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351.
PCB and DDT concentrations were determined in the adipose tissue of cats and dogs from Southern Italy. In cats p,p′-DDE was the most abundant DDT component (95.0%), while in dogs these compounds were absent, except in two specimens. PCB concentrations were higher in cats (199.02 ng g− 1 lipid weight) than in dogs (41.61 ng g− 1 lipid weight). Also there were inter-specific differences in the contribution of the different congeners to PCBs, although PCB 138, PCB 153 and PCB 180 were the most representative congeners in both species. Animals from one location, Taranto City, had significantly elevated concentrations of dioxin-like PCBs compared to the other locations. Consequently the estimated mean 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) of coplanar PCBs were higher in these animals (cats: 0.65 pg g− 1 lipid weight; dogs 0.29 pg g− 1 lipid weight) than in the other ones (cats: 0.12 pg g− 1 lipid weight; dogs: 0.001 pg g− 1 lipid weight).  相似文献   
352.
论述了高层建筑位于多层建筑区供热外网供热范围内时,室内采暖系统如何与外网连接的问题,并通过对传统的和目前非传统的连接方式的技术分析,提出了一种新型连接方式——开式直接连接。该连接方式投资少,可靠度高,不影响建筑的平、立面布置,并通过工程实例提供了合理的选择图示。  相似文献   
353.
Nanoparticles doped with lanthanide ions exhibit stable and visible luminescence under near-infrared excitation via a process known as upconversion, enabling long-duration, low-background biological imaging. However, the complex, overlapping emission spectra of lanthanide ions can hinder the quantitative imaging of samples labeled with multiple upconverting probes. Here, we use combinatorial screening of multiply doped NaYF(4) nanocrystals to identify a series of doubly and triply doped upconverting nanoparticles that exhibit narrow, spectrally pure emission spectra at various visible wavelengths. We then developed a comprehensive kinetic model validated by our extensive experimental data set. Applying this model, we elucidated the energy transfer mechanisms giving rise to spectrally pure emission. These mechanisms suggest design rules for electronic level structures that yield robust color tuning in lanthanide-doped upconverting nanoparticles. The resulting materials will be useful for background-free multicolor imaging and tracking of biological processes.  相似文献   
354.
The possibility of setting up a positron emission tomography (PET) facility with a cyclotron and radiopharmaceutical laboratory in situ, at a feasible price and in a very restricted space, has led to a steady increase both in the use of the PET technique in diagnostic clinical routine imaging and in the number of cyclotrons for drug production. Owing to the progress made in the PET procedures, it is now possible to have not only a highly innovative system of diagnostic examination, with a remarkable improvement in the diagnostic quality and patient care, but also a considerable increase in the number of daily examinations. In this paper, the authors show how the acquired know-how, with respect to radioprotection, has applied to the planning, running and management of the PET/CT unit, installed in the Imaging Diagnostic Department of the Policlinico Tor Vergata (PTV), at Tor Vergata University, Rome.  相似文献   
355.
In this study, the feasibility of the anaerobic co-digestion of a mixed industrial sludge with municipal solid wastes (MSW) was investigated in three simulated anaerobic landfilling bioreactors during a 150-day period. All of the reactors were operated with leachate recirculation. One of them was loaded only with MSW (control reactor); the second reactor was loaded with mixed industrial sludge and MSW, the weight ratio of the MSW to mixed industrial sludge was 1:1 (based on dry solid) (Run 1); the third reactor was loaded with mixed industrial sludge and MSW, the weight ratio of the MSW to mixed industrial sludge was 1:2 (based on dry solid) (Run 2). The VFA concentrations decreased significantly in Run 1 and Run 2 reactors at the end of 150 days. The pH values were higher in Run 1 and Run 2 reactors compared to control reactor. The differences between leachate characteristics, the biodegradation and the bioefficiency of the reactors were compared. The NH(4)-N concentrations released to leachate from mixed sludge in Run 1 and Run 2 reactors were lower than that of control reactor. The BOD(5)/COD ratios in Run 1 and Run 2 reactors were lower than that of control reactor at the end of 150 days. Cumulative methane gas productions and methane percentages were higher in Run 1 and Run 2 reactors. Reductions in waste quantity, carbon percentage and settlement of the waste were better in Run 1 and Run 2 reactors compared to control reactor at the end of 150 days. Furthermore, TN and TP removals in waste were higher in reactors containing industrial sludge compared to control. The toxicity test results showed that toxicity was observed in reactors containing industrial mixed sludge.  相似文献   
356.
An Upflow Anaerobic Sludge Blanket Reactor/Continuous Stirred Tank Reactor was used sequentially to decolorize and mineralize C.I. Direct Black 38 azo dye (3200 mg/L) in a synthetic wastewater containing glucose as co-substrate. At the steady state conditions color was effectively removed under anaerobic condition, while the total aromatic amines and organic fraction could be mainly reduced under aerobic conditions. NO(3)(-)--N, COD, BOD(5,) aromatic amine, HPLC and GC analyses showed that Direct Black 38 could be chiefly mineralized by the sequential system. The toxicity levels were determined using three different test organism (ATA-anaerobic toxicity, respiration/inhibition and Daphnia magna tests) through the continuous operation of anaerobic/aerobic sequential system treating Direct Black 38 dye containing synthetic wastewater. Feed and anaerobic effluent had greater toxicity than the aerobic effluent after mineralization of dye.  相似文献   
357.
Strontium-releasing injectable bone cements may have the potential to prevent implant-related infections through the bactericidal action of strontium, while enhancing bone formation in patients suffering from osteoporosis. A melt-derived bioactive glass (BG) series (SiO2–CaO–CaF2–MgO) with 0–50% of calcium substituted with strontium on a molar base were produced. By mixing glass powder, poly(acrylic acid) and water, cements were obtained which can be delivered by injection and set in situ, giving compressive strength of up to 35 MPa. Strontium release was dependent on BG composition with increasing strontium substitution resulting in higher concentrations in the medium. Bactericidal effects were tested on Staphylococcus aureus and Streptococcus faecalis; cell counts were reduced by up to three orders of magnitude over 6 days. Results show that bactericidal action can be increased through BG strontium substitution, allowing for the design of novel antimicrobial and bone enhancing cements for use in vertebroplasty or kyphoplasty for treating osteoporosis-related vertebral compression fractures.  相似文献   
358.
Purines of ATP, ADP, AMP and adenosine released from rat caudal artery with and without endothelium and the isolated smooth muscle and endothelial cells were examined, in order to determine the source. Treatment of intact segments of caudal arteries with noradrenaline (10 microM) for 3 min induced a large release of ATP, ADP, AMP and adenosine. However, if the artery segments had been denuded of their endothelial lining, noradrenraline induced only a slight release of purines. Endothelial cells in primary culture prepared from caudal arteries, when exposed to noradrenaline for 3 min released large amounts of purines, whereas vascular smooth muscle cells prepared similarly and passaged endothelial cells did not release purines upon exposure to noradrenaline. These results indicate that, of smooth muscle and endothelial cells of the vascular wall, only intact endothelial cells react to alpha-adrenoceptor stimulation by releasing adenine nucleotides and adenosine.  相似文献   
359.
360.
Direct and interactive effects of social support, social burden (caregiving, negative life events, and social strain), education, and income on repeated use of breast cancer screening among a large (N=55,278), national sample of postmenopausal women participating in the Women's Health Initiative observational study were examined. Repeated screening decreased as emotional/informational support and positive social interactions decreased (ps  相似文献   
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