全文获取类型
收费全文 | 922篇 |
免费 | 49篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 21篇 |
综合类 | 1篇 |
化学工业 | 219篇 |
金属工艺 | 14篇 |
机械仪表 | 15篇 |
建筑科学 | 98篇 |
矿业工程 | 1篇 |
能源动力 | 23篇 |
轻工业 | 90篇 |
水利工程 | 5篇 |
石油天然气 | 3篇 |
无线电 | 69篇 |
一般工业技术 | 175篇 |
冶金工业 | 43篇 |
原子能技术 | 17篇 |
自动化技术 | 180篇 |
出版年
2023年 | 13篇 |
2022年 | 16篇 |
2021年 | 32篇 |
2020年 | 14篇 |
2019年 | 15篇 |
2018年 | 15篇 |
2017年 | 13篇 |
2016年 | 39篇 |
2015年 | 26篇 |
2014年 | 27篇 |
2013年 | 60篇 |
2012年 | 42篇 |
2011年 | 83篇 |
2010年 | 50篇 |
2009年 | 53篇 |
2008年 | 54篇 |
2007年 | 55篇 |
2006年 | 48篇 |
2005年 | 47篇 |
2004年 | 33篇 |
2003年 | 26篇 |
2002年 | 25篇 |
2001年 | 16篇 |
2000年 | 9篇 |
1999年 | 17篇 |
1998年 | 10篇 |
1997年 | 21篇 |
1996年 | 15篇 |
1995年 | 15篇 |
1994年 | 7篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1990年 | 9篇 |
1989年 | 4篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 6篇 |
1974年 | 4篇 |
1970年 | 3篇 |
1966年 | 2篇 |
1941年 | 1篇 |
1937年 | 2篇 |
排序方式: 共有974条查询结果,搜索用时 125 毫秒
51.
Schwede Torsten F.; Badeker Mathias; Langer Martin; Retey Janos; Schulz Georg E. 《Protein engineering, design & selection : PEDS》1999,12(2):151-153
Histidase (histidine ammonia-lyase, EC 4.3.1.3) from Pseudomonasputida was expressed in Escherichia coli and purified. In theabsence of thiols the tetrameric enzyme gave rise to undefinedaggregates and suitable crystals could not be obtained. Thesolvent accessibility along the chain was predicted from theamino acid sequence. Among the seven cysteines, only one waslabeled as `solvent-exposed'. The exchange of this cysteineto alanine abolished all undefined aggregations and yieldedreadily crystals diffracting to 1.8 Å resolution. 相似文献
52.
The new ASTM E1989-98 Laboratory Equipment Control Interface Specification (LECIS) is a robust standard definition of equipment behavior while under remote control. The goal of the standardization effort is to facilitate “plug-and-play” integration of laboratory automation with standard hardware behavior and software interfaces. The LECIS standardizes laboratory equipment behavior and a message passing scheme between the controller and equipment that synchronizes this behavior. Commercial adoption of this new standard is well under way. 相似文献
53.
Design of LTCC with High Thermal Expansion 总被引:1,自引:0,他引:1
Markus Eberstein Carsten Glitzky Marion Gemeinert Torsten Rabe Wolfgang A. Schiller Christina Modes 《International Journal of Applied Ceramic Technology》2009,6(1):1-8
New applications of low-temperature co-fired ceramics (LTCC), such as pressure sensors or integrated functional layers, require materials that possess higher coefficients of thermal expansion (CTE). To fabricate LTCC with elevated CTE, two methods of material design are examined: firstly, glass ceramic composites (GCC), which consist of >50 vol% glass in the starting powder, and, secondly, glass-bonded ceramics (GBC), where glass is added as a sintering aid only. The CTE of GBC is mainly determined by the crystalline component. For GCC, the CTE can be well predicted, if CTE and elastic data of each phase in the microstructure are known. A nonlinear characteristic of the CTE versus phase composition was found with increasing E crystals / E glass ratio and absolute CTE difference between the components. The glass composition and glass amount can be used to compensate the fixed properties of a crystalline material in a desired way. However, because the CTE and permittivity of a glass cannot be chosen independently, an optimum glass composition has to be found. For a given LTCC, it is possible to control the devitrification by shifting the glass composition. In this way, the resulting CTE values can be predicted more exactly and tailoring becomes possible. Different LTCC materials, based on the crystalline compounds Ba(La,Nd)2 Ti4 O12 , ZrO2 (Y-TZP), SiO2 (quartz), and specially developed glasses, possessing an elevated CTE of around 10 × 10−6 K−1 while showing permittivity ɛr between 6 and 63, are introduced. 相似文献
54.
Uniform Pointwise Convergence of Finite Difference Schemes Using Grid Equidistribution 总被引:1,自引:0,他引:1
Torsten Linß 《Computing》2001,66(1):27-39
A singularly perturbed quasilinear two-point boundary value problem is considered. The problem is discretized using a simple
upwind finite difference scheme on adapted meshes using grid equidistribution of monitor functions. We derive sufficient conditions
on the monitor function that guarantee uniform convergence in the discrete maximum norm no matter how small the perturbation
parameter is. These results can be used to deduce uniform convergence of the scheme for a number of layer-adapted meshes.
We also propose an adaptive procedure for the numerical treatment of the boundary value problem. Numerical experiments for
the schemes are presented.
Received November 12, 1999; revised April 20, 2000 相似文献
55.
The authors investigated the impact of response activation on dual-task performance by presenting a subliminal prime before the stimulus in Task 2 (S2) of a psychological refractory period (PRP) task. Congruence between prime and S2 modulated the reaction times in Task 2 at short stimulus onset asynchrony despite a PRP effect. This Task 2 congruence effect was paralleled by a Task 1 congruence effect and emerged exclusively under conditions of cross talk, whereas it did not occur under dual-task conditions preventing cross talk between tasks. This suggests that response activation operates during the PRP in dual tasks and affects the response times in Task 2 via cross talk between common processing elements at prebottleneck stages but not by directly affecting the postbottleneck stages. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
56.
Torsten Hägerstrand 《Papers in Regional Science》1989,66(1):1-6
The paper is the text of a speech delivered to the opening session of the Twenty-Eighth European Congress of the Regional Science Association in Stockholm in August 1988. It reflects on an earlier address (Hägerstrand 1970) in the light of numerous comments and criticisms made during the interim period. 相似文献
57.
58.
59.
H. Edin Torsten Helleday und Albert Andersson 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1937,73(4):313-326
Ohne Zusammenfassung 相似文献
60.
Jacob L. Jones Alain B. Kounga Emil Aulbach Torsten Granzow 《Journal of the American Ceramic Society》2008,91(5):1586-1590
In many polycrystalline piezoelectric ceramics, domain switching during the poling process leads to the development of a macroscopic polarization and piezoelectric behavior. Traditionally, poling involves the application of electric fields across two parallel electrodes. In the present work, a radial mechanical compressive stress is applied transverse to the electric field, increasing the potential for domain alignment during poling by taking advantage of ferroelasticity. Experiments demonstrate that poling of lead zirconate titanate using a combination of an electric field and a transverse mechanical compressive stress increases the d 33 coefficient from 435 to 489 pC/N. Using neutron diffraction and pole figure inversion methods, the degree of non-180° domain switching is described using pole density distributions of the tetragonal c -axis (002). The degree of 002 domain alignment parallel to the electric field after the electromechanical poling process increases from 1.30 multiples of a random distribution (mrd) to >1.40 mrd at stresses exceeding 40 MPa. 相似文献