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71.
综述了检测布氏杆菌病的新老方法。布氏杆菌病(Brucellosis)在全球引起巨大的经济损失,对人危害严重,基因苗即将为其防制提供保障。认为,细菌学检验和凝集试验测将淘汰;沉淀试验和补体结合试验不理想;放射免疫试验不能广泛运用;变态反应主要用于绵羊,也用于山羊的筛检,不作山羊个体的诊断依据。竞争酶联免疫吸附试验尚无诊断标准。间接酶联免疫吸附试验是一种先进、快速、可靠的新方法,但不能区别疫苗抗体与致病株抗体。PCR可检1pg的布氏杆菌DNA,应用细菌DNA检测是最可靠的方法。最近建立的荧光探针分析可在野外快速准确地诊断,可用于家畜和野生动物的检测。  相似文献   
72.
2004年兰州商学院小麦研究所引进国际冬小麦改良项目(IWWIP)半干旱地和水地兼性及冬小麦优良品系产量试验(8THEYT-SA,2004—2005和9THEYT-IRR,2004—2005)两套。每套试验实际参试品种(系)20个。试验结果表明,旱地试验中9906、9914、9916、9920和9921等5份材料在生产上有直接利用价值。水地试验中9806和9825等2份材料虽然产量低于对照,但与对照的产量差异不显著,可以考虑在生产上直接利用。试验中对在不同方面(抗锈性、抗旱性、丰产性和品质等)表现突出的材料,应扬长避短进行研究利用。  相似文献   
73.
针对高等农林院校学生高级语言程序设计水平不同,实施分级分层次教学可以较好地实现以人为本,以学生为主体的现代教学理念,提高高级语言程序设计课程教学质量,更好地满足农林专业人才的培养和社会需求。农林院校高级语言程序设计课程分级教学需要解决师资素质、教学成本、教学管理和学生心理等主要问题,需要强化以人为本的教学理念,提升师资队伍教学水平;科学选择或编写教材,认真规划设计教学内容;增加教学软硬件等设施投入,提高现代化教学管理水平;增强教师人文关怀意识,强化学生身心健康水平。  相似文献   
74.
郑莺 《安徽农业科学》2015,43(32):104-106
介绍了在修复富营养化水体中具有重要地位的高等水生植物种类,综述了其在水体治理中的作用机制及高等水生植物修复技术的应用情况,提出了未来高等水生植物修复富营养化水体的研究方向.  相似文献   
75.
Around the world, especially in semi‐arid regions, millions of hectares of irrigated agricultural land are abandoned each year because of the adverse effects of irrigation, mainly secondary salinity and sodicity. Accurate information about the extent, magnitude, and spatial distribution of salinity and sodicity will help create sustainable development of agricultural resources. In Morocco, south of the Mediterranean region, the growth of the vegetation and potential yield are limited by the joint influence of high temperatures and water deficit. Consequently, the overuse of surface and groundwater, coupled with agricultural intensification, generates secondary soils salinity and sodicity. This research focuses on the potential and limits of the advance land imaging (EO‐1 ALI) sensor spectral bands for the discrimination of slight and moderate soil salinity and sodicity in the Tadla's irrigated agricultural perimeter, Morocco. To detect affected soils, empirical relationships (second‐order regression analysis) were calculated between the electrical conductivity (EC) and different spectral salinity indices. To achieve our goal, spectroradiometric measurements (350 to 2500 nm), field observation, and laboratory analysis (EC of a solution extracted from a water‐saturated soil), and soil reaction (pH) were used. The spectroradiometric data were acquired using the ASD (analytical spectral device) above 28 bare soil samples with various degrees of soil salinity and sodicity, as well as unaffected soils. All of the spectroradiometric data were resampled and convolved in the solar‐reflective spectral bands of EO‐1 ALI sensor. The results show that the SWIR region is a good indicator of and is more sensitive to different degrees of slight and moderate soil salinity and sodicity. In general, relatively high salinity soils show higher spectral signatures than do sodic soils and unaffected soils. Also, strongly sodic soils present higher spectral responses than moderately sodic soils. However, in spite of the improvement of EO‐1 ALI spectral bands by comparison to Landsat‐ETM+, this research shows the weakness of multispectral systems for the discrimination of slight and moderate soil salinity and sodicity. Although remote sensing offers good potential for mapping strongly saline soils (dry surface crust), slight and moderately saline and sodic soils are not easily identified, because the optical properties of the soil surfaces (color, brightness, roughness, etc.) could mask the salinity and sodicity effects. Consequently, their spatial distribution will probably be underestimated. According to the laboratory results, the proposed Soils Salinity and Sodicity Indices (SSSI) using EO‐1 ALI 9 and 10 spectral bands offers the most significant correlation (52.91%) with the ground reference (EC). They could help to predict different spatial distribution classes of slight and moderate saline and sodic soils using EO‐1 ALI imagery data.  相似文献   
76.
AIM:To explore the effect of advanced glycosylation end products (AGEs) on the function of human adipose-derived stem cells (hADSCs) in promoting wound healing. METHODS:hADSCs were isolated by conventional method in vitro and divided into control bovine serum albumin (BSA) group, low-dose AGE-BSA group and high-dose AGE-BSA group. The proliferation and migration of hADSCs with different treatments were determined by WST-8 assay and Transwell assay, respectively. In addition, the expression of vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and insulin-like growth factor-1(IGF-1) at mRNA and protein levels was determined by real-time PCR and ELISA analysis. RESULTS:Compared with control group, the proliferation and migration abilities were significantly inhibited in the hADSCs of AGE-BSA group. The mRNA expression of VEGF, HGF and IGF-1 in AGE-BSA group was obviously lower than that in control group. The contents of VEGF, HGF and IGF-1 in hADSCs-conditioned me-dium in AGE-BSA group were also obviously lower than those in control group. CONCLUSION:AGEs alter the intrinsic properties of hADSCs and impair their functions in promoting wound healing, thus affecting the therapeutic potential of hADSCs in the treatment of diabetic ulcers.  相似文献   
77.
近年来,尽管我国乳业在上下游取得了巨大的成就,但是乳业发展仍然存在较为突出的问题。澳大利亚乳业是仅次于小麦和肉牛的第三大农业产业,其得天独厚的地理和气候条件,使其以放牧饲养为主,因此,生产成本较低。优良的牧场、科学的饲养管理、先进的育种技术和乳制品加工工艺,使其在国际乳品市场上具有较强的竞争力。笔者在澳大利亚工作期间,考察学习了澳大利亚乳业发展状况,其高效优质的生产经营模式、先进的研发体系和合理分配利益的合作社模式都值得我们借鉴学习。  相似文献   
78.
Rui WANG 《干旱区科学》2017,9(6):850-864
Detecting near-surface soil freeze-thaw cycles in high-altitude cold regions is important for understanding the Earth's surface system, but such studies are rare. In this study, we detected the spatial-temporal variations in near-surface soil freeze-thaw cycles in the source region of the Yellow River(SRYR) during the period 2002–2011 based on data from the Advanced Microwave Scanning Radiometer for the Earth Observing System(AMSR-E). Moreover, the trends of onset dates and durations of the soil freeze-thaw cycles under different stages were also analyzed. Results showed that the thresholds of daytime and nighttime brightness temperatures of the freeze-thaw algorithm for the SRYR were 257.59 and 261.28 K, respectively. At the spatial scale, the daily frozen surface(DFS) area and the daily surface freeze-thaw cycle surface(DFTS) area decreased by 0.08% and 0.25%, respectively, and the daily thawed surface(DTS) area increased by 0.36%. At the temporal scale, the dates of the onset of thawing and complete thawing advanced by 3.10(±1.4) and 2.46(±1.4) days, respectively; and the dates of the onset of freezing and complete freezing were delayed by 0.9(±1.4) and 1.6(±1.1) days, respectively. The duration of thawing increased by 0.72(±0.21) day/a and the duration of freezing decreased by 0.52(±0.26) day/a. In conclusion, increases in the annual minimum temperature and winter air temperature are the main factors for the advanced thawing and delayed freezing and for the increase in the duration of thawing and the decrease in the duration of freezing in the SRYR.  相似文献   
79.
基于双时相ASAR影像的土壤湿度反演研究   总被引:2,自引:1,他引:1  
地表粗糙度和湿度是影响裸地后向散射系数的重要因素,为了探求ENVISAT-ASAR 数据监测土壤湿度在国内的应用,该文以ASAR影像数据为基础,利用ZSribi-Dechambre(2002)经验模型研究了中国科学院南皮农业生态试验站附近一裸地的表面粗糙度和地表湿度.对雷达入射角进行归一化处理使之满足模型需求,反演结果表明该区地表粗糙度主要分布0.05~0.50 cm之间,土壤体积含水率大多分布存10%~34%之间,局部区域由于一些积水沟渠,使得土壤体积含水率较高,这与调查的实际情况相符合.反演的土壤湿度用地面实测值验证,结果发现模拟值和实测值具有较好的一致性,其RMSE误差为3.7%.该文介绍了在没有地表先验知识的情况下,利用扣除掉土壤粗糙度影响的后向散射反演模型获取土壤湿度的方法.该法仅需要两景相邻近时相并且不同入射角的HH同极化雷达影像,根据其后向散射系数的差值△"'即σ°可估算出粗糙度和土壤湿度参数,从而方便快捷地监测局部区域的土壤湿度状况.  相似文献   
80.
有机废气的危害及治理技术   总被引:9,自引:0,他引:9  
阐述了有机废气的来源及对人体的危害,介绍了几种常用的处理方法。  相似文献   
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