全文获取类型
收费全文 | 1925篇 |
免费 | 106篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 50篇 |
综合类 | 3篇 |
化学工业 | 513篇 |
金属工艺 | 33篇 |
机械仪表 | 54篇 |
建筑科学 | 86篇 |
矿业工程 | 4篇 |
能源动力 | 54篇 |
轻工业 | 208篇 |
水利工程 | 21篇 |
石油天然气 | 5篇 |
无线电 | 172篇 |
一般工业技术 | 319篇 |
冶金工业 | 169篇 |
原子能技术 | 16篇 |
自动化技术 | 328篇 |
出版年
2023年 | 19篇 |
2022年 | 83篇 |
2021年 | 88篇 |
2020年 | 38篇 |
2019年 | 33篇 |
2018年 | 58篇 |
2017年 | 45篇 |
2016年 | 67篇 |
2015年 | 45篇 |
2014年 | 68篇 |
2013年 | 115篇 |
2012年 | 78篇 |
2011年 | 125篇 |
2010年 | 98篇 |
2009年 | 114篇 |
2008年 | 110篇 |
2007年 | 98篇 |
2006年 | 79篇 |
2005年 | 65篇 |
2004年 | 61篇 |
2003年 | 58篇 |
2002年 | 49篇 |
2001年 | 27篇 |
2000年 | 30篇 |
1999年 | 27篇 |
1998年 | 47篇 |
1997年 | 39篇 |
1996年 | 30篇 |
1995年 | 17篇 |
1994年 | 21篇 |
1993年 | 17篇 |
1992年 | 14篇 |
1991年 | 6篇 |
1990年 | 13篇 |
1989年 | 12篇 |
1988年 | 11篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1985年 | 12篇 |
1984年 | 10篇 |
1983年 | 10篇 |
1982年 | 13篇 |
1981年 | 10篇 |
1980年 | 10篇 |
1979年 | 10篇 |
1978年 | 5篇 |
1977年 | 8篇 |
1976年 | 7篇 |
1975年 | 3篇 |
1910年 | 2篇 |
排序方式: 共有2035条查询结果,搜索用时 15 毫秒
1.
2.
Anna Artho Konrad Grob Carlo Mariani 《European Journal of Lipid Science and Technology》1993,95(5):176-180
The previous on-line LC-GC method for the direct analysis of the minor components in oils and fats (without cleavage of esters) was modified: The free alcohols/sterols were silylated instead of acylated, and the LC fraction transferred to GC is widened to range from the beginning of the LC chromatogram up to the sterol esters. Silylation eliminated the problem that acylation may esterify some free alcohols with free fatty acids from the oil if the oil or fat is of high acidity. Widening of the LC fraction to include squalene and the tocopherols added information to that previously obtained. 相似文献
3.
4.
This paper concerns several analytical problems related to linear polyhedra in euclidean three-dimensional-space. Symbolic formulas for line, surface, and volume integration are given, and it is shown that domain integrals are computable in polynomial time. In particular, it is shown that mass, first and second moments, and products of inertia are computable inO(E) time, whereE is the number of edges of the boundary. Simple symbolic expressions for the normal derivatives of domain integrals are also derived. In particular, it is shown that they are closely linked to the topology of the integration domain, as well as that they are expressible as combinations of domain integrals over lower-order domains (faces, edges, and vertices). The symbolic results presented in this paper may lead to an easy incorporation of integral constraints, for example, concerning mass and inertia, in the engineering designing process of solid objects. 相似文献
5.
Carlo Ghezzi Claudio Menghi Amir Molzam Sharifloo Paola Spoletini 《Requirements Engineering》2014,19(3):231-255
Software development processes have been evolving from rigid, pre-specified, and sequential to incremental, and iterative. This evolution has been dictated by the need to accommodate evolving user requirements and reduce the delay between design decision and feedback from users. Formal verification techniques, however, have largely ignored this evolution and even when they made enormous improvements and found significant uses in practice, like in the case of model checking, they remained confined into the niches of safety-critical systems. Model checking verifies if a system’s model \(\mathcal{M}\) satisfies a set of requirements, formalized as a set of logic properties \(\Phi\) . Current model-checking approaches, however, implicitly rely on the assumption that both the complete model \(\mathcal{M}\) and the whole set of properties \(\Phi\) are fully specified when verification takes place. Very often, however, \(\mathcal{M}\) is subject to change because its development is iterative and its definition evolves through stages of incompleteness, where alternative design decisions are explored, typically to evaluate some quality trade-offs. Evolving systems specifications of this kind ask for novel verification approaches that tolerate incompleteness and support incremental analysis of alternative designs for certain functionalities. This is exactly the focus of this paper, which develops an incremental model-checking approach for evolving Statecharts. Statecharts have been chosen both because they are increasingly used in practice natively support model refinements. 相似文献
6.
The addition reactions of ethylene oxide and/or propylene oxide catalyzed by KOH and initiated with compounds containing free hydroxyls are followed by secondary reactions which vary the expected molecular weight. By using ethylene oxide, diols are formed and by using propylene oxide, both diols and unsaturated monofunctional compounds are formed. These products are usually characterized by their hydroxyl number. The average molecular weight is found by taking into consideration the starter functionality only. There are often some behavioral differences among similar products owing to the different quantity and chain length of the secondary products contained therein. The secondary products are analyzed and the quantity of the secondary products were determined from the hydroxyl number values and from the unsaturation of reagents and products. In the case of monofunctional adducts using the calculation method, the results have been experimentally confirmed. 相似文献
7.
The enzymic activity of the GTP-dependent acyl-CoA synthase isolated from rat liver mitochondria is affected by removal and
addition of lecithin (3). Purified preparations of this enzyme contain bound lecithin. In this presentation the nature of
the lecithin-protein interaction is examined. From binding measurements at different temperatures it is possible to postulate
which type of secondary valence bonds is holding the protein and lecithin together.
Presented at AOCS Meeting, Chicago, October 1967. 相似文献
8.
9.
Journal of Electronic Testing - 相似文献
10.
Colussi C Banfi C Brioschi M Tremoli E Straino S Spallotta F Mai A Rotili D Capogrossi MC Gaetano C 《Proteomics. Clinical applications》2010,4(1):71-83
Purpose: Histone Deacetylase Inhibitors (DI) ameliorates dystrophic muscle regeneration restoring muscular strength in the mdx mouse model of Duchenne muscular dystrophy (DMD). The further development of these compounds as drugs for DMD treatment is currently hampered by the lack of knowledge about DIs effect in large dystrophic animal models and that of suitable biomarkers to monitor their efficacy. Experimental design: In this study we applied proteomic analysis to identify differentially expressed proteins present in plasma samples from mdx mice treated with the Suberoylanilide hydroxamic acid (SAHA) and relative normal controls (WT). Results: Several differentially expressed proteins were identified between untreated wild type and mdx mice. Among these, fibrinogen, epidermal growth factor 2 receptor, major urinary protein and glutathione peroxidase 3 (GPX3) were constitutively up‐regulated in mdx, while complement C3, complement C6, gelsolin, leukaemia inhibitory factor receptor (LIFr), and alpha 2 macroglobulin were down‐regulated compared to WT mice. SAHA determined the normalization of LIFr and GPX3 protein level while apoliprotein E was de novo up‐regulated in comparison to vehicle‐treated mdx mice. Conclusions and clinical relevance: Collectively, these data unravel potential serological disease biomarkers of mdx that could be useful to monitor muscular dystrophy response to DI treatment. 相似文献