全文获取类型
收费全文 | 225篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 4篇 |
综合类 | 1篇 |
化学工业 | 22篇 |
金属工艺 | 3篇 |
机械仪表 | 4篇 |
建筑科学 | 8篇 |
轻工业 | 32篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 12篇 |
一般工业技术 | 52篇 |
冶金工业 | 55篇 |
原子能技术 | 4篇 |
自动化技术 | 29篇 |
出版年
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 7篇 |
2018年 | 7篇 |
2017年 | 2篇 |
2016年 | 6篇 |
2015年 | 3篇 |
2014年 | 4篇 |
2013年 | 12篇 |
2012年 | 5篇 |
2011年 | 13篇 |
2010年 | 10篇 |
2009年 | 9篇 |
2008年 | 4篇 |
2007年 | 5篇 |
2006年 | 10篇 |
2005年 | 9篇 |
2004年 | 9篇 |
2003年 | 3篇 |
2002年 | 6篇 |
2001年 | 5篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 17篇 |
1997年 | 7篇 |
1996年 | 9篇 |
1995年 | 6篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1973年 | 3篇 |
1966年 | 1篇 |
1928年 | 2篇 |
排序方式: 共有229条查询结果,搜索用时 734 毫秒
1.
HI Huppertz S Rutkowski S Aleksic H Karch 《Canadian Metallurgical Quarterly》1997,349(9066):1660-1662
BACKGROUND: Enteroaggregative Escherichia coli (EAggEC or EAEC) can spread and cause disease in developing countries, but it is not presently known whether it spreads disease in industrialised countries. Therefore, we did a prospective study to assess the incidence and the clinical manifestations of infections due to EAEC in children in Germany. METHODS: 798 children with diarrhoea, admitted to hospital within a defined geographical area during a 24-month period, were included in the trial. EAEC were cultured from stool specimens, screened by PCR, and identified by colony hybridisation from DNA sequences found on the virulence plasmid. The findings were confirmed by aggregative adherence to HEp-2 cells. Stool samples from 580 children admitted to hospital without diarrhoea were also studied as controls. FINDINGS: EAEC were found in the stools of 16 (2%) of 798 children with diarrhoea, but in none of 580 children without diarrhoea. Only four of the EAEC-infected children had travelled to developing countries. Most EAEC infections were acquired in the summer months. Infection with EAEC was associated with acute, watery diarrhoea in 12 children, and with chronic diarrhoea of up to 5 months' duration in four. Five children had abdominal colic that lasted for 2-4 weeks as their main symptom. The incidence of EAEC infection was 7.7 patients admitted to hospital per 100,000 children in the general population aged younger than 16 years. INTERPRETATION: EAEC infection is associated with acute, watery diarrhoea and may be acquired in industrialised countries. Chronic diarrhoea or abdominal colic of unknown aetiology in young children may also be caused by EAEC infection. 相似文献
2.
HI Huppertz D Busch H Schmidt S Aleksic H Karch 《Canadian Metallurgical Quarterly》1996,128(3):341-346
The aim of this study was to evaluate the way in which short-term protection declines and is eventually lost in preconditioning and to determine the efficacy of a second preconditioning at various reperfusion intervals. Male rabbits were divided into six groups. Forty-five minutes (sustained) ischemia followed by 120 minutes reperfusion was applied 60, 65, 70, 75, and 80 minutes after a 5 minute preconditioning (groups A, B, C, D, and E) and in a control group (F) after no preconditioning. The infarct to risk ratio (I/R) was 38.3 +/- 3.5% in group A, 46.0 +/- 7.8% in B, 61.6 +/- 9.7% in C, 68.1 +/- 4.2% in D, 64.5 +/- 7.8% in E, and 61.0 +/- 7.7% in F. Group A had a smaller I/R compared with groups C, D, E, and F (p < 0.05). In another series, groups G, H, and I were exposed to two 5-minute preconditioning stimuli, separated, respectively, by 45, 60, and 75 minutes of reperfusion; 10 minutes after the last preconditioning, the animals were exposed to 45-minutes ischemia and 120 minutes reperfusion. Groups A and D (with the smaller and higher I/R ratio) were also incorporated into this protocol in order to compare the effect of the additional preconditioning with the single one. The I/R ratio was 25.4 +/- 8.5% in group G, 22.8 +/- 7.0% in group H, and 14.7 +/- 4.0% in group I (p = NS). Group D showed a higher I/R compared with groups G, A, and H (p < 0.01), and group I had a smaller I/R compared with groups A (p < 0.01) and D (p < 0.001). Cardioprotection after a first preconditioning declines gradually and is eventually lost. An additional preconditioning is always effective, and the longer the interval from the first preconditioning, the more potent is the effect. 相似文献
3.
V Thomé-Duret G Reach MN Gangnerau F Lemonnier JC Klein Y Zhang Y Hu GS Wilson 《Canadian Metallurgical Quarterly》1996,68(21):3822-3826
The development of a hypoglycemic alarm system using a subcutaneous glucose sensor implies that a decrease in blood glucose is rapidly followed by a decrease in the signal generated by the sensor. In a first set of experiments the linearity and the kinetics of the response of sensors implanted in the subcutaneous tissue of normal rats were investigated during a progressive increase in plasma glucose concentration: the sensitivities determined between 5 and 10 mM and between 10 and 15 mM were not significantly different, and a 5-10 min delay in the sensor's response was observed. In a second set of experiments, performed in diabetic rats, the kinetics of the decrease in subcutaneous glucose concentration following insulin administration was monitored during a decrease in plasma glucose level, from 15 to 3 mmol/L. During the 20 first min following insulin administration, the sensor monitored glucose concentration in subcutaneous tissue with no lag time. Subsequently, the decrease in the estimation of subcutaneous glucose concentration preceded that of plasma glucose. This phenomenon was not observed when the same sensors were investigated in vitro during a similar decrease in glucose concentration and may be due to a mechanism occurring in vivo, such as the effect of insulin on glucose transfer from the interstitial space to the cells surrounding the sensor. It reinforces the interest of the use of implantable glucose sensors as a part of a hypoglycemic alarm. 相似文献
4.
The phase boundaries between superconductivity and various types of magnetism in the pseudoternary system Ho(Rh1–x
Ru
x
)4B4 were examined by low-temperature measurements of the specific heatc(T), dc magnetizationM(H), superconducting upper critical fieldH
c2
(T), and ac susceptibility xac
(T). For Ru concentrationsx0.37 superconductivity coexists with antiferromagnetic order below about 1 K, as shown by characteristic minima in theH
c2
(T) curves and an extrapolation ofM(H) data. Additionally, theH
c2 (T) measurements exhibit an unusual hysteresis between data taken in increasing and decreasing fields below 0.6 K. As a starting point for a theoretical explanation of this feature, a mean-field model is proposed with antiferromagnetic as well as ferromagnetic interactions, which are tentatively identified as the RKKY and dipole-dipole interactions. The existence of two competing interactions is supported by the observation of a time-dependence of the xac signal at 50 mK for 0.40x0.70, leading to a pronounced hysteresis in xac
(T), which reflects a relaxation of the magnetic structure with time constants of several hours. Forx0.80 the xac
(T) andM(H) data indicate ferromagnetic ordering withT
m
increasing withx. However, an irregular temperature dependence of the Arrott plots forx=1.0 and unusual features of the magneticc(T) anomalies forx=0.95 and 1.0 exclude simple mean-field ferromagnetism. A discussion of the experimental results based on anx-dependent variation of the electronic density of states at the Fermi level is presented. 相似文献
5.
Hakan F. Karagul Donald P. Warsing Jr. Thom J. Hodgson Maaz S. Kapadia 《国际生产研究杂志》2013,51(23):7064-7084
We propose a novel mixed integer programming formulation for the capacitated lot-sizing problem with set-up times and set-up carryover. We compare our formulation to two earlier formulations, the Classical and Modified formulations, and a more recent formulation due to Suerie and Stadtler. Extensive computational experiments show that our formulation consistently outperforms the Classical and Modified formulations in terms of CPU time and solution quality. It is competitive with the Suerie–Stadtler (S&S) formulation, but outperforms all other formulations on the most challenging instances, those with low-capacity slack and a dense jobs matrix. We show that some of the differences in the performance of these various formulations arise from their different use of binary variables to represent production or set-up states. We also show that the LP relaxation of our Novel formulation provides a tighter lower bound than that of the Modified formulation. Our experiments demonstrate that, while the S&S formulation provides a much tighter LP bound, the Novel formulation is better able to exploit the intelligence of the CPLEX solution engine. 相似文献
6.
Railway Engineering Science - A wheel tracking test was modelled to gain better understanding of the deflection and stress–strain distribution in an overlaid cracked pavements with and... 相似文献
7.
Equine milk has important nutritional and therapeutic properties that can benefit the diet of the elderly, convalescent or newborn. The protein content of equine milk is lower than that of bovine milk but similar to that of human milk. In this review qualitative and quantitative differences between the caseins and whey proteins of equine, bovine and human milk are discussed. Important biological and functional properties of specific proteins are reviewed and their significance in human nutrition considered. As well as characterizing equine milk proteins in the context of human nutrition and allergology, the potential industrial exploitation of equine milk is explored. Cross-reactivity of proteins from different species is discussed in relation to the treatment of cows’ milk protein allergy. While there is some scientific basis for the special nutritional and health-beneficial properties of equine milk based on its protein composition and similarity to human milk, further research is required to fully exploit its potential in human nutrition. 相似文献
8.
This paper proposes the hybrid model of autoregressive moving average (ARMA) and generalized autoregressive conditional heteroscedasticity (GARCH) to estimate and forecast the machine state based on vibration signal. The main idea in this study is to employ the linear ARMA model and the nonlinear GARCH model to explain the wear and fault condition of machine, respectively. The successful outcomes of the ARMA/GARCH prediction model can give obvious explanation for future states of machine, which enhance the worth of machine condition monitoring as well as condition-based maintenance in practical applications. The advance of the proposed model is verified in empirical results as applying for a real system of a methane compressor in a petrochemical plant. 相似文献
9.
10.
Reconstruction and quantification of the carotid artery bifurcation from 3-D ultrasound images 总被引:4,自引:0,他引:4
Barratt DC Ariff BB Humphries KN Thom SA Hughes AD 《IEEE transactions on medical imaging》2004,23(5):567-583
Three-dimensional (3-D) ultrasound is a relatively new technique, which is well suited to imaging superficial blood vessels, and potentially provides a useful, noninvasive method for generating anatomically realistic 3-D models of the peripheral vasculature. Such models are essential for accurate simulation of blood flow using computational fluid dynamics (CFD), but may also be used to quantify atherosclerotic plaque more comprehensively than routine clinical methods. In this paper, we present a spline-based method for reconstructing the normal and diseased carotid artery bifurcation from images acquired using a freehand 3-D ultrasound system. The vessel wall (intima-media interface) and lumen surfaces are represented by a geometric model defined using smoothing splines. Using this coupled wall-lumen model, we demonstrate how plaque may be analyzed automatically to provide a comprehensive set of quantitative measures of size and shape, including established clinical measures, such as degree of (diameter) stenosis. The geometric accuracy of 3-D ultrasound reconstruction is assessed using pulsatile phantoms of the carotid bifurcation, and we conclude by demonstrating the in vivo application of the algorithms outlined to 3-D ultrasound scans from a series of patient carotid arteries. 相似文献