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131.
J. Lutz    E. Limpert    P. Barto&#;  F. J. Zeller 《Plant Breeding》1992,108(1):33-39
Major genes for resistance to powdery mildew were analysed in 24 Czechoslovakian wheat cultivars and, in part, in their parents. For this purpose individual isolates of the pathogen, able to differentiate host lines with known resistance genes, were selected. Eight of nineteen winter wheat cultivars do not possess any major resistance gene. Three cultivars have one and seven have two genes. One cultivar carries a combination of three genes (Pm2, Pm4b, Pm8). The most common resistance genes are Pm4b, Pm5 and Pm8. Pm2 is once combined with Pm6. Only one of five spring cultivars lacked a major resistance gene. Mlk is once present alone and twice combined with Pm5. There is one spring cultivar with a novel combination of three genes: Pm1, Pm5 and another gene needing further characterization. The observations are discussed with additional results of parent lines and further information on pedigrees.  相似文献   
132.
Above- and belowground biomass in a Brazilian Cerrado   总被引:1,自引:0,他引:1  
Cerrado is a biome that occupies about 25% of the Brazilian territory and is characterized by a gradient of grassland to savanna and forest formations and by high species richness. It has been severely affected by degradation and deforestation and has been heavily fragmented over the past 4-5 decades. Despite the recognized overall ecological importance of the Cerrado, there are only few studies focusing on the quantification of biomass in this biome. We conducted such a case study in the South-East of Brazil in a cerrado sensu stricto (cerrado s.s.) with the goal to produce estimates of above- and belowground biomass and to develop allometric equations. A number of 120 trees from 18 species were destructively sampled and partitioned into the components: leaves, branches and bole. Five models with DBH (D), height (H), D2H and wood density (WD) as independent variables were tested for the development of allometric models for individual tree aboveground biomass (leaves + branches + bole). One model based on basal area (BA) as a stand parameter was also tested as an alternative approach for predicting aboveground biomass in the stand level. Belowground biomass was estimated by subsampling on 10 sample plots. Mean aboveground tree biomass (bole, branches and leaves) was estimated to be 62,965.5 kg ha−1(SE = 14.6%) and belowground biomass accounted for 37,501.8 kg ha−1 (SE = 23%). The best-fit equation for the estimation of individual tree aboveground biomass include DBH and wood density as explanatory variables (R2 = 0.898; SEE = 0.371) and is applicable for the diameter range of this study (5.0-27.6 cm) and in environments with similar conditions of the cerrado s.s. sampled. In the stand level, the model tested presented a higher goodness of fit than the single tree models (R2 = 0.934; SEE = 0.224). Our estimates of aboveground biomass are higher than reported by other studies developed in the same physiognomy, but the estimates of belowground biomass are within the range of values reported in other studies from sites in cerrado s.s. Both biomass estimates, however, exhibit relatively large standard errors. The root-to-shoot ratio of the sample trees is in the magnitude of reported values for savanna ecosystems, but smaller than estimated from other studies in the cerrado s.s.  相似文献   
133.
Immunoblotting assays using commercial antibodies were established to investigate the unexpected persistence of the immunoactive Cry1Ab protein in the bovine gastrointestinal tract (GIT) previously suggested by enzyme-linked immunosorbent assay (ELISA). Samples of two different feeding experiments in cattle were analyzed with both ELISA and immunoblotting methods. Whereas results obtained by ELISA suggested that the concentration of the Cry1Ab protein increased during the GIT passage, the immunoblotting assays revealed a significant degradation of the protein in the bovine GIT. Samples showing a positive signal in the ELISA consisted of fragmented Cry1Ab protein of approximately 17 and 34 kDa size. Two independent sets of gastrointestinal samples revealed the apparent discrepancy between the results obtained by ELISA and immunoblotting, suggesting that the antibody used in the ELISA reacts with fragmented yet immunoactive epitopes of the Cry1Ab protein. It was concluded that Cry1Ab protein is degraded during digestion in cattle. To avoid misinterpretation, samples tested positive for Cry1Ab protein by ELISA should be reassessed by another technique.  相似文献   
134.
The plant nutrient phosphorus (P) is spread throughout the plant within the transpiration stream after uptake in the form of phosphate via the roots. Short‐term distribution is therefore strongly dependent on transpiration rather than on sinks, so that P mainly enters adult leaves. The objective of this work was to investigate the transport of phosphate in leaf veins and its distribution within the leaf. Experiments were performed with broad bean (Vicia faba L. var. Scirocco) using radioactively labeled phosphate. In a relatively new approach, the tracer was monitored by a sensitive imaging plate using Fujifilm's Bioimaging Analyzer System. Radioactive label could be monitored in fresh leaves (without fixing) using exposure times of only 5–20 min. For this reason, the method offered the possibility to obtain several subsequent autoradiographic images of the same sample after different feeding times. Phosphate tracer quickly reached small veins, which were then more intensely labeled than the tissue between them. Within the first 15 min, intercostal fields were only slightly stained. After application of phosphate tracer onto the leaf blade, export from the leaf was pronounced and started within 30 min. Phosphorus is effectively redistributed from adult leaves to sinks such as the terminal bud or growing root tips. Using the imaging method, an impression of the high velocity and effectiveness of this process was obtained. The results furthermore imply that leaf veins may be one of the most important locations where exchange between xylem and phloem transport takes place, although exchange between xylem and phloem was also observed in the shoot axis and in the petioles.  相似文献   
135.
This paper describes a facility designed to simultaneously generate complex climatic and pollutant conditions for research into the effects of climate and air pollution on plants. The system, commissioned in 1985, consists of a set of 4 environmental chambers which are each equipped with four identical subchambers. These 4 subchambers are subjected to identical climatic conditions, but are equipped with independent gas supplies. The chambers are designed to operate within a temperature range of -20 to +40° C at a relative humidity of 20 to 95 % with an illumination system providing high light intensities at a spectrum very close to sunlight. A computer controlled fumigation system allows the injection of various gases singly and in combination at concentrations between 0.005 to l,000 ppm (SO2, NOx, O3, CO2, PAN).  相似文献   
136.
The feline leukemia virus (FeLV) is a retrovirus of the domestic cat that was described almost 50 years ago. The FeLV-infection may lead to fatal diseases in domestic and small wild cats. The use of efficacious diagnostics assays and vaccines led to a reduction of the FeLV prevalence; however, FeLV still poses a problem for the cat presented with the infection. This article aims to describe recent developments in diagnostics and findings in the infection pathogenesis that are clinically relevant.  相似文献   
137.
The present study was carried out in a herd with concurrent infections of Mycoplasma wenyonii and 'Candidatus M. haemobos', to investigate if transplacental and/or vector-borne transmission is possible for one or both bovine haemoplasma species. For this purpose blood samples were collected from 38 mother animals and their newborn calves; as well as from 17 uninseminated cows twice three months apart. In addition, 311 mosquitoes and blood-sucking flies (Diptera: Culicidae, Tabanidae, Muscidae) were cought near the animals. DNA was extracted from all samples, followed by real-time PCR analysis. In 10.5% of neonate calves, that were born to cows harbouring both haemoplasmas, M. wenyonii and/or 'Candidatus M. haemobos' positivity was detected. Copy numbers in positive samples from cows and their calves indicated that - in comparison with M. wenyonii - 'Candidatus M. haemobos'-bacteraemia had usually lower levels. In samples of uninseminated cows the rate of infection with the latter species decreased. These findings may explain why M. wenyonii was significantly more frequently detected in blood-sucking flies, than 'Candidatus M. haemobos'. In conclusion, molecular evidence is provided for the first time on the transplacental transmission of bovine haemoplasmas. Regarding their spread by blood-sucking arthropods, new potential vectors were identified, i.e. the horn fly (Haematobia irritans), the stable fly (Stomoxys calcitrans) and two species of horse flies (Tabanus bovinus, T. bromius).  相似文献   
138.
Background: Cats with diabetes mellitus frequently achieve clinical remission, suggesting residual β‐cell function. Responsiveness of β‐cells to arginine persists the longest during diabetes progression, making the intravenous arginine stimulation test (IVAST) a useful tool to assess residual insulin and glucagon secretion. Hypothesis: Diabetic cats with and without remission will have different arginine‐induced insulin or glucagon response. Animals: Seventeen cats with diabetes, 7 healthy cats. Methods: Blood samples collected on admission and during subsequent IVAST. Glucose, insulin, and glucagon were measured. Response to IVAST was assessed by calculating the insulin and glucagon area under the curve (AUC) and the AUC glucagon‐to‐insulin ratio. Diabetic cats were treated with insulin and were followed for 18 weeks. Remission was defined as normoglycemia and disappearance of clinical signs of diabetes for ≥4 weeks, without requiring insulin. Results: Seven diabetic cats (41%) achieved remission. On admission, blood glucose concentration was significantly lower in cats with remission (median, 389 mg/dL; range, 342–536 mg/dL) than in those without remission (median, 506 mg/dL; range, 266–738 mg/dL). After IVAST, diabetic cats with remission had higher AUC glucagon‐to‐insulin ratios (median, 61; range, 34–852) than did cats without remission (median, 26; range, 20–498); glucose, insulin, and glucagon AUCs were not different. Diabetic cats had lower insulin AUC than did healthy cats but comparable glucagon AUC. Conclusions and Clinical Importance: Diabetic cats with and without remission have similar arginine‐stimulated insulin secretion on admission. Although cats with remission had lower blood glucose concentrations and higher AUC glucagon‐to‐insulin ratios, large overlap between groups prevents use of these parameters in clinical practice.  相似文献   
139.
"Candidatus Mycoplasma turicensis" infects felids. The pathogenesis of "Candidatus M. turicensis" chronic infection is poorly understood. The goals of the present study were to (1) induce reactivation of the infection in chronic carrier cats by attempted immunosuppression, (2) identify potential tissue sequestration using real-time TaqMan® PCR and (3) monitor the humoral immune response by DnaK enzyme-linked immunosorbent assay (ELISA). Ten specified pathogen-free cats that had ostensibly recovered from experimental "Candidatus M. turicensis" infection were used: five cats (group 1) received high dose methylprednisolone (attempted immunosuppression), while five cats served as untreated controls (group 2). Besides weekly blood samples, tissue samples were collected from bone marrow, kidney, liver and salivary glands at selected time points. The cats in group 1 had significantly lower lymphocyte counts and higher blood glucose levels after methylprednisolone administration than the controls. After methylprednisolone administration one blood and three tissue samples from cats in group 1 tested PCR-positive; before the administration, only one sample was positive. All other samples tested PCR-negative. All cats stayed seropositive; the antibody levels of the cats in group 1 showed a significant transient decrease after methylprednisolone administration. This is the first study to report the presence of "Candidatus M. turicensis" in tissues of chronically infected cats and the persistence of anti-feline hemoplasma antibodies in the absence of detectable bacteremia. Methylprednisolone administration did not lead to a significant reactivation of the infection. Our results enhance the knowledge of "Candidatus M. turicensis" infection pathogenesis and are clinically relevant to the prognosis of hemoplasma-infected cats.  相似文献   
140.
The QBC V hematology system was tested with respect to its application in veterinary medicine. PCV's and counts of total leukocytes, granulocytes, lympho/monocytes and platelets collected from 435 horses, dogs and cats were determined and compared with conventionally measured values. Precision and accuracy were found to be good for the majority of parameters. In the authors' opinion the QBC V hematology system is well suited for use in veterinary practice.  相似文献   
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