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21.
A Frei U Hoffmann-Richter A Bullinger A Finzen 《Canadian Metallurgical Quarterly》1997,68(11):903-906
Assisted suicide has become a topic often and controversally discussed in international literature. Psychiatry and mentally ill, however, have been neglected, probably because the question of competence of judgement and will are a major issue in this matter. Two cases are reported, one of a 60-year old man and a women of 87 years, who have committed suicide a few days after having been dismissed from stationary psychiatric care. The reason of admission had been a psychotic event with manifest AIDS-disease in the first, the public utterance of her wish to die with support of, the swiss "Help to Die" organization "Exit", in the latter. Ethics and means of preentive interventions in such cases are discussed. 相似文献
22.
Coffee is a complex mixture of chemicals that provides significant amounts of chlorogenic acid and caffeine. Unfiltered coffee is a significant source of cafestol and kahweol, which are diterpenes that have been implicated in the cholesterol-raising effects of coffee. The results of epidemiological research suggest that coffee consumption may help prevent several chronic diseases, including type 2 diabetes mellitus, Parkinson's disease and liver disease (cirrhosis and hepatocellular carcinoma). Most prospective cohort studies have not found coffee consumption to be associated with significantly increased cardiovascular disease risk. However, coffee consumption is associated with increases in several cardiovascular disease risk factors, including blood pressure and plasma homocysteine. At present, there is little evidence that coffee consumption increases the risk of cancer. For adults consuming moderate amounts of coffee (3-4 cups/d providing 300-400 mg/d of caffeine), there is little evidence of health risks and some evidence of health benefits. However, some groups, including people with hypertension, children, adolescents, and the elderly, may be more vulnerable to the adverse effects of caffeine. In addition, currently available evidence suggests that it may be prudent for pregnant women to limit coffee consumption to 3 cups/d providing no more than 300 mg/d of caffeine to exclude any increased probability of spontaneous abortion or impaired fetal growth. 相似文献
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Typical thin‐film photovoltaic (PV) cells incorporate a textured transparent conductive oxide to enhance light trapping and efficiently harvest solar energy. Rigorous coherent optical simulations of these devices and a complete characterization of these textured films are a challenging problem because of the several orders of magnitude difference between the wavelengths of interest and the spatial dimension of the sample that needs to be evaluated. In this paper, a practical approach for rigorous and predictive modeling of optical properties of thin‐film PV cells incorporating a vast variety of light‐trapping structures including semi‐coherent textured films and patterned coherent structures is presented. In contrast to the existing semi‐empirical device models, it is demonstrated that the presented methodology can accurately predict the scattering properties of textured fluorine‐doped tin oxide and aluminum‐doped zinc oxide conductive transparent films. It is further shown that the optical response of single‐junction and tandem‐junction PV devices incorporating such films can also be predicted with good accuracy as compared with the measured results. Next, a methodology to identify the sufficient statistical fingerprints of semi‐coherent textured films that are needed to unambiguously predict the light propagation in thin‐film cells is presented. This comprehensive approach then lends itself to identifying the optimal surface morphology needed for strong light trapping. This rigorous approach automatically includes the effects of important loss mechanisms such as the surface plasmon‐enhanced absorption in textured metal surfaces that are otherwise very difficult to account for semi‐coherent approaches based on scalar scattering theory. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
25.
We simultaneously measure conductance and force across nanoscale junctions. A new, two-dimensional histogram technique is introduced to statistically extract bond rupture forces from a large data set of individual junction elongation traces. For the case of Au point contacts, we find a rupture force of 1.4 ± 0.2 nN, which is in good agreement with previous measurements. We then study systematic trends for single gold metal-molecule-metal junctions for a series of molecules terminated with amine and pyridine linkers. For all molecules studied, single molecule junctions rupture at the Au-N bond. Selective binding of the linker group allows us to correlate the N-Au bond-rupture force to the molecular backbone. We find that the rupture force ranges from 0.8 nN for 4,4' bipyridine to 0.5 nN in 1,4 diaminobenzene. These experimental results are in excellent quantitative agreement with density functional theory based adiabatic molecular junction elongation and rupture calculations. 相似文献
26.
As degradation by ageing of solar absorber surfaces was identified to be an important quality factor, the Working Group MSTC (‘Materials in Solar Thermal Collectors') of the IEA-SHCP (International Energy Agency-Solar Heating and Cooling Programme) worked out a general test procedure for accelerated lifetime testing (ALT) of these materials, based on methods established by the former Task X of the IEA SHCP. The qualification test procedure was adopted by ISO and is presently dealt within ISO/TC 180 ‘Solar Energy'. The standard proposal in detail describes a procedure how to test the long-term stability of an absorber surface for the use in flat plate collectors for domestic hot water systems. The collectors service lifetime is assumed to be 25 years, at least. Degradation caused by thermal loads, high humidity and condensation and sulphur dioxide are regarded. In order to examine the feasibility and reproducibility of the test method the Working Group MSTC initiated a round robin test in accelerated life testing of solar absorber surfaces. The test was performed according to the ISO standard proposal dated January 1997. In total, five different industrially manufactured absorber coatings were available to the three participating laboratories. Tests concerning the thermal stability as well as the resistance to high humidity and condensation were performed by all three laboratories. The test for determining absorber surface corrosion resistance to air of high humidity containing sulphur dioxide was carried out by one lab only. The outcome of the round robin test shows very good agreement of the results of the different coatings tested for all of the laboratories. The feasibility and reproducibility of the method was fully confirmed. 相似文献
27.
A general test procedure for the qualification of solar absorber surface durability has been developed based on the results of a comprehensive case study performed within the framework of the IEA Solar Heating and Cooling Programme Task X. It was assumed, in the development of the qualification procedure, that the intended use of the absorber surface to be qualified, was in single-glazed flat plate solar collectors for domestic hot water production. The absorber surface should be considered qualified if it met the requirement of a design service life of 25 years with maximum loss in the optical performance of the absorber surface corresponding to a 5% relative reduction in the performance of a solar domestic hot water system. The testing procedure, consisting of three kinds of constant load-accelerated life-time tests, was limited to simulation of the following three kinds of absorber surface degradation processes: (a) high-temperature degradation, e.g. oxidation, (b) degradation by the action of moisture or condensed water on the absorber surface, e.g. hydration or hydrolysis, and (c) degradation caused by high humidity air containing a small concentration of sulphur dioxide as an airborne pollutant, e.g. atmospheric corrosion. To quantify expected environmental stress on the absorber surface related to the environmental factors of interest, microclimate data, representing typical service conditions for absorbers in single-glazed flat plate collectors for domestic hot water production were used. 相似文献
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The knowledge acquired by many generations of dyers and by today's wool dyeing specialists can now be gathered and stored in databases. This has allowed the development of a computerised expert system capable of solving different standard tasks of the wool dyer. This is demonstrated by simulated screen displays. 相似文献
30.
J Tschudi M Wagner C Klaiber J Brugger E Frei L Kr?henbühl R Inderbitzi J Hüsler S Hsu Schmitz 《Canadian Metallurgical Quarterly》1996,10(8):845-847
BACKGROUND: In February 1993 a prospective randomized multicenter trial was initiated to compare laparoscopic transabdominal preperitoneal hernioplasty to Shouldice herniorrhaphy as performed by surgeons of nonspecialized clinics. METHODS: Until January 1994, 87 patients with 108 hernias took part in the trial (43 Shouldice and 44 laparoscopic repairs). RESULTS: The laparoscopic procedure took significantly longer than did the open operation but caused less pain as measured by pain analogue score and consumption of paracetamol and narcotics. The postoperative complication rate was 26% in the open and 16% in the laparoscopic group. The patients in the laparoscopic group were discharged earlier and their convalescence was shorter than after open hernia repair. There has been one early recurrence in the laparoscopic and two in the open group to date with a mean follow-up of 201 days. CONCLUSIONS: Laparoscopic hernia repair causes less pain than the conventional operation and enables the patient to return to full work and usual activities earlier. The recurrence rate will not be known for 5 years. 相似文献