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41.
The ability to tune both the thermal and mechanical properties of poly(1,3,5‐hexahydro‐1,3,5‐triazine)s (PHTs) is critical to meet the increasingly stringent demands of structural materials. To this end, PHTs are modified during the process of vitrification using a reactive blending technique. Two strategies are employed: (i) the incorporation of a monomer or oligomer that contains amino end groups that are integrated into the network via hemiaminal chemistry and (ii) the incorporation of functional monomers bearing reactive end groups capable of self‐polymerization, as well as insertion by copolymerization with the PHT‐forming reagents to form mixed networks. Both strategies produce homogeneous materials, mitigating any adverse thermal properties of the parent PHT material. Here, a deposition method bringing the PHT technology platform to more diverse, economical and large‐scale applications is also introduced. A unique layer‐by‐layer spray‐coating approach of solutions containing 4,4′‐oxydianiline (ODA) and multifunctional amines obtained by conjugate addition to acrylates is developed, allowing for the preparation of large‐scale PHT‐polymer blend films. The ODA–PHT enables high strength and modulus of the final material, while incorporation of acrylates provide an economical approach to polymer blends with tremendous functional group diversity and will allow for recyclability under mild conditions.  相似文献   
42.
Kinetics and mass transfer effects were studied for the complex catalytic liquid-phase hydrogenation in a semi-batch reactor, where finely dispersed and larger catalyst particles were used. Citral was used as a model molecule. The intrinsic kinetics was determined with crushed catalyst particles at and at pressures ranging from 10 to 40 bar. A kinetic model was proposed and successfully fitted to the experimental data. In order to elucidate the influence of internal diffusion on the selectivity and activity in complex reactions, citral hydrogenation was performed with larger catalyst pellets, in a pressurized autoclave equipped with a catalyst basket. As expected, the activity decreased with increasing catalyst particle size. The product distribution was shifted from the primary hydrogenation product (citronellal) to the fully hydrogenated end product (3,7-dimethyloctanol) as the catalyst particle size was increased. The concentrations of the secondary hydrogenation products were minor throughout the experiment. A complete reaction-diffusion model was developed for large pellets and complex reactions systems.  相似文献   
43.
We study visual servoing in a framework of detection and grasping of unknown objects. Classically, visual servoing has been used for applications where the object to be servoed on is known to the robot prior to the task execution. In addition, most of the methods concentrate on aligning the robot hand with the object without grasping it. In our work, visual servoing techniques are used as building blocks in a system capable of detecting and grasping unknown objects in natural scenes. We show how different visual servoing techniques facilitate a complete grasping cycle.  相似文献   
44.
The diversification and proliferation of doctoral programs in clinical psychology call for their periodic comparative analysis to inform prospective applicants, their advisors, and the entire field. The authors surveyed directors of the 232 American Psychological Association (APA)–accredited doctoral programs in clinical psychology (98% response) regarding application numbers, acceptance rates, financial assistance, and credentials of incoming students. Results are summarized for all clinical programs and then separately for 6 types of programs along the practice–research continuum: freestanding PsyD, university professional school PsyD, university department PsyD, practice-oriented PhD, equal-emphasis PhD, and research-oriented PhD. Lower acceptance rates and higher Graduate Record Examination scores were strongly associated with programs oriented toward more research training; for example, research-oriented PhD programs admitted far fewer applicants (7% vs. 50%) than did freestanding PsyD programs. Freestanding PsyD programs awarded significantly less full financial assistance to incoming students (1% vs. 89%) and required 1 less year to complete than did PhD programs. Overall, PhD-level students were more likely to secure an APA or Association of Psychology Postdoctoral and Internship Centers internship than were PsyD students. The authors conclude with observations about the historical changes and heightened differentiation of doctoral training in clinical psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
45.
Microbial removal of the poorly degradable antibiotic sulfamethoxazole (SMX) from surface water was investigated in laboratory columns to identify critical factors for SMX removal during bank filtration, such as the substrate concentration, redox conditions and the availability of biodegradable DOC. About 60% of SMX at a start concentration of 0.25 μg/L in surface water were removed within 14 d of column passage under aerobic conditions while no removal occurred under anoxic conditions. The adaptation time was very long and was not completed after 2 years of operation. Adaptation was faster and SMX degradation was improved at an elevated concentration of SMX (4.5 μg/L) with 90% removal in 3.5 d under aerobic conditions. SMX removal was less effective under anoxic conditions (27% in 14 d) but increased again under anaerobic conditions (51% in 14 d). According to the half-lives for SMX determined from the column data (1-9 d aerobic, 49 d anoxic and 16 d anaerobic) it is essential to provide several weeks up to months of travel time in bank filtration to allow for the degradation of SMX, and likely, also for other poorly degradable compounds. Thus, the occurrence of SMX in groundwater samples does not indicate persistency of SMX but reflects insufficient residence time or unfavorable respective redox conditions. Adaptation times of years may also be required for new bank filtration sites to develop their full removal potential towards trace pollutants. Long operation time, a comparable concentration level and similar redox conditions as in the field appear to be essential to obtain realistic results with laboratory column experiments that can be transferred to real bank filtration sites.  相似文献   
46.
47.
This article reviews past research and projects future research directions regarding women's health. Sex differences in mortality and morbidity, along with evidence that the quality and quantity of these differences are changing, are examined. Over the past decade, concurrent with dramatic changes in lifestyle and social roles for women, mortality rates have shifted, resulting in a decreasing advantage for women. Explaining the consequences of these dynamic changes requires understanding the health effects of such variables as perceived control, the experience of life roles, perceived and actual social support, and redefinition of gender roles. The future portends additional changes that will significantly affect women's health. In establishing an explicit psychological research agenda on women's health, (a) general recommendations for research are provided and (b) important issues that have not yet received a great deal of research attention (e.g., women and acquired immune deficiency syndrome [AIDS], psychopharmacology, reproductive technologies) are highlighted. This article expands the current discourse in health psychology and raises a number of issues for serious consideration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
48.
Laterality was assessed in 100 human (Homo sapiens) subjects through the use of five measures of motoric behavior in three categories: locomotor, manual, postural. Locomotor meaures included leading limb for initiation of walking and whole-body turning. Performance and questionnaire measures were used to assess lateral hand bias. Postural bias was assessed as the weight distribution in quiet standing. Population-level biases on the manual and leading limb measures were to the right; on posture and turning, to the left. Locomotor measure were found to be altered by marching experience. Only the manual measures were correlated. We compare the results with those of nonhuman primate studies (e.g., C. Forsythe et al, see PA, Vol 76:477, G. W. Milliken et al, see PA, Vol 77:9169) that have used similar measures and discuss some patterns of laterality common to human and nonhuman primates. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
49.
Ischemic stroke is a leading cause of mortality and chronic disability. Either recovery or progression towards irreversible failure of neurons and astrocytes occurs within minutes to days, depending on remaining perfusion levels. Initial damage arises from energy depletion resulting in a failure to maintain homeostasis and ion gradients between extra- and intracellular spaces. Astrocytes play a key role in these processes and are thus central players in the dynamics towards recovery or progression of stroke-induced brain damage. Here, we present a synopsis of the pivotal functions of astrocytes at the tripartite synapse, which form the basis of physiological brain functioning. We summarize the evidence of astrocytic failure and its consequences under ischemic conditions. Special emphasis is put on the homeostasis and stroke-induced dysregulation of the major monovalent ions, namely Na+, K+, H+, and Cl, and their involvement in maintenance of cellular volume and generation of cerebral edema.  相似文献   
50.
A pilot plant for ozonation and UV-disinfection received effluent from a German municipal sewage treatment plant (STP) to test the removal of pharmaceuticals, iodinated X-ray contrast media (ICM) and musk fragrances from municipal wastewater. In the original STP effluent, 5 antibiotics (0.34-0.63 microgl(-1)), 5 betablockers (0.18-1.7 microgl(-1)), 4 antiphlogistics (0.10-1.3 microgl(-1)), 2 lipid regulator metabolites (0.12-0.13 microgl(-1)), the antiepileptic drug carbamazepine (2.1 microgl(-1)), 4 ICM (1.1-5.2 microgl(-1)), the natural estrogen estrone (0.015 microgl(-1)) and 2 musk fragrances (0.1-0.73 microgl(-1)) were detected by LC-electrospray tandem MS and/or GC/MS/MS. ICM, derived from radiological examinations, were present with the highest concentrations (diatrizoate: 5.7 microgl(-1), iopromide: 5.2 microgl(-1)). By applying 10-15 mgl(-1) ozone (contact time: 18 min), all the pharmaceuticals investigated as well as musk fragrances (HHCB, AHTN) and estrone were no longer detected. However, ICM (diatrizoate, iopamidol, iopromide and iomeprol) were still detected in appreciable concentrations. Even with a 15 mgl(-1) ozone dose, the ionic diatrizoate only exhibited removal efficiencies of not higher than 14%, while the non-ionic ICM were removed to a degree of higher than 80%. Advanced oxidation processes (O(3)/UV-low pressure mercury arc, O(3)/H(2)O(2)), which were non-optimized for wastewater treatment, did not lead significantly to a higher removal efficiency for the ICM than ozone alone.  相似文献   
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