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101.
TopBP1 is aberrantly expressed in human and feline mammary carcinomas, but expression of this BRCA1-related protein has not been investigated in canine mammary carcinomas. In this study, 132 canine mammary tumours (46 benign, 86 carcinomas) were examined immunohistochemically for expression of TopBP1, oestrogen receptor α (ERα), Ki67 and p53. Positive staining for TopBP1 was evident in all canine mammary lesions, although five samples had <20% positive cells. The number of samples with high levels of staining increased in different categories from benign mixed tumour to adenoma to carcinoma. Most TopBP1 staining was nuclear, but both nuclear and cytoplasmic staining were observed as the degree of malignancy increased, similar to human and feline mammary carcinomas. Benign mixed tumours, however, had more cytoplasmic staining than adenomas. Expression of p53 and the proliferation marker Ki67 increased from benign mixed tumour to adenoma to carcinoma, but the differences between benign and malignant tumours were more distinct than for TopBP1 expression. ERα expression decreased from malignant to benign tumours, although over half of the benign mixed tumours were negative. TopBP1 was expressed in canine mammary tumours at higher levels than has been reported previously for cats, although the shift in cellular localisation with malignancy was similar.  相似文献   
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We assessed the impact of domestic cats on population persistence of native and exotic urban bird populations using a model adjusted for habitat-specific catch rates, cat ownership and hunting activity data. GPS-derived home ranges of 32 cats and resource selection indices demonstrated the degree of penetration and preference for native vegetation fragments. Owners reported on prey brought back by 144 domestic cats in Dunedin, New Zealand, during 12 months. One third of cats never brought back prey, and 21% returned more than one item/month. Cats brought back a mean of 13.4 prey items/year (median = 4), with cats aged <1 year returning more prey than older cats. Birds were the most common prey, followed by rodents. Although cats penetrated adjacent vegetation fragments they did not catch more birds and preferred garden habitat, suggesting that predation pressure may be reduced in fragments. Cat home range size appears to be constrained by cat density while the number of birds caught depends on the density of available prey. Estimates of city-wide catch for six bird species were either more than total urban population size estimates or close to lower confidence intervals. Modelling of three species indicated low likelihood of population persistence with cat predation. The observed persistence of these prey species suggests a meta-population structure with urban populations acting as sinks with source populations located on the city fringe.  相似文献   
104.
Structural materials in nature exhibit remarkable designs with building blocks, often hierarchically arranged from the nanometer to the macroscopic length scales. We report on the structural properties of biosilica observed in the hexactinellid sponge Euplectella sp. Consolidated, nanometer-scaled silica spheres are arranged in well-defined microscopic concentric rings glued together by organic matrix to form laminated spicules. The assembly of these spicules into bundles, effected by the laminated silica-based cement, results in the formation of a macroscopic cylindrical square-lattice cagelike structure reinforced by diagonal ridges. The ensuing design overcomes the brittleness of its constituent material, glass, and shows outstanding mechanical rigidity and stability. The mechanical benefits of each of seven identified hierarchical levels and their comparison with common mechanical engineering strategies are discussed.  相似文献   
105.
Herbicides entering the aquatic environment by spray drift, run-off and leaching to field drains may cause adverse effects on non-target aquatic vegetation. The potential for such effects has typically been evaluated from tests with floating, monocotyledonous Lemna sp. However, concern has been expressed as to whether this species could be used to indicate potential effects on other vegetation types, particularly rooted, submerged, emergent or dicotyledonous species. In 1997, the Centre for Aquatic Plant Management undertook development of new tests based on the additional species, Glyceria maxima (Hartm) Holmb, Lagarosiphon major (Ridl) Moss and Myriophyllum spicatum L. The resulting methodology was used to assess the effects of the sulfonylurea herbicide, sulfosulfuron on these species. Data presented here demonstrate that exposure to initial sulfosulfuron concentrations of 3.33 microg litre(-1) for up to 21 days was tolerated by these species and that adverse effects were observed only when plants were exposed to initial concentrations of 3.33 and 10 microg litre(-1) for 70 days. As the occurrence of such high initial concentrations for long periods is unlikely in the aquatic environment, sulfosulfuron is not expected to have adverse effects on the growth of these species. This study has also demonstrated that G maxima, L major and M spicatum grown in small outdoor tanks can be used successfully to assess the effects of crop-protection products on non-target aquatic flora.  相似文献   
106.
OBJECTIVE: To evaluate changes in serum concentrations of biochemical markers of bone metabolism and insulin-like growth factor I (IGF-I) associated with treadmill exercise in young horses. ANIMALS: 12 two-year-old Thoroughbred mares. PROCEDURE: During a 20-week study period, 6 horses were exercised on a treadmill 3 times a week (exercise group) and 6 horses received walking exercise 6 days a week (controls). Serum concentrations or activity of biochemical markers and IGF-I were assessed biweekly. Bone mineral density and content of the first phalanx were measured by dual-energy X-ray absorbiometry (DEXA) on completion of the study. RESULTS: Compared with values in controls, bone mineral density and content were higher and serum concentrations of osteocalcin (a marker of bone formation) and the carboxy-terminal telopeptide of type I collagen (a marker of bone resorption; ICTP) were lower in exercised horses. Serum concentration and activity of the bone formation markers carboxy-terminal propeptide of type I collagen and bone-specific alkaline phosphatase (BAP) were not different between the 2 groups. Serum IGF-I concentration was lower in the exercise group, compared with control values; there was a significant correlation between change in IGF-I values and changes in osteocalcin, ICTP, and BAP values at the end of the study. CONCLUSIONS AND CLINICAL RELEVANCE: Treadmill exercise over 20 weeks induced adaptive changes in bones of 2-year-old Thoroughbreds; training appears to increase bone mineral density, thereby enhancing mechanical strength of bone, but decreases bone turnover. Results indicated an association between changes in serum IGF-I concentration and bone cell activity in horses.  相似文献   
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The goal of this study was to give insight into the lesser known action of neutrophils in the course of bovine respiratory disease (BRD). Neutrophils are principally involved in resistance to infection but under certain conditions these cells participate in lung injury. TNFalpha and IL-8, primary cytokines which play an essential role in neutrophil activation during the inflammatory process, may lead not only to host defence reaction but also to destructive responses. Neutrophil constituents, such as elastase, myeloperoxidase (MPO), alkaline phosphatase (ALKP) and superoxide among others, contribute to tissue destruction. Also, 5-oxo-eicosatetraenoic acid (5-oxo-ETE), the potent activator of neutrophil chemotaxis and degranulation, can cause lung injury. This study revealed that neutrophils under the influence of TNFalpha exacerbated the release of elastase, MPO, ALKP and superoxide. IL-8, in turn, triggered those neutrophils which were isolated from heifers suffering from BRD, and released elastase, ALKP and 5-oxo-ETE, but not MPO or superoxide (O2(-)). The most pronounced degranulative response was observed in the acute form of BRD and a lesser response was seen in the chronic form. The secretory action of neutrophils varied not only depending on the form and phase of the disease but it also diminished successively during recovery.  相似文献   
110.
The middle-latency auditory-evoked potential (MLAEP) has been investigated as means of monitoring anesthesia in dogs. The goals of this study were to develop a technique to record MLAEPs in awake dogs and to determine the effects of sedation. The MLAEP was recorded in 12 dogs with and without sedation with acepromazine. Three needle electrodes were inserted SC. Click stimuli were delivered biaurally. Signal acquisition, averaging, and analysis were performed by software developed in-house. Signals were recorded for 128 milliseconds, and the responses to 1,024 stimuli were averaged. The waveforms from 10 recordings were averaged, and the amplitudes and latencies of peaks that could be consistently identified were measured. Data measured were compared by means of a paired 2-sided Student's t-test. Interpretable MLAEPs were recorded in 10 of the 12 dogs. Three peaks were consistently identified (Pa, Nb, and Pb). The latencies of these peaks were significantly (P = .032, .035, and .028, respectively) shorter in awake (mean +/- SD milliseconds) (Pa = 18.85 +/- 1.36, Nb = 30.50 +/- 3.55, and Pb = 47.70 +/- 5.53) than in sedated (Pa = 22.40 +/- 3.88, Nb = 35.75 +/- 6.77, and Pb = 55.30 +/- 10.55) dogs. The Pb amplitude was not significantly different (2.51 +/- 1.30 microV awake and 2.19 +/- 1.10 microV sedated). This study demonstrates that acepromazine sedation causes changes in MLAEP.  相似文献   
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