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   1406篇
  免费   147篇
  国内免费   155篇
测绘学   21篇
大气科学   209篇
地球物理   342篇
地质学   580篇
海洋学   258篇
天文学   4篇
综合类   51篇
自然地理   243篇
  2024年   8篇
  2023年   15篇
  2022年   34篇
  2021年   37篇
  2020年   41篇
  2019年   43篇
  2018年   15篇
  2017年   79篇
  2016年   60篇
  2015年   72篇
  2014年   76篇
  2013年   73篇
  2012年   41篇
  2011年   79篇
  2010年   52篇
  2009年   112篇
  2008年   108篇
  2007年   85篇
  2006年   90篇
  2005年   65篇
  2004年   57篇
  2003年   41篇
  2002年   57篇
  2001年   36篇
  2000年   49篇
  1999年   45篇
  1998年   40篇
  1997年   31篇
  1996年   34篇
  1995年   38篇
  1994年   15篇
  1993年   20篇
  1992年   15篇
  1991年   13篇
  1990年   7篇
  1989年   9篇
  1988年   3篇
  1987年   3篇
  1985年   3篇
  1984年   2篇
  1983年   1篇
  1982年   2篇
  1980年   1篇
  1976年   1篇
排序方式: 共有1708条查询结果,搜索用时 15 毫秒
151.
Exploring the environmental impact of dietary consumption has become increasingly important to understand the carbon-water-food nexus, vital to achieving UN sustainable development goals. However, the research on diet-based nexus assessment is still lacking. Here, we developed an Environmentally Extended Multi-Regional Input-Output (EE-MRIO) model with compiling a global MRIO table based on the latest Global Trade Analysis Project (GTAP) 10 database, where we specifically constructed a water withdrawal account and matched it to each economy at the sectoral level. The regional heterogeneity and synergy of carbon-water nexus affected by dietary patterns in nine countries was explored. The results show that: (1) Dietary consumption is the main use of water withdrawal for each country; Japan, the US, South Korea, and India have a high per capita dietary water footprint. Mainly due to consumption of processed rice, Japan has the highest per capita value of 488 M3/year, accounting for 63.4% of the total water footprint. (2) The total dietary carbon footprints in China, India, and the US are high, which is mainly caused by the high consumption of animal products (including dairy) either due to the large population (China, India) or animal-based diet (the US). Americans have the highest per capita dietary carbon footprint, reaching 755.4 kg/year, 2.76 times that of the global average. (3) Generally, imported/foreign footprints account for a greater share in dietary water and carbon footprints of developed countries with an animal-based diet. (4) In the nexus analysis, the US, Japan, and South Korea are key-nexus countries, vegetables, fruit and nuts, tobacco and beverages, and other food products are selected as key-nexus sectors with relatively high dietary water and carbon footprint. Furthermore, dietary consumption choices lead to different environmental impacts. It is particularly important to find a sustainable dietary route adapted to each country considering that heterogeneity and synergism exist in key-nexus sectors to achieve the relevant Sustainable Development Goals.  相似文献   
152.
This article proposes a fundamental methodological shift in the modelling of policy interventions for sustainability transitions in order to account for complexity (e.g. self-reinforcing mechanisms, such as technology lock-ins, arising from multi-agent interactions) and agent heterogeneity (e.g. differences in consumer and investment behaviour arising from income stratification). We first characterise the uncertainty faced by climate policy-makers and its implications for investment decision-makers. We then identify five shortcomings in the equilibrium and optimisation-based approaches most frequently used to inform sustainability policy: (i) their normative, optimisation-based nature, (ii) their unrealistic reliance on the full-rationality of agents, (iii) their inability to account for mutual influences among agents (multi-agent interactions) and capture related self-reinforcing (positive feedback) processes, (iv) their inability to represent multiple solutions and path-dependency, and (v) their inability to properly account for agent heterogeneity. The aim of this article is to introduce an alternative modelling approach based on complexity dynamics and agent heterogeneity, and explore its use in four key areas of sustainability policy, namely (1) technology adoption and diffusion, (2) macroeconomic impacts of low-carbon policies, (3) interactions between the socio-economic system and the natural environment, and (4) the anticipation of policy outcomes. The practical relevance of the proposed methodology is subsequently discussed by reference to four specific applications relating to each of the above areas: the diffusion of transport technology, the impact of low-carbon investment on income and employment, the management of cascading uncertainties, and the cross-sectoral impact of biofuels policies. In conclusion, the article calls for a fundamental methodological shift aligning the modelling of the socio-economic system with that of the climatic system, for a combined and realistic understanding of the impact of sustainability policies.  相似文献   
153.
春小麦单叶气孔行为及蒸腾作用的模拟   总被引:1,自引:0,他引:1  
郑海雷  黄子琛 《高原气象》1992,1(4):423-430
  相似文献   
154.
基于2002—2019年高空、地面常规观测资料,卫星云图,部分新一代天气雷达单站资料以及2009年以后的中国雷达拼图资料,采用个例筛选与统计、动态合成分析、层次聚类和雷达图分析等方法,对发生在中国的大范围雷暴大风事件(Derechos)的时空分布、环境背景和对流系统形态特征进行了分析.结果表明:(1)Derechos事...  相似文献   
155.
156.
A dramatic escalation of extreme climate events is challenging the capacity of environmental governance regimes to sustain and improve ecosystem outcomes. It has been argued that actors within adaptive governance regimes can help to steer environmental systems toward sustainability in times of crisis. Yet there is little empirical evidence of how acute climate crises are navigated by actors operating within adaptive governance regimes, and the factors that influence their responses. Here, we qualitatively assessed the actions key governance actors took in response to back-to-back mass coral bleaching – an extreme climate event – of the Great Barrier Reef in 2016 and 2017, and explored their perceptions of barriers and catalysts to these responses. This research was, in part, a product of collaboration and knowledge co-production with Great Barrier Reef governance actors aimed at improving responses to climate crises in the region. We found five major categories of activity that actors engaged with in the wake of recurrent mass coral bleaching: assessing the scale and extent of bleaching, sharing information, communicating bleaching to the public, building local resilience, and addressing global threats. These actions were both catalyzed and hindered by a range of factors that fall within different domains of adaptive capacity; such as assets, social organization, and agency. We discuss the implications of our findings as they relate to existing research on adaptive capacity and adaptive governance. We conclude by coalescing insights from our interviews and a participant engagement process to highlight four key ways in which the ability of governance actors, and the Great Barrier Reef governance regime more broadly, can be better prepared for, and more effectively respond to extreme climate events. Our research provides empirical insight into how crises are experienced by governance actors in a large-scale environmental system, potentially providing lessons for similar systems across the globe.  相似文献   
157.
In light of the challenges posed by contemporary environmental changes, interest in past environmental impacts and societies’ responses to them is burgeoning. The main strength of such research lies in its ability to analyze completed society-environment interactions. Scholars have argued that such analyses can improve our understanding of present challenges and offer useful lessons to guide adaptation responses. Yet despite considerable differences between past and present societies, our inherently limited knowledge of the past and our changing understanding of it, much of this research uses historical antecedents uncritically, assuming that past societal impacts and responses are directly analogous to contemporary ones. We argue that this approach is unsound both methodologically and theoretically, thus drawing insights that might offer an erroneous course of action.To illustrate the challenges in drawing historical analogies, we outline several fundamental differences between past and present societies as well as broader limitations of historical research. Based on these points, we argue that scholars who apply historical inference in their work should do so critically, while reflecting on the objectives of learning from the past and the limitations of this process. We suggest a number of ways to improve past-present analogies, such as defining more explicitly what we can learn from the past, clarifying the rationale for using the analogy, and reducing the number of variables compared between past and present.  相似文献   
158.
Following the collapse of the Soviet Union, the predicted scenarios of Central Asian water wars and catastrophic nuclear accidents have failed to materialize. However, the Aral Sea continues to shrink apace, and dangerous Soviet-built nuclear reactors have since proliferated in the former eastern bloc. These seemingly paradoxical outcomes can in part be attributed to the framing of these environmental issues as security matters by leading international regulatory, aid and lending institutions. Integrating these environmental concerns with the realist worldview of security studies systematically emphasized security dimensions at the expense of ecological concerns even amongst organizations distant from traditional defense affairs. This article proposes that international security strategy in this period is one of environmental appeasement defined as the systematic granting of ecologically unfriendly concessions in order to reduce short-term security risks. The article presents evidence that this appeasement strategy generated seemingly impressive results in terms of ameliorating short-term security risks, while actually exacerbating the underlying ecological situation. The article argues that while the foundational environmental risks remain unaddressed, the associated security threats have likewise not been ultimately resolved.  相似文献   
159.
Understanding how science, technology and innovation can best help to accelerate progress in achieving sustainable development remains a grand challenge for researchers and practitioners. In the context of the global consultation process for preparing a post-2015 Sustainable Development Agenda, various science-based actor networks have emerged, aiming to translate research into political decision-making and to inform transformations towards sustainability. Over the last years, these networks seem to have taken an ever-growing role in structuring the science-policy interface in global sustainability governance. The question arises, however, how they understand and organize ‘scientific knowledge integration’ in sustainability politics.This study offers a structured comparison of twelve global science-based actor networks engaged in the implementation of the Sustainable Development Goals. It shows that these networks use two types of strategies to foster scientific knowledge integration in sustainability governance. A new framework emerges, in which each strategy corresponds to two main approaches of scientific knowledge integration: The entrepreneurial strategy generally seeks to advance advice-oriented and solution-oriented knowledge processes, while assessment-oriented and learning-oriented processes in scientific knowledge integration are mainly promoted through a mediating strategy.  相似文献   
160.
The long-standing academic and public debate on economic growth, prosperity and environmental sustainability has recently gained new momentum. It lacks, however, a broad perspective on public opinion. Prior opinion surveys typically offered a simple dichotomous choice between growth and environmental protection. This study examines public beliefs and attitudes about a wider range of aspects of the growth debate. To this end, we conducted an online questionnaire survey including a country-wide, representative sample of 1008 Spanish citizens. Using factor analysis, we identify six distinct dimensions of public attitudes, referred to as: prosperity with growth; environmental limits to growth; general optimism; wrong priority; overrated GDP; and governmental control. We further analyze several specific questions associated with the growth debate, such as those concerning the desired GDP growth rate, the preferred growth-environment position, and beliefs about, as well as reasons for, a possible end or continuation of growth. We find that most respondents favor GDP growth rates of more than 3%. A majority views growth and environmental sustainability as compatible (green growth), while about one-third prefers either ignoring growth as a policy aim (agrowth), or stopping it altogether (degrowth). Only very few people want growth unconditionally (growth-at-all-costs). About one-third of the respondents believe that growth may be never-ending. We examine how support for or disagreement with different statements on growth are related to each other, as well as how they are influenced by socio-demographic, knowledge and ideology/values variables. Overall, our findings can inform public debates about the growth paradigm and its potential alternatives by providing a more nuanced understanding of public opinion. We make suggestions for future research, including modifying poll questions on growth and environment through offering a more diverse set of response options.  相似文献   
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