全文获取类型
收费全文 | 275篇 |
免费 | 8篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 26篇 |
金属工艺 | 2篇 |
机械仪表 | 7篇 |
建筑科学 | 22篇 |
矿业工程 | 6篇 |
能源动力 | 4篇 |
轻工业 | 20篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 19篇 |
一般工业技术 | 52篇 |
冶金工业 | 67篇 |
自动化技术 | 54篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 10篇 |
2017年 | 7篇 |
2016年 | 2篇 |
2015年 | 4篇 |
2014年 | 8篇 |
2013年 | 17篇 |
2012年 | 9篇 |
2011年 | 22篇 |
2010年 | 5篇 |
2009年 | 8篇 |
2008年 | 16篇 |
2007年 | 14篇 |
2006年 | 8篇 |
2005年 | 9篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 6篇 |
2001年 | 9篇 |
2000年 | 4篇 |
1999年 | 9篇 |
1998年 | 13篇 |
1997年 | 9篇 |
1996年 | 13篇 |
1995年 | 6篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1967年 | 2篇 |
1964年 | 1篇 |
排序方式: 共有283条查询结果,搜索用时 656 毫秒
111.
Zvi?Rosenstock Irena?Feldman Yotam?Gil Ilan?RiessEmail author 《Journal of Electroceramics》2005,14(3):205-212
Semi-conductors with mobile acceptors or donors show a new type of I-V relations. This paper presents experimental results for solid state devices based on copper oxide, found to be Cu2O, which exhibit these I-V relations. The cells examined are Cu| Cu2O| In and Cu| Cu2O| Ag and similar ones tested at room temperature. The measured I-V relations are different from those reported for the same type of cells in the past, which were explained to be fixed by a Schottky barrier Cu| Cu2O. We find that the I-V relations relax over a long time which we claim is due to ion redistribution. The new I-V relations can then be explained by assuming that Cu2O is a mixed-ionic-electronic-conductor and adopting a theory developed by us in the past and modified to be applicable to the relevant defect model here. In this case the contribution of Schottky barriers is insignificant. 相似文献
112.
Gérard Demazeau Patrick Maestro Théophile Plante Michel Pouchard Paul Hagenmuller 《Materials Research Bulletin》1979,14(1):121-126
A new method is described for the preparation of ferromagnetic chromium dioxide by high-pressure oxidation. A new ferromagnetic ternary oxide of formula Cr1?xRhxO2 (0 < x < 0.5) has also been prepared. It has a high coercive field () at Rh contents as low as and shows therefore promise for use in magnetic recording, especially for video applications. 相似文献
113.
Goshen L Shimshoni I 《IEEE transactions on pattern analysis and machine intelligence》2008,30(7):1230-1242
The estimation of the epipolar geometry is especially difficult when the putative correspondences include a low percentage of inlier correspondences and/or a large subset of the inliers is consistent with a degenerate configuration of the epipolar geometry that is totally incorrect. This work presents the Balanced Exploration and Exploitation Model Search (BEEM) algorithm that works very well especially for these difficult scenes. The algorithm handles these two problems in a unified manner. It includes the following main features: (1) Balanced use of three search techniques: global random exploration, local exploration near the current best solution and local exploitation to improve the quality of the model. (2) Exploits available prior information to accelerate the search process. (3) Uses the best found model to guide the search process, escape from degenerate models and to define an efficient stopping criterion. (4) Presents a simple and efficient method to estimate the epipolar geometry from two SIFT correspondences. (5) Uses the locality-sensitive hashing (LSH) approximate nearest neighbor algorithm for fast putative correspondences generation. The resulting algorithm when tested on real images with or without degenerate configurations gives quality estimations and achieves significant speedups compared to the state of the art algorithms. 相似文献
114.
The introduction of wet SEM imaging technology permits electron microscopy of wet samples. Samples are placed in sealed specimen capsules and are insulated from the vacuum in the SEM chamber by an impermeable, electron-transparent membrane. The complete insulation of the sample from the vacuum allows direct imaging of fully hydrated, whole-mount tissue. In the current work, we demonstrate direct inspection of thick pancreatic tissue slices (above 400 mum). In the case of scanning of the pancreatic surface, the boundaries of intracellular features are seen directly. Thus no unfolding is required to ascertain the actual particle size distribution based on the sizes of the sections. This method enabled us to investigate the true granule size distribution and confirm early studies of improved conformity to a Poisson-like distribution, suggesting that the homotypic granule growth results from a mechanism, which favors the addition of a single unit granule to mature granules. 相似文献
115.
A highly accurate numerical scheme is presented for the Serre system of partial differential equations, which models the propagation of dispersive shallow water waves in the fully-nonlinear regime. The fully-discrete scheme utilizes the Galerkin / finite-element method based on smooth periodic splines in space, and an explicit fourth-order Runge–Kutta method in time. Computations compared with exact solitary and cnoidal wave solutions show that the scheme achieves the optimal orders of accuracy in space and time. These computations also show that the stability of this scheme does not impose very restrictive conditions on the temporal stepsize. In addition, solitary, cnoidal, and dispersive shock waves are studied in detail using this numerical scheme for the Serre system and compared with the ‘classical’ Boussinesq system for small-amplitude shallow water waves. The results show that the interaction of solitary waves in the Serre system is more inelastic. The efficacy of the numerical scheme for modeling dispersive shocks is shown by comparison with asymptotic results. These results have application to the modeling of shallow water waves of intermediate or large amplitude. 相似文献
116.
We construct a general-purpose multi-input functional encryption scheme in the private-key setting. Namely, we construct a scheme where a functional key corresponding to a function f enables a user holding encryptions of \(x_1, \ldots , x_t\) to compute \(f(x_1, \ldots , x_t)\) but nothing else. This is achieved starting from any general-purpose private-key single-input scheme (without any additional assumptions) and is proven to be adaptively secure for any constant number of inputs t. Moreover, it can be extended to a super-constant number of inputs assuming that the underlying single-input scheme is sub-exponentially secure. Instantiating our construction with existing single-input schemes, we obtain multi-input schemes that are based on a variety of assumptions (such as indistinguishability obfuscation, multilinear maps, learning with errors, and even one-way functions), offering various trade-offs between security assumptions and functionality. Previous and concurrent constructions of multi-input functional encryption schemes either rely on stronger assumptions and provided weaker security guarantees (Goldwasser et al. in Advances in cryptology—EUROCRYPT, 2014; Ananth and Jain in Advances in cryptology—CRYPTO, 2015), or relied on multilinear maps and could be proven secure only in an idealized generic model (Boneh et al. in Advances in cryptology—EUROCRYPT, 2015). In comparison, we present a general transformation that simultaneously relies on weaker assumptions and guarantees stronger security. 相似文献
117.
We present a construction of a private-key functional encryption scheme for any family of randomized functionalities based on any such scheme for deterministic functionalities that is sufficiently expressive. Instantiating our construction with existing schemes for deterministic functionalities, we obtain schemes for any family of randomized functionalities based on a variety of assumptions (including the LWE assumption, simple assumptions on multilinear maps, and even the existence of any one-way function) offering various trade-offs between security and efficiency. Previously, Goyal et al. (Proceedings of the 12th theory of cryptography conference (TCC), pp 325–351, 2015) constructed a public-key functional encryption scheme for any family of randomized functionalities based on indistinguishability obfuscation. One of the key insights underlying our work is that, in the private-key setting, a sufficiently expressive functional encryption scheme may be appropriately utilized for implementing proof techniques that were so far implemented based on obfuscation assumptions [such as the punctured programming technique of Sahai and Waters (Proceedings of the 46th annual ACM symposium on theory of computing (STOC), pp. 475–484, 2014)]. We view this as a contribution of independent interest that may be found useful in other settings as well. 相似文献
118.
Dr. Fayçal Touti Dr. Guillaume Lautrette Kenneth D. Johnson Dr. James C. Delaney Dr. Andrew Wollacott Hamid Tissire Dr. Karthik Viswanathan Dr. Zachary Shriver Dr. Surin K. Mong Dr. Alexander J. Mijalis Dr. Obadiah J. Plante Prof. Dr. Bradley L. Pentelute 《Chembiochem : a European journal of chemical biology》2018,19(19):2039-2044
To combat antimicrobial infections, new active molecules are needed. Antimicrobial peptides, ever abundant in nature, are a fertile starting point to develop new antimicrobial agents but suffer from low stability, low specificity, and off‐target toxicity. These drawbacks have limited their development. To overcome some of these limitations, we developed antibody–bactericidal macrocyclic peptide conjugates (ABCs), in which the antibody directs the bioactive macrocyclic peptide to the targeted Gram‐negative bacteria. We used cysteine SNAr chemistry to synthesize and systematically study a library of large (>30‐mer) macrocyclic antimicrobial peptides (mAMPs) to discover variants with extended proteolytic stability in human serum and low hemolytic activity while maintaining bioactivity. We then conjugated, by using sortase A, these bioactive variants onto an Escherichia coli targeted monoclonal antibody. We found that these ABCs had minimized hemolytic activity and were able to kill E. coli at nanomolar concentrations. Our findings suggest macrocyclic peptides if fused to antibodies may facilitate the discovery of new agents to treat bacterial infections. 相似文献
119.
The determination of tolerance allocations among design parameters is an integral phase of product/process design. Such allocations are often necessary to achieve desired levels of product performance. We extend our prior research on tolerance allocation by developing both parametric and nonparametric methods for a multivariate set of performance measures that are functions of a common set of design parameters. The parametric method is novel and assumes full information about the probability distribution of design parameter processes. The proposed nonparametric method assumes that only partial information is available and significantly extends prior research by considering a more contemporary and realistic model for manufacturer costs. For both methods we derive economically based models that represent the costs, both internal (supplier) and external (manufacturer), of tolerance allocation under several different process scenarios. These scenarios are based on the manner of disposition of nonconforming product. For the parametric methods we derive tolerance allocation solutions that jointly minimize expected total cost of the supplier and manufacturer. For the nonparametric methods we derive solutions for tolerance allocation that jointly minimizes the maximum expected total cost. An example in the fabrication of a rubber tread compound is used to: (i) demonstrate the implementation of our proposed methodologies for tolerance allocation; (ii) illustrate and compare the nonparametric and parametric methods; land iii) assess the sensitivity of optimal tolerance allocations to changes in process model types, cost coefficient estimates, and manner of disposition of nonconforming product. 相似文献
120.
Ausaid Garra Sharon Alkalai-Tuvia Alona Telerman Ilan Paran Elazar Fallik Anat Elmann 《International Journal of Food Science & Technology》2020,55(12):3574-3584
Peppers are rich in health-promoting phytochemicals, which are involved in the defence mechanisms against cancer. To select a lead variety of pepper with anti-proliferative activity against colon cancer cells and liver cancer cells, high antioxidant activity, and high concentrations of capsaicin, flavonoids and phenolics, we compared these attributes in nine different pepper accessions belonging to Capsicum annuum and C. chinense. Quality parameters such as weight loss and total soluble solids content were tested as well. The different parameters were determined immediately after harvest and after prolonged storage and marketing simulation. A significant variation of these traits was detected among the accessions. C. chinense line 1745 had the highest antioxidant activity, the highest levels of capsaicin and flavonoids, a high and specific anti-cancer activity, and the lowest weight loss level during postharvest storage. It is proposed that line 1745 has potential for use as a source for health-promoting traits and should be further evaluated for use as a nutraceutical for the prevention and treatment of colon and liver cancers. 相似文献