全文获取类型
收费全文 | 2366篇 |
免费 | 91篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 19篇 |
综合类 | 2篇 |
化学工业 | 467篇 |
金属工艺 | 60篇 |
机械仪表 | 36篇 |
建筑科学 | 95篇 |
矿业工程 | 5篇 |
能源动力 | 61篇 |
轻工业 | 257篇 |
水利工程 | 18篇 |
石油天然气 | 4篇 |
无线电 | 172篇 |
一般工业技术 | 379篇 |
冶金工业 | 623篇 |
原子能技术 | 18篇 |
自动化技术 | 243篇 |
出版年
2023年 | 23篇 |
2022年 | 63篇 |
2021年 | 77篇 |
2020年 | 32篇 |
2019年 | 55篇 |
2018年 | 59篇 |
2017年 | 56篇 |
2016年 | 60篇 |
2015年 | 41篇 |
2014年 | 53篇 |
2013年 | 118篇 |
2012年 | 93篇 |
2011年 | 110篇 |
2010年 | 83篇 |
2009年 | 77篇 |
2008年 | 78篇 |
2007年 | 84篇 |
2006年 | 80篇 |
2005年 | 62篇 |
2004年 | 51篇 |
2003年 | 52篇 |
2002年 | 54篇 |
2001年 | 43篇 |
2000年 | 35篇 |
1999年 | 43篇 |
1998年 | 107篇 |
1997年 | 73篇 |
1996年 | 59篇 |
1995年 | 55篇 |
1994年 | 56篇 |
1993年 | 64篇 |
1992年 | 27篇 |
1991年 | 15篇 |
1990年 | 31篇 |
1989年 | 28篇 |
1988年 | 25篇 |
1987年 | 21篇 |
1986年 | 28篇 |
1985年 | 19篇 |
1984年 | 16篇 |
1983年 | 19篇 |
1982年 | 22篇 |
1981年 | 12篇 |
1980年 | 13篇 |
1979年 | 15篇 |
1977年 | 14篇 |
1976年 | 31篇 |
1975年 | 18篇 |
1974年 | 11篇 |
1972年 | 9篇 |
排序方式: 共有2459条查询结果,搜索用时 579 毫秒
91.
Anke H?llig Anita Schug Astrid V. Fahlenkamp Rolf Rossaint Mark Coburn Argon Organo-Protective Network 《International journal of molecular sciences》2014,15(10):18175-18196
Argon belongs to the group of noble gases, which are regarded as chemically inert. Astonishingly some of these gases exert biological properties and during the last decades more and more reports demonstrated neuroprotective and organoprotective effects. Recent studies predominately use in vivo or in vitro models for ischemic pathologies to investigate the effect of argon treatment. Promising data has been published concerning pathologies like cerebral ischemia, traumatic brain injury and hypoxic ischemic encephalopathy. However, models applied and administration of the therapeutic gas vary. Here we provide a systematic review to summarize the available data on argon’s neuro- and organoprotective effects and discuss its possible mechanism of action. We aim to provide a summary to allow further studies with a more homogeneous setting to investigate possible clinical applications of argon. 相似文献
92.
Nur Fatihah Mohd Yatim Masitah Abd. Rahim Kavitha Menon Faisal Muti Al-Hassan Rahimah Ahmad Anita Bhajan Manocha Mohamed Saleem Badrul Hisham Yahaya 《International journal of molecular sciences》2014,15(5):8835-8845
Both α- and β-thalassaemia syndromes are public health problems in the multi-ethnic population of Malaysia. To molecularly characterise the α- and β-thalassaemia deletions and mutations among Malays from Penang, Gap-PCR and multiplexed amplification refractory mutation systems were used to study 13 α-thalassaemia determinants and 20 β-thalassaemia mutations in 28 and 40 unrelated Malays, respectively. Four α-thalassaemia deletions and mutations were demonstrated. −−SEA deletion and αCSα accounted for more than 70% of the α-thalassaemia alleles. Out of the 20 β-thalassaemia alleles studied, nine different β-thalassaemia mutations were identified of which βE accounted for more than 40%. We concluded that the highest prevalence of (α- and β-thalassaemia alleles in the Malays from Penang are −−SEA deletion and βE mutation, respectively. 相似文献
93.
Anita Lee-Post 《国际生产研究杂志》2013,51(4):793-810
Past research in part family identification has focused mainly on the development of efficient procedures for manufacturing-oriented part family formation in which similarities among parts are established primarily on machine or operation requirements. While these part families are essential in cellular manufacturing, they are not well suited for other areas of production, in particular, part design and process planning. A new part family identification technique using a simple genetic algorithm is proposed in this paper to first determine a set of part family differentiating attributes, and second to use these attributes to guide the formation of part families. The technique is implemented in C using a SUN SPARC workstation 1+. Empirical analyses of the technique on both artificially generated data and a real application are performed and discussed. 相似文献
94.
Shuo Huang Ádám Vida Anita Heczel Erik Holmström Levente Vitos 《JOM Journal of the Minerals, Metals and Materials Society》2017,69(11):2107-2112
The effects of V, Cr, and Mn on the magnetic, elastic, and thermal properties of FeCoNiCu high-entropy alloy are studied by using the exact muffin-tin orbitals method in combination with the coherent potential approximation. The calculated lattice parameters and Curie temperatures in the face-centered-cubic structure are in line with the available experimental and theoretical data. A significant change in the magnetic behavior is revealed when adding equimolar V, Cr, and Mn to the host composition. The three independent single-crystal elastic constants are computed using a finite strain technique, and the polycrystalline elasticity parameters including shear modulus, Young’s modulus, Pugh ratio, Poisson’s ratio, and elastic anisotropy are derived and discussed. The effects of temperature on the structural parameters are determined by making use of the Debye–Grüneisen model. It is found that FeCoNiCuCr possesses a slightly larger thermal expansion coefficient than do the other alloys considered here. 相似文献
95.
Industrially manufactured carbon blacks (CBs) provide highly dispersed carbon materials with a specific surface of up to 1700 m2 g–1. Precompaction at p > 10 MPa in the presence of 3–10 wt% PTFE (provided as a dispersion) is known to lead to stable electrodes for electrochemical supercapacitors. Specific capacitances for single electrodes (C
s,1) were measured by constant current cycling (CCC) at 34 mA cm–2 to be up to 250 F g–1. It is shown that substitution of PTFE by fluorine-free binders, such as aqueous dispersions of polystyrene, styrene/butadien-copolymer and ethylene/acrylic acid copolymer is possible. Optimum systems were with 3–10 wt% binders of butadiene/styrene copolymers. They allowed stable results within hundreds of cycles. No shedding of the CB particles was observed, and swelling of the electrode was minimum. 相似文献
96.
Precursor-Derived Si-B-C-N Ceramics: Oxidation Kinetics 总被引:1,自引:0,他引:1
Elke Butchereit Klaus G. Nickel Anita Müller 《Journal of the American Ceramic Society》2001,84(10):2184-2188
The oxidation behavior of three precursor-derived ceramics—Si4.46 BC7.32 N4.40 (AMF2p), Si2.72 BC4.51 N2.69 (AMF3p), and Si3.08 BC4.39 N2.28 (T2/1p)—was investigated at 1300° and 1500°C. Scale growth at 1500°C in air can be approximated by a parabolic rate law with rate constants of 0.0599 and 0.0593 μm2 /h for AMF3p and T2/1p, respectively. The third material does not oxidize according to a parabolic rate law, but has a similar scale thickness after 100 h. The results show that at least within the experimental times these ceramics develop extremely thin scales, thinner than pure SiC or Si3 N4 . 相似文献
97.
98.
Understanding the individual's collectivistic orientations toward group goals and task activities is critical for developing cooperative and productive teams. The complex environment of modern construction, where the emphasis shifts from individually oriented to team‐based work, has led to many challenges. There are important issues of cooperative behaviours in a world of cultural pluralism in which interpersonal cooperation is juxtaposed with organizational citizenship behaviour. Behaviours of construction project participants are important manifestations of culture that are dependent upon norms, values and beliefs. Certain organizational cultures support individualistic behaviours while others emphasize the benefits to the collective whole. Collectivistic orientation is examined as the cultural dimension of individualism‐collectivism (IC) and found to be related to organizational citizenship behaviour (OCB) where the correlations of IC and most OCB variables are significant for quantity surveyors in Hong Kong. Generally, the (more) individualistic persons are less likely to exhibit organizational citizenship behaviours. 相似文献
99.
100.
Stephen Wu James L. Beck Thomas H. Heaton 《Computer-Aided Civil and Infrastructure Engineering》2013,28(10):737-752
The benefits and feasibility of earthquake early warning (EEW) are becoming more appreciated throughout the world. An EEW system detects an earthquake initiation based on a seismic sensor network and broadcasts a warning of the predicted location and magnitude shortly before an earthquake hits a site. The typical range of this lead time is very short, for example, from a few seconds up to a minute in California, which is a huge challenge for applications taking advantage of EEW. As a result, a robust automated decision process about whether to initiate a mitigation action is essential. Recent approaches based on cost–benefit analyses to properly treat the trade‐off between false alarms and missed alarms still face challenges in practical use, such as the exclusion of an important factor, lead time, in the real‐time decision process. In this study, we lay out an earthquake probability‐based automated decision‐making (ePAD) framework to give a general decision criterion based on basic decision theory and an existing cost–benefit analysis procedure. The concepts of decision function, decision contour, and surrogate model are utilized to achieve fast computation and to allow comparison between various decision criteria. A value of information model is developed to handle the lead time of EEW and its uncertainty to reduce the “false response rate” in the cost–benefit trade‐off. An illustrative example is presented to demonstrate how this framework allows more flexibility for users to adapt ePAD to correspond to their desired rational decision behavior. 相似文献