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排序方式: 共有125条查询结果,搜索用时 15 毫秒
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MC Esteso MR Fernández-Santos AJ Soler V Montoro A Quintero-Moreno JJ Garde 《Reproduction in domestic animals》2006,41(3):241-246
Computer-automated sperm-head morphometry was used in this study to determine the effects of cryopreservation on red deer sperm-head morphometry. Epididymal sperm samples were collected from 40 mature stags and were divided. One portion was diluted at room temperature in a Tris-citrate egg yolk medium, containing 6% glycerol. A microscope slide was prepared from single extended sperm samples prior to freezing. The remainder of each sample was frozen in nitrogen vapours. After thawing, sperm smears were prepared as described above. All slides were air dried and stained with Hemacolor. The sperm-head dimensions for length, width, area, perimeter and shape factor (length/width), for a minimum of 135 spermatozoa were determined for each slide by means of the Sperm-Class Analyser (SCA). Firstly, our results show that cryopreservation substantially reduced (p < 0.001) sperm motility and plasma membrane and acrosome integrities. In addition, sperm heads were significantly smaller in cryopreserved spermatozoa than in the companion extended samples for area (32.05 microm2 vs 32.56 microm2; p < 0.05), length (8.46 microm vs 8.53 microm; p < 0.0001) and shape factor (1.833 vs 1.849; p < 0.0001) for all stags. These differences were found within 29 of 40 stags (75%) for at least three of the morphometric parameters. The individual variability (CV) of sperm head measurements from extended samples was negatively correlated (p < 0.005) with the per cent of change in sperm head measurements after cryopreservation for area (r = -0.465), width (r = -0.483) and perimeter (r = -0.375). Thus, the lower the sperm head variability in the extended samples, the greater the sperm change as a consequence of the cryopreservation. These results suggest that the variability (heterogeneity) in sperm head dimensions of individual stags may be a good indicator of sperm freezability. 相似文献
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Digitaria sanguinalis, Eleusine indica, Setaria glauca and S. viridis are troublesome summer annual weeds in turf. For taking rational decisions on the necessity for the level and type of weed management, it is important to know when weeds are ready to emerge (dormancy status) and also how long weed seeds can survive in the soil. Seeds of these four species were buried 4.0–4.5 cm deep in steel mesh net bags placed under permanent turf and periodically exhumed for 3 years to evaluate viability and determine the dormancy/non‐dormancy cycle. D. sanguinalis, S. glauca and S. viridis showed the typical dormancy cycle of summer annual species, and their seed viability declined completely after 3 years of burial. In contrast, E. indica demonstrated unusual behaviour, with long persistence and no dormancy. 相似文献
75.
S Villaverde‐Morcillo MC Esteso C Castaño A Toledano Díaz A López‐Sebastián JL Campo J Santiago‐Moreno 《Reproduction in domestic animals》2015,50(5):750-755
Computer‐assisted systems for the assessment of sperm morphometry (ASMA systems) have been used successfully with several mammalian species. Unfortunately, they have so far been of little use for assessing bird semen, a consequence of the filiform shape of avian spermatozoa. This study compares two staining techniques (Hemacolor® and aniline blue staining) for the morphometric analysis of rooster and red‐legged partridge spermatozoa as part of a computer‐assisted light microscopy method. For both species, Hemacolor® staining provided a significantly higher percentage of measurable cells (93.7 ± 11.7% in roosters and 71.9 ± 15.3% in red‐legged partridges). Hemacolor® also showed greater repeatability (lower coefficients of variation) for length and area in roosters' sperm and for width in the case of red‐legged partridge's sperm. In the roosters, the Hemacolor® technique returned significantly (p < 0.05) larger sperm head width and area values than did the aniline blue technique, while the latter resulted in greater sperm head length values (p < 0.05). In the red‐legged partridge, no differences were seen in the results for sperm head width and area provided by the two techniques, but aniline blue staining was associated with longer length measurements. In conclusion, the morphometric values recorded differed depending on the staining method and species. However, the Hemacolor® technique might be deemed the more appropriate for computerized sperm assessment systems as it provides larger percentages of measureable cells and shows greater repeatability. 相似文献
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Effect of the Interaction Between Cryoprotectant Concentration and Cryopreservation Method on Frozen/Thawed Chicken Sperm Variables 下载免费PDF全文
FMK Abouelezz C Castaño A Toledano‐Díaz MC Esteso A López‐Sebastián JL Campo J Santiago‐Moreno 《Reproduction in domestic animals》2015,50(1):135-141
This work examines the effect of the interaction between different concentrations of two cryoprotectants – glycerol (GLY) and dimethylacetamide (DMA) – and two methods of cryopreservation – pellets produced by plunging into liquid nitrogen and gradual in‐straw freezing – on frozen/thawed chicken sperm variables. Sperm was cryopreserved using: (i) 6% DMA, following the in‐straw and the pellet methods (ii) 11% GLY, following the in‐straw and the pellet methods; and (iii) 8% GLY in the in‐straw method and 3% DMA in the pellet method (i.e. reduced cryoprotectant concentrations). When 6% DMA was used as the cryoprotectant, no differences were seen between the in‐straw and pellet methods in terms of frozen/thawed sperm variables or fertility (10.8% and 12.8%, respectively). The viability and motility variables of the frozen/thawed sperm produced using the in‐straw method with 11% GLY were higher (p < 0.05) than those recorded for the sperm preserved using the same cryoprotectant and concentration in the pellet method. However, fertility was extremely low in both groups (2.1% and 4.2% for the in‐straw and pellet methods, respectively). Finally, the use of 8% GLY in the in‐straw method returned higher sperm viability, intact acrosome and motility values than the use of 3% DMA in the pellet method (p < 0.01). No differences were seen, however, in the fertility results obtained (28.8% and 25.0%, respectively). These results suggest that cryoprotectant concentrations can be reduced and still provide acceptable fertility rates. 相似文献
77.
Percolation of core melts at lower mantle conditions 总被引:1,自引:0,他引:1
Experiments at high pressure and temperature to determine the dihedral angle of core melts in lower mantle phases yielded a value of approximately 71 degrees for perovskite-dominated matrices. This angle, although greater than the 60 degrees required for completely efficient percolation, is considerably less than the angles observed in mineral matrices at upper mantle pressure-temperature conditions in experiments. In other words, molten iron alloy can flow much more easily in lower mantle mineralogies than in upper mantle mineralogies. Accordingly, although segregation of core material by melt percolation is probably not feasible in the upper mantle, core formation by percolation may be possible in the lower mantle. 相似文献
78.
In situ adherence of Vibrio spp. to cryosections of Atlantic salmon, Salmo salar L., tissue. 总被引:1,自引:1,他引:0
Pathogenic and presumed non-pathogenic bacteria isolated from fish were tested for their adhesion to cryosections from different mucosal surfaces of Atlantic salmon, Salmo salar L. Adhered bacteria were detected by immunohistochemistry. Mucus was stained and fixed with Alcian blue after incubation of bacteria. The majority of the bacteria tested, i.e. Vibrio anguillarum serotype O1 , Vibrio salmonicida , Vibrio viscosus, Flexibacter maritimus and 'gut vibrios', i.e. Vibrio iliopiscarius and intestinal isolates of V. salmonicida , all adhered to mucus on all salmon epithelial surfaces tested, including sections from the foregut, hindgut, pyloric caeca, gills and skin. In contrast, V. anguillarum serotype O2, including both serotypes O2a and O2b, did not adhere to mucus, but did adhere to all other components of the tissues. As a positive control for adhesion of bacteria on cryosections, Escherichia coli was bound to piglet ileal mucosal lining, and as a negative control for adhesion, Staphylococcus aureus was found not to bind to any of the tissues tested. The present study shows that adhesion to mucus was not restricted to pathogenic bacteria, and furthermore, that not all pathogenic bacteria studied adhered to mucus. Hence, on the basis of these findings, the present authors suggest that V. anguillarum O2 may have an invasion strategy which does not involve adhesion to mucus, and thus, differs from the other pathogenic bacteria in the present study, which all bound to salmon mucus. 相似文献
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Christopher T. Solomon Colin J. Dassow Carolyn M. Iwicki Olaf P. Jensen Stuart E. Jones Greg G. Sass Ashley Trudeau Brett T. van Poorten Dane Whittaker 《Fish and Fisheries》2020,21(5):973-991
Recreational fisheries are culturally and economically important around the world. Recent research emphasizes that understanding and managing these systems requires a social–ecological perspective. We systematically reviewed quantitative social–ecological models of marine and freshwater recreational fisheries to summarize their conceptualization of social, ecological, and social–ecological dynamics and identify research frontiers. From a candidate set of 626 studies published between 1975 and 2018, 49 met criteria for inclusion in our review. These studies, though diverse in terms of focal species and processes considered, were geographically limited to a few locations and ignored large regions of the globe where recreational fishing is important. There were also important gaps in the social and ecological processes that were included in published models. Reflecting on these patterns in the context of previous conceptual frameworks, we define five key frontiers for future work: 1) exploring the implications of social and behavioural processes like heuristics, social norms, and information sharing for angler decisions and fishery dynamics; 2) modelling governance with more realistic complexity; 3) incorporating ideas from resilience thinking and complex adaptive systems, including slow variables, destabilizing feedbacks, surprises and diversity; 4) considering key ideas in fisheries systems, including spatial and temporal effort dynamics, catch hyperstability, and stocking; and 5) thinking synthetically about the models that we use to describe social–ecological dynamics in recreational fisheries, via explicit comparisons and formal integration with data. Exploration of these frontiers, while remembering the distinction between model complexity and model usefulness, will improve our ability to understand and sustain recreational fisheries. 相似文献
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