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41.
Callaway TR Anderson RC Tellez G Rosario C Nava GM Eslava C Blanco MA Quiroz MA Olguín A Herradora M Edrington TS Genovese KJ Harvey RB Nisbet DJ 《Journal of food protection》2004,67(10):2274-2276
Escherichia coli O157:H7 is a foodborne pathogenic bacterium that can reside undetected in the gastrointestinal tract of cattle because colonization by this bacterium is asymptomatic. Recent research has indicated that swine can carry and transmit this pathogen as well. The development of more advanced and sensitive detection techniques has improved the limit of detection and increased sensitivity for this important pathogen. This study was undertaken to determine the prevalence of E. coli O157 in cattle and swine in Mexico with the more sensitive detection technique of immunomagnetic bead separation. Samples (n = 60 per farm) were taken from four cattle and four swine farms (n = 240 cattle samples, n = 240 swine samples) located throughout central Mexico in October 2001. The prevalence of E. coli O157 was found to be only 1.25% on cattle farms and 2.1% on swine farms. The prevalence in cattle in this study is lower than that reported in the United States and could be related to the lower reported prevalence of E. coli O157 in humans in Mexico. However, further research is needed to verify prevalence throughout other regions of Mexico, as well as prevalence during other seasons of the year. 相似文献
42.
Pignatello R Spadaro D Vandelli MA Forni F Puglisi G 《Drug development and industrial pharmacy》2004,30(3):277-288
The present study is a preliminary exploration of the affinity between a carboxylic model drug, the nonsteroidal antiinflammatory agent ibuprofen (IBU) and Eudragit RL100 (RL) polymer. Due to the presence of a variable amount of quaternary ammonium groups in this matrix, physical and chemical interaction with the carboxylic drug can occur, which reinforces its scant mechanical dispersion in the polymer network and can ultimately affect its release profile in vitro and in vivo. To study these aspects, IBU was mixed at increasing weight ratios and in different chemical forms (free acid, sodium salt, and n-butyl ester), to investigate further the role of the carboxylic group in the interaction with the RL polymer. Therefore, IBU-RL solid dispersions (coevaporates) were obtained and fully characterized in the solid state through spectroscopic, calorimetric, and x-ray diffractometric analyses. The in vitro release pattern of the drug, in the different chemical states, was studied for the coevaporates, compared with drug-RL physical mixtures, along with drug adsorption profiles from aqueous solutions on the surface of the polymer granules. 相似文献
43.
44.
M. M. Rosario H. Wang Yu. Zadorozhny Y. Liu 《Journal of Low Temperature Physics》2007,147(5-6):623-631
We report the observation of an apparent metallic state induced by a parallel magnetic field in Au0.7In0.3 samples with very low normal-state sheet resistance. These samples can be modeled as a random array of superconductor-normal
metal-superconductor (SNS) junctions. For both the thin planar and cylindrical films, the magnetic field was applied parallel
to the substrate of the sample and measurement currents. For the mesoscopic rings, however, a perpendicular field was used.
Our electrical transport and tunneling measurements suggest that the samples consist of superconducting In-rich islands not
linked by Josephson coupling in the metallic state. The physical origin of the metallic state is discussed.
相似文献
45.
46.
Rosario G. Garroppo Stefano Giordano Davide Iacono Luca Tavanti 《Wireless Networks》2011,17(6):1441-1459
In WiMAX systems the Base Station scheduler plays a key role as it controls the sharing of the radio resources among the users.
The goal of the scheduler is multiple: achieve fair usage of the resources, satisfy the QoS requirements of the users, maximize
goodput, and minimize power consumption, and at the same time ensuring feasible algorithm complexity and system scalability.
Since most of these goals are contrasting, scheduler designers usually focus their attention on optimizing one aspect only.
In this scenario, we propose a scheduling algorithm (called GTSN\mathrm{GTS_N}) whose goal is to contemporaneously achieve efficiency and fairness, while also taking into account the QoS requirements
and the channel state. GTSN\mathrm{GTS_N} exploits the properties of Time Utility Functions (TUFs) and Game Theory. Simulations prove that the performance of GTSN,\mathrm{GTS_N}, when compared to that of several well-known schedulers, is remarkable. GTSN\mathrm{GTS_N} provides the best compromise between the two contrasting objectives of fairness and efficiency, while QoS requirements are
in most cases guaranteed. However, the exponential complexity introduced by the game theory technique makes it rather impractical
and not computationally scalable for a large number of users. Thus we developed a suboptimal version, named sub-GTSN.\mathrm{GTS_N}. We show that this version retains most of the features and performance figures of its brother, but its complexity is linear
with the number of users. 相似文献
47.
Rosario Barón Manuel Mayen Julieta Merida M. Medina 《European Food Research and Technology》1997,205(6):474-478
Changes in the concentrations of hydroxybenzoic acids, hydroxycinnamic acids and their esters, monomeric and dimeric derivatives
of flavan-3-ol, and flavonols, as well as in the UV-visible absorbances of pale Sherry wines were studied. The wines were
subjected to four different fining treatments: casein + bentonite, casein + bentonite + activated charcoal, casein + bentonite
+ polyvinylpyrrolidone (PVPP) and casein + bentonite + Riduxhigh. Based on the results, the treatments including activated
charcoal and PVPP were the most effective at decreasing the overall concentration phenolic compounds, with no significant
difference between them. Likewise, these treatments provided the best results in relation to wine colour in the visible spectral
region, and particularly at 420 nm, at which wavelength browning compounds are usually measured.
Received: 24 March 1997 / Revised version: 11 June 1997 相似文献
48.
At EuroCrypt '99 Paillier proposed a new encryption scheme based on higher residuosity classes. The new scheme was proven
to be one-way under the assumption that computing
N -residuosity classes in Z
N2
*
is hard. Similarly the scheme can be proven to be semantically secure under a much stronger decisional assumption: given w ∈ Z
N2
*
it is impossible to decide if w is an N -residue or not.
In this paper we examine the bit security of Paillier's scheme. We prove that if computing residuosity classes is hard, then
given a random w it is impossible to predict the least significant bit of its class significantly better than at random. This immediately
yields a way to obtain semantic security without relying on the decisional assumption (at the cost of several invocations
of Paillier's original function).
In order to improve efficiency we then turn to the problem of simultaneous security of many bits. We prove that Paillier's
scheme hides n-b (up to O(n) ) bits if one assumes that computing the class c of a random w remains hard even when we are told that c<2
b
. We thoroughly examine the security of this stronger version of the intractability of the class problem.
An important theoretical implication of our result is the construction of the first trapdoor function that hides super-logarithmically
(up to O(n) ) many bits. We generalize our techniques to provide sufficient conditions for a trapdoor function to have this property. 相似文献
49.
Effect of the long-term intake of an egg white hydrolysate on the oxidative status and blood lipid profile of spontaneously hypertensive rats 总被引:1,自引:0,他引:1
María A. Manso Marta Miguel Jeanne Even Rosario Hernández Amaya Aleixandre Rosina López-Fandiño 《Food chemistry》2008
This paper examines the effects of the long-term consumption of egg white hydrolysed with pepsin (hEW) on the antioxidant status and lipid profile of spontaneously hypertensive rats (SHR). The antioxidant capacity was measured by the oxygen radical absorbance capacity (ORAC) and the oxidative status by the malon-dialdehyde (MDA) assay. The lipid profile was analysed spectrophotometrically. The radical-scavenging capacity of the plasma was increased and the MDA concentration in the aorta was decreased in the SHR treated with 0.5 g/kg/day of hEW. Our findings indicate that hEW played an important role in antioxidative defence of SHR and exerted a beneficial effect on the lipid profile, lowering triglycerides and total cholesterol without changing HDL levels. Therefore, hEW may be useful to prevent or reverse abnormalities associated with the metabolic syndrome and its complications, such as hypertension, oxidative stress and hyperlipidemia. 相似文献
50.
Redesigning an assembly line through lean manufacturing tools 总被引:1,自引:1,他引:0
Roberto Álvarez Roque Calvo Marta M. Peña Rosario Domingo 《The International Journal of Advanced Manufacturing Technology》2009,43(9-10):949-958
The implementation of a lean manufacturing strategy represents a robust contribution to the phase sequence that leads to operational excellence and the continuous improvement through the elimination of nonvalue-added activities. Therefore, lean practices contribute substantially to plant operational performance. This paper studies the use of value stream mapping (VSM) as a tool in lean manufacturing implementation and a framework of improvement activities, in particular for an efficient introduction of kanban and milkrun techniques. A case study illustrates VSM use, as well as kanban and milkrun systems application on an assembly line. Finally, the results obtained show the path of improvement, measured through the lean rate (LR) and dock-to-dock time (DtD). 相似文献