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   25篇
  免费   0篇
安全科学   1篇
废物处理   1篇
综合类   11篇
基础理论   3篇
污染及防治   7篇
评价与监测   1篇
灾害及防治   1篇
  2022年   2篇
  2021年   2篇
  2020年   1篇
  2019年   2篇
  2017年   1篇
  2016年   1篇
  2013年   1篇
  2011年   1篇
  2009年   2篇
  2007年   2篇
  2003年   1篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1975年   1篇
  1971年   1篇
排序方式: 共有25条查询结果,搜索用时 500 毫秒
1.
2.
Maternal serum alpha-fetoprotein (AFP) and beta-human chorionic gonadotropin (βhCG) measurements taken prior to chorionic villus sampling (CVS) in 21 patients who subsequently miscarried were compared with measurements in a control group of 113 patients with uneventful pregnancies. Patients with AFP levels of 10 iu/ml or more prior to the CVS had a 4·3 times greater risk of miscarriage (95 per cent confidence interval 1·3–13·6). AFP levels obtained 1 week after the CVS in the 13 patients with late miscarriages were higher than in the control group (P = 0·06). Patients miscarrying had a greater rise in AFP (P = 0·06) and a greater fall in βhCG levels (P = 0·04) following the CVS procedure, compared with the control subjects. Each 10-unit change in the difference between AFP or βhCG levels prior to and 1 week following the CVS was associated with a significantly increased risk for late miscarriage. Elevated maternal serum AFP levels early in pregnancy and changes in AFP and βhCG levels following CVS may predict an increased risk for subsequent miscarriage.  相似文献   
3.
Information on maternal age and maternal serum alpha-fetoprotein, unconjugated oestriol (uE3), and human chorionic gonadotrophin (hCG) levels was used to investigate retrospectively the effect of estimating Edward's syndrome risk in women having multi-marker screening for Down's syndrome. The screened population comprised 15 pregnancies affected by Edward's syndrome, 15 with Down's syndrome and 5472 unaffected pregnancies. The use of all three markers to estimate Edward's syndrome risk would have led to the detection of 10–12 (67–80 per cent) cases with a false-positive rate of 0.3–0.6 per cent depending on the risk cut-off. A further case would have been detected as a result of screening for Down's syndrome alone. Similar results were obtained when the Edward's syndrome risk was based on uE3 and hCG only. These data suggest that extending Down's syndrome screening to include Edward's syndrome risk will yield a high detection rate with only a small increase in the false-positive rate.  相似文献   
4.
Most of coastal area in Nile Delta, Egypt, is salt-affected soils and have low carbon (C) and nitrogen (N) inputs as a result of declining vegetation growth and low net primary production. Therefore, this study amid to compare between C and N pools in degraded (uncultivated and salt-affected soil) and restored (cultivated and reclaimed 20 years ago) locations in North Nile Delta. and to examine the impact of cultivation on sequestering C and N pools in this area as one of the most important methods for mitigating climate change impacts. C and N pools increased significantly in surface soil from 2.99 and 0.43 Mgh?1 in uncultivated sites to 19.26 and 1.66 Mgh?1 in cultivated ones as salinity was reduced and net primary production was increased due to leaching and reclamation. Particulate (associated with sand) and nonparticulate (associated with clay +silt) soil organic C or N was significantly higher cultivated sites. In addition, nonparticulate organic C or N was lower than particulate part indicating and supporting the strong relationship between organic matter and clay. The sequestration rate (in approximately 1 m profile) was 1.69 and 0.14 Mgh?1 yr.?1 C and N pools respectively. Although the cultivation is leading to loss of organic matter in some areas; C and N in this coastal area are partially restored and stored. Therefore, restoration and appropriate management practices will lead to mitigate the negative impacts of climate change in this area.  相似文献   
5.
Environmental Science and Pollution Research - Hydroxyurea (HDU), a class of antineoplastic drugs, has a powerful efficacy in the treatment of several types of malignancies. However, it has...  相似文献   
6.
Environmental Science and Pollution Research - Diazinon (DZN), a common organophosphorus insecticide (OPI), has hazardous effect to human and animals with its ubiquitous use. Considering the...  相似文献   
7.
Environmental Science and Pollution Research - COVID-19 was first discovered in Wuhan, China in December 2019. It is one of the worst pandemics in human history. Recent studies reported that...  相似文献   
8.
The aim of this study was to use a new approach to investigate aeolian particle granulometry and micromorphology. Taking total aeolian deposition into account, we used parameters such as, particle area, perimeter, shape analysis for particle roughness (area/perimeter) and elongation (long/short axis). These parameters were analyzed on temporal and spatial scales at four study sites in the eastern Negev Desert, Israel. The total collection of particles was sorted into three size groups based on particle area to facilitate comparison. The classic definition of particle size (equating particle length with particle diameter) produced relatively small variations among the three size classes (25-38.6%). Our proposed comprehensive method demonstrated significant variation among the three size classes (13.9-60.8%), e.g. the classic method placed 36.4% of the particles in size class two while the new method placed 60.8% of the particles in this size class; the differences were even more significant regarding size class 3 (38.6% vs. 13.9%, respectively). The classic method did not facilitate investigation of particle roughness and elongation. With this new approach, it was possible to clearly define the particles by size class, based on these characteristics. With roughness, the variation among size classes 2 and 3 was about 27%. With elongation, the variation among size classes two and three was about 21%. Applying similar investigation method to study the aeolian particle granulometry and micromorphology can better facilitate more detailed calculation of particle size distribution, roughness and elongation.  相似文献   
9.

Introduction

Although prior studies of road traffic accidents have found between-group differences in risk, little attention has been given to the encounter between drivers involved in severe collisions.

Method

The present study empirically evaluates two different possible causes of "social accidents," which are defined as collisions between two or more drivers where some faulty social interaction might be assumed, and which are the most prevalent cause of road injuries. The analyses use merged Israeli collision records from 1983 to 2004 with data from two national censuses, thus providing an unprecedented empirical basis to study the social foundations of car accidents. The data are used to adjudicate between two alternative hypotheses: the heterogeneity hypothesis (socially different drivers tend to collide) versus the homogeneity hypothesis (socially similar drivers tend to collide).

Results

Multivariate analyses provide preliminary support for the latter hypothesis. Given an accident, there are more collisions among drivers from the same broad educational group, and the factors that influence this correlation are independent of geography. The paper thus leads to the idea that severe collisions reflect a sociological or ecological process that is akin to acciphilia.

Impact on Industry

The preliminary findings suggest that variation between drivers may be preferable to similarity, since apparently there is a greater tendency toward collisions between similar drivers.  相似文献   
10.
Two premature triplet pregnancies underwent repeated treatment aimed at acceleration of individual fetal lung maturity while administering intravenous tocolytic treatment. From the early third trimester, repeated amniocenteses were used for intra-amniotic administration of thyroxine to each sac, while the individual fetal lung maturation rate was determined by surfactant microviscosity until lung maturity was achieved.  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