首页 | 官方网站   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   105篇
  免费   3篇
工业技术   108篇
  2020年   1篇
  2019年   1篇
  2018年   1篇
  2017年   2篇
  2016年   2篇
  2015年   2篇
  2013年   7篇
  2012年   3篇
  2011年   2篇
  2010年   3篇
  2009年   2篇
  2008年   5篇
  2007年   5篇
  2006年   2篇
  2005年   5篇
  2004年   2篇
  2003年   3篇
  2002年   2篇
  1998年   4篇
  1997年   3篇
  1996年   5篇
  1994年   2篇
  1993年   2篇
  1991年   3篇
  1990年   4篇
  1989年   5篇
  1988年   2篇
  1987年   2篇
  1986年   1篇
  1985年   2篇
  1984年   2篇
  1983年   2篇
  1982年   1篇
  1981年   1篇
  1980年   2篇
  1978年   2篇
  1976年   4篇
  1975年   2篇
  1973年   1篇
  1958年   1篇
  1949年   1篇
  1937年   2篇
  1934年   1篇
  1933年   1篇
排序方式: 共有108条查询结果,搜索用时 703 毫秒
11.
12.
13.
14.
A female patient presenting with B-CLL and coincident eosinophilia-myalgia syndrome (EMS) after ingestion of L-tryptophan is described. The manifestations of EMS disappeared completely during treatment with cyclophosphamide/prednisone. and there was an intermittent clinical remission of CLL with absence of the monoclonal B-cell population. A few years later, the B-CLL relapsed, but without sign and symptoms of EMS. Whereas other eosinophilic syndromes such as eosinophilic fasciitis, panniculitis, or cellulitis Wells have been found to occur in relation to malignant underlying diseases, only a single patient with malignant fibrous histiocytoma following EMS has been described. There are no reports about an increased occurrence of B-CLL or other non-Hodgkin's lymphomas combined with or following EMS or related to L-tryptophan itself. The variant types of eosinophilic syndromes occurring due to malignant disorders, the differentiation from EMS, and the possible association between B-CLL and L-tryptophan-related EMS are discussed.  相似文献   
15.
16.
Visual information processing is impaired in schizophrenia patients and their biological relatives. The authors measured vernier thresholds in 72 schizophrenia patients, their 86 siblings, and 60 healthy control subjects. Subjects were asked to detect the direction of the horizontal displacement of 2 stimuli (left or right). During magnocellular (M) pathway tests, stimuli were dots with low contrast (5%) or counterphase-modulated gratings (25 Hz). For parvocellular (P) pathway tests, isoluminant blue-red dots with yellow-green background were used. Results revealed that patients with schizophrenia and their siblings were more impaired in M pathway conditions than in P pathway conditions. There was no color-specific impairment. The patients and their siblings displayed lower performances on tests of executive functions, psychomotor speed, and verbal memory compared with the controls. Visual-perceptual and neuropsychological data did not correlate. In conclusion, M pathway dysfunction is a potential endophenotype of schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
17.
A versatile approach based on nanosphere lithography is proposed to generate surface‐imprinted polymers for selective protein recognition. A layer of 750 nm diameter latex bead‐protein conjugate is deposited onto the surface of gold‐coated quartz crystals followed by the electrosynthesis of a poly(3,4‐ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) film with thicknesses on the order of the bead radius. The removal of the polymer bead‐protein conjugates, facilitated by using a cleavable protein‐nanosphere linkage is shown to result in 2D arrays of periodic complementary size cavities. Here it is demonstrated by nanogravimetric measurements that the imprinting proceeds further at molecular level and the protein (avidin) coating of the beads generates selective recognition sites for avidin on the surface of the PEDOT/PSS film. The binding capacity of such surface‐imprinted polymer films is ca. 6.5 times higher than that of films imprinted with unmodified beads. They also exhibit excellent selectivity against analogues of avidin, i.e., extravidin, streptavidin, and neutravidin, the latter being in fact undetectable. This methodology, if coupled with properly oriented conjugation of the macromolecular template to the nanoparticles, offers the possibility of site‐directed imprinting.  相似文献   
18.
This study intends to explain the fluid dynamic characteristics of a Pulsed Microplasma Cluster Source (PMCS). An axially symmetric steady state simulation is performed for modeling the real-life three-dimensional unsteady flow of hypersonic helium inside our PMCS. Hypersonic helium flow is simulated using Realizable k-epsilon turbulent model. We obtained the jet velocity, density, and pressure field inside our PMCS for the conditions considered and discussed them with respect to our experimental observations. We also presented a qualitative discussion on the formation-termination process of this hypersonic jet. In particular, simulation, in agreement with the experiment, indicates that the middle stage of the injection process, where the Mach disk stands close to the ablation target and at the same time the mass flow rate is relatively high, is almost the appropriate time for firing the electric discharge. We simulated the jet-electrode impingement and tracked the trajectory of the ablated carbon clusters, considered as rigid spheres, inside the PMCS. We noticed that the spatial distribution of the clusters inside PMCS is highly conserved during the free expansion of the cluster beam out of the nozzle (in the vacuum chambers) and is recognizable in the deposited carbon film. This indicates that the geometry of PMCS plays a significant role in the uniformity of the deposited film.  相似文献   
19.
20.
A pattern is a finite string of constant and variable symbols. The language generated by a pattern is the set of all strings of constant symbols which can be obtained from the pattern by substituting (non-empty) strings for variables. The pattern languages are one of language family which is orthogonal to the Chomsky-type languages hierarchy. They have many applications, such as the extended regular expressions, for instance, in languages Perl, awk, etc. They are well applicable in machine learning as well. There are erasing and non-erasing patterns are used. For non-erasing pattern languages the equivalence of languages is decidable but the inclusion problem for them is undecidable. In extended regular expressions one can use union, concatenation and Kleene star to make more complex patterns. It is also known, that the equivalence problem of extended regular expressions is undecidable. However, the problem, whether the equivalence is decidable for patterns using only concatenation and star still open. In this paper there are some interesting results about inclusion properties and equivalences of some kinds of erasing and non-erasing pattern languages. We show that the equivalence problem of non-erasing patterns in some cases can be reduced to the decidability problem of some very special inclusion properties. These results may be useful to decide whether the language equivalence of non-erasing star-patterns is decidable or not.  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-23

京公网安备 11010802026262号