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排序方式: 共有705条查询结果,搜索用时 15 毫秒
1.
Spyra Marcin Kleemann Janina Cetin Nuket Ipek Vázquez Navarrete Cesar Jesús Albert Christian Palacios-Agundez Igone Ametzaga-Arregi Ibone La Rosa Daniele Rozas-Vásquez Daniel Adem Esmail Blal Picchi Paolo Geneletti Davide König Hannes J. Koo HongMi Kopperoinen Leena Fürst Christine 《Landscape Ecology》2019,34(7):1715-1735
Landscape Ecology - Several case studies investigated the role of ecosystem services in participatory planning processes. However, no systematic study exists that cuts across a large number of... 相似文献
2.
Saeid Mobini Hamid Khazaei Thomas D. Warkentin Albert Vandenberg 《Plant Breeding》2020,139(6):1181-1189
The aim of this study was to reduce the length of the breeding cycle for faba bean by accelerating seed setting. We examined the mode and time of exogenous 6-benzylaminopurine (BAP) (cytokinin) application, and cold treatments and their combinations in two faba bean genotypes. Acropetal node number of pod and seed set and pollen viability were recorded during the experiments. Application of BAP improved pollen germination. The application of 10–5 M BAP 4 days after flowering increased seed set at the lower nodes. Cold treatment (8/4°C day/night for 2 days) after the onset of flowering induced the formation of more pods and faster pod set compared to the non-cold treatment. The time to first seed was significantly reduced, and pollen viability was increased in plants exposed to cold treatment. Increased pollen viability also showed a significant positive correlation with seed setting. The combinations of 10–5 BAP and cold treatment together had similar and independent effects. These results will accelerate plant breeding in faba bean by providing additional tools for reducing generation time. 相似文献
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Pierre-Olivier Godart Yannick Ruel Mileva Bertal Shanti Esmieu Vassiliki Gouni Albert Agoulon Hugues Gaillot 《Veterinary radiology & ultrasound》2023,64(2):173-182
Thoracic radiography is commonly used to assess the size of the heart and diagnose cardiac disease in ferrets. Several standardized radiographic heart size indicators have been introduced in this species and values in healthy ferrets have been reported. To date, none of these indicators has been tested in ferrets with cardiac disease. The aim of this prospective and retrospective, analytical observational design study was to assess the accuracy of the modified vertebral heart score (mVHS) and the cardio-vertebral ratio (CVR) in the radiographic detection of cardiomegaly in ferrets. Thoracic radiographs of 24 ferrets with confirmed heart diseases, 22 ferrets with non-cardiac diseases and normal-sized hearts on echocardiogram, and 24 healthy ferrets were mixed and examined by three independent and blinded radiologists who measured mVHS and CVR in right lateral (RL) and ventrodorsal (VD) radiographs. For all readers, ferrets with cardiac disease had significantly higher mVHS and CVR than ferrets without cardiac disease on echocardiography. Optimal cut-points for predicting cardiac enlargement were 6.25 vertebrae and 7.25 vertebrae for RL-mVHS and VD-mVHS, and 1.58 and 1.80 for RL-CVR and VD-CVR, respectively. Using these cut-points, the accuracy was good for indicators measured in RL radiographs (92.9% for RL-mVHS; 91.4% for RL-CVR) and moderate for indicators measured in VD radiographs (88.6% for VD-mVHS; 85.7% for VD-CVR). Findings supported the use of mVHS and CVR for evaluating the size of the heart in diseased ferrets, with caution in values interpretation when pericardial fat prevents precise delineation of the cardiac silhouette contour especially on VD radiographs. 相似文献
6.
Bruce R. Ellender Ryan J. Wasserman Albert Chakona Paul H. Skelton Olaf L.F. Weyl 《水产资源保护:海洋与淡水生态系统》2017,27(4):867-879
- Mediterranean climate regions are globally recognized as hotspots of endemism in fishes; however, these unique assemblages are increasingly threatened by human mediated impacts including water abstraction, damming and non‐native species introductions.
- The Cape Fold aquatic ecoregion (CFR) of South Africa supports an assemblage of range‐restricted endemic freshwater fishes, the majority of which are conservation priorities because they are under severe threat of extinction. Effective conservation and management are constrained by the lack of readily available information on this imperilled group of fishes because research efforts over the last century have been temporally disjointed and relatively uncoordinated.
- This review provides an exhaustive appraisal of published literature on the taxonomy, biogeography, life history, ecology and physiology of freshwater fishes in the CFR, and the human impacts that affect them. Its aim is to direct future research needs for effective management and conservation of this imperilled group.
- Only 103 peer‐reviewed articles on CFR fishes were recorded and the majority of available research is on taxonomy and biogeography (40.8%), followed by ecological investigations (22.3%), conservation (19.4%) and human impacts (17.5%).
- Despite a plethora of studies on taxonomy and biogeography, recent genetic evidence suggests that fish diversity in the CFR has been severely underestimated and requires urgent attention. Human impacts severely threaten the existence of many native CFR fishes and require further study. Information on the biology and ecology of CFR fishes is limited to studies on selected species; of particular note is the lack of physiological information which is particularly pertinent given projected climate change scenarios.
7.
Stéphanie Houle Kevin K Schrader Nathalie R Le François Yves Comeau Mourad Kharoune Steven T Summerfelt Arianne Savoie Grant W Vandenberg 《Aquaculture Research》2011,42(3):360-365
The ‘earthy’ and ‘muddy’ off‐flavours in pond‐reared fish are due to the presence of geosmin or 2‐methylisoborneol in the flesh of the fish. Similar off‐flavours have been reported in fish raised in recirculating aquaculture systems (RAS); however, little information is available regarding the cause of these off‐flavours. Our hypothesis was that earthy and muddy off‐flavour compounds, found previously in pond‐raised fish, are also responsible for off‐flavours in fish raised in RAS. In this preliminary study, we examined water, biofilms in RAS and fillets from cultured arctic charr known to have off‐flavours and requiring depuration using instrumental [solid‐phase microextraction procedure and gas chromatograph‐mass spectrometry (GC‐MS)] and human sensory analyses. Geosmin was present in the samples taken from the biofilter and on the side walls of the tanks. Two‐methylisoborneol was only found in low levels in the samples. The GC‐MS results indicated the presence of geosmin in the fillets (705 ng kg?1), but lower levels were found in the water (30.5 ng L?1). Sensory analyses also detected an earthy flavour (i.e., geosmin presence) in the fillets, and, therefore, it appears that geosmin is the main compound responsible for the off‐flavour in RAS. Further studies are being performed to identify the microorganisms responsible for geosmin production in RAS. 相似文献
8.
Effect of Density at Harvest on the Growth Performance and Profitability of Hatchery‐reared Spotted Rose Snapper,Lutjanus guttatus,Cultured in Floating Net Cages 下载免费PDF全文
Carlos Humberto Hernández Crisantema Hernández Francisco Javier Martínez‐Cordero Nicolás Castañeda‐Lomas Guillermo Rodríguez‐Domínguez Albert G. J. Tacon Eugenio Alberto Aragón‐Noriega 《Journal of the World Aquaculture Society》2016,47(1):51-60
This study evaluated the effect of the density at harvest on the performance and profitability of hatchery‐reared spotted rose snapper cultured in cages. The fish were stocked at harvest densities of 15, 20, and 22 kg/m3 in cages of 222 and 286 m3. More than 39,000 snapper fingerlings with an initial weight of 14 g were stocked. The fish were fed an extruded diet and cultured over a 360 d period. The thermal growth coefficient ranged from 0.04 to 0.05 and survival was 95% for all treatments, with the highest final weight (436.8 g) observed for fish reared at a density of 20 kg/m3. The allometric value b indicated that hatchery‐raised, cage‐cultured snapper were heavier than their wild counterparts. The major costs were feed (ranging from 44.7–45.9%), labor (22.4–32.6%), and seed costs (20.2–26.1%). The total production cost ranged from US$ 6.5 to US$ 7.5/kg. The baseline scenario was not economically feasible. However, a 10% increase in the sales price resulted in increases in the internal rate of return (183%) and net present value (US$ 97,628.9). These results suggest that L. guttatus has the potential for commercial production in cages. 相似文献
9.
Albert Weiss 《Irrigation Science》1983,4(4):267-275
Summary The Pruitt and Doorenbos version of the Penman equation developed from information given in Appendix II of FAO Irrigation and Drainage Paper No. 24 is calculated mainly from tables and is based on measurements made over a grass surface. Procedures are presented here to quantify these relationships, such as the calculation of net radiation, and to extend this approach to measurements made over alfalfa (Medicago sativa, L.). The latter was achieved by using a wind function that takes into account the height of the alfalfa and the use of mean rather than maximum relative humidity to calculate the correction factor used to take into account day and night weather conditions on calculated reference crop evapotranspiration. Using the above procedures, calculated values of evapotranspiration overestimated measured values from alfalfa by 13%. From data collected with an automated weather station near Broadwater, Nebraska, a much better agreement was obtained between these general procedures and a Penman equation with a locally derived- wind function. With greater utilization of low cost, automated weather stations for agricultural use, the procedures given for calculating reference crop evapotranspiration can easily be implemented in irrigation scheduling programs.Published as paper no. 6865, Journal Series, Nebraska Agricultural Experiment Station 相似文献
10.
Dimensional analysis in surface irrigation 总被引:1,自引:0,他引:1
The surface-irrigation design process requires multiple analyses of surface irrigations to test tentative values of design parameters in the search for an optimum. Preparation of general design charts can aid the design process if the users' test cases fall within the scope of the charts. The large number of independent variables in surface irrigation preclude the generation of charts covering the practical range of all independent variables, when these are in dimensioned form. Dimensionless formulations allow significant reductions in the amount of data generated and presented, without loss of generality. Relationships pertinent to surface-irrigation analyses and design are reviewed in dimensionless terms. Dimensionless forms are developed primarily from an examination of the equations governing surface-irrigation phenomena. Additionally, dimensionless forms are derived from a study of the dimensions of the pertinent variables, without recourse to the governing equations. The Buckingham Pi Theorem is derived in the context of surface irrigation. Different choices for reference variables, leading to different meanings for the resulting dimensionless parameters, have advantages and disadvantages for analysis and design of surface irrigation systems. The different systems developed in the past for border irrigation are reviewed and their consequences noted; new systems with potential for future studies are suggested. Particular attention is devoted to those dimensionless representations useful in design. 相似文献