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   18405篇
  免费   1132篇
  国内免费   35篇
电工技术   202篇
综合类   43篇
化学工业   4012篇
金属工艺   347篇
机械仪表   396篇
建筑科学   811篇
矿业工程   50篇
能源动力   616篇
轻工业   1778篇
水利工程   151篇
石油天然气   70篇
无线电   1305篇
一般工业技术   3414篇
冶金工业   2356篇
原子能技术   130篇
自动化技术   3891篇
  2023年   183篇
  2022年   382篇
  2021年   707篇
  2020年   484篇
  2019年   505篇
  2018年   612篇
  2017年   568篇
  2016年   668篇
  2015年   574篇
  2014年   737篇
  2013年   1336篇
  2012年   1202篇
  2011年   1415篇
  2010年   1012篇
  2009年   931篇
  2008年   961篇
  2007年   920篇
  2006年   700篇
  2005年   598篇
  2004年   447篇
  2003年   444篇
  2002年   406篇
  2001年   248篇
  2000年   219篇
  1999年   231篇
  1998年   241篇
  1997年   205篇
  1996年   205篇
  1995年   197篇
  1994年   165篇
  1993年   166篇
  1992年   127篇
  1991年   82篇
  1990年   129篇
  1989年   121篇
  1988年   83篇
  1987年   95篇
  1986年   102篇
  1985年   105篇
  1984年   92篇
  1983年   81篇
  1982年   99篇
  1981年   95篇
  1980年   72篇
  1979年   71篇
  1978年   63篇
  1977年   79篇
  1976年   63篇
  1975年   45篇
  1974年   43篇
排序方式: 共有10000条查询结果,搜索用时 237 毫秒
11.
This study aimed to evaluate the physicochemical characteristics and sensory attributes of beef burgers with the addition of pea fibre as a partial substitute of meat or fat. Three formulations were prepared: control (CON) – similar to the commercial formulation; fibre/less meat (FLM)—5% meat reduction and addition of 1% pea fibre; fibre/less fat (FLF)—7% fat reduction and addition of 1% pea fibre. Non-significant differences were obtained for pH, colour parameters (L* and b*), texture profile, cooking loss and size reduction among formulations. Moreover, sensory analysis with consumers of beef burgers did not indicate differences among the formulations for all the analysed attributes. Therefore, pea fibre is a promising partial replacer for meat and fat in beef burgers due to the preservation of technological parameters and sensory acceptance.  相似文献   
12.
13.
Bacterial pathogens sense specific cues associated with different host niches and integrate these signals to appropriately adjust the global gene expression. Bordetella pertussis is a Gram-negative, strictly human pathogen of the respiratory tract and the etiological agent of whooping cough (pertussis). Though B. pertussis does not cause invasive infections, previous results indicated that this reemerging pathogen responds to blood exposure. Here, omics RNA-seq and LC–MS/MS techniques were applied to determine the blood-responsive regulon of B. pertussis. These analyses revealed that direct contact with blood rewired global gene expression profiles in B. pertussis as the expression of almost 20% of all genes was significantly modulated. However, upon loss of contact with blood, the majority of blood-specific effects vanished, with the exception of several genes encoding the T3SS-secreted substrates. For the first time, the T3SS regulator BtrA was identified in culture supernatants of B. pertussis. Furthermore, proteomic analysis identified BP2259 protein as a novel secreted T3SS substrate, which is required for T3SS functionality. Collectively, presented data indicate that contact with blood represents an important cue for B. pertussis cells.  相似文献   
14.
This study deals with the formulation of natural drugs into hydrogels. For the first time, compounds from the sage essential oil were formulated into chitosan hydrogels. A sample preparation procedure for hydrophobic volatile analytes present in a hydrophilic water matrix along with an analytical method based on the gas chromatography coupled with the mass spectrometry (GC-MS) was developed and applied for the evaluation of the identity and quantity of essential oil components in the hydrogels and saline samples. The experimental results revealed that the chitosan hydrogels are suitable for the formulation of sage essential oil. The monoterpene release can be effectively controlled by both chitosan and caffeine concentration in the hydrogels. Permeation experiment, based on a hydrogel with the optimized composition [3.5% (w/w) sage essential oil, 2.0% (w/w) caffeine, 2.5% (w/w) chitosan and 0.1% (w/w) Tween-80] in donor compartment, saline solution in acceptor compartment, and semi-permeable cellophane membrane, demonstrated the useful permeation selectivity. Here, (according to lipophilicity) an enhanced permeation of the bicyclic monoterpenes with antiflogistic and antiseptic properties (eucalyptol, camphor and borneol) and, at the same time, suppressed permeation of toxic thujone (not exceeding its permitted applicable concentration) was observed. These properties highlight the pharmaceutical importance of the developed chitosan hydrogel formulating sage essential oil in the dermal applications.  相似文献   
15.
16.
International Journal of Computer Vision - The original version of this article was unfortunately omitted to publish the footnote “The best result per row is highlighted in bold” in...  相似文献   
17.
18.
19.
20.
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