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   517篇
  免费   19篇
  国内免费   2篇
测绘学   5篇
大气科学   28篇
地球物理   142篇
地质学   141篇
海洋学   32篇
天文学   108篇
综合类   1篇
自然地理   81篇
  2021年   7篇
  2020年   6篇
  2019年   3篇
  2018年   12篇
  2017年   15篇
  2016年   11篇
  2015年   16篇
  2014年   7篇
  2013年   42篇
  2012年   21篇
  2011年   18篇
  2010年   11篇
  2009年   28篇
  2008年   20篇
  2007年   22篇
  2006年   19篇
  2005年   24篇
  2004年   16篇
  2003年   13篇
  2002年   11篇
  2001年   14篇
  2000年   15篇
  1999年   9篇
  1998年   11篇
  1997年   19篇
  1996年   8篇
  1995年   7篇
  1994年   7篇
  1993年   4篇
  1992年   3篇
  1991年   5篇
  1990年   5篇
  1989年   3篇
  1988年   5篇
  1987年   11篇
  1986年   3篇
  1985年   5篇
  1984年   4篇
  1983年   3篇
  1982年   13篇
  1981年   3篇
  1980年   4篇
  1979年   7篇
  1977年   8篇
  1976年   5篇
  1975年   4篇
  1974年   9篇
  1973年   9篇
  1970年   2篇
  1875年   2篇
排序方式: 共有538条查询结果,搜索用时 15 毫秒
41.
GeoFEST (Geophysical Finite Element Simulation Tool) is a two- and three-dimensional finite element software package for the modeling of solid stress and strain in geophysical and other continuum domain applications. It is one of the featured high-performance applications of the NASA QuakeSim project. The program is targeted to be compiled and run on UNIX systems, and is running on diverse systems including sequential and message-passing parallel systems. Solution to the elliptical partial differential equations is obtained by finite element basis sampling, resulting in a sparse linear system primarily solved by conjugate gradient iteration to a tolerance level; on sequential systems a Crout factorization for the direct inversion of the linear system is also supported. The physics models supported include isotropic linear elasticity and both Newtonian and power-law viscoelasticity, via implicit quasi-static time stepping. In addition to triangular, quadrilateral, tetrahedral and hexahedral continuum elements, GeoFEST supports split-node faulting, body forces, and surface tractions. This software and related mesh refinement strategies have been validated on a variety of test cases with rigorous comparison to analytical solutions. These include a box-shaped domain with imposed motion on one surface, a pair of strike slip faults in stepover arrangement, and two community-agreed benchmark cases: a strike slip fault in an enclosing box, and a quarter-domain circular fault problem. Scientific applications of the code include the modeling of static and transient co- and post-seismic earth deformation, Earth response to glacial, atmospheric and hydrological loading, and other scenarios involving the bulk deformation of geologic media.  相似文献   
42.
43.
44.
45.
Climate change disproportionately impacts the world’s poorest countries. A recent World Bank report highlighted that over 100 million people are at risk of falling into extreme poverty as a result of climate change. There is currently a lack of information about how to simultaneously address climate change and poverty. Climate change challenges provide an opportunity for those impacted most to come up with new and innovative technologies and solutions. This article uses an example from Mozambique where local and international partners are working side-by-side, to show how developing countries can simultaneously address climate change and poverty reduction using an ecosystem-based adaptation approach. Using ecosystem-based adaptation, a technique that uses the natural environment to help societies adapt to climate change, developing countries can lead the way to improve climate adaptation globally. This paradigm shift would help developing countries become leaders in ecosystem-based adaptation and green infrastructure techniques and has implications for climate policy worldwide.

POLICY RELEVANCE

The Paris Agreement resulting from the United Nations Framework Convention on Climate Change (UNFCCC) 21st Conference of Parties (COP 21) in December 2015 was rightly lauded for its global commitment to cut greenhouse gas emissions. However, COP 21 was also historic because of its call for non-party stakeholders to address climate change, inclusion of a global goal of ‘enhancing adaptive capacity, strengthening resilience and reducing vulnerability’, and the United States’ commitment of $800 million to adaptation funding. The combination of recognizing the need for new stakeholders to commit to climate change adaptation, the large impact climate change will have on the developing world, and providing access to funds for climate change adaptation creates a unique opportunity for developing countries to pave the way in adaptation policies in practices. Currently, developing countries are creating National Adaptation Plans (NAPs) for the UNFCCC. Through including a strong component of ecosystem-based adaptation in NAPs, developing countries can shape their countries’ policies, improve local institutions and governments, and facilitate a new generation of innovative leaders. Lessons learned in places like Mozambique can help lead the way in other regions facing similar climatic risks.  相似文献   

46.
47.
Several detergent-washing/air-drying decontamination protocols were tested to determine their ability to remove residual contamination from two types of ground water sampling devices. We tested a relatively simply constructed device, a bailer, and a much more complex, and theoretically more difficult to decontaminate, bladder pump. The devices were decontaminated after sampling ground water that was contaminated with organics that varied in their hydrophobic nature and propensity to be sorbed by the materials in the devices. These studies showed that a hot-detergent wash, hot-water rinse, and hot-air drying protocol was effective.  相似文献   
48.
49.
US public awareness of the reality and risks of human-caused climate change remains limited, despite strong evidence presented in the IPCC and other major climate assessments. One contributing factor may be that the immense collective effort to produce periodic climate assessments is typically not well matched with public communication and outreach efforts for these reports, leaving a vacuum to be filled by less authoritative sources. Print and online media coverage provides one metric of the US public reach of selected climate assessments between 2000 and 2010. The number of Lexis-Nexis articles for the search terms “climate change” or “global warming” within 14 days of each report’s release varied significantly over time with a peak occurring in 2007. When compared to background “chatter” relating to climate change, each assessment had widely diverse penetration in the US media (~4% for US National Climate Assessment in 2000; ~17% for Arctic Climate Impacts Assessment in 2004; ~19% and ~10% for Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report Working Group I and Working Group II respectively in 2007; ~4% for the US Global Change Research Program (USGCRP) assessment report in 2009; and ~5% for US National Research Council’s America’s Climate Choices reports in 2010). We propose ways to improve the public reach of climate assessments, focusing in particular on approaches to more effectively characterize and communicate the role of uncertainty in human actions as distinct from other sources of uncertainty across the range of possible climate futures.  相似文献   
50.
Global economic restructuring has not only intensified the shift in reproductive work from the household to the market, but it has been predicated on the international mobility of labour to countries where locals are no longer willing to work in low-paying menial jobs. This paper focuses on Singapore as a country which has drawn upon female migrant workers from neighbouring developing countries to work as domestic helpers in Singapore such that the gainful entry of its own women into the formal economy has been facilitated. Drawing upon a range of secondary sources as well as field data, the paper demonstrates how state policies on labour migration in Singapore have played a crucial role in influencing the uneven employer-employee relationships that migrant female domestic helpers in Singapore households find themselves in. More generally, it argues that the availability of foreign domestic helpers in Singapore and the state discourse on the issue has contributed to perpetuating the patriarchal ideology of housework as women's work and of housework as non-work.  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