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161.
162.
Jinze Noordijk Katrien Delille Andr P. Schaffers Karl V. Sýkora 《Biological conservation》2009,142(10):2097-2103
The decline of flower-visiting insects is a threat to ecological processes and to the services these insects provide. Roadside verges in the Netherlands span approximately 80,000 km and are often covered with semi-natural grasslands. As such, they also provide a suitable habitat for many insects, but this has received little attention so far. We investigated the effects of different management treatments on flower-visiting insects. We studied flower visitation in a 3 years old experimental set-up with five mowing treatments each replicated five times. Management types were: no management and mowing once or twice per year with and without the removal of hay, representing common forms of management and neglect. During an entire growing season, both flowers (number of species and inflorescences) as well as insects (total abundance and actual flower visits) were investigated. Mowing twice per year with removal of hay showed highest values for all measured variables and this effect persisted throughout the growing season. The early summer cut proved to be very important for insect feeding opportunities, due to the re-flowering of plants later in the growing season. Flower abundance showed high correlations with both plant species richness and the number of insect visits. Although overall, mowing twice a year with hay removal was the most beneficial treatment for flower-visiting insects, these plots were entirely devoid of flowers for some period right after mowing, indicating that a rotational scheme might further promote insect diversity and abundance. 相似文献
163.
164.
35 个草坪草品种对禾谷缢管蚜抗性的研究 总被引:2,自引:0,他引:2
研究了禾本科7 个属35 个草坪草品种对禾谷缢管蚜〔Rhopalosiphum padi (L. ) 〕的抗性, 鉴定出高抗品种15 个, 中抗品种3 个, 低抗品种2 个。匍匐翦股颖( Agrostis stolonifera L. ) 和野牛草〔Buchloe dactyloides (Nutt. ) Engelm. 〕抗性最好, 均为免疫级。其次是狗牙根〔Cynodon dactylon (L. ) Pers. 〕, 6 份材料中, 有4 份属于免疫级。高羊茅( Festuca arundinacea Schreb. ) 在免疫至低抗间变化, 草地早熟禾( Poa pratensis L. ) 在高抗至中感间变化。结缕草( Zoysia japonica Steud. ) 为低感、中感水平。多年生黑麦草(Lolium perenne L. ) 抗性最差, 10 份材料均为高感。症状分析、虫口数量与受害程度关系分析初步表明,草坪草对禾谷缢管蚜的抗性包括抗生性和耐害性。 相似文献
165.
Habitat fragmentation strongly affects insect species diversity and community composition, but few studies have examined landscape
effects on long term development of insect communities. As mobile consumers, insects should be sensitive to both local plant
community and landscape context. We tested this prediction using sweep-net transects to sample insect communities for 8 years
at an experimentally fragmented old-field site in northeastern Kansas, USA. The site included habitat patches undergoing secondary
succession, surrounded by a low turf matrix. During the first 5 years, plant richness and cover were measured in patches.
Insect species richness, total density, and trophic diversity increased over time on all transects. Cover of woody plants
and perennial forbs increased each year, adding structural complexity to successional patches and potentially contributing
to increased insect diversity. Within years, insect richness was significantly greater on transects through large successional
patches (5000 m2) than on transects through fragmented arrays of 6 medium-sized (total area 1728 m2) or 15 small (480 m2) patches. However, plant cover did not differ among patch types and was uncorrelated with insect richness within years. Insect
richness was strongly correlated with insect density, but trophic and α diversities did not differ among patch types, indicating
that patch insect communities were subsets of a common species pool. We argue that differences in insect richness resulted
from landscape effects on the size of these subsets, not patch succession rates. Greater insect richness on large patches
can be explained as a community-level consequence of population responses to resource concentration. 相似文献
166.
国际鳞翅目昆虫基因组筑波会议与中国家蚕基因组 总被引:8,自引:2,他引:6
首届国际鳞翅目昆虫基因组研讨会于 2 0 0 2年 9月在日本召开 ,来自 12个国家的 12 0名科学家就鳞翅目昆虫基因组的研究现状进行了广泛的交流 ,并正式成立了鳞翅目昆虫基因组国际筹划指导委员会 ,初步决定在2 0 0 4年前完成家蚕这一鳞翅目的模式昆虫的全基因组测序。我国作为世界蚕丝业中心 ,有关家蚕基因组的研究应如何对应 ?值得业内人士深思。 相似文献
167.
168.
5种昆虫生长调节剂防治黄脊竹蝗(Ceracriskiangsu)1~2龄跳蝻的室内药效试验结果表明:灭幼脲3号、卡死克和抑太保对跳蝻的致死作用较大;灭幼脲3号增效粉剂有明显的速效作用 相似文献
169.
DPC对棉花生长发育及棉田主要昆虫的影响 总被引:5,自引:2,他引:3
大田试验结果表明:与不施用DPC处理相比,施用DPC处理的棉花株高和蕾铃脱落率均有所下降,其成铃数和产量分别提高10.00% ~10.04% 和7.46% ~8.13% ;棉田盲蝽象、棉铃虫和玉米螟的累计虫量分别下降18.90% 、38.89% 和40% ~50% ,盲蝽象和棉铃虫对蕾铃的为害率分别下降15.01% 和39.74% ~66.55% ;棉田天敌累计数量上升13.49% 。大田普查结果与上述结果相似。 相似文献
170.
本文以四川汉源县核桃为对象,开展核桃病虫害调查,获得以下主要结果:汉源县核桃有害生物共计30种,其中危害较为严重的虫害为云斑天牛、木橑尺蠖、黄刺蛾、桃蛀螟、核桃举肢蛾等,病害普遍发生的是核桃炭疽病、核桃黑斑病、核桃缩叶病,具有潜在危害性的较大的是核桃木腐病、核桃枝枯病、核桃溃疡病和星天牛、茶丽天牛等对核桃枝干危害的有害生物。调查发现核桃有害生物种类随着温度的变化呈现周期性变化。汉源县4月气温10~30°C时虫害开始危害植株,病害也开始侵染植株,并随温度升高,种类增多,危害加重。11月气温10~20°C时有害生物危害降低,开始越冬。核桃有害生物种类以及危害程度与其种植环境有关。四旁树核桃、核桃和玉米混合种植有害生物危害较核桃纯林严重,核桃柑橘混合种植时有害生物种类较核桃纯林种类多,这可能与混栽植物间有共同有害生物有关,有关机理将进一步研究。 相似文献