全文获取类型
收费全文 | 174篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 4篇 |
废物处理 | 9篇 |
环保管理 | 24篇 |
综合类 | 63篇 |
基础理论 | 25篇 |
污染及防治 | 39篇 |
评价与监测 | 10篇 |
社会与环境 | 2篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 1篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 1篇 |
2018年 | 3篇 |
2017年 | 7篇 |
2016年 | 5篇 |
2015年 | 9篇 |
2014年 | 6篇 |
2013年 | 16篇 |
2012年 | 10篇 |
2011年 | 10篇 |
2010年 | 8篇 |
2009年 | 5篇 |
2008年 | 10篇 |
2007年 | 7篇 |
2006年 | 8篇 |
2005年 | 12篇 |
2004年 | 7篇 |
2003年 | 10篇 |
2002年 | 7篇 |
2001年 | 5篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有177条查询结果,搜索用时 140 毫秒
111.
Zara Richmond Ron Fleischer Maya Chopra Jason Pinner Mario D'Souza Yelena Fridgant Jonathan Hyett 《黑龙江环境通报》2017,37(10):975-982
Objective: The aim of this study was to (1) examine the psychological impact of non-invasive prenatal testing (NIPT) in women with a high-risk (≥1 : 300) and low-risk (≤1 : 301) result on combined first trimester screening (cFTS) and (2) to examine factors influencing anxiety and decision-making in both risk populations. Method: Questionnaires and structured interviews were administered to low (n = 50) and high (n = 63) risk women at the time of NIPT blood draw (point A) and again at least 1 week after receiving their NIPT result (point B). Anxiety levels were measured at these two time points using the State–Trait Anxiety Inventory. Results: Both high-risk and low-risk cFTS groups demonstrated similar intrinsic (trait) anxiety levels (36 ± 10 vs 35 ± 10; p = 0.70). High-risk women had significantly higher levels of state anxiety at point A than low-risk women (42 ± 11 vs 36 ± 11; p < 0.01). Both groups had a statistically significant reduction (p < 0.01), to similar final levels of state anxiety at point B (30 ± 11 vs 29 ± 8; p = 0.61). Conclusion: Women receiving a high-risk result on cFTS have higher levels of state anxiety than their low-risk counterparts. Following a low-risk NIPT result, the anxiety levels in both populations are reduced to similar levels. © 2017 John Wiley & Sons, Ltd. 相似文献
112.
Jason Chibuk Jill Rafalko Theresa Boomer Ron McCullough Graham McLennan Philip Wyatt Eyad Almasri 《黑龙江环境通报》2020,40(10):1321-1329
Objective
Outcome data from cell-free DNA (cfDNA) screening in twin gestations are limited. This study adds an appreciable number of confirmed outcomes to the literature, and assesses performance of cfDNA screening in twins over a 4.5-year period at one large clinical laboratory.Method
Prenatal cytogenetic and SNP microarray results were cross-referenced with cfDNA results for twin pregnancies, yielding 422 matched cases. Using diagnostic results as truth, performance of cfDNA screening in this population was assessed.Results
Of the 422 twin pregnancies with both cfDNA and diagnostic results, 3 specimens failed amniocyte analysis, and 48 samples (11.5%) were nonreportable from the initial cfDNA draw. Analysis of the 371 reportable samples demonstrated a collective sensitivity of 98.7% and specificity of 93.2% for trisomies 21/18/13. Positive predictive values (PPVs) in this study population, which is enriched for aneuploidy, were 78.7%, 84.6%, and 66.7% for trisomy 21, 18, and 13, respectively.Conclusion
CfDNA screening in a cohort of twin pregnancies with matched diagnostic results showed superior performance compared to traditional serum biochemical screening in twins. This study adds to a growing body of evidence suggesting that cfDNA is an accurate and reliable screening tool for the major trisomies in twin pregnancies.113.
114.
This study examined children's moral, social and personal reasoning patterns about different neighborhood contexts. Three hundred and seventy-seven participants were selected from grades 2, 4, 6, and 8. Participants were shown 2 sets of photographs depicting the exact same houses and neighborhoods. One photograph displayed higher levels of physical incivilities and the other displayed higher levels of territoriality and place attachments. The vast majority of participants made strong social attributions of both danger and poverty towards physical contexts, depending on the level of incivilities depicted in the photographs. Moreover, an overwhelming majority gave justifications that fell into the moral domain. For most of the participants, the immorality of retribution overrode the negative attributions surrounding context. However, for those that approved of retribution behaviors, the physical setting appeared to influence their judgments. The findings suggest that the concept of extreme poverty (as represented by physical incivilities) and danger are fused at the cognitive level through linked interpretations of the same environmental cues. 相似文献
115.
116.
Charles M. Buchanan Christy N. Boggs Debra D. Dorschel Robert M. Gardner Ron J. Komarek Thelma L. Watterson Alan W. White 《Journal of Polymers and the Environment》1995,3(1):1-11
A series of miscible blends consisting of cellulose acetate propionate (CAP) and poly(ethylene glutarate) (PEG) or poly(tetramethylene glutarate) (PTG) were evaluated in a static bench-scale simulated municipal compost environment. Samples were removed from the compost at different intervals, and the weight loss was determined before evaluation by gel permeation chromatography, scanning electron microscopy, and1H NMR. The type of polyester (PEG versus PTG) in the blend made no difference in composting rates. At fixed CAP degree of substitution (DS), when the content of polyester in the blend was increased, the rate of composting and the weight loss due to composting increased. When the CAP was highly substituted, little degradation was observed within 30 days and almost all of the weight loss was ascribed to loss of polyester. Although the polyester was still observed to degrade faster, when the CAP DS was below approximately 2.0, both components are observed to degrade. The data suggests that initial degradation of the polyester is by chemical hydrolysis and the rate of this hydrolysis is very dependent upon the temperature profile of the compost and upon the DS of the CAP. 相似文献
117.
Summary Red squirrels defend exclusive, individual territories year round, 20% to 50% of females do not breed in any given year, and breeding females raise juveniles on their territories. Breeding is asynchronous, and the offspring of early-breeding females are more likely to hold an independently won territory than are late-born offspring. Based on the asymmetric war of attrition, we made the following predictions: (1) squirrels would respond more intensely to the calls of unfamiliar individuals than to the calls of neighbors; (2) breeding females would respond more intensely to unknown calls than would non-breeding females or males; (3) early-breeding females would respond more intensely than would late-breeding females to unknown calls; and (4) all classes of squirrels would respond similarly to the calls of neighbors. Playback experiments supported the predictions. Alternative hypotheses of kin selection, risk of infanticide, and seasonal difference in intruder pressure could not explain the results. 相似文献
118.
119.
120.
Gowland B Webster L Fryer R Davies I Moffat C Stagg R 《Environmental pollution (Barking, Essex : 1987)》2002,120(3):805-811
Wild and farmed mussels, Mytilus edulis, coexist with salmon farms in Scottish sea lochs. A synthetic pyrethroid, cypermethrin, is licensed for use on fish farms to control sea lice infestations as a formulation called Excis. In this study, uptake of cypermethrin from Excis exposure is investigated through the use of gas chromatography with mass-spectrometry. The effects of Excis on mussels are also examined by measuring the neutral red retention time of lysosomes, aerial survival and shell closure. The isomeric ratios of cis:trans cypermethrin measured in mussels are around 80:20; a marked increase from 40:60 to which the mussels were exposed. This is most likely due to preferential metabolism of trans-isomers, as the same response is seen in vertebrates. There is a pronounced behavioural effect of shell closure, where mussels exposed to 1000 microg/l cypermethrin shut their shells within an hour of exposure. Arguments are presented for this effect being either a voluntary response on recognition of cypermethrin, or an effect arising from an involuntary action of cypermethrin on the adductor muscle. Even at 1000 microg/l cypermethrin, neutral red retention time and aerial survival are not affected. The data suggest that the responses of mussels shown here are unlikely to occur in the field, even at the concentrations of cypermethrin used in fish cages, for the treatment of sea lice. 相似文献