全文获取类型
收费全文 | 398篇 |
免费 | 23篇 |
国内免费 | 5篇 |
专业分类
安全科学 | 37篇 |
废物处理 | 10篇 |
环保管理 | 99篇 |
综合类 | 44篇 |
基础理论 | 134篇 |
环境理论 | 2篇 |
污染及防治 | 53篇 |
评价与监测 | 26篇 |
社会与环境 | 16篇 |
灾害及防治 | 5篇 |
出版年
2023年 | 9篇 |
2022年 | 6篇 |
2021年 | 8篇 |
2020年 | 14篇 |
2019年 | 11篇 |
2018年 | 21篇 |
2017年 | 16篇 |
2016年 | 25篇 |
2015年 | 19篇 |
2014年 | 17篇 |
2013年 | 28篇 |
2012年 | 36篇 |
2011年 | 27篇 |
2010年 | 14篇 |
2009年 | 27篇 |
2008年 | 22篇 |
2007年 | 20篇 |
2006年 | 21篇 |
2005年 | 13篇 |
2004年 | 7篇 |
2003年 | 10篇 |
2002年 | 9篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1973年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有426条查询结果,搜索用时 31 毫秒
201.
Yung Hang Lam Mary Hoi Yin Tang Chin Peng Lee Sai Yuen Sin Rebecca Tang Hong Soo Wong Sai Fun Wong 《黑龙江环境通报》2001,21(8):627-629
Recent data have suggested that fetal nuchal translucency (NT) is affected by fetal gender. We investigated the size of this effect in 12 189 unselected pregnancies with known normal outcomes that had undergone NT measurements between 10 and 14 weeks of gestation. NT increased with gestation and was converted to multiples of the median (MoM) for the gestational day. The median NT MoM (95% CI) for female fetuses was 0.98 (0.97–0.99). This was significantly lower than that of the male fetuses (1.03; range1.02–1.04) (p<0.0005; Wilcoxon rank-sum test). The gender difference was not observed at 10 weeks but was observed from 11 weeks onwards. There is no obvious explanation for the above findings. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
202.
203.
Projections of the number, rate and cost of fall-related hospitalised injuries for individuals aged 65 years and older in New South Wales (NSW), Australia were estimated to 2051 for two scenarios: (1) demographic change only using 2008 admission rates; and (2) modelled change using negative binominal regression taking into account current trends in admission rates. Based on demographic change alone, the number and cost of fall injury hospitalisations among older people is expected to increase almost three-fold by 2051. Transfers to permanent residential aged care will also increase 3.2 fold. However, if the fall-related hospitalisation rate sustains its current trend, these increases are projected to be more than ten-fold by 2051. Even with demographic change alone, there will be a significant impact on the resources required to care for older people suffering a fall injury hospitalisation over the next forty years in NSW. The impact on the hospital and aged care sectors will be considerable unless significant improvements occur in the prevention and treatment of fall-related injury in older people. 相似文献
204.
Assessing Integrated Pest Management Adoption: Measurement Problems and Policy Implications 总被引:1,自引:0,他引:1
For more than a decade, the U.S. government has promoted integrated pest management (IPM) to advance sustainable agriculture.
However, the usefulness of this practice has been questioned because of lagging implementation. There are at least two plausible
rationales for the slow implementation: (1) growers are not adopting IPM—for whatever reason—and (2) current assessment methods
are inadequate at assessing IPM implementation. Our research addresses the second plausibility. We suggest that the traditional
approach to measuring IPM implementation on its own fails to assess the distinct, biologically hierarchical components of
IPM, and instead aggregates growers’ management practices into an overall adoption score. Knowledge of these distinct components
and the extent to which they are implemented can inform government officials as to how they should develop targeted assistance
programs to encourage broader IPM use. We address these concerns by assessing the components of IPM adoption and comparing
our method to the traditional approach alone. Our results indicate that there are four distinct components of adoption—weed,
insect, general, and ecosystem management—and that growers implement the first two components significantly more often than
the latter two. These findings suggest that using a more nuanced measure to assess IPM adoption that expands on the traditional
approach, allows for a better understanding of the degree of IPM implementation. 相似文献
205.
Linda Stalker Prokopy Z. Asligül Göçmen Jing Gao Shorna Broussard Allred Joseph E. Bonnell Kenneth Genskow Alicia Molloy Rebecca Power 《Journal of the American Water Resources Association》2011,47(1):196-202
Prokopy, Linda Stalker, Z. Asligül Göçmen, Jing Gao, Shorna Broussard Allred, Joseph E. Bonnell, Kenneth Genskow, Alicia Molloy, and Rebecca Power, 2011. Incorporating Social Context Variables Into Paired Watershed Designs to Test Nonpoint Source Program Effectiveness. Journal of the American Water Resources Association (JAWRA) 47(1):196‐202. DOI: 10.1111/j.1752‐1688.2010.00508.x Abstract: In a traditional paired watershed study, watersheds are selected to be as similar as possible so that conclusions may be drawn about the performance of Best Management Practices. We have extended the paired watershed concept to examine the effectiveness of watershed management programs by adding comparative criteria for social characteristics. For four different 8 or 11/12 digit hydrologic unit code (HUC) watersheds in the Midwest, we have piloted a systematic method for selecting paired subwatersheds. First, we developed a list of 11 key variables. Next, a factor analysis was conducted to determine the underlying structure of the 11 input variables. Finally, in each of the four watersheds, potential paired subwatersheds (all 14 digit HUCs) were selected using the factors in a cluster analysis. Informal interviews were then held with key informants in each watershed to provide qualitative assessments of criteria that could impact the comparability of the subwatersheds. This method for selecting paired watersheds should be helpful for other researchers to test the effectiveness of watershed management programs focused on behavior change. 相似文献
206.
Seasonal migration occurs in many animal systems and is likely to influence interactions between animals and their parasites. Here, we focus on monarch butterflies (Danaus plexippus) and a protozoan parasite (Ophryocystis elektroscirrha) to investigate how host migration affects infectious disease processes. Previous work showed that parasite prevalence was lower among migratory than nonmigratory monarch populations; two explanations for this pattern are that (1) migration allows animals to periodically escape contaminated habitats (i.e., migratory escape), and (2) long-distance migration weeds out infected animals (i.e., migratory culling). We combined field-sampling and analysis of citizen science data to examine spatiotemporal trends of parasite prevalence and evaluate evidence for these two mechanisms. Analysis of within-breeding-season variation in eastern North America showed that parasite prevalence increased from early to late in the breeding season, consistent with the hypothesis of migratory escape. Prevalence was also positively related to monarch breeding activity, as indexed by larval density. Among adult monarchs captured at different points along the east coast fall migratory flyway, parasite prevalence declined as monarchs progressed southward, consistent with the hypothesis of migratory culling. Parasite prevalence was also lower among monarchs sampled at two overwintering sites in Mexico than among monarchs sampled during the summer breeding period. Collectively, these results indicate that seasonal migration can affect parasite transmission in wild animal populations, with implications for predicting disease risks for species with threatened migrations. 相似文献
207.
208.
Early adolescence (12–13 years old) is a critical but under-researched demographic for the formation of attitudes related to climate change. We address this important area by exploring adolescent views about climate change. This paper presents opinions collected from surveys of 463 1st-year secondary school students (12–13 years old) in public secondary schools in inner-urban centres in Austria and Australia on whether climate change is (1) something about which to worry, (2) caused by humans and (3) happening now. Eligible respondents in both countries showed similar levels of agreement that climate change was probably or definitely something we should (1) worry about (84.6% Austria, 89.1% Australia), which is significantly higher than either country’s adult population. Eligible respondents agreed that climate change probably or definitely is (2) caused by humans (75.6% Austria, 83.6% Australia) and that climate change is probably or definitely something that is (3) happening now (73.1% Austria, 87.5% Australia). Their response differed from the respective adult populations, but in opposite directions. Our results suggest that socio-cultural worldview may not have as much influence on this age group as it does on the respective adult populations and suggests that this age group would be receptive and ready for climate science education and engagement initiatives.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01356-2) contains supplementary material, which is available to authorized users. 相似文献
209.
210.