   20篇
  2019年   28篇
  2018年   29篇
  2017年   31篇
  2016年   42篇
  2015年   26篇
  2014年   29篇
  2013年   50篇
  2012年   51篇
  2011年   46篇
  2010年   45篇
  2009年   38篇
  2008年   37篇
  2007年   19篇
  2006年   20篇
  2005年   13篇
  2004年   4篇
  2003年   10篇
  2002年   4篇
  2001年   7篇
  2000年   3篇
  1999年   4篇
  1998年   8篇
  1997年   7篇
  1996年   3篇
  1995年   6篇
  1994年   2篇
  1993年   4篇
  1992年   3篇
  1991年   4篇
  1990年   4篇
  1986年   2篇
  1985年   2篇
  1979年   3篇
  1977年   2篇
  1976年   2篇
  1974年   1篇
  1973年   1篇
  1972年   2篇
  1971年   3篇
  1970年   4篇
  1968年   1篇
  1967年   4篇
  1966年   4篇
  1964年   3篇
  1962年   5篇
  1955年   4篇
排序方式: 共有738条查询结果,搜索用时 31 毫秒
1.
2.
Abstract. This contribution introduces MOBSY, a fully integrated, autonomous mobile service robot system. It acts as an automatic dialogue-based receptionist for visitors to our institute. MOBSY incorporates many techniques from different research areas into one working stand-alone system. The techniques involved range from computer vision over speech understanding to classical robotics. Along with the two main aspects of vision and speech, we also focus on the integration aspect, both on the methodological and on the technical level. We describe the task and the techniques involved. Finally, we discuss the experiences that we gained with MOBSY during a live performance at our institute.  相似文献   
3.
For logistics centers the disposition and dispatch of goods has reached a high standard of automation. However, the trucks and trailers bringing and taking wares are driven manually. This offers a enormous potential for automation for the yards of logistics centers. The availability of this potential is correlated to the autonomous forward and backward motion control for standard transportation vehicles. By an experimental system it has been shown that truck and trailer can be maneuvered autonomously at a high degree of precision. For purposes of safety it is necessary to guarantee that at any instant of time the vehicle is within some predefined area. Therefore, this paper introduces the principle of safe cover segments which are never left by the vehicle in motion and defines rules for the connection of such segments forming a safe corridor.  相似文献   
4.
5.
Developing independence involves mastering the tasks of each life transition. Those more anxious about developing independence will become more invested in the normative tasks of each transition, and this anxiety will spread to the domain represented by these tasks. In Study 1, Honors College students expressed their anxiety about developing independence in academic performance at the beginning of college when this was the normative task and in social relationships after college when this was the normative task. This anxiety could be distinguished from other (e.g., academic) anxiety. In Study 2, sorority women expressed anxiety about developing independence in family and sorority relationships. Data demonstrate the social construction of anxiety and the dynamics of personality change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
6.
Justin Zobel  Philip Dart 《Software》1995,25(3):331-345
Approximate string matching is used for spelling correction and personal name matching. In this paper we show how to use string matching techniques in conjunction with lexicon indexes to find approximate matches in a large lexicon. We test several lexicon indexing techniques, including n-grams and permuted lexicons, and several string matching techniques, including string similarity measures and phonetic coding. We propose methods for combining these techniques, and show experimentally that these combinations yield good retrieval effectiveness while keeping index size and retrieval time low. Our experiments also suggest that, in contrast to previous claims, phonetic codings are markedly inferior to string distance measures, which are demonstrated to be suitable for both spelling correction and personal name matching.  相似文献   
7.
8.
Quantitative cellular in vitro nanoparticle uptake measurements are possible with a large number of different techniques, however, all have their respective restrictions. Here, we demonstrate the application of synchrotron-based X-ray fluorescence imaging (XFI) on prostate tumor cells, which have internalized differently functionalized gold nanoparticles. Total nanoparticle uptake on the order of a few hundred picograms could be conveniently observed with microsamples consisting of only a few hundreds of cells. A comparison with mass spectroscopy quantification is provided, experimental results are both supported and sensitivity limits of this XFI approach extrapolated by Monte-Carlo simulations, yielding a minimum detectable nanoparticle mass of just 5 pg. This study demonstrates the high sensitivity level of XFI, allowing non-destructive uptake measurements with very small microsamples within just seconds of irradiation time.  相似文献   
9.
The increasing emergence of fungicide-resistant pathogens requires urgent solutions for crop disease management. Here, we describe a structural investigation of new fungicides obtained by combining strobilurin and succinate dehydrogenase inhibitor pharmacophores. We identified compounds endowed with very good activity against wild-type Pyricularia oryzae, combined in some cases with promising activity against strobilurin-resistant strains. The first three-dimensional model of P. oryzae cytochrome bc1 complex containing azoxystrobin as a ligand was developed. The model was validated with a set of commercially available strobilurins, and it well explains both the resistance mechanism to strobilurins mediated by the mutation G143A and the activity of metyltetraprole against strobilurin-resistant strains. The obtained results shed light on the key recognition determinants of strobilurin-like derivatives in the cytochrome bc1 active site and will guide the further rational design of new fungicides able to overcome resistance caused by G143A mutation in the rice blast pathogen.  相似文献   
10.
Hepatocellular carcinoma (HCC) still remains a difficult to cure malignancy. In recent years, the focus has shifted to lipid metabolism for the treatment of HCC. Very little is known about hepatitis B virus (HBV) and C virus (HCV)-related hepatic lipid disturbances in non-malignant and cancer tissues. The present study showed that triacylglycerol and cholesterol concentrations were similar in tumor adjacent HBV and HCV liver, and were not induced in the HCC tissues. Higher levels of free cholesterol, polyunsaturated phospholipids and diacylglycerol species were noted in non-tumorous HBV compared to HCV liver. Moreover, polyunsaturated phospholipids and diacylglycerols, and ceramides declined in tumors of HBV infected patients. All of these lipids remained unchanged in HCV-related HCC. In HCV tumors, polyunsaturated phosphatidylinositol levels were even induced. There were no associations of these lipid classes in non-tumor tissues with hepatic inflammation and fibrosis scores. Moreover, these lipids did not correlate with tumor grade or T-stage in HCC tissues. Lipid reprogramming of the three analysed HBV/HCV related tumors mostly resembled HBV-HCC. Indeed, lipid composition of non-tumorous HCV tissue, HCV tumors, HBV tumors and HBV/HCV tumors was highly similar. The tumor suppressor protein p53 regulates lipid metabolism. The p53 and p53S392 protein levels were induced in the tumors of HBV, HCV and double infected patients, and this was significant in HBV infection. Negative correlation of tumor p53 protein with free cholesterol indicates a role of p53 in cholesterol metabolism. In summary, the current study suggests that therapeutic strategies to target lipid metabolism in chronic viral hepatitis and associated cancers have to consider disease etiology.  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