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31.
The study of the discharge of metallic pollutants into the marine environment through biological material such as sardines makes it possible to evaluate the quality of the biological resources and of the marine environment. The sardine (Sardina pilchardus) is the most popular species for fishing and the most consumed species by the Algiers population. Two toxic metals that can affect human health are studied in this fish. A year of sampling with fishermen was conducted. Sampling was done in the spring, in the autumn, and in April between April 2014 and April 2015. Sampled sardines were grouped by size classes. The gills and muscle were recovered by size classes. The results were explored using a principal components analysis and compared by a Mann-Whitney distribution test. An atomic absorption spectrophotometer was used in the laboratory for analysis. The most important results show that lead levels were higher than those of cadmium in the gills and muscle. For sardines, lead contamination appears to have both gill and food origins. Mann-Whitney comparison tests confirmed this homogeneous distribution of lead between the gills and muscle. The correlation between cadmium in the gills and height or weight is more substantial than that with muscle. The origin of cadmium in sardines is branchial. The food origin appears secondary. From our point of view, the effect of season, i.e., winter (December) and spring (April), favors an increase in metal levels in parallel to the production reserves planned for spawning. The effect of season was observed by use of a biplot. A significant reduction in cadmium and lead content was observed in September. The high temperature, an environmental factor, induced stress that reduced the metal concentrations and the decontamination induced by the issuance of genital products in early summer.  相似文献   
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33.
长枝木霉TlCC鉴定及其生物学特性研究   总被引:1,自引:1,他引:1  
从土壤中分离得到1株木霉TlCC,为明确其分类地位及其生物学特性,对该菌进行形态学鉴定和分子鉴定,并对其生长培养基、光照、温度、碳源、氮源、微量元素和pH等生物学特性进行研究。鉴定结果显示,该菌株为长枝木霉(Trichoderm longibrachiatum)。生物学特性结果表明:菌株TlCC在PDA上生长量最大,查氏培养基和基本培养基上生长量最小;不同光照条件下,菌丝生长无明显差异,但在连续光照条件下可明显促进孢子产生;在15~40℃范围能够生长产孢,在35℃时菌丝生长最快,但产孢量在25~35℃最大;果糖最能促进菌丝生长,果糖、可溶性淀粉最有利于产孢;谷氨酸对菌丝生长和孢子产生都有促进作用;Cu最能促进菌丝生长,而Zn、K和Mg则对菌丝生长有一定抑制作用,Cu最有利于产孢,Zn对产孢明显抑制;在pH值在2~10范围内均可生长,在pH为5时为生长最佳,在pH值3~7范围内最有利于产孢。  相似文献   
34.
Analytical scanning and transmission electron microscopy, sequential chemical extraction, and pyrolysis?Cgas chromatography on solvent-extractable organic matter are used to provide both direct and indirect speciation of heavy metals and organic matter in sewage-suspended solids and in biofilms taken from an urban sewer in an emerging country. Compared to developed countries where the domestic activities represent the main source of heavy metal pollution in wastewater, the combined sewer system of an emerging country also integrates significant contributions originating from the private drinking water supply system (Zn, Cu, Cr, and Ni), industrial discharges (Cu, Mn), and road dust transported by street washing (Pb). The relative importance of those sources changes drastically over time as evidenced by the difference in metal levels recorded between weekday and weekend effluents. Nevertheless, sewer biofilms are found to provide a good averaging of contaminant loads and they can be used as environmental archives. The speciation study reveals the predominance of neoformed minerals such as sulfides and phosphates and highlights the strong biogeochemical dynamics that takes place within the sewer system. Electron microscope observations of heavy metal-bearing phases proved to be necessary to provide a consistent interpretation of chemical extraction results. The molecular characterization of the solvent-extractable organic matter from biofilms reveals the presence of classical fingerprints of domestic activity such as fecal sterols and detergents but also confirms a major contribution of petroleum by-products consistent with a traffic-related pollution.  相似文献   
35.
The phenolic constituents and antioxidant activity of ethanol and water extract of the flowers of Hypericum venustum, collected in Turkey, were investigated. The extracts possess strong reducing power, free radicals and hydrogen peroxide scavenging activity, as well as metal chelating ability.  相似文献   
36.
The impact of tropical seasons (dry and wet) and growth stages (8, 10 and 12 weeks) of Cosmos caudatus on the antioxidant activity (AA), total phenolic content (TPC) as well as the level of bioactive compounds were evaluated using high performance liquid chromatography (HPLC). The plant morphology (plant height) also showed variation between the two seasons. Samples planted from June to August (during the dry season) exhibited a remarkably higher bioactivity and height than those planted from October to December (during the wet season). The samples that were harvested at eight weeks of age during the dry season showed the highest bioactivity with values of 26.04 g GAE/100 g and 22.1 μg/ml for TPC and IC50, respectively. Identification of phytochemical constituents in the C. caudatus extract was carried out by liquid chromatography coupled with diode array detection and electrospray tandem mass (LC-DAD-ESIMS/MS) technique and the confirmation of constituents was achieved by comparison with literature data and/or co-chromatography with authentic standards. Six compounds were indentified including quercetin 3-O-rhamnoside, quercetin 3-O-glucoside, rutin, quercetin 3-O-arabinofuranoside, quercetin 3-O-galactoside and chlorogenic acid. Their concentrations showed significant variance among the 8, 10 and 12-week-old herbs during both seasons.  相似文献   
37.
In this study, central composite design (CCD) based on response surface methodology (RSM) was employed to optimize parameters of melt-spinning process of poly(ethylene terephthalate) partially oriented multifilament yarn (POMFY). On the basis of a four-variable CCD, RSM was used to determine the effects of spinning temperature, spinning pressure, take-up velocity and quenching air velocity on the levels of the elongation of POMFY as the response. The POMFY samples were also characterized by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. By applying a quadratic regression analysis, an equation indicating the effect of each variables on the response was developed. The predicted values of the parameters showed excellent agreement with the experimental values (R 2=0.9565, Adjusted-R 2=0.916). Moreover, the results confirmed that the CCD mathematical model was a suitable method to optimize the melt-spinning parameters of POMFY in an industrial scale.  相似文献   
38.

Background

Attempts for early detection of gastric cancer have recently focused on host''s genetic susceptibility factors and gene-environment interactions. We have, herein, studied the association of MTHFR C677T single nucleotide polymorphism (SNP) and its interaction with Helicobacter pylori infection, smoking, age and gender on the risk of gastric cancer among an Iranian population.

Methods

Gastric cancer patients (n = 450) and cancer-free controls (n = 780) were studied for serum H. pylori-specific IgG antibodies by ELISA and MTHFR C677T polymorphism (SNP) by PCR-RFLP. Demographic and life style data were collected through patient interviews. Unconditional logistic regression model estimated odds ratio (OR) and the corresponding 95% confidence intervals (CI).

Results

The interactions of MTHFR genotype with H. pylori infection (P = 0.03), age (P = 0.049) and gender (P = 0.007) were statistically significant. Accordingly, MTHFR C677T carriers who were also positive for H. pylori infection exhibited 80% (OR = 1.8, 95% CI = 1.0-2.9) significant excess risk of non-cardia gastric cancer. Furthermore, subjects over the age of 50 or female subjects carrying MTHFR C677T SNP showed 40 (OR = 1.4, 95% CI = 1.0-2.0) and 100 (OR = 2.0, 95% CI = 1.2-3.2) percent increased risk of gastric cancer, respectively.

Conclusion

MTHFR C677T SNP seems to increase the risk of gastric cancer and the effect is significantly inflated by interactions with H. pylori infection, age and gender. Key Words: Helicobacter pylori, Smoking, Gender identity, Age group, Methylenetetrahydrofolate reductase  相似文献   
39.
Particle size distribution (PSD) is among basic parameters in soil and sediment characterization and provides essential information in sedimentological and environmental studies. The problem with the PSD determination is that for any given sample the result depends not only on the method used but also on the sample pre‐treatment, making them seldom comparable. In this study, the PSD of seven non‐treated and pre‐treated soil samples were determined by four granulometric methods (pipette, sedigraph, particle counter and laser diffraction analysis). Samples were subjected to pre‐treatments commonly used in sample preparation for the PSD determination, i.e., addition of dispersant (sodium metaphosphate) and removal of the organic matter (with hydrogen peroxide). The total organic carbon (TOC) analysis was used to estimate the content of organic matter before and after its removal. The effect of different pre‐treatments was evaluated based on the PSD variations and the changes in the specific surface area (SSA) of the samples. The results highlighted differences in the PSD curves of samples depending on the granulometric method and pre‐treatment applied. The most pronounced difference was the higher amount of clay fraction determined by settling techniques. The role of hydrogen peroxide in disruption of aggregates was evident in the increase in the SSA as well as the share of fine fraction determined by all four techniques, while sodium metaphosphate made no modifications of the SSA but acted in favour of prolonging settling of clay particles and increasing its content obtained by settling techniques.  相似文献   
40.
Field experiments were conducted in two growing seasons as a split plot based on a randomized complete block design with four replications. Irrigation intervals (irrigation after 70 and 170 mm evaporation from class A pan) were assigned to main plots and spraying of polyamines (putrescine 0.1 mM, spermidine 0.1 mM, and spermine 0.1 mM) were allocated to the subplots. T nitrogen and sulfur content of different parts of mung bean, nitrogen uptake, protein filling duration, protein percentage of grain, maximum protein content per grains, grain and protein yields per unit area, methionine and serine contents reduced under water limitation, but grain filling rate, isoleucine, leucine, threonine, aspartic acid, glutamic acid, glycine, proline, tyrosine and arginine contents in grains raised. Treatment of plants with polyamines improved the contents of nitrogen and sulfur, nitrogen uptake, protein-filling duration, protein percentage, grain and protein yield per unit area, and histidine, methionine, phenylalanine, threonine, aspartic acid, glutamic acid, tyrosine, and arginine contents in grain. Putrescine had the highest grain and protein yields. Our results clearly indicated that polyamines with improving histidine, methionine, phenylalanine, and threonine content in mung bean grains improved the quality of mung bean protein.  相似文献   
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