全文获取类型
收费全文 | 102篇 |
免费 | 2篇 |
国内免费 | 2篇 |
专业分类
林业 | 8篇 |
农学 | 6篇 |
基础科学 | 4篇 |
7篇 | |
综合类 | 49篇 |
农作物 | 7篇 |
水产渔业 | 2篇 |
畜牧兽医 | 10篇 |
园艺 | 12篇 |
植物保护 | 1篇 |
出版年
2023年 | 1篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 6篇 |
2014年 | 10篇 |
2013年 | 6篇 |
2012年 | 9篇 |
2011年 | 7篇 |
2010年 | 8篇 |
2009年 | 8篇 |
2008年 | 6篇 |
2007年 | 4篇 |
2006年 | 10篇 |
2005年 | 4篇 |
2004年 | 1篇 |
2003年 | 4篇 |
2002年 | 1篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1994年 | 1篇 |
排序方式: 共有106条查询结果,搜索用时 31 毫秒
11.
12.
13.
陈作新 《农业图书情报学刊》2012,24(4):52-55
提出的加密方案是AES算法在数字图书馆中的应用和改进。改进的新算法采用Logistic映射初值作为种子密钥生成混沌序列,对该序列进行域值量化得到二进制密钥流,对其分组作为AES算法的初始密钥,实现了一次一密;通过用动态密码对明文修补,实现密文与明文的长度相同;通过减少加密轮次,降低其时间复杂度,从而使其在数字图书馆数据加密系统中的应用可行。计算机仿真结果验证了该算法的正确性以及密文对密钥的高度敏感性。 相似文献
14.
15.
16.
Ginger is considered by many people to be the outstanding member among 1400 other species in the family Zingiberaceae. Not only it is a valuable spice used by cooks throughout the world to impart unique flavour to their dishes but it also has a long track record in some Chinese and Indian cultures for treating common human ailments such as colds and headaches. Ginger has recently attracted considerable attention for its anti-inflammatory, antibacterial and antifungal properties. However, ginger as a crop is also susceptible to at least 24 different plant pathogens, including viruses, bacteria, fungi and nematodes. Of these, Pythium spp. (within the kingdom Stramenopila, phyllum Oomycota) are of most concern because various species can cause rotting and yield loss on ginger at any of the growth stages including during postharvest storage. Pythium gracile was the first species in the genus to be reported as a ginger pathogen, causing Pythium soft rot disease in India in 1907. Thereafter, numerous other Pythium spp. have been recorded from ginger growing regions throughout the world. Today, 15 Pythium species have been implicated as pathogens of the soft rot disease. Because accurate identification of a pathogen is the cornerstone of effective disease management programs, this review will focus on how to detect, identify and control Pythium spp. in general, with special emphasis on Pythium spp. associated with soft rot on ginger. 相似文献
17.
A long history of human presence in the Alps has made studies of natural forest structure, composition, and disturbance processes difficult. In the Slovenian Alps, we identified a mixed European beech (Fagus sylvatica L.)-silver fir (Abies alba Mill.)-Norway spruce (Picea abies (L.) Karst.) stand with old-growth characteristics that escaped past cutting. We reconstructed the dynamics of the stand using a combination of stand and age structure analyses, dendroecological evidence of past canopy disturbance, and historical evidence of past human activities. The disturbance reconstruction revealed a stand-scale disturbance in the 1850s. Based on the presence of pit-and-mound topography throughout much of the stand and the absence of logging activities found in historical records, we assume this event was caused by strong winds. The current structure and composition of the stand are largely a result of this event. Post-disturbance forest development was dominated by the release of shade tolerant regeneration, especially F. sylvatica. The windthrow also created appropriate conditions (i.e. increased light and exposed mineral soil) for recruitment of less shade tolerant species, including larch (Larix decidua Mill.) and maple (Acer pseudoplatanus L.). The results suggest that periodic, intermediate severity wind disturbances, similar to the event documented here, may have had an important influence on pre-settlement forest dynamics in mixed mountain forests of the Alps, and add to the limited available information regarding the historic range of natural variability of disturbance processes. This information may be useful for forest management that attempts to emulate natural processes. 相似文献
18.
19.
20.