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1.
2.
The metabolic response to L-lysine of Escherichia coli ATCC 13002, a lysine-histidine double auxotroph, has been examined in a synthetic medium containing sucrose. In shaken cultures largest amounts of extracellular DAP were produced with an initial lysine concentration of 7·5 mg/1 and in static cultures of 2·5 mg/1. Considerably smaller amounts of DAP accumulated under stationary conditions. In cultures shaken for 20 and 43 h there was an overall decrease in the yields of DAP, expressed in terms of cell biomass and of sucrose consumed, as the initial concentration of lysine was increased from 0·75 mg/1 in steps up to 25 mg/1. The regulatory effect of lysine on DAP production was also observed when lysine was supplied to cultures at a constant rate employing diffusion capsules. 相似文献
3.
SH Chew 《Biotechnic & histochemistry》2013,88(5-6):177-183
The phagocytic activity of neuroglial cells in adult feline degenerating optic nerve was investigated by immunocytochemistry at both light and electron microscopy levels. Degeneration was initiated by unilateral eye enucleation and the segment distal to the transection showing true Wallerian degeneration was examined. Following enucleation, twelve adult domestic cats were examined over a period of seven to 215 days. All cases showed slow clearance of myelin debris and absence of proliferating monocytes throughout the post-enucleation period. All phagocytic cells present were neuroglial cells, and many of these cells expressed oligodendroglial antigens. These findings demonstrate the persistence of an active population of oligodendrocytes that might play an additional functional role during Wallerian degeneration of feline optic nerve. 相似文献
4.
Ramirez DM Leppla SH Schneerson R Shiloach J 《Journal of industrial microbiology & biotechnology》2002,28(4):232-238
The protective antigen (PA) is one of the three components of the anthrax toxin. It is a secreted nontoxic protein with a
molecular weight of 83 kDa and is the major component of the currently licensed human vaccine for anthrax. Due to limitations
found in the existing vaccine formulation, it has been proposed that genetically modified PA may be more effective as a vaccine.
The expression and the stability of two recombinant PA (rPA) variants, PA-SNKE-ΔFF-E308D and PA-N657A, were studied. These
proteins were expressed in the nonsporogenic avirulent strain BH445. Initial results indicated that PA-SNKE-ΔFF-E308D, which
lacks two proteolysis-sensitive sites, is more stable than PA-N657A. Process development was conducted to establish an efficient
production and purification process for PA-SNKE-ΔFF-E308D. pH, media composition, growth strategy and protease inhibitors
composition were analyzed. The production process chosen was based on batch growth of B. anthracis using tryptone and yeast extract as the only source of carbon, pH control at 7.5, and antifoam 289. Optimal harvest time
was 14–18 h after inoculation, and EDTA (5 mM) was added upon harvest for proteolysis control. Recovery of the rPA was performed
by expanded-bed adsorption (EBA) on a hydrophobic interaction chromatography (HIC) resin, eliminating the need for centrifugation,
microfiltration and diafiltration. The EBA step was followed by ion exchange and gel filtration. rPA yields before and after
purification were 130 and 90 mg/l, respectively. The purified rPA, without further treatment, treated with small amounts of
formalin or adsorbed on alum, induced, high levels of IgG anti-PA with neutralization activities. Journal of Industrial Microbiology & Biotechnology (2002) 28, 232–238 DOI: 10.1038/sj/jim/7000239
Received 28 August 2001/ Accepted in revised form 20 December 2001 相似文献
5.
Second‐derivative synchronous spectrofluorimetric determination of nebivolol hydrochloride and amlodipine besylate in their combined dosage form
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A rapid, simple, accurate and highly sensitive spectrofluorimetric method was developed for the simultaneous analysis of nebivolol hydrochloride (NEB) and amlodipine besylate (AML). The method was based on measuring the synchronous fluorescence intensity of the drugs at Δλ = 40 nm in methanol. Various experimental parameters affecting the synchronous fluorescence of the studied drugs were carefully studied and optimized. The calibration plots were rectilinear over concentration ranges of 0.05–1.5 µg/mL and 0.5–10 µg/mL for NEB and AML with limits of detection (LOD) of 0.010 and 0.051 µg/mL and limits of quantitation (LOQ) of 0.031 and 0.156, respectively. The peak amplitudes (2D) of the second derivative synchronous fluorimetry (SDSF) were estimated at 282 nm for NEB and at 393 nm for AML. Good linearity was obtained over the concentration ranges. The proposed method was successfully applied to the determination of the studied compounds in laboratory‐prepared mixtures, commercial single and laboratory‐prepared tablets. The results were in good agreement with those obtained using the comparison method. The mean percent recoveries were found to be 100.12 ± 0.77 and 99.91 ± 0.77 for NEB and AML, respectively. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
6.
Little is known about the effect of exercise training on the expression of adiponectin receptor genes in peripheral blood mononuclear cells (PBMCs). In this study, we investigated the effects of aerobic training on the expression of AdipoR1 and AidpoR2 mRNAs in PBMCs, whole body insulin sensitivity, and circulating adiponectins in men. Thirty young men were randomly assigned to either a control (n=15) or an exercise (n=15) group. Subjects assigned to the exercise group underwent a 12-week jogging and/or running programme on a motor-driven treadmill at an intensity of 60%-75% of the age-based maximum heart rate with duration of 40 minutes per session and a frequency of 5 days per week. Two-way mixed ANOVA with repeated measures was used to test any significant time-by-group interaction effects for the measured variables at p=0.05. We found significant time-by-group interaction effects for waist circumference (p=0.001), VO2max (p<0.001), fasting insulin (p=0.016), homeostasis model assessment for insulin resistance (HOMA-IR) (p=0.010), area under the curve (AUC) for insulin response during the 75-g oral glucose tolerance test (p=0.002), high-molecular weight (HMW) adiponectin (p=0.016), and the PBMC mRNA levels of AdipoR1 (p<0.001) and AdipoR2 (p=0.001). The exercise group had significantly increased mRNA levels of AdipoR1 and AdipoR2 in PBMCs, along with increased whole body insulin sensitivity and HMW adiponectin, decreased waist circumference, and increased VO2max compared with the control group. In summary, the current findings suggest that exercise training modulates the expression of AdipoR1 and AdipoR2 mRNAs in PBMCs, implying that manipulation of the expression of these genes could be a potential surrogate for lifestyle intervention-mediated improvements of whole body insulin sensitivity and glucose homeostasis. 相似文献
7.
8.
Oyeshola F. Kofoworola Shabbir H. Gheewala 《The International Journal of Life Cycle Assessment》2008,13(6):498-511
Background, aim, and scope To minimize the environmental impacts of construction and simultaneously move closer to sustainable development in the society,
the life cycle assessment of buildings is essential. This article provides an environmental life cycle assessment (LCA) of
a typical commercial office building in Thailand. Almost all commercial office buildings in Thailand follow a similar structural,
envelope pattern as well as usage patterns. Likewise, almost every office building in Thailand operates on electricity, which
is obtained from the national grid which limits variability. Therefore, the results of the single case study building are
representative of commercial office buildings in Thailand. Target audiences are architects, building construction managers
and environmental policy makers who are interested in the environmental impact of buildings.
Materials and methods In this work, a combination of input–output and process analysis was used in assessing the potential environmental impact
associated with the system under study according to the ISO14040 methodology. The study covered the whole life cycle including
material production, construction, occupation, maintenance, demolition, and disposal. The inventory data was simulated in
an LCA model and the environmental impacts for each stage computed. Three environmental impact categories considered relevant
to the Thailand context were evaluated, namely, global warming potential, acidification potential, and photo-oxidant formation
potential. A 50-year service time was assumed for the building.
Results The results obtained showed that steel and concrete are the most significant materials both in terms of quantities used, and
also for their associated environmental impacts at the manufacturing stage. They accounted for 24% and 47% of the global warming
potential, respectively. In addition, of the total photo-oxidant formation potential, they accounted for approximately 41%
and 30%; and, of the total acidification potential, 37% and 42%, respectively. Analysis also revealed that the life cycle
environmental impacts of commercial buildings are dominated by the operation stage, which accounted for approximately 52%
of the total global warming potential, about 66% of the total acidification potential, and about 71% of the total photo-oxidant
formation potential, respectively. The results indicate that the principal contributor to the impact categories during the
operation phase were emissions related to fossil fuel combustion, particularly for electricity production.
Discussion The life cycle environmental impacts of commercial buildings are dominated by the operation stage, especially electricity
consumption. Significant reductions in the environmental impacts of buildings at this stage can be achieved through reducing
their operating energy. The results obtained show that increasing the indoor set-point temperature of the building by 2°C,
as well as the practice of load shedding, reduces the environmental burdens of buildings at the operation stage. On a national
scale, the implementation of these simple no-cost energy conservation measures have the potential to achieve estimated reductions
of 10.2% global warming potential, 5.3% acidification potential, and 0.21% photo-oxidant formation potential per year, respectively,
in emissions from the power generation sector. Overall, the measures could reduce approximately 4% per year from the projected
global warming potential of 211.51 Tg for the economy of Thailand.
Conclusions Operation phase has the highest energy and environmental impacts, followed by the manufacturing phase. At the operation phase,
significant reductions in the energy consumption and environmental impacts can be achieved through the implementation of simple
no-cost energy conservation as well as energy efficiency strategies. No-cost energy conservation policies, which minimize
energy consumption in commercial buildings, should be encouraged in combination with already existing energy efficiency measures
of the government.
Recommendations and perspectives In the long run, the environmental impacts of buildings will need to be addressed. Incorporation of environmental life cycle
assessment into the current building code is proposed. It is difficult to conduct a full and rigorous life cycle assessment
of an office building. A building consists of many materials and components. This study made an effort to access reliable
data on all the life cycle stages considered. Nevertheless, there were a number of assumptions made in the study due to the
unavailability of adequate data. In order for life cycle modeling to fulfill its potential, there is a need for detailed data
on specific building systems and components in Thailand. This will enable designers to construct and customize LCAs during
the design phase to enable the evaluation of performance and material tradeoffs across life cycles without the excessive burden
of compiling an inventory. Further studies with more detailed, reliable, and Thailand-specific inventories for building materials
are recommended. 相似文献
9.
Disturbance plays an integral part in generating heterogeneity required for ecosystem persistence, but the increased amplitude and duration of disturbances linked to drivers of global change could result in ecosystem shifts or collapse. Biomonitoring over time provides insights into trajectories of ecosystem change. The responses of two instream animal taxa to two contrasting disturbance events, a major flood event and the long-term cumulative effects of land-use changes, were assessed in 1999–2012 by quantifying variation and change in abundance of functional groups based on flow rate sensitivity, water quality and metrics of ecological condition. All metrics recovered to pre-flood conditions within seven months after the flood event. Similarly, cumulative impacts of land use effected significant decreases in some but not all metrics. Indices that did not change, including SASS total score and ASPT, were the result of insufficient consideration of the decrease in the abundance of sensitive taxa specifically, and the abundance of all taxa in general. The decrease in abundance of sensitive taxa could signal imminent collapse in certain metrics. Evidence is also provided for a shift in the structure of fish assemblages linked to the decrease and loss of taxa sensitive to ecosystem degradation caused by the longer-term impacts of land-use change. 相似文献
10.
Sureeporn Khonpikul Napat Jakrawatana Piyapong Sangkaew Shabbir H. Gheewala 《The International Journal of Life Cycle Assessment》2017,22(11):1692-1704