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   1399篇
  免费   55篇
  国内免费   7篇
电工技术   9篇
化学工业   298篇
金属工艺   20篇
机械仪表   43篇
建筑科学   71篇
矿业工程   12篇
能源动力   72篇
轻工业   148篇
水利工程   26篇
石油天然气   3篇
无线电   107篇
一般工业技术   215篇
冶金工业   259篇
原子能技术   2篇
自动化技术   176篇
  2023年   19篇
  2022年   17篇
  2021年   24篇
  2020年   23篇
  2019年   25篇
  2018年   35篇
  2017年   24篇
  2016年   27篇
  2015年   28篇
  2014年   41篇
  2013年   87篇
  2012年   56篇
  2011年   86篇
  2010年   66篇
  2009年   52篇
  2008年   74篇
  2007年   70篇
  2006年   43篇
  2005年   46篇
  2004年   27篇
  2003年   34篇
  2002年   27篇
  2001年   19篇
  2000年   19篇
  1999年   16篇
  1998年   37篇
  1997年   25篇
  1996年   30篇
  1995年   23篇
  1994年   28篇
  1993年   27篇
  1992年   21篇
  1991年   12篇
  1990年   10篇
  1989年   12篇
  1988年   20篇
  1987年   11篇
  1986年   11篇
  1985年   20篇
  1984年   14篇
  1983年   16篇
  1982年   14篇
  1981年   12篇
  1980年   13篇
  1979年   18篇
  1978年   14篇
  1977年   17篇
  1976年   12篇
  1975年   8篇
  1974年   11篇
排序方式: 共有1461条查询结果,搜索用时 15 毫秒
1.
We investigate the challenges of building an end-to-end cloud pipeline for real-time intelligent visual inspection system for use in automotive manufacturing. Current methods of visual detection in automotive assembly are highly labor intensive, and thus prone to errors. An automated process is sought that can operate within the real-time constraints of the assembly line and can reduce errors. Components of the cloud pipeline include capture of a large set of high-definition images from a camera setup at the assembly location, transfer and storage of the images as needed, execution of object detection, and notification to a human operator when a fault is detected. The end-to-end execution must complete within a fixed time frame before the next car arrives in the assembly line. In this article, we report the design, development, and experimental evaluation of the tradeoffs of performance, accuracy, and scalability for a cloud system.  相似文献   
2.
Loss of β-cell mass and function can lead to insufficient insulin levels and ultimately to hyperglycemia and diabetes mellitus. The mainstream treatment approach involves regulation of insulin levels; however, approaches intended to increase β-cell mass are less developed. Promoting β-cell proliferation with low-molecular-weight inhibitors of dual-specificity tyrosine-regulated kinase 1A (DYRK1A) offers the potential to treat diabetes with oral therapies by restoring β-cell mass, insulin content and glycemic control. GNF4877, a potent dual inhibitor of DYRK1A and glycogen synthase kinase 3β (GSK3β) was previously reported to induce primary human β-cell proliferation in vitro and in vivo. Herein, we describe the lead optimization that lead to the identification of GNF4877 from an aminopyrazine hit identified in a phenotypic high-throughput screening campaign measuring β-cell proliferation.  相似文献   
3.
4.
The original Smoking Consequences Questionnaire (SCQ; T. H. Brandon & T. B. Baker, 1991) measured college students' outcome expectancies for cigarette smoking. A version (SCQ-Adult) was needed for assessing expectancies in more typical, older, nicotine-dependent smokers. Two separate versions of the SCQ were developed and compared. Tests of construct validity provided greater support for the version comprising probability items over the version comprising subjective expected utility items. As expected, principal components analyses revealed a greater number of factors than the original SCQ suggesting that expectancies become more specific with smoking experience. All scales showed good reliability. Over the course of smoking cessation treatment, expectancies became less positive, especially for abstaining participants. Other validity tests also tended to be consistent with research on alcohol expectancies and with contemporary models of drug outcome expectancies. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
5.
Some complex thinking requires active guidance by the self, but simpler mental activities do not. Depletion of the self's regulatory resources should therefore impair the former and not the latter. Resource depletion was manipulated by having some participants initially regulate attention (Studies 1 and 3) or emotion (Study 2). As compared with no-regulation participants who did not perform such exercises, depleted participants performed worse at logic and reasoning (Study 1), cognitive extrapolation (Study 2), and a test of thoughtful reading comprehension (Study 3). The same manipulations failed to cause decrements on a test of general knowledge (Study 2) or on memorization and recall of nonsense syllables (Study 3). Successful performance at complex thinking may therefore rely on limited regulatory resources. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
6.
Ground-based remote profiling in atmospheric studies: an overview   总被引:2,自引:0,他引:2  
Over the last 25 years, ground-based remote profiling has found increasing applications in atmospheric studies where its high vertical and temporal resolution and extended vertical coverage are giving scientists a clearer understanding of atmospheric processes in the troposphere. The authors describe the current status of techniques for vertical profiling of mean wind speeds, temperature, and humidity, and discuss options for combining them  相似文献   
7.
This paper reports the evaluation of five tetrahydro-beta-carboline carboxylic acids, formed from the interaction of woodsmoke carbonyls and tryptophan, for mutagenicity in the Ames test. Three of the compounds tested have been detected recently in smoked foods at levels in the micrograms/kg or mg/kg range. None of the compounds induced mutagenicity in TA 97, TA 98 or TA 100 strains of Salmonella typhimurium either with or without prior activation. However, tetrahydro-beta-carboline-3-carboxylic acid, and to a lesser extent 1-methyl-tetrahydro-beta-carboline-3-carboxylic acid were toxic to the strains of Salmonella typhimurium used. The inability of these beta-carbolines to induce mutation contrasts markedly with the mutagenicity of some beta-carbolines found in grilled meat products.  相似文献   
8.
The effect of a permanent transection on myelin gene expression in a regenerating sciatic nerve and in an adult sciatic nerve was compared to establish the degree of axonal control exerted upon Schwann cells in each population. First, the adult sciatic nerve was crushed, and the distal segment allowed to regenerate. At 12 days post-crush, the sciatic nerve was transected distal to the site of crush to disrupt the Schwann cell-axonal contacts that had reformed. Messenger RNA (mRNA) levels coding for five myelin proteins were assayed in the distal segment of the crush-transected nerve after 9 days and were compared to corresponding levels in the distal segments of sciatic nerves at 21 days post-crush and 21 days post-transection using Northern blot and slot-blot analysis. Levels of mRNAs found in the distal segment of the transected and crush-transected nerve suggested that Schwann cells in the regenerating nerve and in the mature adult nerve are equally responsive to axonal influences. The crush-transected model allowed the genes that were studied to be classified according to their response to Schwann cell-axonal contact. The levels of mRNAs were 1) down-regulated to basal levels (P0 and MBP mRNAs), 2) down-regulated to undetectable levels (myelin-associated glycoprotein mRNAs), 3) upregulated (mRNAs encoding 2'3'-cyclic nucleotide phosphodiesterase and beta-actin), or 4) not stringently controlled by the removal of Schwann cell-axonal contact (proteolipid protein mRNAs). This novel experimental model has thus provided evidence that the expression of some of the important myelin genes during peripheral nerve regeneration is dependent on continuous signals from the ingrowing axons.  相似文献   
9.
Although nanoelectronics won't replace CMOS for some time, research is needed now to develop the architectures, methods, and tools to maximally leverage nanoscale devices and terascale capacity. Addressing the complementary architectural and system issues involved requires greater collaboration at all levels. The effective use of nanotechnology calls for total system solutions  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