首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1894篇
  免费   134篇
  国内免费   110篇
测绘学   212篇
大气科学   22篇
地球物理   239篇
地质学   366篇
海洋学   71篇
天文学   2篇
综合类   166篇
自然地理   1060篇
  2024年   6篇
  2023年   15篇
  2022年   46篇
  2021年   86篇
  2020年   77篇
  2019年   74篇
  2018年   58篇
  2017年   91篇
  2016年   72篇
  2015年   70篇
  2014年   90篇
  2013年   138篇
  2012年   119篇
  2011年   122篇
  2010年   67篇
  2009年   112篇
  2008年   106篇
  2007年   108篇
  2006年   112篇
  2005年   110篇
  2004年   68篇
  2003年   86篇
  2002年   71篇
  2001年   53篇
  2000年   37篇
  1999年   34篇
  1998年   23篇
  1997年   20篇
  1996年   9篇
  1995年   13篇
  1994年   7篇
  1993年   7篇
  1992年   4篇
  1991年   1篇
  1990年   3篇
  1989年   1篇
  1988年   4篇
  1987年   4篇
  1986年   4篇
  1985年   3篇
  1984年   2篇
  1983年   2篇
  1982年   2篇
  1976年   1篇
排序方式: 共有2138条查询结果,搜索用时 772 毫秒
931.
932.
The global shift to small- and medium-scale irrigation is potentially compatible with high-agrobiodiversity production. A case study of the Cochabamba region in central Bolivia between 1990 and 2002 is designed to examine new interactions of irrigation with agrobiodiversity through change and continuity of landscape structures and functions. Irrigation change contributed to increased commercial potato and peach farming. Still persistent interactions of canal woodland habitat (landscape matrix including uncultivated or “wild” agrobiodiversity) with patches of cultivated agrobiodiversity helped ensure nutrient transfer and likelihood of gene flow. Farmers' field-level responses continued to include agrobiodiversity, especially multiple farmer varieties (FVs) of Andean maize. Capacities of social–ecological resilience in the period from 1990 to 2002 are estimated to have been moderate in anthropogenic canal woodlands (> 95 percent continued cover, albeit with reduced connectivity) and cultivated agrobiodiversity (viable with local loss of Andean potato FVs) and moderate-high in wild agrobiodiversity (viable with reduced capacity due to modified weed management). Indigenous “ethnodevelopment” applied to Andean community irrigation contributed positively to social–ecological resilience, albeit with significant limitations. Findings recommend that global change policies build emphasis on the interactions of water resource and agrobiodiversity management.  相似文献   
933.

Positioned on the northern edge of the Hispano homeland, the southern portion of the old Sangre de Cristo Land Grant (present-day Costilla County, Colorado) provides an interesting empirical study of cultural change. After economically displacing Spanish-American residents from villages throughout the homeland's core, incoming Anglos have adopted the region's rich Spanish culture as their own. On the homeland's periphery, however, the cultural traditions of Hispanos and Anglos have been, for the most part, at odds. Most resident Hispanos desire to maintain ties to their traditional past, while the younger generations embrace Anglo cultural norms. Considering the vital role it plays in the maintenance of culture, religion provides a window to the study area's modified cultural environment. In 1900 the population in this region was predominantly Catholic Hispano; by 1990 Protestant-dominated Anglos comprised a sizeable proportion of the population. Comparisons are made between traditional Hispano and Anglo-influenced religious landscapes. Changes in church affiliation, the distribution of active Penitente moradas, and the characteristics of community cemeteries demonstrate ongoing cultural change. Geographically isolated communities, where Anglo intrusion is limited, retain their strong Hispano cultural integrity.  相似文献   
934.
Produced over the past decade, monuments and museums dedicated to the Civil Rights movement of the 1950s and 1960s have desegregated America's memorial landscape. Tracing a broad arc across the US South, the material elements of this landscape — historic markers, monuments, parks, registered buildings, and museums — present a distinct challenge to representations of an elite, white American past. This challenge, however, is offered in a distinctly gendered manner, inasmuch as the role of women in organizing and leading the movement is obscured. Further, the historical narratives concretized at these sites are mediated by conventions associated with civil rights historiography and the tourism development industry. The result is a complex, sometimes ironic landscape. Via the narratives they embed and the crowds they attract, these landscapes are co-constitutive with contemporary politics of representing the past in the United States. This paper offers an overview of current memorial practices and representations of the Civil Rights movement found at the country's major memorial landscapes.  相似文献   
935.

Because the property tax is structurally tied to market values of dwellings through the assessment function, rapidly increasing market values may beget rapid increases in property taxes. Public awareness of this process was instrumental in California's 1978 passage of the Jarvis-Gann Amendment. Millage rates should be indexed to counterbalance changes in market values.  相似文献   
936.
This article analyses the creation and implications for cultural identity of a hybrid tourism landscape on Taiwan's Orchid Island (Lanyu). It particularly argues that Lanyu's native Tao people have begun to gain a somewhat stronger cultural identity and autonomy through this landscape. Orchid Island underwent rapid modernization within the past 60 years. The article not only shows how tourism was imposed by Taiwan's government, but also how the Tao have made greater use of tourism's landscape over time for their own purposes. Not without sociocultural problems and contradictions, Lanyu's tourism landscape has been polysemic enough to allow for gradually improving relationships between Taiwanese and Tao and for gradually increasing Tao participation in modernity on their own terms.  相似文献   
937.
938.
Black Rock     
  相似文献   
939.
近年来,古镇旅游发展迅猛.这一现象吸引了大批学者从不同角度对其进行了充分的研究,但关于古村镇文化景观变迁方面的研究不多,有必要弥补这一不足.利用文献分析、实地调研、遥感影像等研究方法,从文化学、历史学、地理学等角度深入探讨了周庄古镇的旅游景点的类型和分布,民居的功能和结构以及土地利用的总体特征和类型的变迁过程,指出周庄古镇文化景观的变迁受到旅游发展、经济发展、人口变动、政府干预、科技发展5种因素的影响.  相似文献   
940.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号