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91.
The endemic midwife toad of Mallorca (Alytes muletensis) is restricted to a small number of breeding populations in the mountainous northwest of the island. The decline of the species has been attributed to the impacts of introduced species such as the viperine snake (Natrix maura) and green frog (Rana perezi), and toads may be surviving only in areas that are suboptimal for these predators. The influence of landscape features (elevation, aspect and maximum slope) on the distribution of toads and associated predators was therefore investigated using GIS. The presence of toads was positively associated with steep slopes. At sites where they occurred with toads, the distribution of predators was negatively associated with elevation. Reproductive success within toad populations was strongly associated with the number of pools at each site, while reproductive success within individual pools was positively associated with elevation. These findings may be used to optimise the design and location of future reintroduction sites. 相似文献
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93.
水产种质资源地理信息系统是为了实现水产种质资源数据共享而开发的一个C/S模式共享平台。采用VB+MapX的二次开发方式,实现了空间数据与属性数据互相查询、数据管理以及报表输出等功能,另外还绘制了水产物种地理的分布图和水系分布图。 相似文献
94.
基于掌上电脑的农田信息快速采集与处理系统的研究 总被引:4,自引:9,他引:4
为了解决精细农业中空间信息及属性信息的快速获取与分析处理问题,提出并实现了基于掌上电脑的农田信息快速采集与实时处理系统。分析了具体实现系统功能的若干关键技术,如地理信息系统(GIS)、空间索引、Windows CE数据库技术、采样控制等因硬件环境的不同而产生的问题及相应的解决方案,又针对农场环境下的特殊性,提出并实现了一个面向对象的农场模型,以便于更好的描述农场环境及更方便的确定采样方案。作为一种实时系统,该系统可结合全球定位系统(GPS)和各种传感器,快速地测量和分析农田信息。应用该系统对两种GPS(Ag132与MAP330)进行了精度比较试验,快速而方便地证实了Ag132有更好的精确性与稳定性,更适于农业生产要求。试验的过程与结果也间接表明了该系统具有较好的实用性,为精细农业田间信息快速采集和处理设备的研制与开发奠定了基础。 相似文献
95.
“3S”技术在水土保持工作中的应用及展望 总被引:6,自引:0,他引:6
随着遥感(RS)、地理信息系统(GIS)与全球定位系统(GPS)三项技术的飞速发展,其在水土保持工作中的应用也得到不断加强。基于“3S”技术在水土保持工作中的应用,提出了“3S”技术的集成构想,最后对“3S”技术在水土保持中的应用做了相应的展望。 相似文献
96.
四川省南充市GIS土壤数据库系统设计的理论研究 总被引:12,自引:0,他引:12
在调查、收集大量土壤资料的基础上,以地理信息系统(G IS)为支撑、以试验对比分析作验证,对南充土壤数据库设计与应用进行了系统的研究,首次建立基于G IS的南充市土壤数据库系统,提出了建立市级土壤数据库系统的原则、方法、模式和土壤数据库系统推广应用新的技术路线。 相似文献
97.
98.
Spatial modeling of wind speed around windbreaks 总被引:3,自引:0,他引:3
This paper presents a model to integrate windbreak shelter effects into a Geographic Information System (GIS). The GIS procedure incorporates the 1999 version windbreak sub-model of the Wind Erosion Prediction System (WEPS). Windbreak shelter is modeled in terms of friction velocity reduction, which is a function of wind speed and direction, distance from the barrier, windbreak height, porosity, width, and orientation. A first application of the model was conducted at a study area with an extensive windbreak network in England (Thetford, East Anglia). Windbreak characteristics (windbreak type, height, width, porosity, and location) were recorded. Porosity was estimated from digitized B/W silhouettes. To evaluate the network effectiveness, a windbreak network shelter index (SI) was proposed in terms of average reduction of friction velocity over the area due to network shelter. The network was found to give good protection, but the windbreak distribution was not optimal in relation to the wind vector distribution. 相似文献
99.
Shengxiang Xu Xuezheng Shi Yongcun Zhao Dongsheng Yu Changsheng Li Manzhi Tan 《Geoderma》2011,166(1):206-213
China's rice paddies, accounting for 19% of the world's total, play an important role in soil carbon (C) sequestration. In order to reduce uncertainties from upscaling spatial processes of the DeNitrification-DeComposition (DNDC) model for improving the understanding of C sequestration under recommended management practices (RMPs), we parameterized the DNDC model with a 1:1,000,000 polygonal soil database to estimate how RMPs influence potential C sequestration of the top 30 cm of Chinese paddy soils and to identify which management practices have the greatest potential to increase soil organic carbon (SOC) in these soils. These practices include reduced/no tillage, increasing crop residue return, and increasing manure applications. A baseline and eleven RMP scenarios were projected from 2009 to 2080, including traditional and conservation tillage, increasing crop residue return, increasing manure incorporation, and the combination of these practices. The results indicated that C sequestration potential under modeled RMPs increased compared to the baseline scenario, and varied greatly from 29.2 to 847.7 Tg C towards the end of the study period with an average rate of 0.7 to 20.2 Tg C yr− 1. In general, increasing crop residue return was associated with higher rates of C sequestration when compared to increasing manure application or practicing conservation tillage. The simulations demonstrated that the most effective soil C sequestration strategy probably involves the implementation of a combination of RMPs, and that they vary by location. 相似文献
100.