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排序方式: 共有396条查询结果,搜索用时 15 毫秒
61.
We present a simple phenomenological theory of the optogalvanic effect based on the multiplication of an electron within the plasma. The dependence of the signal on current and pressure and its temporal behavior are predicted for atoms irradiated by chopped CW lasers and pulsed lasers. Experimental data obtained by pulsed lasers are presented and interpreted. 相似文献
62.
Discusses several methodological, statistical, and interpretative problems in a study of interpersonal stress, facial expressivity, and physiological reactivity conducted by C. I. Notarius et al (see record 1983-05644-001). (2 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
63.
64.
Examined the effects of 3 factors on the attribution process: (a) Ss made attributions for behaviors that were either completely voluntary (actions) or not completely voluntary (occurrences). (b) The behaviors were either accompanied (experimental condition) or not (control condition) by consensus, distinctiveness, and consistency information. (c) Consensus, distinctiveness, and consistency were presented in 1 of 3 orders, with each information variable varied over 2 (high/low) conditions. 252 undergraduates served as Ss. In the control condition only, actions were more often attributed to specific factors, whereas occurrences were more often attributed to a combination of factors. Consensus had more impact on attributions for occurrences than on attributions for actions. A recency effect in the use of consensus was found for attributions of occurrences but not for attributions of actions. Finally, highly consistent actions were more likely to be endogenously attributed. The range of behaviors to which different attribution models may be applied is discussed. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
65.
Economic models of urban spatial patterns have largely ignored complexity as an attribute of urban systems. Complexity theorists
on the other hand have not made sufficiently serious and sustained attempts to verify empirically the relevance of complex
systems models for urban spatial patterns. This research bridges this gap by simulating the evolution of an urban employment
pattern as a self-organizing complex system and seeking its empirical validation. It estimates the model’s parameters by using
firm data aggregated to the level of municipalities in Cleveland-Akron Consolidated Metropolitan Statistical Area in Ohio.
The interaction among four parameters, forces of attraction and dispersion and their respective rates of dissipation with
distance, are modeled as a two-dimensional complex system. The research compares the states of the modeled system with empirical
data to present viable methods for verification, calibration and validation of such models.
相似文献
66.
The purpose of this study was to investigate the photocatalytic oxidation of a reactive azo dye. The photocatalytic activity of the TiO2 was studied using a reactor equipped with UV-A sources, with maximum emission at 365 nm. The photocatalytic activity of the TiO2 powder (99.9% anatase) and thin films has been measured through the decomposition of methyl orange solutions. The thin film was prepared by doctor blade and spray pyrolysis deposition (SPD). The TiO2 suspensions were prepared at 1 g/L concentration, and the initial methyl orange concentration was fixed at 7.8125 mg/L. The influence of the TiO2 (powder or thin films) and/or O2 and H2O2 on the photobleaching rate, was tested under different experiments, at pH = 5. Thin films (doctor blade) of TiO2 formed of mezo-sized aggregates formed of nanosized anatase crystallites show better photobleaching efficiency than thin film (SPD) due to their large internal surface. The rate is even higher in H2O2 compared to oxygen environment. 相似文献
67.
Mihaela Ionescu Anca Pantea Stoian Manfredi Rizzo Dragos Serban Domenico Nuzzo Laura Mazilu Andra Iulia Suceveanu Ana Maria Dascalu Irinel Raluca Parepa 《International journal of molecular sciences》2021,22(21)
The 2019 novel coronavirus, known as severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) or coronavirus disease 2019 (COVID-19), is causing a global pandemic. The virus primarily affects the upper and lower respiratory tracts and raises the risk of a variety of non-pulmonary consequences, the most severe and possibly fatal of which are cardiovascular problems. Data show that almost one-third of the patients with a moderate or severe form of COVID-19 had preexisting cardiovascular comorbidities such as diabetes mellitus, obesity, hypertension, heart failure, or coronary artery disease. SARS-CoV2 causes hyper inflammation, hypoxia, apoptosis, and a renin–angiotensin system imbalance in a variety of cell types, primarily endothelial cells. Profound endothelial dysfunction associated with COVID-19 can be the cause of impaired organ perfusion that may generate acute myocardial injury, renal failure, and a procoagulant state resulting in thromboembolic events. We discuss the most recent results on the involvement of endothelial dysfunction in the pathogenesis of COVID-19 in patients with cardiometabolic diseases in this review. We also provide insights on treatments that may reduce the severity of this viral infection. 相似文献
68.
S. Weyl-Feinstein A. Markovics H. Eitam A. Orlov M. Yishay R. Agmon J. Miron I. Izhaki A. Shabtay 《Journal of dairy science》2014
Cryptosporidium parvum is considered one of the most common enteropathogens, responsible for the high incidence of diarrhea and deleterious implications on immunity and health in neonatal calves. The pomegranate is well known for its health-promoting properties. Two experiments were designed to test the antiparasitical and antidiarrheal effects of concentrated pomegranate extract (CPE) supplement in milk in neonatal Holstein calves. Forty-one calves were randomly divided into control (n = 20) and treatment (n = 21) groups. For the first experiment, the treatment group was supplemented with 3.75% CPE in the daily milk ration, between 3 and 14 d of age, whereas the control group received only milk. Fecal samples were collected between d 5 and 13 to quantify Cryptosporidium oocysts, and the duration and intensity of diarrhea were evaluated. Reduced fecal oocyst count and diarrhea intensity and duration were revealed in the 3.75% CPE calves. No difference was noted in average daily gain between groups. In a second experiment, which was designed to test the effect of a lower CPE concentration (0.6% of daily milk allocation), no effects on fecal oocyst count and average daily gain were observed. However, compared with control, the lower CPE group was characterized by a shorter duration of diarrhea and higher weight gain among males at 14 d of age. These results suggest that the CPE supplement-to-calf milk ratio may potentially alleviate intestinal morbidity caused by Cryptosporidium. 相似文献
69.
70.
Christine M. Wickens Robert E. Mann Gina Stoduto Jennifer E. Butters Anca Ialomiteanu Reginald G. Smart 《Accident; analysis and prevention》2012