排序方式: 共有51条查询结果,搜索用时 15 毫秒
1.
[目的]探讨陕西省"三农"融合发展路径,并揭示生态—社会—环境系统变迁对"三农"融合发展的影响,为实现建设"富裕陕西""和谐陕西"及"美丽陕西"的目标服务。[方法]通过实地调研与文献研究,分析生态—社会—环境系统变迁与"三农"融合发展的关联性及趋势。[结果]"三农"融合发展路径沿着消费结构→产业结构→职业结构→收入结构→阶层结构→社会结构的脉络依次展开。影响陕西省"三农"融合发展的压力在于"三农"割裂式发展形成相互牵制的循环圈,以及滞后于经济社会总进程的"三农"发展和生态保育;"三农"融合发展的潜力源自"三农"自身及变革中的生态—社会—环境系统;促使"三农"兼容和协调发展的5大动力分别是:国家作用、市场力量、组织角色、职业农民和生态环境。[结论]为了保证陕西省"三农"融合发展路径的顺畅,应从顶层设计、内涵发展和协同视角三方面,进一步健全与完善生态—社会—环境系统。 相似文献
2.
基于林分空间结构分析方法的土壤大孔隙空间结构研究 总被引:3,自引:0,他引:3
土壤大孔隙的形成和分布具有重要的生态学意义,但尚未有研究者利用生态学方法研究其空间结构。以三峡库区紫色砂岩区的3种典型土地利用类型下的土壤大孔隙为研究对象,将图像处理技术与林分空间结构分析方法相结合,从形态学和生态学角度量化分析土壤大孔隙的空间结构。结果表明:3种土地利用类型的土壤大孔隙形状、空间结构复杂程度高,空间分布格局随土壤深度的增加均呈聚集分布趋势,且深层土壤的大孔隙组成较表层单一,其中草地最明显,大孔隙发育程度均随土壤深度的增加而降低;3种土地利用类型的土壤优先流发育程度由大到小为:草地、果园、农地,同一土地利用类型不同孔径范围的大孔隙所形成的优先路径的连通性、导水性和发育程度由大到小依次为:草地孔径范围[5.0 mm,∞)、[2.5 mm,5.0 mm)、[1.0 mm,2.5 mm)、(0,1.0 mm),农地和果园孔径范围[1.0 mm,2.5 mm)、[2.5 mm,5.0 mm)、(0,1.0 mm)、[5.0 mm,∞);将林分空间结构分析方法与土壤大孔隙位置密度分布、大孔隙变异度和复杂度指标进行对比,并与以往研究土壤大孔隙空间结构的方法进行比较,所得结果相同,证明该方法可以用于土壤大孔隙空间结构的分析和研究。林分空间结构分析方法简单易行,从生态学的角度完善了大孔隙空间结构的分析,弥补了目前基于物理化学方法在大孔隙结构理论分析的不足,进一步揭示了土壤大孔隙空间结构形成和分布的原因。 相似文献
3.
三峡库区就业结构偏差的成因与加速城镇化进程的路径 总被引:1,自引:1,他引:0
本文基于1992年到2009年的数据,研究了三峡库区的就业结构偏差问题,发现三峡库区就业结构偏差呈扩大趋势,已严重影响了三峡库区农业产业结构调整和农业现代化步伐,并使库区农村长期处于贫困落后状态。从制度、政策和人口素质等方面,探讨了就业结构偏差大的原因。从优化库区城镇体系、统筹城镇基础设施建设、突破城镇发展体制和资金瓶颈等方面,提出了加速三峡库区城镇化进程的政策建议。 相似文献
4.
杨雪 《吉林农业科技学院学报》2011,(4):72-73
随着课改的深入,有效教学成了讨论的焦点,然而只要存在教学,教师作为教学工作的中心地位就不能动摇。美国教育家鲍里奇提出的"有效教师"的概念无疑为开拓教学方法改革提供了新的思路。本文旨在通过分析教师教学行为的"有效性",在教学准备上探索成为"有效教师"的新路径。 相似文献
5.
网络旅游产业链的构建及其实现途径分析 总被引:1,自引:0,他引:1
结合当前实际,简述了构建网络旅游产业链的构建准则,并在此基础上选择一定的构建模式,分析其实现途径。 相似文献
6.
Heath TJ 《Australian veterinary journal》2007,85(7):296-299
OBJECTIVE: To compare the career paths of veterinarians who had grown up on farms with animals with those of veterinarians from other backgrounds, during the first 15 years after they graduated. PROCEDURE: Questionnaires were completed by veterinary students in their first and fifth year, and after 1, 5, 10 and 15 years after they graduated. The most recent questionnaires were returned by 134 of 137 graduates, 20% of whom had grown up, or lived for at least two years, on farms where animals were a primary source of income. This paper includes findings from that questionnaire but also contains comparisons with previous ones. RESULTS: Fifteen years after they graduated, veterinarians who had grown up on farms with animals were more likely than those of other backgrounds to be living in centres with < 10,000 people (58% farm, 20% other), irrespective of the type of work they were doing. Although they were more likely to be doing no veterinary work (42% farm, 21% other), they were also more likely to be working in mixed practice (15% farm, 9% other) and with cattle and sheep generally (11% full time equivalent farm, 5% full time equivalent other). However, > 80% of those who had started their careers in mixed practice were no longer in mixed practice after 15 years. Veterinarians of farm origin who were in private practice were more likely to be sole or part owners (93% farm, 46% other) and less likely to be employees (7% farm, 54% other). CONCLUSIONS: In this study, veterinarians who had grown up on farms with animals seemed slightly more likely than those from other backgrounds to continue working in mixed practice and to work with cattle or sheep, although the numbers were small and the differences not significant. Whatever their background, the majority who started their careers in mixed practice left over the next few years, and by 15 years only 15% remained. 相似文献
7.
8.
9.
洞庭湖湿地的外来入侵植物研究 总被引:1,自引:1,他引:0
2007-2011年间通过对洞庭湖湿地大面积实地踏察,对外来植物的种类、分布、来源、生活型、入侵生境、引入途径以及危害程度进行了统计分析.研究表明,该湿地有外来入侵植物19科34属43种,以菊科和苋科植物最常见,分别有7种和6种.危害较大的有美洲杨树(Populus deltoides)、意大利杨(Populus euramevicana)、空心莲子草(Alternanthera philoxeroides)、野胡萝卜(Daucus carota)、积雪草(Centella asiatica)、凤眼莲(Eichhomia crassipes)、垂序商陆(Phytolacca A mericana)、五叶地锦(Phytolacca Americana)和大藻(Pistia stratiotes)等.外来入侵植物以草本植物为主,占总数的86%.入侵种主要分布于防洪大堤及路边,占总数的62.8%.外来入侵种主要来源于美洲,占55.8%.入侵途径主要是通过人类有意(48.8%)或无意引入(37.2%). 相似文献
10.