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   227篇
  免费   16篇
电工技术   1篇
化学工业   84篇
金属工艺   2篇
机械仪表   3篇
建筑科学   5篇
能源动力   5篇
轻工业   39篇
水利工程   3篇
无线电   15篇
一般工业技术   36篇
冶金工业   22篇
自动化技术   28篇
  2023年   5篇
  2022年   24篇
  2021年   29篇
  2020年   9篇
  2019年   5篇
  2018年   7篇
  2017年   10篇
  2016年   15篇
  2015年   6篇
  2014年   6篇
  2013年   16篇
  2012年   17篇
  2011年   12篇
  2010年   8篇
  2009年   6篇
  2008年   12篇
  2007年   3篇
  2006年   6篇
  2005年   6篇
  2004年   5篇
  2003年   6篇
  2002年   2篇
  2001年   1篇
  1998年   4篇
  1997年   2篇
  1996年   4篇
  1995年   1篇
  1994年   1篇
  1993年   2篇
  1991年   4篇
  1990年   4篇
  1989年   3篇
  1981年   1篇
  1977年   1篇
排序方式: 共有243条查询结果,搜索用时 0 毫秒
91.
Diesel exhaust particles (DEP) are major constituents of ambient air pollution and are associated with respiratory and cardiovascular diseases as well skin cell alterations in vitro. The epidermal cells are among the first cell populations exposed to chemical pollutants, including DEP, and are an important source of pro-inflammatory mediators. We evaluated the effects of carbonaceous soot particles from current low-emission (Euro IV) diesel engines on the oxidative and inflammatory response of normal human skin cells and compared the results with those induced by carbonaceous soot particles from an older diesel engine (BS) operating under black smoke conditions. We observed that both soot nanoparticles were spontaneously internalised by keratinocytes and distributed mostly around the cell nucleus. Moreover, at the same mass concentration, Euro IV soot particles exhibited a much higher oxidative, pro-fibrotic and toxic potential on these cell types than soot particles from the older diesel engine. These results are in agreement with and confirm our previous findings on human macrophage cells and strengthen the assumption that, at the same mass concentration, soot particles produced under low emission conditions are more cytotoxic than particles from the older diesel engine. This effect could be assigned to the defective surface structure of Euro IV diesel soot, rendering it highly active. Our findings highlight that the reduction of soot emission in terms of mass does not automatically lead to a reduction of the dangerous effects and show that soot particles from different diesel engines possess different biological behaviour towards human cells.  相似文献   
92.
In the latest years, innovative nanomaterials have attracted a dramatic and exponentially increasing interest, in particular for their potential applications in the biomedical field. In this paper, we reported our findings on the cytocompatibility of barium titanate nanoparticles (BTNPs), an extremely interesting ceramic material. A rational and systematic study of BTNP cytocompatibility was performed, using a dispersion method based on a non-covalent binding to glycol-chitosan, which demonstrated the optimal cytocompatibility of this nanomaterial even at high concentration (100 μg/ml). Moreover, we showed that the efficiency of doxorubicin, a widely used chemotherapy drug, is highly enhanced following the complexation with BTNPs. Our results suggest that innovative ceramic nanomaterials such as BTNPs can be realistically exploited as alternative cellular nanovectors.  相似文献   
93.
Aging is associated with a progressive loss of maximal cell functionality, and mitochondria are considered a key factor in aging process, since they determine the ATP availability in the cells. Mitochondrial performance during aging in skeletal muscle is reported to be either decreased or unchanged. This heterogeneity of results could partly be due to the method used to assess mitochondrial performance. In addition, in skeletal muscle the mitochondrial population is heterogeneous, composed of subsarcolemmal and intermyofibrillar mitochondria. Therefore, the purpose of the present review is to summarize the results obtained on the functionality of the above mitochondrial populations during aging, taking into account that the mitochondrial performance depends on organelle number, organelle activity, and energetic efficiency of the mitochondrial machinery in synthesizing ATP from the oxidation of fuels.  相似文献   
94.
Shelf life of products is a key parameter for any company at local and international level that wish to improve their competitiveness; thus, there is a need to search for methods that allow one to predict the shelf life of bottled wines. In this view, the progress of chemical oxidative reactions of six Italian white wines during storage (10 months after bottling), in different packaging, was monitored by means of selected oenological parameters. The optical density at 420 nm, an index of browning, showed a progressive increase that fitted the zero‐order kinetic rate. The onset of wine browning was further tested by means of accelerated ageing in controlled temperature conditions which results, modelled using the rate constants approach, showed an Arrhenius‐like dependence from temperature, allowing to estimate apparent activation energies of oxidative chemical browning (range: 46.8–88.3 kJ mol?1). Kinetic and thermodynamic approach provided a useful tool to predict quality changes of white wines during storage with respect to packaging conditions.  相似文献   
95.
Experimental research was carried out in order to ascertain whether administration of drugs capable of acting on the renal circulation, such as mannitol and propanol, in addition to improving the renal function, also have a protective effect on the histomorphological alterations induced by the acute renal ischemia. On the basis of the results of the research the Authors conclude by asserting that the combined use of mannitol and propanol has a real protective effect in preventing or attenuating lesions of the kidney caused by serious acute renal failure.  相似文献   
96.
Long- and medium-term production planning are tools to match production orders with resource capacity and that can also be used as a baseline for material procurement. The lack of a detailed schedule for the manufacturing operations, however, may cause difficulties in providing a proper material requirements planning and may affect the feasibility of the production plan itself. This paper proposes an approach, based on production process knowledge, to extract scheduling information from an aggregate production plan in order to support material procurement. The proposed approach is applied to an industrial case involving machining center production.  相似文献   
97.
Advanced mask aligner lithography (AMALITH) is a holistic approach to improve shadow printing (contact and proximity lithography) in mask aligners. AMALITH is based on two tools, the MO Exposure Optics®, a new illumination system allow shaping the angular spectrum of the illumination light, and LAB, a software tool for full 3D simulation of the shadow printing process. MO Exposure Optics® is provided by SUSS MicroTec AG (http://www.suss.com), as an upgrade for all current and older mask aligner models. MO Exposure Optics® decouples the illumination from lamp misplacement (self-calibrated light source), improves the light uniformity, provides telecentric illumination and enables customized illumination in mask aligners. LAB is a software tool provided by GenISys GmbH (http://www.genisys-gmbh.com), and allows simulating the complete chain from illumination, mask pattern, photoresist and resist processing. The combination of both tools allows optimizing mask aligner lithography beyond today’s limits.  相似文献   
98.
Deletion of phenylalanine at position 508 (F508del) in the CFTR chloride channel is the most frequent mutation in cystic fibrosis (CF) patients. F508del impairs the stability and folding of the CFTR protein, thus resulting in mistrafficking and premature degradation. F508del-CFTR defects can be overcome with small molecules termed correctors. We investigated the efficacy and properties of VX-445, a newly developed corrector, which is one of the three active principles present in a drug (Trikafta®/Kaftrio®) recently approved for the treatment of CF patients with F508del mutation. We found that VX-445, particularly in combination with type I (VX-809, VX-661) and type II (corr-4a) correctors, elicits a large rescue of F508del-CFTR function. In particular, in primary bronchial epithelial cells of CF patients, the maximal rescue obtained with corrector combinations including VX-445 was close to 60–70% of CFTR function in non-CF cells. Despite this high efficacy, analysis of ubiquitylation, resistance to thermoaggregation, protein half-life, and subcellular localization revealed that corrector combinations did not fully normalize F508del-CFTR behavior. Our study indicates that it is still possible to further improve mutant CFTR rescue with the development of corrector combinations having maximal effects on mutant CFTR structural and functional properties.  相似文献   
99.
Nowadays, two of the main challenges involving spatio-temporal databases concern the integration of their spatial and temporal features to store and query spatial objects changing over time, and the development of a simple and friendly language to query spatio-temporal data. In this paper we gather these two challenges by proposing Moving GeoPQL, a language defined in order to express spatio-temporal queries, extending the Geographical Pictorial Query language (GeoPQL). The proposed evolution is based on the concept of temporal layer that allows specifying the spatial configuration of moving objects in a time interval. More layers allow representing changes in terms of spatial configurations. Some examples of query formulation and system operation are described in the article. Finally, an experiment has been carried out for evaluating the usability of the Moving GeoPQL system. Results of this experiment showed that it facilitates the spatio-temporal query formulation since it is more user-friendly and ease to use compared to textual query languages.  相似文献   
100.
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