全文获取类型
收费全文 | 1601篇 |
免费 | 100篇 |
国内免费 | 5篇 |
学科分类
工业技术 | 1706篇 |
出版年
2023年 | 10篇 |
2022年 | 25篇 |
2021年 | 51篇 |
2020年 | 42篇 |
2019年 | 38篇 |
2018年 | 49篇 |
2017年 | 49篇 |
2016年 | 39篇 |
2015年 | 53篇 |
2014年 | 51篇 |
2013年 | 93篇 |
2012年 | 70篇 |
2011年 | 97篇 |
2010年 | 79篇 |
2009年 | 78篇 |
2008年 | 87篇 |
2007年 | 74篇 |
2006年 | 62篇 |
2005年 | 38篇 |
2004年 | 41篇 |
2003年 | 35篇 |
2002年 | 38篇 |
2001年 | 40篇 |
2000年 | 28篇 |
1999年 | 29篇 |
1998年 | 103篇 |
1997年 | 67篇 |
1996年 | 52篇 |
1995年 | 28篇 |
1994年 | 25篇 |
1993年 | 27篇 |
1992年 | 3篇 |
1991年 | 12篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 9篇 |
1984年 | 10篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 13篇 |
1975年 | 3篇 |
1973年 | 2篇 |
1972年 | 2篇 |
排序方式: 共有1706条查询结果,搜索用时 0 毫秒
1.
Christian P. Romero Jonathan I. Avila Edgardo Cisternas Guerau B. Cabrera Alejandro L. Cabrera Kristiaan Temst Margriet J. Van Bael 《Journal of Materials Science》2007,42(18):7667-7672
Hydrogen desorption curves were obtained from a sample composed of a square arrangement of Co dots with average diameter of
4.4 μm, separated by a distance of 11.6 μm. A macroscopic sample of Co dots grown on a 2.5 × 2.5 cm Si substrate was made
by standard lithographic techniques and used in these experiments. Thermal programmed desorption (TPD) was performed under
ultra-high vacuum conditions. Hydrogen TPD curves were obtained from a 1 × 1 cm Co dots samples displaying a maximum of intensity
at 425 K. Hydrogen TPD curve was also obtained from 1 cm× 1 cm samples of Co films and Co foils for comparison. The hydrogen
TPD curves have decreasing intensity from the Co foils to the Co dots and finally to the Co films. This indicates that there
are more sites for hydrogen adsorption on the Co dots than in the Co films. This is a surprising result because there is approximately
8.7 times less Co atoms exposed in the Co dots that in the Co film sample. A desorption energy of 27 kcal/mol was obtained
for the Co dots suggesting that hydrogen is adsorbed on an hcp hollow site of the Co dot crystalline structure. 相似文献
2.
Lithiasis may develop in the prostate loge following prostate surgery. Calculus formation in the prostate can be ascribed basically to foreign bodies, residual adenomatous spheroids and clots or fragments of sphacelous mucosa in the presence of a stenotic area after surgery and/or infection. The diagnosis is based on the physical examination and particularly on the radiological findings. Treatment is by open surgery or endoscopic or extracorporeal lithotripsy. 相似文献
3.
The authors provide a convergence analysis for the Kohonen learning algorithm (KLA) with respect to vector quantizer (VQ) optimality criteria and introduce a stochastic relaxation technique which produces the global minimum but is computationally expensive. By incorporating the principles of the stochastic approach into the KLA, a deterministic VQ design algorithm, the soft competition scheme (SCS), is introduced. Experimental results are presented where the SCS consistently provided better codebooks than the generalized Lloyd algorithm (GLA), even when the same computation time was used for both algorithms. The SCS may therefore prove to be a valuable alternative to the GLA for VQ design 相似文献
4.
M Pan J Suárez de Lezo A Medina M Romero E Hernández J Segura F Melian F Wangüemert M Landin F Benítez M Amat F Velasco A Torres 《Canadian Metallurgical Quarterly》1997,80(10):1336-1338
Two hundred twenty-eight patients with successful coronary stent implantation were randomized either to protamine administration and femoral sheath removal (group I, n = 117) or no heparin neutralization and delayed sheath removal (group II, n = 111). The hospital stay after treatment was shorter in patients receiving protamine; therefore, protamine use for neutralizing circulating heparin may be safely administered immediately after stent implantation. 相似文献
5.
MP Romero A García-Perga?eda JM Guerrero C Osuna 《Canadian Metallurgical Quarterly》1998,12(13):1401-1408
Melatonin has been suggested as a physiological antagonist of calmodulin. In this work, we have characterized melatonin binding sites in Xenopus laevis oocyte membranes. Binding of [125I]melatonin by X. laevis oocyte membranes fulfills all criteria for binding to a receptor site. Binding was dependent on time, temperature, and membrane concentration and was stable, reversible, saturable, and specific. The binding site was also pharmacologically characterized. Stoichiometric studies showed a high-affinity binding site with a Kd of 1.18 nM. These data are in close agreement with data obtained from kinetic studies (Kd=0.12 nM). In competition studies, we observed a low-affinity binding site (Kd=63.41 microM). Moreover, the binding site was characterized as calmodulin. Thus, binding was dependent on calcium and blocked by anti-CaM antibodies in a concentration-dependent manner. Calmodulin inhibitor chlorpromazine also inhibited binding of the tracer. From these results, it is suggested that membrane-bound calmodulin acts as a melatonin binding site in Xenopus laevis oocytes, where it might couple cellular activities to rhythmic circulating levels of melatonin. This hypothesis correlates with the previous findings describing melatonin as a physiological antagonist of calmodulin. 相似文献
6.
7.
8.
Luengo M. A.; Carrillo-de-la-Pe?a M. T.; Otero J. M.; Romero E. 《Canadian Metallurgical Quarterly》1994,66(3):542
Analyzes the relationships between impulsivity and antisocial behavior in a noninstitutionalized sample, taking into account the multidimensional nature of impulsivity and the diversity of types of antisocial behavior. Data were obtained in 1989 and 1990 from 1,226 adolescents aged 12–18 yrs as part of a longitudinal study of risk factors for drug abuse and delinquency. The patterns of stability or change of the various dimensions of antisocial behavior (rule breaking, vandalism, theft, aggression, and drug taking) in relation to impulsivity were investigated. The results support that self-report measures of impulsivity are closely correlated with antisocial behavior among adolescents. The longitudinally-oriented analysis of this work also shows that impulsivity is associated with a future increase in antisocial behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
Influence of electroosmotic treatment on the hydro-mechanical behaviour of clayey silts: preliminary experimental results 总被引:1,自引:0,他引:1
Laura Gabrieli Cristina Jommi Guido Musso Enrique Romero 《Journal of Applied Electrochemistry》2008,38(7):1043-1051
Preliminary results of an investigation focused on the influence of electrokinetic treatment on the mechanical and hydraulic
behaviour of clayey soils are presented. The experimental programme aims at providing a contribution to the sustainability
of contaminant extraction or containment via electroosmosis. Changes in the hydraulic and mechanical properties of two illitic
clayey soils, subjected to a DC electric field, were investigated. Samples of the two soils were subjected to electrokinetic
filtration, for different periods of time, and under different constant loads. Afterwards, they were tested under one-dimensional
compression to detect changes in stiffness and hydraulic conductivity due to the electrical treatment. After the application
of a DC field for a few hours, a small reversible increment in the average soil stiffness was observed, with respect to the
untreated soil, while the hydraulic conductivity was not affected substantially. Dramatic changes of the mechanical and hydraulic
soil properties, correlated to changes of the soil pH, were observed following non-conditioned electrokinetic treatment with
duration of the order of days. 相似文献
10.