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51.
52.
René-Maxime Gracien Sarah C. Reitz Marlies Wagner Christoph Mayer Steffen Volz Stephanie-Michelle Hof Vinzenz Fleischer Amgad Droby Helmuth Steinmetz Sergiu Groppa Elke Hattingen Johannes C. Klein Ralf Deichmann 《Magma (New York, N.Y.)》2017,30(1):75-83
Objective
Proton density (PD) mapping requires correction for the receive profile (RP), which is frequently performed via bias-field correction. An alternative RP-mapping method utilizes a comparison of uncorrected PD-maps and a value ρ(T1) directly derived from T1-maps via the Fatouros equation. This may be problematic in multiple sclerosis (MS), if respective parameters are only valid for healthy brain tissue. We aimed to investigate whether the alternative method yields correct PD values in MS patients.Materials/methods
PD mapping was performed on 27 patients with relapsing-remitting MS and 27 healthy controls, utilizing both methods, yielding reference PD values (PDref, bias-field method) and PDalt (alternative method).Results
PDalt-values closely matched PDref, both for patients and controls. In contrast, ρ(T1) differed by up to 3 % from PDref, and the voxel-wise correlation between PDref and ρ(T1) was reduced in a patient subgroup with a higher degree of disability. Still, discrepancies between ρ(T1) and PDref were almost identical across different tissue types, thus translating into a scaling factor, which cancelled out during normalization to 100 % in CSF, yielding a good agreement between PDalt and PDref.Conclusion
RP correction utilizing the auxiliary parameter ρ(T1) derived via the Fatouros equation provides accurate PD results in MS patients, in spite of discrepancies between ρ(T1) and actual PD values.53.
Emmanuelle Dupont Jacques J.F. Commandeur Sylvain Lassarre Frits Bijleveld Heike Martensen Constantinos Antoniou Eleonora Papadimitriou George Yannis Elke Hermans Katherine Pérez Elena Santamariña-Rubio Davide Shingo Usami Gabriele Giustiniani 《Accident; analysis and prevention》2014
In this paper a unified methodology is presented for the modelling of the evolution of road safety in 30 European countries. For each country, annual data of the best available exposure indicator and of the number of fatalities were simultaneously analysed with the bivariate latent risk time series model. This model is based on the assumption that the amount of exposure and the number of fatalities are intrinsically related. It captures the dynamic evolution in the fatalities as the product of the dynamic evolution in two latent trends: the trend in the fatality risk and the trend in the exposure to that risk. Before applying the latent risk model to the different countries it was first investigated and tested whether the exposure indicator at hand and the fatalities in each country were in fact related at all. If they were, the latent risk model was applied to that country; if not, a univariate local linear trend model was applied to the fatalities series only, unless the latent risk time series model was found to yield better forecasts than the univariate local linear trend model. In either case, the temporal structure of the unobserved components of the optimal model was established, and structural breaks in the trends related to external events were identified and captured by adding intervention variables to the appropriate components of the model. As a final step, for each country the optimally modelled developments were projected into the future, thus yielding forecasts for the number of fatalities up to and including 2020. 相似文献
54.
Heme-dependent and heme-independent nitrite reduction by lactic acid bacteria results in different N-containing products 总被引:1,自引:0,他引:1
Gudrun Wolf Elke K. Arendt Ute Pfhler Walter P. Hammes 《International journal of food microbiology》1990,10(3-4):323-329
Seventy strains of lactic acid bacteria were investigated for nitrite reductase activity. Two types of this activity were detected. Type I was found in Lactobacillus plantarum, L. pentosus and Pediococcus pentosaceus. This activity is heme-dependent with ammonia as the sole product. Type II mechanism is heme-independent and reduces nitrite to NO and N2O. 相似文献
55.
The increasing demand for high quality gluten-free (GF) bread, clean labels and natural products is raising the need for new approaches in GF bread-making. Sourdough is the foremost fermentation used for baking purposes and it has been proven to be ideal for improving the texture, palatability, aroma, shelf life and nutritional value of wheat and rye breads. These characteristic features derive from the complex metabolic activities of the sourdough-resident lactic acid bacteria and yeasts, e.g. acidification, production of exopolysaccharides, proteolytic- amylolytic- and phytase activity, and production of antimicrobial substances. These effects have been extensively studied and well described for traditional baking, whereas little is known about the role of sourdough in GF baking. Yet, the microbiological and qualitative characterisation of local GF fermented products indicate an overlap with the microbiota of wheat/rye fermentation and suggest that the positive metabolic activities of the sourdough microbiota are still retained during fermentation of GF crops. Thus, the use of sourdough in GF baking may be the new frontier for improving the quality, safety and acceptability of GF bread. 相似文献
56.
To test the hypothesis that mood level is related to a tendency to underestimate the amount of positive reinforcement received, 104 undergraduates were administered a depression scale and given trials on a multiple-choice learning task with correctness of responses signaled by the experimenter saying "right" or "wrong." Estimates of number of correct response correlated significantly and positively with number of correct responses. Part correlations between the depression scale and estimates, with number of correct responses partialed out of the estimates, were negative and were significant for women alone and both sexes combined, thus confirming the hypothesis. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
57.
Critically examines A. E. Wener and L. P. Rehm's (see record 1975-25511-001) study in which Ss who were told that 80% of their responses were correct gave higher certainty ratings for their responses and had shorter latencies than Ss who were told that 20% of their responses were correct. The present article argues that to interpret these findings as evidence that a low rate of reinforcement leads to depression is gratuitous. Further, the danger of artifacts in Wener and Rehm's reanalyses of data is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
58.
59.
This research examined whether people can accurately predict the risk preferences of others. Three experiments featuring different designs revealed a systematic bias: that participants predicted others to be more risk seeking than themselves in risky choices, regardless of whether the choices were between options with negative outcomes or with positive outcomes. This self–others discrepancy persisted even if a monetary incentive was offered for accurate prediction. However, this discrepancy occurred only if the target of prediction was abstract and vanished if the target was vivid. A risk-as-feelings hypothesis was introduced to explain these findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
60.
A videokeratoscope based on the imaging of a gridlike pattern is introduced. Unlike conventional videokeratoscopes that rely on Placido disks, the new measurement principle allows an exact reconstruction of the surface and the display of fine details. The experimental instrument was tested on precision glass spheres; the maximum error of the height data was less than 3 microm. The sensitivity and the potential to resolve fine details were demonstrated with irregular surfaces of specially prepared contact lenses. Structures with height deviations of 0.1 microm are well identifiable. The eyes of 18 individuals were investigated, and fine structures were found on these cornea surfaces. Conventional videokeratoscopes do not resolve such detail. 相似文献