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21.
Journal of Crop Science and Biotechnology - To achieve food security and increase crop productivity in a sustainable way, keeping soil fertile and balanced fertilization is vital. Soil fertility...  相似文献   
22.
23.
Dead wood in European beech (Fagus sylvatica) forest reserves   总被引:10,自引:0,他引:10  
Data were analysed on the volume of dead wood in 86 beech forest reserves, covering most of the range of European beech forests. The mean volume was 130 m3/ha and the variation among reserves was high, ranging from almost nil to 550 m3/ha. The volume depended significantly on forest type, age since reserve establishment and volume of living wood. More dead wood was found in montane (rather than lowland/submontane) reserves, longer-established reserves (time since designation) and reserves with higher volumes of living wood.

On average, fallen dead wood contributed more to the total dead wood volume than standing dead wood. The percentage of dead wood that was standing was almost twice as high in montane than in lowland/submontane forest reserves (45% versus 25%). The volume of dead wood at selected sites changed considerably over time. The fluctuations were significantly higher in lowland/submontane than montane reserves, possibly connected with differences in the disturbance regimes and especially damage caused by windstorms. In NW Europe, the blow down of formerly managed, even-aged stands led to extraordinary high volumes of dead wood shortly after reserve establishment.

The implications for forest management and biodiversity conservation are discussed. An increase in dead wood volumes must be carried out in accordance with the local/regional forest type and disturbance regime. Thus, in order to fulfil the requirements of as many wood-depending organisms as possible, it is important to preserve not only larger amounts of dead wood, but also dead wood of different types and dimensions as well as securing a long-term continuity of dead wood.  相似文献   

24.
Herpesviruses are an important cause of epidemic disease in tortoises. There are at least two serologically distinct herpesviruses capable of infecting tortoises. Methods for the diagnosis of herpesvirus infections in tortoises include virus isolation and a number of different PCRs. We have compared 11 virus isolates collected from various species in different countries over several years using sequences from three different viral genes. During this study we used four different PCR protocols described for the diagnosis of herpesvirus infections in tortoises. The protocols used included two based on portions of the DNA polymerase gene, one targeting the UL5 homologue, and one targeting the UL39 homologue. Comparison of the methods showed that the tortoise herpesvirus-specific protocols were all serotype specific. Sequences of the obtained amplicons were compared with one another and with sequences of herpesviruses available in GenBank. The sequence alignments showed that the tortoise herpesviruses were most closely related to members of the subfamily Alphaherpesvirinae. They also showed that the tortoise isolates could be clearly divided into two genogroups.  相似文献   
25.
A total of 36 single-lesion isolates were collected from 9 crops of potato and 13 of tomato in different regions of Hungary in the past decade, particularly in 1998. These were analysed for mating type, sensitivity to metalaxyl, allozyme genotype at glucose-6-phosphate isomerase and peptidase loci and genotype at 24 loci detected using the multilocus RFLP probe RG57. The ratios of the mating types A1 to A2 were 8:9 and 4:15 among isolates recovered from potato and tomato, respectively. Resistance to metalaxyl was found more frequently among isolates from potato and in the A1 mating type. The populations were not clearly differentiated on the basis of host origin. All isolates were homozygous (100/100) at the locus for glucose-6-phosphate isomerase. Unlike in other European countries, the most common peptidase allele was 96. Genotypes at the peptidase locus were 96/96 (50%), 96/100 (27.7%) and 100/100 (16.6%). In addition, one isolate from 1993 and another from 1998, were defined as 83/96, a genotype that had not been described elsewhere. The 18 RG57 fingerprints that were observed among 36 isolates, with one exception, seem to be unique to Europe. On the basis of combined genotypic traits, 20 multilocus genotypes were designated. These data, which reveal a remarkable variability with unique genotypes of the late blight pathogen, suggest that migration and sexual and/or asexual recombination have a role in the recent evolution of the pathogen in Hungary.  相似文献   
26.
The fetal stress responses in sows euthanized by electrical current during their second and last trimester of pregnancy (G1 and G2) were evaluated. Three methods of euthanasia of pregnant sows generally applicable to cases of epizootic or emergency slaughter were investigated: 1. conventional application of electrical current to the head and heart (HH); 2. application of electrical current to the head, heart and the uterus (HHU); 3. application of electrical current to the head, heart and from the upper body to the vagina (HHV). Fetuses were delivered by cesarean section at intervals of 3 to 4 minutes and remained attached to the sow by the umbilical cord. Fetal vitality, reflexes, heart rate, blood pressure, rectal body temperature, intracardial arteriovenous pCO2, pH and lactic acid were monitored for a period of 30 minutes. No method was found to kill the fetal pigs immediately. In fetuses at G1 there were no significant differences between the HH and HHU and HHV methods. Fetuses at G2 showed a significantly faster decrease in heart rate and blood pressure as well as a shorter period of time for the absence of fetal body movements and reflexes for the HHT method, compared to the other methods. Since it is not yet known to what extent the fetal pig experiences pain and suffering, the prolonged process of dying for the in utero fetus due to hypoxia which includes struggling and gasps is inconsistent with criteria for humane euthanasia and animal welfare.  相似文献   
27.
Plieninger  Tobias  Torralba  Mario  Hartel  Tibor  Fagerholm  Nora 《Landscape Ecology》2019,34(7):1565-1581
Context

Around 30% of European agricultural landscapes are classified as high nature value (HNV) farmlands. Current policies emphasize the multifunctionality of these landscapes, but little is known about the positive and negative associations of multiple ecosystem services within HNV farmland.

Objectives

This study aims to identify perceived ecosystem services synergies, trade-offs, and bundles in agricultural landscapes of HNV from a socio-cultural perspective.

Methods

We performed a participatory mapping survey of 10 ecosystem services categories among 2301 rural residents in 13 European sites. We analyzed bivariate synergies and trade-offs between perceived ecosystem services through nonparametric correlation analyses. Spatial bundles of perceived ecosystem services were identified through hierarchical cluster analysis. Multinomial logit models were used to assess the influence of land cover on generating associations of ecosystem services.

Results

We find two strong and 16 moderate synergies of perceived ecosystem services (out of 46 possible ecosystem services pairs), mainly among different cultural ecosystem services. We do not reveal moderate or strong trade-offs. We identify five spatial bundles of ecosystem services, termed “Ecosystem services coldspots”, “Wild harvesting ranges”, “Nature areas”, “Recreational spaces”, and “Ecosystem services hotspots”. Of all land-cover co-variates, natural areas, urban areas, and roads have the strongest explanatory power.

Conclusions

Our study complements prevailing biophysical and economic analyses of ecosystem services synergies, trade-offs and bundles by a spatially explicit, socio-cultural perspective. We conclude that socio-cultural mapping of ecosystem services is useful for understanding the perceived multifunctionality of a landscape.

  相似文献   
28.
For many species, one important key to persistence is maintaining connectivity among local populations that allow for dispersal and gene flow. This is probably true for carabid species (Coleoptera:Carabidae) living in the fragmented forests of the Bereg Plain (NE Hungary and W Ukraine). Based on field data, we have drafted a landscape graph of the area representing the habitat network of these species. Graph nodes and links represented two kinds of landscape elements: habitat (forest) patches and corridors, respectively. The quality of habitat patches and corridors were ranked (from low (1) to high (4)), reflecting local population sizes in the case of patches and estimated permeability in the case of corridors. We analysed (1) the positional importance of landscape elements in maintaining the connectivity of the intact network, (2) the effect of inserting hypothetical corridors into the network, (3) the effects of improving the quality of the existing corridors, and (4) how to connect every patch in a cost-effective way. Our results set quantitative priorities for conservation practice by identifying important corridors: what to protect, what to build and what to improve. Several network analytical techniques were used to account for the directed (source-sink) and highly fragmented nature of the landscape graph. We provide conservation priority ranks for the landscape elements and discuss the conditions for the use of particular network indices. Our study could be of extreme relevance, since a new highway is being planned through the area.  相似文献   
29.
Invertebrate iridoviruses (IIV) have been a regular problem for insect breeders. They have also recently been isolated from various lizard species. An iridovirus isolated from several tissues of a high-casqued chameleon (Chamaeleo hoehnelii) was identified as an IIV on the basis of electron microscopy (EM), sequencing of a portion of the major capsid protein (MCP) gene, and restriction endonuclease analysis of viral DNA. The pathogenicity of this isolate for crickets of the species Gryllus bimaculatus was tested by using 3 experimental infection studies. The mortality rates in the infected crickets ranged between 20% and 35%. The fat bodies of the crickets were examined on cell culture, with a nested PCR targeting the MCP gene, histologically, with in situ hybridization and by EM. Nested PCR was the most sensitive method for detecting IIV in the fat-body samples. Virus was re-isolated from several fat-body samples. In some fat bodies of infected crickets, massive arrays of viruses could be detected by EM. These findings support the hypothesis that IIV from insects are able to infect reptiles.  相似文献   
30.
For the purpose of detecting the synthesis of zinc metalloenzymes after zinc supplementation in an experiment using rats the animals were first depleted for 15 days and subsequently injected a labelled zinc salt solution (65Zn-ZnCl2) in a dosis of 0.4 mg (in terms of Zn) and with an activity of 3.0 muCi/100microliter. After a 5-day depletion period, the activity of the metallo-enzymes alkaline phosphatase in plasma and in the femur and carboxy-peptidase A and B in the pancreatic gland was found to rise at the same rate as the 65Zn-measuring rate in plasma, femur and pancreatic gland. By calculating correlations this interdependence was demonstrated. Thus the highly significant correlation coefficients prove for these metalloenzymes that a synthesis with the injected zinc salt has taken place whilst for carbo-anhydrase in blood this evidence was not furnished. As the zinc dosis is not exclusively used for the enzyme synthesis, but additional 65Zn is incorporated into the individual organs, it does not appear to be possible to draw conclusions from the 65 Zn-measuring rate in the individual organs on the intermediary availability.  相似文献   
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