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721.
Alternatives to the use of conventional veterinary drugs in food-producing animals have gained attention, such as the use of natural products (NPs), mainly to soften the risks to the animal, the environment, and consumer's health. Although NPs have consistent advantages over conventional drugs, they cannot be considered risk free under food safety matters. In this way, this document presents a comprehensive overview of the importance of considering both the pharmacological and toxicological properties of the constituents of a NP from plants intending the standardization and regulation of its use in food-producing animals. Terpenes are the most diverse class of natural substances present in NP of vegetal origin with a broad range of biological activities that can be explored in veterinary science; however, certain plants and terpenes also have significant toxic effects, a fact that can harm the health of animals and consequently generate economic losses and risks for humans. In this context, this review gathered scientific data of vegetal species of importance to ethnoveterinary for food-producing animals, which produce terpenes, its biological effects, and their implications on food safety issues for consumers. For this, more than 300 documents were selected from different online scientific databases. The present data and discussion may contribute to the rational commercial exploration of this class of NPs in veterinary medicine.  相似文献   
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723.
The focus of this study was the development of a CAS glass-ceramic (14.0CaO·5.5Al2O3.80·5SiO2) for use in civil engineering as a decorative material. This glass-ceramic system was chosen because it can be used to produce plates with a similar appearance to those of marble and granite materials. Ceramic plates were produced by the Grain Glass Sintering process from frits with a coarse grain size (2.1 mm average particle size). Powder frit samples (5.3-μm average particle size) were prepared and characterized. The results were compared with those obtained with coarse particles. Thermal treatment was performed in one stage, with the heating rate varying from 2 to 25 °C min?1. Temperatures were defined by differential thermal analysis and heating microscopy. With these results, it was possible to establish correlations among the esthetic effects, the microstructure, and the heat treatment conditions (temperature, heating rate, and holding time). The relative density ranged from 0.92 to 0.96. The formation of wollastonite and pseudowollastonite was observed. An esthetic effect similar to that of natural marble was more apparent in those samples in which the microstructure presented a visual contrast between the bulk and the coarse frit. Lower heating rates intensified the visual contrast and reduced porosity near the surface regions.  相似文献   
724.

Background

The influence of feed restriction and different diet's caloric value on the aerobic and anaerobic capacity is unclear in the literature. Thus, the objectives of this study were to determine the possible influences of two diets with different caloric values and the influence of feed restriction on the aerobic (anaerobic threshold: AT) and anaerobic (time to exhaustion: Tlim) variables measured by a lactate minimum test (LM) in rats.

Methods

We used 40 adult Wistar rats. The animals were divided into four groups: ad libitum commercial Purina? diet (3028.0 Kcal/kg) (ALP), restricted commercial Purina? diet (RAP), ad libitum semi-purified AIN-93 diet (3802.7 Kcal/kg) (ALD) and restricted semi-purified AIN-93 diet (RAD). The animals performed LM at the end of the experiment, 48 h before euthanasia. Comparisons between groups were performed by analysis of variance (p < 0,05).

Results

At the end of the experiment, the weights of the rats in the groups with the restricted diets were significantly lower than those in the groups with ad libitum diet intakes. In addition, the ALD group had higher amounts of adipose tissue. With respect to energetic substrates, the groups subjected to diet restriction had significantly higher levels of liver and muscle glycogen. There were no differences between the groups with respect to AT; however, the ALD group had lower lactatemia at the AT intensity and higher Tlim than the other groups.

Conclusions

We conclude that dietary restriction induces changes in energetic substrates and that ad libitum intake of a semi-purified AIN-93 diet results in an increase in adipose tissue, likely reducing the density of the animals in water and favouring their performance during the swimming exercises.  相似文献   
725.
Paracoccidioides brasiliensis is the agent of paracoccidioidomycosis, the most prevalent deep mycosis in Latin America. The production of eicosanoids during fungal infection has been associated with the biology of these microorganisms and modulation of host immune response. The aim of our study was to evaluate whether P. brasiliensis strains with high or low virulence produce leukotriene B4 (LTB4), using endogenous and/or exogenous sources of arachidonic acid (AA). Moreover, we assessed whether this fungus might use the same metabolic pathway, described for mammalian cells, that involves the lipoxygenase (LOX) enzyme. The association between the production of this eicosanoid and fungus survival and growth was also evaluated. Our results showed that P. brasiliensis, irrespective of its virulence, produces high levels of LTB4 using endogenous AA. In addition, in cultures treated with exogenous AA, LTB4 levels were significantly higher, showing that this fungus also uses exogenous sources of fatty acids. Treatment with MK886, which blocks the activity of lipoxygenase, by inhibiting five-lipoxygenase-activating protein (FLAP) or with nordihydroguaiaretic acid (NDGA), a non-selective lipoxygenase inhibitor, resulted in a significant reduction in LTB4 levels, indicating that the fungus produces this eicosanoid by using the LOX pathway or an enzyme with biochemically similar function. The significant reduction in viability detected in cultures treated with these inhibitors was, however, restored by adding exogenous LTB4 , confirming the role of this eicosanoid in fungus survival. Moreover, the addition of LTB4 to cultures capable of producing LTs induces fungal growth. These results provide a foundation for additional studies on the contributions of LTB4 in P. brasiliensis virulence.  相似文献   
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728.
It is essential for environments that aim at helping people in their daily life that they have some sort of Ambient Intelligence. Learning the preferences and habits of users then becomes an important step in allowing a system to provide such personalized services. Thus far, the exploration of these issues by the scientific community has not been extensive, but interest in the area is growing. Ambient Intelligence environments have special characteristics that have to be taken into account during the learning process. We identify these characteristics and use them to highlight the strengths and weaknesses of developments so far, providing direction to encourage further development in this specific area of Ambient Intelligence.  相似文献   
729.
The objective of this study is to evaluate the influence of different soybean oil (SO) and selenium yeast (SeY) levels in the diet of meat quails on productive performance, physicochemical, quality measurements, fatty acid profile, enzyme activity estimation, and oxidative stability of meat. A total of 288 one-day old commercial meat quails are allocated into four groups according to a completely randomized experimental design, with two levels of SO (1.5% and 3.0%) and SeY (0 and 0.15 mg kg−1) in the feed. The supplementation period is 42 days. The use of up to 3% supplementation of SO in the diet improves (p < 0.05) the productive performance. The polyunsaturated acid content and thiobarbituric acid value in the meat are increased (p < 0.05) as an effect of the SO increase in the diet. The use of SeY in quail diets associates with 3% inclusion of SO and promotes improvements in the qualitative parameters of the quail meat. Therefore, the inclusion of 0.15 mg kg−1 of SeY in the diets is a viable alternative for improving the oxidative stability of meat since it improves the qualitative parameters of quail meat in diets with a high inclusion of SO. Practical Applications: These results have practical applicability in the meat industry, since it is possible to change the lipid profile of this raw material, meeting the requirement of the consumer market for healthy foods, reducing the total cholesterol content, and nutritionally desirable, through enrichment with polyunsaturated fatty acids.  相似文献   
730.
This research used a factorial model containing two levels and three variables to evaluate the partial substitution of sodium feldspar (albite) by a talc ore found in abundance in the region of Itaiacoca—Brazil. The model can also be used to verify the influence of initial talc particle size, proportion, and sintering threshold temperature on the following physical properties, such as linear shrinkage, water absorption, bulk density, total porosity, and firing color. In this study, the mechanical strength of the compositions was evaluated by the flexural strength test. The factorial model indicated the sintering temperature as the variable that most affects the samples’ densification and the proportion of talc as the variable that changes the firing color. The experiment that used a higher sintering temperature combined with a coarser talc granulometry presented the highest mechanical strength. When more refined granulometry was used, there was the beginning of an overfire process. Water absorption values in the range of .04% and modulus of rupture of 49 MPa were obtained, confirming the talc's effectiveness as a secondary flux agent suitable for the formulation of ceramic bodies.  相似文献   
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