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81.
Climate change towards a warmer and dryer vegetation period may negatively impact growing conditions for Scots pine monocultures situated on dry, sandy soils in Central Europe. The purpose of the study was to evaluate the effect of thinning on precipitation throughfall in young Scots pine stands on typical pine sites. In 1992, observation of precipitation and throughfall started at the Tyniště research site (lowland of Eastern Bohemia) in a 7-year-old pine stand planted in rows at a stocking of ca 10,000 trees ha−1. Throughfall was measured at weekly intervals during the growing season (April-September) by gauges randomly located in two treatments - variant 1C - Control without thinning and variant 2T - Thinned - and compared to precipitation at an open space outside of the canopy. The results demonstrated the positive effects of heavy low thinning (removal of 47% of the total number of trees and 31% of total pre-treatment basal area) on the water supply of young Scots pine stands. On the Thinned treatment, throughfall increased by 2-8% compared to Control plot. This positive effect persisted for six years after the first canopy reduction and the differences were significant for the first four years after thinning. After the second treatment (high thinning), throughfall on the Thinned treatment showed a nominal, but statistically insignificant increase. The likely reason for this result is that the application of a different type of thinning increased the variability of the canopy and, consequently, the effect of released crowns could not be detected.  相似文献   
82.
The study deals with the monitoring of the content of antioxidant components in grape juice in the course of cold maceration of grapevine varieties ‘Italian Riesling’ and ‘Cabernet Sauvignon’, vintages 2011 and 2012. For analyses, grape juice was sampled after the maceration intervals of 0; 2; 4; 6; 8; 12 and 24?h. Spectrophotometry was used to estimate antioxidant activity (by the DPPH test), total flavanols, contents of anthocyans and contents of hydroxycinnamic acids. The content of total acidity and pH were estimated as well. Obtained results indicated that contents of aforementioned compounds increased with the increasing time of mush maceration.  相似文献   
83.
Background: The histone code is an established epigenetic regulator of early embryonic development in mammals.The lysine residue K9 of histone H3(H3 K9) is a prime target of SIRT1, a member of NAD+-dependent histone deacetylase family of enzymes targeting both histone and non-histone substrates. At present, little is known about SIRT1-modulation of H3 K9 in zygotic pronuclei and its association with the success of preimplantation embryo development. Therefore, we evaluated the effect of SIRT1 activity on H3 K9 methylation and acetylation in porcine zygotes and the significance of H3 K9 modifications for early embryonic development.Results: Our results show that SIRT1 activators resveratrol and BML-278 increased H3 K9 methylation and suppressed H3 K9 acetylation in both the paternal and maternal pronucleus. Inversely, SIRT1 inhibitors nicotinamide and sirtinol suppressed methylation and increased acetylation of pronuclear H3 K9. Evaluation of early embryonic development confirmed positive effect of selective SIRT1 activation on blastocyst formation rate(5.2 ± 2.9% versus 32.9 ± 8.1% in vehicle control and BML-278 group, respectively; P ≤ 0.05). Stimulation of SIRT1 activity coincided with fluorometric signal intensity of ooplasmic ubiquitin ligase MDM2, a known substrate of SIRT1 and known limiting factor of epigenome remodeling.Conclusions: We conclude that SIRT1 modulates zygotic histone code, obviously through direct deacetylation and via non-histone targets resulting in increased H3 K9 me3. These changes in zygotes lead to more successful pre-implantation embryonic development and, indeed, the specific SIRT1 activation due to BML-278 is beneficial for in vitro embryo production and blastocyst achievement.  相似文献   
84.

Purpose

The main purpose of this study was to evaluate temporal and regional variability of contamination by heavy metals (HMs) in river sediments using their enrichment factors (EFs) and benchmarking according to sediment quality guidelines (SQGs). The Zlin region in the Czech Republic (Morava and Drevnice River basins) represents a model area where several regionally specific ecological risk assessment studies have recently been conducted with a focus on organic pollution, eco-toxicity, geological, and geochemical characteristics.

Materials and methods

Four consecutive sediment sampling campaigns were undertaken in spring and autumn 2005–2006. Aqua-regia leachable content of Cd, Co, Cr, Cu, Ni, Pb, Sb, V, and Zn in surface sediments from 14 sites was analyzed using ICP-MS, and Hg content was analyzed using AMA-254 analyzer. EFs were calculated to identify the human impact on pollution in the area. Comparisons to SGQs were conducted to identify the areas and HMs of greatest risk.

Results and discussion

Calculation of EFs contributed to the effective clustering of HMs. Median EFs of Co, Ni, and V ranged from 0.9 to 1.4 at all sites indicating concentrations very close to natural geological background levels. There was greater enrichment at locally polluted sites, the highest in the cases of Cd, Sb, Hg, and Cr. Widespread influence of diffuse HM sources (traffic, agriculture, and urban wastes) was apparent from elevated concentrations of Pb, Cu, and Zn at all sites. EF values also helped to identify the greatest temporal changes and shifts in HMs contamination between adjacent sites caused by 50-year recurrence interval floods in early spring 2006. The impact was most apparent in downstream sites; namely directly below the confluence of the two major rivers.

Conclusions

The overall contamination of HMs in the region was classified as low-to-moderate with significantly contaminated sub-areas. The study showed relatively stable spatial distributions of HMs, indicating potential sources of pollution. Cu was identified as the HM of greatest risk. The study emphasizes the necessity of considering both environmental circumstances and background HM occurrence to prevent misinterpretation of the pollution situation. The use of EFs which include grain size proxy normalization and HM background levels, along with the comparison of the detected concentrations to SQGs, proved an efficient way to identify hazardous contamination from anthropogenic sources.  相似文献   
85.
Abstract

The choice of prospective type of farming requires knowledge about the specific relationships that exist between farm management practices and base environmental conditions. Nowadays the protection of soil organic carbon is one of the main tasks, because organic carbon in addition to soil fertility can act in elimination of soil contamination and carbon sequestration. Field experiments were focused on the effect of intensive farming without organic inputs versus grassland on organic carbon content. Organic carbon content (Cox) and humic substance fractions (C-humic acids and fulvic acid fractions), hot water extractable carbon and selected microbial characteristics in Eutric Cambisol were monitored during the period 1999–2010. A priming effect of soil cultivation was detected immediately after tillage. Arable soil with ‘intensive’ crop sequences (exclusively cash crops, cereals, oil plants) and with an optimal level of chemical inputs (mineral fertilizers, pesticides), but without organic farmyard manure had lower content of all carbon forms compared with grassland. 13C NMR spectroscopy and thermal analysis (TGA) were applied to characterize humic acid (HA) structure and stability. More carbon, less oxygen and more aromatic compounds were detected in grassland HA. Slight differences were found in HA thermo-oxidative stability and degradability, which was probably caused by changes in elemental composition and structure. Even the land use had no significant effect on basic microbiological characteristics (basal respiration, microbial biomass and qCO2); the physiology of the microbial community of grassland was altered by a higher ability to utilize L- and D-glutamic acid. The L/D ratio of glutamic acid mineralization indicated no occurrence of stress in soil for both types of farming. It has been demonstrated that although losses of carbon as a result of land-use conversions are generally more rapid, gains of carbon in grassland followed by changes in management practices can also occur.  相似文献   
86.
Mespilus germanica, known as the medlar, is a large shrub or small tree. The fruit has been cultivated since Roman times, and is unusual in being available in winter, and in being eaten when bletted.  In this study twelve medlar (Mespilus germanica L.) genotypes were harvested at commercial maturity stage (skin brownish, pulp white, fruit hard) from Rize provinces located eastern black sea region and were analyzed for their some important fruit phenotypic (fruit mass, shape index, fruit firmness, ostiole diameter and fruit flesh ratio) and bioactive characteristics (total phenolic content, total antioxidant capacity, vitamin C and phenolic compounds). A wide variation among genotypes on most of the searched parameters was found. Fruit mass and flesh ratio varied from 12.3 g (KRD-1) to 23.6 g (KRD-8) and 83.6?% (KRD-2) to 93.0?% (KRD-4) indicating high variability among genotypes. The total phenolic contents of twelve medlar genotypes varied from 157 to 227 mg gallic acid equivalent in 100 g fresh weight basis. Chlorogenic acid, rutin and p-coumaric acid were dominant in medlar fruits.  相似文献   
87.
应用灰色关联度分析方法,对6个农户中影响产量因素的6个主要性状进行了分析,结果表明小坚果数/株、分枝数/株对产量的高低起主要作用。  相似文献   
88.
The estimation of antioxidants in fruit, vegetables, beverages, and foodstuffs has been discussed in a great number of scientific studies, but until now, problems concerning the analysis of antioxidant components of rosé wine has not been adequately investigated. This paper presented results of a study on antioxidant components contained in some samples of rosé wine originating from the Moravian wine growing region. The experiments involved altogether 48 samples of rosé wine made of grapes of the varieties ‘Blaufränkisch’, ‘Blauer Portugieser’, ‘Pinot Noir’, ‘Sankt Laurent’, and ‘Zweigeltrebe’. Grapes were harvested in 2013. Spectrophotometry was used to estimated antioxidant activity (53–73?mg?L?1 GAE), content of total polyphenols (152–369?mg?L?1), hydrocinnamic acid (52–148?mg?L?1), flavonols (25–294?mg?L?1) and anthocyanins (88–1754?mg?L?1). The HPLC method was used for the detection of some important antioxidants, i.?e. catechin, epicatechin, malvidin-3-glucoside, cis- and trans-resveratrol, ferrulic acid, coumaric acid and caftaric acid. This study enabled to determine basic profiles of the most important antioxidant components of the most popular Moravian red grapevine varieties. The studied wines were analyzed from several different aspects, which is not standard.  相似文献   
89.
Runoff and atmospheric chemistry in the Krusne hory Mts. have changed significantly from 1978 to 1994. Forest die-back related deforestation resulted in decreased dry deposition of SO2 and changes in streamwater chemical composition. Atmospheric sulphur (S) deposition decreased from extremely high values of 66.6 kg S ha?1 year?1, in the early 1980s to 35.5 kg S ha?1 year?1 in 1994. Decreasing S input is reflected in decrease of streamwater sulphate (SO4 2?) concentrations, which decreased from 1560 μeq l?1 to 1164 μeq l?1. Runoff export of S was 53 kg S ha?1 year?1 in 1993, S is not retained in the catchments. Nitrogen (N) budget indicates accumulation in the catchment, which is attributed to forest regrowth.  相似文献   
90.
不同基因型欧洲梨离体繁殖研究   总被引:14,自引:0,他引:14  
试验用12个基因型欧洲梨茎尖作外植体,以MS作基本培养基进行高体繁殖试验。结果表明,不同基因型外植体增殖和形态分化显著不同。其中Koporeka仅经过28d便获得了5.6倍的增殖。生根培养14d后,生根率达88.65%,每植株生根2.86条。Vila连续培养60d,仅有少量的外植体形成了愈伤组织,无芽和根分化。参试的12个基因型,只有5个类型可以进行规模离体繁殖。  相似文献   
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