全文获取类型
收费全文 | 3331篇 |
免费 | 131篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 46篇 |
综合类 | 1篇 |
化学工业 | 648篇 |
金属工艺 | 217篇 |
机械仪表 | 55篇 |
建筑科学 | 151篇 |
矿业工程 | 4篇 |
能源动力 | 97篇 |
轻工业 | 280篇 |
水利工程 | 39篇 |
石油天然气 | 37篇 |
无线电 | 225篇 |
一般工业技术 | 461篇 |
冶金工业 | 743篇 |
原子能技术 | 29篇 |
自动化技术 | 436篇 |
出版年
2023年 | 21篇 |
2022年 | 34篇 |
2021年 | 63篇 |
2020年 | 44篇 |
2019年 | 53篇 |
2018年 | 59篇 |
2017年 | 55篇 |
2016年 | 74篇 |
2015年 | 67篇 |
2014年 | 66篇 |
2013年 | 200篇 |
2012年 | 136篇 |
2011年 | 154篇 |
2010年 | 108篇 |
2009年 | 119篇 |
2008年 | 154篇 |
2007年 | 132篇 |
2006年 | 97篇 |
2005年 | 97篇 |
2004年 | 105篇 |
2003年 | 90篇 |
2002年 | 69篇 |
2001年 | 56篇 |
2000年 | 51篇 |
1999年 | 65篇 |
1998年 | 101篇 |
1997年 | 69篇 |
1996年 | 75篇 |
1995年 | 65篇 |
1994年 | 60篇 |
1993年 | 71篇 |
1992年 | 56篇 |
1991年 | 41篇 |
1990年 | 57篇 |
1989年 | 47篇 |
1988年 | 50篇 |
1987年 | 51篇 |
1986年 | 40篇 |
1985年 | 44篇 |
1984年 | 51篇 |
1983年 | 45篇 |
1982年 | 40篇 |
1981年 | 34篇 |
1980年 | 43篇 |
1979年 | 43篇 |
1978年 | 32篇 |
1977年 | 24篇 |
1976年 | 30篇 |
1975年 | 28篇 |
1974年 | 21篇 |
排序方式: 共有3469条查询结果,搜索用时 15 毫秒
231.
232.
The classes of cooked foods that contain detectable levels of mutagenic activity are discussed together with the effects of different cooking procedures on the extent of mutagen formation. Analytical procedures that have so far been devised to quantify the concentrations of specific mutagenic compounds are described and the levels of these species that have been detected in cooked foods are detailed. 相似文献
233.
234.
235.
Psychology as a discipline has contributed significantly to the development of new treatment methods for severe behavior problems such as those found in the chronically mentally ill. Nevertheless, there are relatively few psychologists practicing in state mental hospitals, and it is difficult to attract and retain young qualified psychologists in these settings. The current article examines some of the more common problems that psychologists face in state facilities, with specific focus on organizational, physician-related, and staff-related issues. Recommendations are provided on ways to cope with problems in these three areas. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
236.
237.
238.
This paper provides powerful evidence empirically demonstrating for the first time the reliability of the co-heating test. The test is widely used throughout Europe to measure the total heat transfer through the fabric of buildings and to calculate the heat-transfer coefficient (HTC; units W/K). A reliable test is essential to address the ‘performance gap’, where in-use energy performance is consistently, and often substantially, poorer than predicted. The co-heating test could meet this need, but its reliability requires confirmation. Seven teams independently conducted co-heating tests on the same detached house near Watford, UK. Despite differences in the weather and in the experimental and analytical approaches, the teams’ final reported HTC measurements were within ±10% of the mean. With further standardization it is likely to be possible to improve upon this reproducibility. Furthermore, uncertainty analysis based upon a 95% confidence interval resulted in an estimated uncertainty in HTC measurements of ±8%. This research addresses persistent doubts about the reliability of the co-heating test. Avenues to further improvement of the test are discussed. This work helps to enable the test’s wider adoption as a component of the regulatory process and thus improvements to standards of house construction. 相似文献
239.
240.
Influence of the Multivalency of Ultrashort Arg‐Trp‐Based Antimicrobial Peptides (AMP) on Their Antibacterial Activity
下载免费PDF全文
![点击此处可从《ChemMedChem》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Barbara C. Hoffknecht Dennis J. Worm Sandra Bobersky Pascal Prochnow Prof. Dr. Julia E. Bandow Prof. Dr. Nils Metzler‐Nolte 《ChemMedChem》2015,10(9):1564-1569
Peptide dendrimers are a class of molecules of high interest in the search for new antibiotics. We used microwave‐assisted, copper(I)‐catalyzed alkyne–azide cycloaddition (CuAAC; “click” chemistry) for the simple and versatile synthesis of a new class of multivalent antimicrobial peptides (AMPs) containing solely arginine and tryptophan residues. To investigate the influence of multivalency on antibacterial activity, short solid‐phase‐ synthesized azide‐modified Arg‐Trp‐containing peptides were “clicked” to three different alkyne‐modified benzene scaffolds to access scaffolds with one, two, or three peptides. The antibacterial activity of 15 new AMPs was investigated by minimal inhibitory concentration (MIC) assays on five different bacterial strains, including a multidrug‐resistant Staphylococcus aureus (MRSA) strain. With ultrashort (2–3 residues) peptides, a clear synergistic effect of the trivalent display was observed, whereas this effect was not apparent with longer peptides. The best candidates showed activities in the low‐micromolar range against Gram‐positive MRSA. Surprisingly, the best activity against Gram‐negative Acinetobacter baumannii was observed with an ultrashort dipeptide on the trivalent scaffold (MIC: 7.5 μM ). The hemolytic activity was explored for the three most active peptides. At concentrations ten times the MIC values, <1 % hemolysis of red blood cells was observed. 相似文献