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71.
不同耕作方式对水稻经济性状的影响   总被引:1,自引:1,他引:0  
采用稻草还田免耕直播、稻草还田翻耕直播、非稻草还田免耕直播和非稻草还田翻耕直播4种耕作方式,探讨其对水稻经济性状的影响.结果表明,水稻免耕直播比翻耕直播能极显著提高结实率,显著增加穗粒数和着粒密度.从而显著提高水稻产量.稻草还田比非稻草还田也能显著提高水稻的结实率.但两者对水稻有效穗、株高、穗长、千粒重等性状没有影响.  相似文献   
72.
钱彬 《湖南农机》2008,(4):146-147
本文分析了驷马山引江水道切岭滑坡产生的主要原因,提出几种治理滑坡措施,取得了良好的滑坡治理效果,以供借鉴参考。  相似文献   
73.
辽宁朝阳清风岭省级自然保护区是重要的动物栖息地。通过对保护区动物多样性进行调查,分析保护区内两栖爬行动物、鸟类、兽类、鱼类的资源价值、区系成分与分布特点,阐述动物栖息地保护的意义,以期为清风岭保护区管护工作提供参考。  相似文献   
74.
为了研究原始热带雨林鹦歌岭土壤放线菌(Streptomyces sp.)YG-7的次生代谢产物及其α-葡萄糖苷酶抑制活性,采用多种柱色谱方法对土壤放线菌YG-7的发酵产物进行分离纯化得到9个化合物,经过波谱数据分析分别鉴定为:(1) 2-acetamido-5-chlorobenzamide, (2) cyclo (L-Pro-L-Leu), (3) 3,6-dibenzylidene-2,5-piperazinedione, (4) albonoursin, (5) (3Z,6S)-3-benzylidene-6-isobutylpiperazine-2,5-dione, (6) 3-hydroxy-2-methyl-4-pyrone, (7) isophthalic acid, (8) methyl 3-carbamoylbenzoate, (9) 2,3-dihydroxypropyl hexadecanoate. 其中,化合物1、7和8为新天然产物。活性测试结果表明化合物1、3~5和7~8对α-葡萄糖苷酶具有明显的抑制活性。  相似文献   
75.
I studied ground beetles in clear-cuts that represent six treatments: (i) manual plowing, (ii) plowing with a FAO-FAR FV 4088 cutter, (iii) plowing with an active single-moldboard U-162, (iv) plowing with a double moldboard forest plow LPz, (v) active piling of logging slash and (vi) no plowing or slash piles. The four plowing techniques differed in the depth and extent of their impact. Manual scarification of soil had the least effect on the species diversity, abundance and ecological traits of carabids. The larger the area and the deeper the plowing, the greater was the transformation of carabid assemblages. Piles of branches proved to be beneficial for the preservation of forest species, large species, mesophilic species and those with low dispersal power in clear-cut areas. In general, deep plowing was conducive to an increase in the proportion of individuals representing early succession species, whereas shallow plowing and especially manual scarification favored late succession species. The results suggest that for effective support of carabid beetles in a clear-cut area, only shallow plowing should be used. Piles of branches can be retained in a clear-cut area to provide a shelter supporting for forest fauna.  相似文献   
76.
[目的]探寻不同垄体覆盖方式对文山地区烤烟产质量的影响。[方法]以烤烟云烟87为材料,在大田条件设计4种不同垄体覆盖方式,研究对其烤烟生理特性、品质及产量的影响。[结果]与CK相比,烟草生长前期采用地膜覆盖,团棵期揭膜后覆盖玉米秸秆的处理方式可以提高上、中部叶总糖和还原糖含量,降低烟碱含量;改善烟叶主要化学成分的协调性,并且揭膜后覆盖秸秆(T_2处理)的烤后烟叶产量、均价、产值和中上等烟比例等的均优于其他处理。[结论]揭膜后覆盖秸秆为文山烤烟生产中较优的垄体覆盖方式。  相似文献   
77.
密度和施氮量对垄膜沟播春玉米干物质积累和产量的影响   总被引:3,自引:2,他引:1  
2012、2014年,以玉米杂交种沈禾201为试验材料,探讨垄膜沟播条件下种植密度和施氮量对植株干物质积累和产量的影响。两年试验结果表明,在抽雄期和灌浆期,玉米个体干物质积累量随密度的增加而减小,随施氮量的增加而增加;群体干物质积累量随密度和施氮量的增加而增加。种植密度和施氮量对玉米群体产量的综合影响呈开口向下的凸面体,2012年施氮量对群体产量的影响大于密度处理,2014年施氮量对群体产量的影响小于密度处理。通过对产量方程模型寻优,得到超过平均产量的管理方案,2012、2014年种植密度分别为69 727~84 818株/hm~2、39 880~51 778株/hm~2;施氮量分别为342~478 kg/hm~2、223~413 kg/hm~2。在试验区特定的生态环境条件下,适宜的种植密度和中高施氮量可显著增加垄膜沟播春玉米产量。  相似文献   
78.
The system of rice intensification (SRI) developed in Madagascar in the 1980s has been promoted as an integrated crop and resource management approach to rice-cultivation, especially for resource-limited smallholder farms. While advocates have claimed that SRI could boost rice yields with less external input, many criticisms have challenged its effectiveness regarding yields and applicability to larger-scale rice farming systems. In this study, we conducted a field survey and on-farm experiments to assess rice yield performance and key management practices on a few of the early SRI-practicing smallholder farms in the central highland of Madagascar.Rice grain yields at the survey fields were 9.9 t ha−1 maximum without using mineral fertilizer. Deep plowing to the depth of 25–30 cm as well as SRI practices have been conducted continuously since the early 1990s. In addition, an effective drainage system facilitated intensive water management at these high-yielding fields. On-farm experiments demonstrated some yield increases with no interaction for the examined SRI practices, though the effects were not great enough to explain the high yields at these fields. The soils of these high-yielding fields contained relatively large amounts of soil organic carbon (SOC) from the surface to the deep soil layers, and the soil mineralizable nitrogen was closely correlated with rice grain yields.The results indicated that the high yields at the fields of those who were early to adopt SRI were mainly due to the soil fertility associated with great nitrogen-supplying ability, rather than ‘synergetic effects’ of the SRI components. This high N-supplying ability of the soil and accumulated SOC from surface to deep soil layers were attributable to the long-term combined practices of extensive organic applications and deep plowing. Soil hydrology could be another key factor stimulating high rates of soil N-mineralization.These management practices were, however, only applied to the limited numbers of fields within less than 1.0 ha of total landholdings of these farmers due to the great demand in labor and organic resources and the difficulty in controlling irrigation water. Intensive weeding and widely spaced transplanting of young seedlings were also performed in the fields with irrigation and drainage systems sufficient to avoid yield losses from flooding and drought. Although extensive and long-term systematic research is further required to fully assess the benefits of this sort of intensive management as opposed to conventional methods, the preferential allocation of intensive management by the successful SRI-adopters might be the implication of its location-specificity and difficulty in scaling up even within the resource-limited smallholder farms.  相似文献   
79.
MZPH-820型单行马铃薯收获机设计   总被引:12,自引:0,他引:12  
针对现有小型马铃薯收获机作业过程中,行进阻力大、易于壅堵、伤薯率高,以及垄高适应性差等问题,设计了MZPH-820型单行马铃薯收获机.该机挖掘铲各铲片相互分离,间隙通畅;升运链导向撑链轮通过悬臂板支撑,承力通轴实现向上移动,作业时入土部件仅有挖掘铲及切土防漏圆盘,可有效防止秧茎缠绕及壅土;挖掘铲角度调节机构可实现挖掘铲与升运链导向撑链轮角度的同步调节,使挖掘铲铲面倾角在18°~30°内连续可调,便于不同土质条件下优化作业性能;导向限深轮及支撑行走轮二者高度的协调调整使得收获机能够满足100~400 mm垄高地块的作业要求,保证挖掘铲预设铲面倾角的实现,垄高适应性得到增强.宽行高垄地块的田间试验表明:MZPH-820型单行马铃薯收获机挖掘、输运顺畅,分离效果明显,纯小时生产率为0.10 hm2/h,伤薯率为0.3%,损失率为3.9%,性能达到技术规范要求.  相似文献   
80.
甘肃省埂坎资源利用区划研究   总被引:2,自引:0,他引:2  
依据甘肃省各县年降水量、年蒸发量、平均湿度、无霜期、≥10℃年活动积温、极限低温、平均低温7个变量进行聚类分析。全省划分的埂坎利用的7个类型区为:白银庆阳北耐旱灌草利用区、兰州白银南庆中灌草利用区、定西临夏灌草乔利用区、平凉庆阳南天水北乔灌草利用区、甘南灌草利用区、陇南天水南乔灌草利用区、河西灌溉乔灌草利用区,并提出了各区适生的经济植物种类。  相似文献   
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