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201.
The results of a pluridisciplinary epidemiological study carried out on a series of 225 adults from rural areas, in whom the prevalence of arterial hypertension disease (AHTD) and borderline (AHTB) was of 19.0% and 14.4%, respectively, are presented. In 19.0% of the carriers of over five associated risk factors for cardiovascular disease, the classical lipid constants (triglycerides-TG. total lipids-TL. total cholesterol-TC. HDL-cholesterol-HDL-c), plasma (PML) and erythrocyte magnesium level (EML), as compared to the degree of drinking water mineralization were determined. The environmental conditions, also expressed in water hardness (21.650 G) or magnesium water intake (85.13 mg/l) correlate in 41.0% of the subjects with a decrease in PML (1.8 mg/l) and in 70.48 with a decrease in EML (4.8 mg/l) through the association of some behavioral or metabolic risk factors: stress, consumption of atherogenic foods, excess alcohol and lipid dysmetabolism (TG: 130-140 mg/l = 59.5%; TL: 8 g%-30.9%; TC: 220 mg/l = 19%; HDL-c: 35 mg/l + 1.9%).  相似文献   
202.
Zusammenfassung Um die Frage zu beantworten, ob Aflatoxine im Käse vorkommen können, mußten käsereitechnische Erfahrungen über toxinproduzierende Mikroorganismen gesammelt werden. Zunächst wurden 169 Käseproben des Handels auf das mögliche Vorkommen von Aflatoxin B1 geprüft. Bei keiner der 19 Käsesorten, in der Hauptsache Tilsiter, Edamer, Romadur und Camembert, konnte dieses Toxin nachgewiesen werden.Bei Modelluntersuchungen zur Entwicklung von Aflatoxin B1 wurden einzelne Käse mit aflatoxinbildenden Schimmelpilzen künstlich infiziert, das Toxin nach der Mycelbildung isoliert und quantitativ bestimmt.Der Kulturschimmel des Camembertkäses (Penicillium candidum) verhindert das Wachstum B1-Aflatoxin bildender Pilze, so daß kein Aflatoxin B1 nachweisbar war. Auch beim Romadur kann das Vorkommen von Aflatoxin B1 wegen der Pilzwachstumshemmung, vermutlich durch die Schmierenbildung, ausgeschlossen werden.Dagegen gelang es, auf Tilsiterkäse mitAspergillus flavus undAspergillus parasiticus bei 18–30° C und mitPenicillium puberulum bei 5–20° C größere Mengen von Aflatoxin B1 anzureichern. Hierbei muß die relative Luftfeuchtigkeit mehr als 79% betragen. 18 bzw. 5° C sind die unteren Grenzwerte für das Wachstum der betreffenden Schimmelpilze auf dem Käse. Unter optimalen Einflüssen (Temp. 26° C; rel. Luftfeuchtigkeit 99%) ist das Aflatoxin B1 bereits 3–4 Tage nach Pilzbefall durchAspergillus flavus im Käse vorhanden. Durch Vergleiche der gefundenen Ergebnisse mit den Verhältnissen in Käsereien kann eine Bildung von Aflatoxin B1 in Käse durch die genannten Organismen nicht ausgeschlossen werden, so daß weitere Untersuchungen erforderlich sind.
About the formation of aflatoxin B1 in cheese
Summary In order to answer the question whether aflatoxins can be present in cheese, observations on toxin-producing micro-organisms during manufacture of cheese had to be undertaken. 169 cheese samples, taken from the market, were tested for possible presence of aflatoxin B1. In none of the 19 cheese varities, mainly Tilsiter, Edamer, Romadur, and Camembert, toxins could be found.By artificial infection of cheese with aflatoxin-producing fungi, the toxin was isolated after mycel-formation and quantitatively determined.The starter fungus of Camembert cheese (Penicillium candidum) pevents the growth of aflatoxin B1 forming fungi so that no aflatoxin B1 was detected. Also in Romadur cheese the presence of aflatoxin B1 can be excluded due to growth prevention, probably by smear formation.It was possible, however, to obtain larger amounts of aflatoxin B1 on Tilsiter cheese by growth ofAspergillus flavus andAspergillus parasiticus at 18–30° C. The relative humidity has to be more than 79%. 18° C resp. 5° C are the lower tolerance values for the growth of these fungi on cheese. Under optimal conditions (temperature: 26° C, relative humidity: 99%) aflatoxin B1 is present in cheese 3–4 days after infection byAspergillus flavus. By comparing these results with the conditions in cheese factories, the formation of aflatoxin B1 in cheese, caused by the organisms mentioned, cannot be excluded, so that further investigations are necessary.


Auszug aus der Dissertation Lebensmittelchemiker Dieter Groll: Zur Aflatoxin-Entwicklung in Käse. Dissertation TH München 1969.

Für die Unterstützung dieser Arbeit durch das Bundesministerium für Gesundheitswesen sei an dieser Stelle herzlich gedankt.  相似文献   
203.
Microfluidic devices have become more and more important in the field of thermal or chemical process engineering within the last years (by Schubert et al. Microscale Thermophys Eng 5:17–39, 2001). Cooling is one point of research where microchannels and other microstructured geometries provide significant advantages compared to conventional devices as they offer much higher possible surface to volume ratios and short characteristic distances. Therefore, an intense amount of heat can be transferred by these devices, which can be significantly increased by phase transition. Thus, evaporation of a fluid flow in microchannels allows very compact, fast, and powerful cooling devices. In this research study a novel microstructured evaporator geometry consisting of curved microchannels was evaluated on its evaporation properties compared to previous studies dealing with evaporation of R134a (Tetrafluoroethane) in straight microchannels (by Wibel et al. Chem Eng J 167:705–712, 2011). This novel evaporator design takes advantage of the strong centrifugal forces acting on the (evaporating) two phase flow in the curved microchannels. Due to the feasibility of very small radii of curved microchannels, strong centrifugal forces can be obtained for the fluid flow inside the microstructures. Additionally, those forces are boosted as flow velocities within the channels become higher due to the volume increase induced by evaporation. Therefore, a phase separation could take place inside the microstructure with a higher liquid fraction of evaporating coolant near one side of the curved channels during the transition to vapor. A high liquid fraction inside the evaporator is aimed by an intended removal of the evaporated gas phase from the microstructure. Experimental results of the evaporation of water and R134a as coolants demonstrate the potential of this curved geometry in comparison to evaporation in straight channels. Optical investigations of the new micro evaporator concept by high-speed videography (by Maikowske et al. Appl Therm Eng 30:1872–1876, 2010) are carried out for further improvements of the design. Various bubble formations and movements of the evaporating fluid flow were studied for various vapor fractions by using different fluids. These investigations show how the separation and extraction of the vapor fraction of the novel microstructure concept could be improved.  相似文献   
204.
Opus , which stands for “Optimized Uniformity Simulator”, has been described in the literature as a powerful tool to assist in the optimization of temperature uniformity in the STEAG Electronic Systems series of rapid thermal processors. Historically, this tool has been used extensively for a variety of silicon processing. With this simulation, the temperature uniformity of 100 mm Si3N4 encapsulated GaAs with a dual silicon implant anneal at 847°C, 40 s was optimized to <2°C across the wafer. Ramp rates ≤20°C/s were obtained without slip.  相似文献   
205.
The pre-treatment of work-piece surfaces is decisive for improved adhesion of tribological, decorative, sensor, biocompatible, etc. coatings subsequently deposited by vacuum coating techniques. Most current industrial techniques (mainly glow discharges) miss the requirements for activating temperature-sensitive and electrically insulating materials. Gridless plasma sources like the linear anode layer ion source are an excellent alternative due to their low investment and operating costs and scalability to many industrial applications, and also due to the measured plasma characteristics (low surface charging, broad energy distribution). The appreciable increase of adhesion by anode layer source plasma pre-treatment and the effects of ion energy and gas composition are presented for room temperature sputtered titanium nitride coatings polyamide, polycarbonate, and poly(ethyleneterephtalate). For these polymers, the oxygen-based functionalization (chain-scissoring and cross-linking) strongly influence the wetting behaviour and improve the adhesion by suppressing adhesive cracking at low scratching loads. Low O2 contents in Ar-O2 discharge of ∼400 eV average ion energy lead to best coating adhesion.  相似文献   
206.
The presented new type of interferometer combines the principle of two-beam interferometry and the technique of phase-shift keying of holographic gratings. On the basis of the phase-shift keying technique, the interferometer employs two different geometries for the recording and the readout process. Two holographic Bragg gratings are recorded in transmission geometry and simultaneously read out in reflection geometry using a tunable IR laser. Both gratings have the same grating period but a relative phase shift. The wavelength of the readout beam is fitted to the Bragg condition for the gratings. Using a tunable IR laser for the readout process, we can measure the spectral transfer function of both combined gratings. The shape of the measured transfer function is extremely sensitive to the phase shift between the two gratings. We demonstrate an application of this method by the measurement of refractive-index variations of gases due to pressure changes of the gases. The achieved resolution with respect to the measurement of phase shifts is approximately 1/40 pi. We present experimental investigations on two kinds of gas (an inert gas and a gas composition) as well as an efficient numerical approach to simulate the transfer function for Bragg gratings with a phase shift. Furthermore, we present a method to increase the resolution based on the controlled manipulation of the transfer function.  相似文献   
207.
The flow of water and steam in an electrically powered micro heat exchanger consisting of an array of 68 wavy microchannels in parallel, each 200-m wide, 100-m deep and approximately 40-mm long, was investigated by high-speed videography. Semi-quantitative, time- and space-resolved information about the void fraction was extracted by pixel intensity calculations. Fluctuations at sub-audio frequencies (pulsation) were always visible in the microchannel array. Pulsation at the outlet reached a minimum with increasing heating power, but below the power required to achieve complete evaporation. This minimum was accompanied by a shift in the lateral distribution of channels filled with more steam or water. The differences between the test device and typical devices for applications in thermal and process engineering are also identified.  相似文献   
208.
A new experimental technique is reported to visualize agglomeration of submicron aerosol particles by laser-induced fluorescence (LIF). The basic idea is to produce or activate the fluorescent tracer material by a chemical reaction triggered by the agglomeration between two chemically different primary particles. Different types of chemical reactions are able to fulfil this task, among others acid–base reactions or molecule solvation. In this work, we demonstrate the feasibility of the fluorescent tracer activation by means of solvation. The fluorescence is activated almost instantaneously when the dry fluorescent material (Fluorescein or Rhodamine B) contained in the dye aerosol is dissolved by a water/glycerol mixture constituting the particles of the solvent aerosol. Estimations of the timescale for diffusional mixing suggest that the fluorescence is activated within 1 ms. Agglomerates can be detected as single particles or in bulk quantities depending on the available laser excitation energy and light sensitivity. In order to enhance agglomeration in the validation experiments, two aerosol streams were electrostatically charged with opposite polarity. Finally, potential variations and applications of the newly introduced technique are briefly discussed, mentioning the detection of humidity among others.

© 2017 American Association for Aerosol Research  相似文献   

209.
This study examined the utility of the concept of expressive aesthetics by testing websites that did or did not match this concept. A website scoring highly on this concept was created and was then compared to websites that were either non-aesthetic or corresponded to the concept of classical aesthetics. Sixty website users of a broad age range (18–60 years) were allocated to three experimental groups (expressive, classical, and non-aesthetic) and asked to complete a series of information search tasks. During the experiment, measures were taken of performance, perceived usability, perceived aesthetics, emotion, and trustworthiness. The results showed that expressive aesthetics can be considered a distinct concept. It also emerged that the website scoring high on expressive aesthetics shows a similar pattern of results to classical aesthetics. Both aesthetically appealing websites received higher ratings of perceived usability and trustworthiness than the non-aesthetic website. The effects of website aesthetics on subjective measures were not moderated by age.  相似文献   
210.
The glidobactin-like natural products (GLNPs) glidobactin A and cepafungin I have been reported to be potent proteasome inhibitors and are regarded as promising candidates for anticancer drug development. Their biosynthetic gene cluster (BGC) plu1881–1877 is present in entomopathogenic Photorhabdus laumondii but silent under standard laboratory conditions. Here we show the largest subset of GLNPs, which are produced and identified after activation of the silent BGC in the native host and following heterologous expression of the BGC in Escherichia coli. Their chemical diversity results from a relaxed substrate specificity and flexible product release in the assembly line of GLNPs. Crystal structure analysis of the yeast proteasome in complex with new GLNPs suggests that the degree of unsaturation and the length of the aliphatic tail are critical for their bioactivity. The results in this study provide the basis to engineer the BGC for the generation of new GLNPs and to optimize these natural products resulting in potential drugs for cancer therapy.  相似文献   
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