全文获取类型
收费全文 | 266篇 |
免费 | 9篇 |
专业分类
电工技术 | 5篇 |
化学工业 | 68篇 |
金属工艺 | 1篇 |
机械仪表 | 2篇 |
建筑科学 | 25篇 |
矿业工程 | 6篇 |
能源动力 | 2篇 |
轻工业 | 20篇 |
水利工程 | 5篇 |
无线电 | 17篇 |
一般工业技术 | 40篇 |
冶金工业 | 41篇 |
原子能技术 | 1篇 |
自动化技术 | 42篇 |
出版年
2023年 | 2篇 |
2022年 | 18篇 |
2021年 | 21篇 |
2020年 | 6篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2016年 | 11篇 |
2015年 | 5篇 |
2014年 | 11篇 |
2013年 | 16篇 |
2012年 | 22篇 |
2011年 | 22篇 |
2010年 | 10篇 |
2009年 | 10篇 |
2008年 | 25篇 |
2007年 | 15篇 |
2006年 | 5篇 |
2005年 | 4篇 |
2004年 | 5篇 |
2003年 | 8篇 |
2002年 | 5篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1969年 | 2篇 |
1967年 | 2篇 |
1966年 | 1篇 |
排序方式: 共有275条查询结果,搜索用时 500 毫秒
21.
Arcidiacono C Diolaiti E Tordi M Ragazzoni R Farinato J Vernet E Marchetti E 《Applied optics》2004,43(22):4288-4302
The Layer-Oriented Simulation Tool (LOST) is a numerical simulation code developed for analysis of the performance of multiconjugate adaptive optics modules following a layer-oriented approach. The LOST code computes the atmospheric layers in terms of phase screens and then propagates the phase delays introduced in the natural guide stars' wave fronts by using geometrical optics approximations. These wave fronts are combined in an optical or numerical way, including the effects of wave-front sensors on measurements in terms of phase noise. The LOST code is described, and two applications to layer-oriented modules are briefly presented. We have focus on the Multiconjugate adaptive optics demonstrator to be mounted upon the Very Large Telescope and on the Near-IR-Visible Adaptive Interferometer for Astronomy (NIRVANA) interferometric system to be installed on the combined focus of the Large Binocular Telescope. 相似文献
22.
In this paper, a probabilistic generalized traveling salesperson problem (PGTSP) is introduced to address several applications. In the PGTSP, each customer belongs to a cluster that consists of a set of customers. Whether or not any given customer will be present during actual operations is known a priori only probabilistically. The PGTSP seeks the minimum expected length tour to visit a subset of all customers such that the tour traverses each cluster at least once. If when implementing the tour it is revealed that there is no demand for service within the cluster to which a customer stop belongs, that stop will be skipped. An exact solution algorithm based on the integer L-shaped method and three tour construction-based heuristics for quickly solving this problem are described in the paper. Computational experiments were conducted to assess computational requirements and solution quality of the proposed solution techniques. These experiments show that the exact method is able to solve small- and moderate-size problems to optimality. In addition, one of the proposed heuristics (the MMI heuristic), in particular, gives good approximate solutions (often a few percent from optimal) in very reasonable computational time. 相似文献
23.
Elise McAbee Michael J. Bodnar William C. Tanner David W. Levi 《The Journal of Adhesion》2013,89(2):87-93
Shear strengths of adhesive bonds using AF126 and two thicknesses of aluminum were measured at constant rate of crosshead separation. It was found that the shear strength could be related to temperature and strain rate or failure time over the range of deformation rates used. 相似文献
24.
Microstructure and protein digestibility of beef: The effect of cooking conditions as used in stews and curries 总被引:1,自引:0,他引:1
Beef meat was cooked at 373 K for 10 and 30 min to investigate the effect of the cooking conditions generally used during beef stew and curry preparation on protein digestibility. The cooked meats, along with a raw control, were digested using an in vitro digestion model to simulate gastric and small-intestinal conditions. Samples taken at different digestion times were analyzed using SDS-PAGE, RP-HPLC, ninhydrin assays for amino N and transmission electron microscopy. Simulated gastric conditions quickly led to the loss of basic sarcomere structure in raw meat myofibrils whereas the sarcomere structure of the compact cooked meat myofibrils remained intact after 30 min of gastric digestion. Prolonged cooking of meat (30 min) resulted in incomplete digestion of small MW (<10 kDa) peptides, as observed from SDS-PAGE. This agreed with the amount of ninhydrin-reactive amino N released during digestion, which decreased with an increase in cooking time. The RP-HPLC peak areas of the major identified amino acids (tryptophan, tyrosine and phenylalanine) also decreased with an increase in cooking time. This suggested the formation of “limit peptides” during prolonged cooking of beef, which were not further broken down into free amino acids by digestive enzymes and therefore might not be bioavailable. 相似文献
25.
Starting from a characterization of the level of internationalization of SCI journals, based on their authoring scope, the
process of internationalization of scientific communication throughout the period 1981–97 is described. The growth of the
classes of international journals at the expense of national-oriented ones, appears as a general trend in all disciplines.
A kindred measure of internationalization at the country-level is proposed, based on the balance of country-authored publications
between national-oriented and international-oriented journals. A typology of countries is sketched. The general trend towards
internationalization is also clear at the country level. It can be generally interpreted as a positive evolution, with some
exceptions as Russia in the recent period, where it appears together with the output decline, a counterpart of the disappearance
of many journals from SCI. Some other examples of shocks with a covariation of internationalization and output are given.
Country internationalization indexes also express the sensitivity of the country output indicators to the possible restriction
of SCI sample to the international fraction. Considering evolutions of internationalization may be helpful for a comprehensive
study of scientific long-term evolutions at the country level. 相似文献
26.
Marius Eugen Ciurea Ada Maria Georgescu Stefana Oana Purcaru Stefan-Alexandru Artene Ghazaleh Hooshyar Emami Mihai Virgil Boldeanu Daniela Elise Tache Anica Dricu 《International journal of molecular sciences》2014,15(5):8169-8185
Almost all tumors are composed of a heterogeneous cell population, making them difficult to treat. A small cancer stem cell population with a low proliferation rate and a high tumorigenic potential is thought to be responsible for cancer development, metastasis and resistance to therapy. Stem cells were reported to be involved in both normal development and carcinogenesis, some molecular mechanisms being common in both processes. No less controversial, stem cells are considered to be important in treatment of malignant diseases both as targets and drug carriers. The efforts to understand the role of different signalling in cancer stem cells requires in depth knowledge about the mechanisms that control their self-renewal, differentiation and malignant potential. The aim of this paper is to discuss insights into cancer stem cells historical background and to provide a brief review of the new therapeutic strategies for targeting cancer stem cells. 相似文献
27.
Configuration for mass customization: how to extend product configuration towards requirements and process configuration 总被引:1,自引:1,他引:0
In order to develop mass customization, many companies use configuration software to customize their products. Although many
studies already exist about Product Configuration, Requirements and Process Configuration have not been studied in detail.
As all these three aspects must be considered for mass customization, the aim of this paper is to show how Product Configuration,
when considered as a constraint satisfaction problem, can be extended upstream towards Requirements Configuration and downstream
towards Process Configuration. Product Configuration basics are first reviewed thanks to a constraint based approach, and
an analysis of industrial configuration situations is done in order to clarify mass customization needs in terms of configuration.
Then upstream Requirements Configuration and downstream Process Configuration are defined and generic models are proposed.
It is shown that the proposed elements allow a global and consistent flow of configuration activities. A detailed example
illustrates the different configuration problems and a discussion terminates the paper. 相似文献
28.
Delineation of the genomics field by hybrid citation-lexical methods: interaction with experts and validation process 总被引:1,自引:0,他引:1
In advanced methods of delineation and mapping of scientific fields, hybrid methods open a promising path to the capitalisation
of advantages of approaches based on words and citations. One way to validate the hybrid approaches is to work in cooperation
with experts of the fields under scrutiny. We report here an experiment in the field of genomics, where a corpus of documents
has been built by a hybrid citation-lexical method, and then clustered into research themes. Experts of the field were associated
in the various stages of the process: lexical queries for building the initial set of documents, the seed; citation-based
extension aiming at reducing silence; final clustering to identify noise and allow discussion on border areas. The analysis
of experts’ advices show a high level of validation of the process, which combines a high-precision and low-recall seed, obtained
by journal and lexical queries, and a citation-based extension enhancing the recall. This findings on the genomics field suggest
that hybrid methods can efficiently retrieve a corpus of relevant literature, even in complex and emerging fields. 相似文献
29.
30.
一位"植物猎人"在维也纳第三区的一个公寓屋顶创造了他的天堂。公寓的主人同意他暂时使用屋顶,但必须保证使用期限到时,花园可以容易地进行清理。一个低造价的简易软木结构牢固地悬挂在屋顶上,这样负荷就不会直接传给下面的屋顶。冬天来临时,可以用背包把花盆里的植物搬到屋子里。背包其实是一种叫做"Buckelkraxen"的传统搬运工具,它常为奥地利阿尔卑斯山上的农夫们所使用。因此,除了少数种类外,大多数植物只有在夏天的时候,才会留在屋顶上。这个花园还有另外一个好处:园丁可以随性改变植物的摆放位置。设计者筛选植物的最重要标准是香味、气氛和 相似文献