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21.
Rats were exposed to an aerosol of 10% papain for 8 h found in pilot studies to produce marked emphysema. One week after exposure some animals were forced to exercise in a motor-driven activity wheel 2 h daily for 4 wk, while others remained at rest. Another group of rats which served as the control were exposed to saline under the same conditions and divided into exercise and rest groups. Elastic recoil pressure (Pst) of lung was measured from static deflation pressure-volume curves with air and saline. Pst measured in air-filled lungs was not significantly different between the emphysema-rest and emphysema-exercise groups. When inflated with saline the Pst was significantly reduced in the emphysema-exercise compared to the emphysema-rest group at high and mid (100, 80, 60%) lung volumes. Pst in air- and saline-filled lungs was not significantly different between the control-rest and control-exercise groups. We therefore conclude that mechanical stress resulting from physical exercise decreased Pst of lung tissue in emphysematous rats.  相似文献   
22.

Purpose

To assess corneal epithelial microstructure via confocal microscopy and determine if cellular changes are associated with lens care solutions during daily wear of silicone hydrogel contact lenses.

Methods

Corneal in vivo confocal microscopy with the Nidek ConfoScan4 was performed at baseline and after 5 months of lotrafilcon A daily contact lens wear. Enrolled participants were randomized to use either a polyhexamethylene biguanide (PHMB) preserved multipurpose care solution (MPS) or a peroxide based solution system. Lens and storage case bioburden were assessed with aerobic culture methods. Univariate and multivariable analyses were done to evaluate the association between solution use, or solution-related clinical covariates, and morphologic differences (hyper-reflectivity) in the superficial epithelial cells and epithelial basal cell density.

Results

Data on 139 participants were available for analysis of superficial epithelial cells while data on 92 participants were available for epithelial basal cell density. Five months after randomization to the solution groups, 33% of participants had visible hyper-reflective cells. More participants using MPS had ≥1 hyper-reflective cells compared to peroxide users at 5 months (44% vs. 22%; p = 0.006). Similarly at 5 months, more participants with solution-induced corneal staining (SICS) had ≥1 hyper-reflective cells compared to non-SICS participants (57% vs. 29%; p = 0.010). The adjusted odds ratios (ORs) for risk of presenting with hyper-reflective cells in MPS users or SICS participants was 2.7 (95% CI; 1.27–5.65) and 3.4 (95% CI; 1.29–8.97), respectively. Basal cell density decreased by over 350 cells/mm2 over time (about 6%) in participants who had substantial bioburden on their lenses or in their storage case.

Conclusion

The confocal microscope can detect epithelial cellular changes in vivo during contact lens wear. Hyper-reflective superficial epithelial cells are associated with a PHMB preserved solution and decreases in basal epithelial cell density may be associated with bacterial bioburden.  相似文献   
23.
A multicomponent reactive solute-transport model was used to study the migration of dissolved heavy metals (Cd2+, Pb2+, Cu2+, and Zn2+) in a clay barrier subject to two leachates having different pH values. This solute-transport model is capable of simulating simultaneous processes of water flow, advective-dispersive-solute transport, and chemical reactions. The migration of these metals was simulated in a kaolinite landfill liner, which was assigned realistic physical and chemical properties and boundary conditions to model one-dimensional contaminant transport. The leachate input properties to the model were those of an actual leachate containing the four heavy metals. The numerical simulations were focused on the concentration profiles of these metals in the simulated clay barrier and leachate pH affects their mobilities. The numerical results indicate that with a nearly neutral leachate, the heavy metals mobility follows: Cd2+ < Pb2+ < Cu2+ < Zn2+. With an acidic leachate, the order changes to Pb2+ < Cu2+ < Zn2+ < Cd2+. Leachate pH has a significant effect on Cd2+ and Pb2+ mobility and a small effect on Cu2+ and Zn2+.  相似文献   
24.
For diagnostic purposes, cryofixation of tissues is a daily routine technique to investigate rapidly about the presence of tumours during a surgical procedure in patients. We performed morphometric analysis of cryofixed muscular tissues according to different techniques. About 1,000 muscle fibers and 1,493 nuclei, were automatically examined. After freezing, ice tissue interfaces shrinkage of the cells were present. Liquid isopentane or liquid nitrogen produced a statistical increase of fractal dimension, D, of the ice‐tissue interfaces, P < 0.001 respect to the formalin‐fixed samples, cryofixation performed inside the cryostat chamber at t = ?20°C produced a D value close to the formalin‐fixed samples. Shrinkage of the muscle fibers was higher in the samples cryofixed inside the cryostat chamber (P < 0.001). Cryofixation inside cryostat or by liquid nitrogen caused decreases of the nuclei dimensions and altered nuclear morphology (P < 0.01), liquid isopentane appeared not affecting the nuclei of the fibers. Cryofixation inside the cryostat chamber produced the highest shrinkage but it was reduced performing cryofixation in liquid nitrogen or isopentane. Freezing damage inside the muscle cells was absent in the samples cryofixed inside the cryostat, it was present after cryofixation by liquid nitrogen or isopentane. Subcellular components like the nuclei were preserved by isopentane. This paper present, for the first time, an objective method able to quantify and characterize the damages produced by cryofixation in biological sample for intraoperative consultation. Microsc. Res. Tech. 79:155–161, 2016. © 2016 Wiley Periodicals, Inc.  相似文献   
25.
Measurements of carbon dioxide (CO2) concentration carried out in the city of Rome in the period January–December 2005 showed a mean yearly CO2 concentration of 414 ± 45 ppm; polluted sites (P sites) had 21% higher CO2 concentration than control sites (C sites). The significant (p < 0.01) correlation analysis between CO2 concentration and traffic density measured during the study period at P sites showed that traffic density explained 51% of the CO2 variation. The CO2 trend during the traffic limitation days (provision imposed by ordinance of the City Council) did not show significant differences as regards regular traffic days, suggesting the ineffectiveness of this provision. Leaf area index (LAI) of Platanus hybrida Brot. was on an average 11% lower at P sites than at C ones associated with a lower total photosynthetic leaf surface area (SPT, 34% lower at P sites than at C ones). P. hybrida had a total carbon sequestration of 117 ± 13 kg year−1 (mean value of P and C sites) playing an important role in sequestering CO2. Thus, the choice of plant species for urban areas may be set out taking into account their own air amelioration capability. Plant traits of each species may be used for urban tree planting programs to ameliorate urban air pollution.  相似文献   
26.
D. J. Levinson's (see record 1986-19674-001) conceptualization of adult development presents a rich avenue for exploring personal growth and the effects of life-cycle changes both in and out of therapy. Research in this area can elucidate such issues as sociocultural changes in the timing of major life-cycle events (e.g., childbearing, retirement) and life-crisis stressors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
27.
This study is related to the application of the X‐ray dual‐energy microradiography technique together with the atomic absorption spectroscopy (AAS) for the detection of lead on Zea mays stem, ear, root, and leaf samples. To highlight the places with lead intake, the planar radiographs taken with monochromatic X‐ray radiation in absorption regime with photon energy below and above the absorption edge of a given chemical element, respectively, are analyzed and processed. To recognize the biological structures involved in the intake, the dual‐energy images with the lead signal have been compared with the optical images of the same Z. mays stem. The ear, stem, root, and leaf samples have also been analyzed with the AAS technique to measure the exact amount of the hyperaccumulated lead. The AAS measurement revealed that the highest intake occurred in the roots while the lowest in the maize ears and in the leaf. It seems there is a particular mechanism that protects the seeds and the leaves in the intake process. Microsc. Res. Tech., 2010. © 2009 Wiley‐Liss, Inc. This article was published online on 1 December 2009. An error was subsequently identified. This notice is included in the online and print version to indicate that both have been corrected 19 February 2010.  相似文献   
28.
Over the last several decades, forensic examiners of impression evidence have come under scrutiny in the courtroom due to analysis methods that rely heavily on subjective morphological comparisons. Currently, there is no universally accepted system that generates numerical data to independently corroborate visual comparisons. Our research attempts to develop such a system for tool mark evidence, proposing a methodology that objectively evaluates the association of striated tool marks with the tools that generated them. In our study, 58 primer shear marks on 9?mm cartridge cases, fired from four Glock model 19 pistols, were collected using high-resolution white light confocal microscopy. The resulting three-dimensional surface topographies were filtered to extract all "waviness surfaces"-the essential "line" information that firearm and tool mark examiners view under a microscope. Extracted waviness profiles were processed with principal component analysis (PCA) for dimension reduction. Support vector machines (SVM) were used to make the profile-gun associations, and conformal prediction theory (CPT) for establishing confidence levels. At the 95% confidence level, CPT coupled with PCA-SVM yielded an empirical error rate of 3.5%. Complementary, bootstrap-based computations for estimated error rates were 0%, indicating that the error rate for the algorithmic procedure is likely to remain low on larger data sets. Finally, suggestions are made for practical courtroom application of CPT for assigning levels of confidence to SVM identifications of tool marks recorded with confocal microscopy.  相似文献   
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