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71.
A 60-day feeding experiment was conducted to investigate the influence of dietary omega-3 long-chain polyunsaturated fatty acids(n-3 LC-PUFA) on growth, nutritional composition and immune function of marine fish Sebastiscus marmoratus. Five diets containing 3.6, 10.2, 18.2, 26.5, or 37.0 g/kg n-3 LC-PUFA were prepared. The results reveal significant influences of dietary n-3 LC-PUFA on the final weight, weight gain, specific growth rate, feed conversion ratio, and condition factor. As dietary n-3 LCPUFA increased, weight gain and specific growth rate increased and were significantly higher in groups fed 18.2, 26.5 and 37.0 g/kg than in groups fed 3.6 and 10.2 g/kg( P 0.05); there was no significant difference between groups fed 18.2, 26.5, or 37.0 g/kg( P 0.05). With increasing dietary n-3 LC-PUFA, eicosapentaenoic acid and docosahexenoic acid content in muscle and liver increased significantly, immunoglobulin class M content gradually increased from 9.1 to 14.8 μg/L, and lysozyme activity content increased from 1355 to 2268 U/mL. Broken line model analysis according to weight gain indicated that a dietary n-3 LC-PUFA level of 18.2 g/kg is essential for normal growth at a fat level of 125 g/kg. Therefore, appropriate dietary n-3 LC-PUFA not only promote growth and improve the n-3 LC-PUFA content, but also enhance immune function in S. marmoratus.  相似文献   
72.
The effect of a potential probiotic on the growth performance and immune response of sea cucumber(Apostichopus japonicus) was investigated. Bacillus baekryungensis YD13 isolated from sea cucumber culturing ponds was added to sea cucumber basal feed as a probiotic in different doses(0, the control; 1×10^4(YD134), 1×10^6(YD136) and 1×10^8(YD138) CFU g-1 of diet), and administered orally to A. japonicus(initial mean wet weight 5.44 g ± 0.17 g). The sea cucumbers were fed in 20 aquaria, 5 each treatment, for 60 d. At the end of growth trial, 20 sea cucumbers from each treatment were challenged with Vibrio splendidus. A. japonicus in YD134 and YD136 exhibited significantly better growth performance than control(P 〈0.05). Five non-specific immune parameters including lysozyme, acid phosphatase, alkaline phosphatase, superoxide dismutase and catalase in coelomic fluid were measured to evaluate the immune response of A. japonicus to the probiotics. Results showed that all parameters were significantly improved when YD11 was supplemented in the dose of 1×10^6 CFU g^-1(P 〈0.05). The cumulative incidence and mortality after the Vibrio splendidus challenge decreased significantly in sea cucumbers of YD136. Accordingly, 1×10^6 CFU g^-1 of YD13 in diet was recommended for the growth promotion and immune enhancement of A. japonicus.  相似文献   
73.
利用国家气象信息中心2013年发布的逐日均一化气温资料,对沈阳站资料均一化处理前后平均气温和极端气温指数序列的线性趋势及其城市化影响偏差进行了比较评价。结果表明:1)资料均一化处理对日最高气温及其衍生的极端气温指数序列趋势估计的影响较弱,但对日最低气温及其衍生的极端气温指数序列趋势估计具有显著影响。2)经资料均一化处理后,平均气温序列中的城市化影响偏差有所增大,平均最低气温序列中的城市化影响偏差增大尤其明显;与冷事件有关的极端气温指数序列的城市化影响偏差数值有所减小,与暖事件有关的极端气温指数序列的城市化影响偏差数值有所增加。3)资料均一化处理有效纠正了因迁站等原因造成的地面气温观测记录中的非均一性,但却在很大程度上还原了城市站地面气温观测记录中的城市化影响偏差。  相似文献   
74.
The spider crab Maja brachydactyla is an important commercial species in Europe and supports intensive fisheries in the NE Atlantic. A field survey was performed to assess long‐term and consecutive interannual (2005–2010) variation of the biochemical composition of newly hatched larvae of M. brachydactyla. Larval biochemical profiles differed significantly among years, with pronounced differences being recorded in 2010. Differences among batches of newly hatched larvae were mainly explained by the contribution of triacylglycerols and, to a lesser degree, by protein and lipid content. The use of different nutrition indices is discussed. The biochemical composition of newly hatched larvae from M. brachydactyla was highly variable, even though surveyed broodstock was obtained from the same local population and was always sampled during the same season. The unpredictable biochemical profiles of newly hatched larvae may condition their survival and recruitment. This largely overlooked aspect of larval variability should be considered in future fisheries management strategies and captive production of marine organisms that still rely on wild seeds.  相似文献   
75.
连续降温对大菱鲆成鱼代谢机能的影响   总被引:2,自引:0,他引:2  
为了探寻连续降温对大菱鲆(Scophthalmus maximus)成鱼血清、肝脏及肌肉能量代谢等指标的影响,作者将大菱鲆从正常养殖水温18℃快速、连续降温至1℃,并在18℃、13℃、8℃、5℃、3℃和1℃共计6个温度点取血采样,分别测定血清中的总蛋白(TP)、白蛋白(ALB)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)、甘油三酯(TG)、总胆固醇(TC)、血糖(GLU)以及肝脏中的糖原和肌肉中的乳酸等指标。结果发现,随着温度降低,大菱鲆的血清TP浓度呈先下降后升高的趋势,各实验组与对照组无显著差异(P0.05),但在13℃和3℃之间出现显著性差异(P0.05);血清ALB浓度则呈现升高趋势,在3℃时显著高于1℃(P0.05);血清TC浓度呈现升高趋势,且3℃时显著高于18℃(P0.05);GLU浓度呈先降低后升高趋势,且8℃、5℃、3℃实验组浓度显著高于其余实验组(P0.05);尿素浓度呈先降低后升高再降低趋势,且8℃时显著高于1℃(P0.05);肝糖原浓度呈先降低后升高趋势,且8、5、3℃实验组浓度显著高于其余实验组(P0.05);肌肉中乳酸含量呈先升高后降低趋势,且5℃时显著高于18℃(P0.05);其余指标则无显著性差异(P0.05)。结果表明:当温度在18~8℃时,降温对大菱鲆体内代谢影响不大;当温度降到8~3℃时,大菱鲆体内开始出现应激反应;当温度继续降低至1℃时,大菱鲆体内的各种代谢基本处于停滞状态。综合分析各温度下的代谢指标得出结论,3~1℃温度区间与大菱鲆的生态冰温点比较接近,可以在此温度区间附近进一步进行无水保活的探索,在保证大菱鲆无水运输可行性的基础上优化经济成本。  相似文献   
76.
Remotely and accurately quantifying the canopy nitrogen status in crops is essential for regional studies of N budgets and N balances. In this study, we optimised three-band spectral algorithms to estimate the N status of winter wheat. This study extends previous work to optimise the band combinations further and identifies the optimised central bands and suitable bandwidths of the three-band nitrogen planar domain index (NPDI) for estimating the aerial N uptake, N concentration and aboveground biomass. Analysis of the influence of bandwidth change on the accuracy of estimating the canopy N status and aboveground biomass indicated that the suitable bandwidths for optimised central bands were 37 nm at 846 nm, 13 nm at 738 nm and 57 nm at 560 nm for assessing the aerial N uptake and were 37 nm at 958 nm, 21 nm at 696 nm and 73 nm at 578 nm for the assessment of the aerial N concentration and were 49 nm at 806 nm, 17 nm at 738 nm and 57 nm at 560 nm for the estimation of aboveground biomass. The optimised three-band NPDI could consistently and stably estimate the aerial N uptake and aboveground biomass of winter wheat in the vegetative stage and the aerial N concentration in the reproductive stage compared to the fixed band combinations. With suitable bandwidths, the broadband NPDI demonstrated excellent performance in estimating the aerial N concentration, N uptake and biomass. We conclude that the band-optimised algorithm represents a promising tool to measure the improved performance of the NPDI in estimating the aerial N uptake and biomass in the vegetative stage and the aerial N concentration in the reproductive stage, which will be useful for designing improved nitrogen diagnosis systems and for enhancing the applications of ground- and satellite-based sensors.  相似文献   
77.
This study integrated environmental variables together with high spectral resolution WorldView-2 imagery to detect and map Thaumastocoris peregrinus damage in Eucalypt plantation forests in KwaZulu-Natal, South Africa. The WorldView-2 bands, vegetation indices and environmental variables were entered separately into PLS regression models to predict T. peregrinus damage. The datasets were then integrated to test the collective strength in predicting T. peregrinus damage. Important variables were identified by variable importance (VIP) scores and were re-entered into a PLS regression model. The VIP model was then extrapolated to map the severity of damage and predicted T. peregrinus damage with an R2 value of 0.71 and a RMSE of 3.26% on an independent test dataset. The red edge and near-infrared bands of the WorldView-2 sensor together with the temperature dataset were identified as important variables in predicting T. peregrinus damage. The results indicate the potential of integrating WorldView-2 data and environmental variables to improve the mapping and monitoring of insect outbreaks in plantation forests. The result is critical for plantation health monitoring using a new sensor which contains important vegetation wavelengths.  相似文献   
78.
This study is an attempt of a semi-automatic geomorphological GIS analysis based on morphometric indices. In the study, 10-m-resolution Digital Elevation Models (DEMs) are used to assess the neotectonic signals regarding the recent topographic developments and to attach additional significance to active tectonics in the Bingöl basin area. The methodology incorporates the determination of the structural similarities of the faults in the basins using fractal concepts and the application of four morphometric indices (Stream Power Index (SP), Multi-resolution Index of Valley Bottom Flatness (MRVBF), Terrain Ruggedness Index (TRI) and Valley Width-to-Height Ratio (Vf)). In order to detect the deviation from spatial randomness of the applied indices, the weighted correlation coefficient Moran’s I is used and the results are interpreted at a confidence interval of 99%. The spatial distribution of integrated index values is evaluated with the tectonically active fault zones in order to determine the probable activity and the structural deformation in the basin.The applied methodology reveals that the fractal analysis of the fault lines and the spatial analysis of the morphometric indices proved to be effective tools in analyzing the tectonic influence of the fault system on the basin area. Within the basin area, a relatively lesser degree of tectonic activity is observed, in contrast with the high tectonic activity outside the basin.  相似文献   
79.
深海沉积物分类与命名的参数指标和主成分分析   总被引:1,自引:0,他引:1  
对于南海中部(118个表层沉积物样,水深82~4 420 m)、东部(106个表层沉积物样,水深700~4 508 m)海域的表层沉积物的粒度资料按小于200 m,200~2 000 m,大于2 000 m水深段对水深、平均粒径、黏土含量进行统计分析,结果表明从陆架到陆坡再到深海,平均粒径和黏土含量随水深增加呈非常有规律的变化;把大于2 000 m水深区域再细分为大于2 500 m,大于3 000 m,大于3 500 m,结果表明平均粒径和黏土含量随水深增加几乎无变化,在南海中部水深大于2 000 m海域平均粒径为3.39~3.54μm,黏土平均含量为54.91%~55.47%;在南海东部水深大于2 000 m海域平均粒径为3.25~3.37μm,黏土平均含量为53.91%~54.56%。研究表明2 000 m水深具有划分深海沉积物的指示意义。南海中部水深大于2 000 m海域黏土平均含量为55.19%,平均粒径为3.39μm;在南海东部水深大于2 000 m海域黏土平均含量为53.91%,平均粒径为3.37μm;在南海中部、东部水深大于2 000 m海域平均粒径均小于4μm,黏土平均含量均大于50%,表明深海沉积物粒度特征是平均粒径小于4μm和黏土平均含量大于50%。黏土含量是非生物组分的代表和划分深海沉积物类型的一个独立参数,钙质生物和硅质生物组分是另外两个独立参数。南海东部海域表层沉积物中55种元素总含量为47.50%,硅、铝、钛、钠、钾、磷、钙、镁、铁、锰十种主元素含量为47.03%,其他45种元素含量为0.47%,虽然沉积物来源复杂、成因不同,但沉积物化学主成分并不复杂,主要由前10种主元素和氧元素组成。沉积物主元素铝、钙、硅分别富集于黏土、钙质沉积、硅质沉积中。通过建立沉积物生源组分与碳酸钙、三氧化二铝、二氧化硅的量化关系,可把碳酸钙、生物二氧化硅作为钙质生物和硅质生物的两个替代参数。  相似文献   
80.
A comprehensive framework for the assessment of water and salt balance for large catchments affected by dryland salinity is applied to the Boorowa River catchment (1550 km2), located in south‐eastern Australia. The framework comprised two models, each focusing on a different aspect and operating on a different scale. A quasi‐physical semi‐distributed model CATSALT was used to estimate runoff and salt fluxes from different source areas within the catchment. The effects of land use, climate, topography, soils and geology are included. A groundwater model FLOWTUBE was used to estimate the long‐term effects of land‐use change on groundwater discharge. Unlike conventional salinity studies that focus on groundwater alone, this study makes use of a new approach to explore surface and groundwater interactions with salt stores and the stream. Land‐use change scenarios based on increased perennial pasture and tree‐cover content of the vegetation, aimed at high leakage and saline discharge areas, are investigated. Likely downstream impacts of the reduction in flow and salt export are estimated. The water balance model was able to simulate both the daily observed stream flow and salt load at the catchment outlet for high and low flow conditions satisfactorily. Mean leakage rate of about 23·2 mm year?1 under current land use for the Boorowa catchment was estimated. The corresponding mean runoff and salt export from the catchment were 89 382 ML year?1 and 38 938 t year?1, respectively. Investigation of various land‐use change scenarios indicates that changing annual pastures and cropping areas to perennial pastures is not likely to result in substantial improvement of water quality in the Boorowa River. A land‐use change of about 20% tree‐cover, specifically targeting high recharge and the saline discharge areas, would be needed to decrease stream salinity by 150 µS cm?1 from its current level. Stream salinity reductions of about 20 µS cm?1 in the main Lachlan River downstream of the confluence of the Boorowa River is predicted. The FLOWTUBE modelling within the Boorowa River catchment indicated that discharge areas under increased recharge conditions could re‐equilibrate in around 20 years for the catchment, and around 15 years for individual hillslopes. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   
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