全文获取类型
收费全文 | 163篇 |
免费 | 10篇 |
国内免费 | 25篇 |
专业分类
安全科学 | 21篇 |
废物处理 | 1篇 |
环保管理 | 3篇 |
综合类 | 82篇 |
基础理论 | 25篇 |
污染及防治 | 20篇 |
评价与监测 | 31篇 |
社会与环境 | 2篇 |
灾害及防治 | 13篇 |
出版年
2024年 | 6篇 |
2023年 | 5篇 |
2022年 | 8篇 |
2021年 | 6篇 |
2020年 | 11篇 |
2019年 | 9篇 |
2018年 | 5篇 |
2017年 | 5篇 |
2016年 | 6篇 |
2015年 | 9篇 |
2014年 | 12篇 |
2013年 | 11篇 |
2012年 | 11篇 |
2011年 | 13篇 |
2010年 | 4篇 |
2009年 | 8篇 |
2008年 | 6篇 |
2007年 | 12篇 |
2006年 | 6篇 |
2005年 | 3篇 |
2004年 | 7篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 9篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1992年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有198条查询结果,搜索用时 93 毫秒
131.
Jing Nie Peter Yaro Kaifeng He Haihong Hu 《Journal of environmental science and health. Part. B》2020,55(3):175-183
AbstractThe purpose of this study was to study the excretion stereoselectivity of triticonazole enantiomers in rat urine and faeces. Six male Sprague-Dawley (SD) rats were administrated 50?mg/kg rac-triticonazole. Rats urine and faeces were separately and quantitatively collected at the following intervals: 0–3, 3–6, 6–9, 9–12, 12–24, 24–36 and 36–48?h. The faeces samples were homogenized in an aqueous solution containing 0.2% DMSO at the ratio of 1?g: 40?mL. An aliquot of 100?μL rats urine or faeces homogenate was spiked and mixed with 6.0?μL of 1.00?μg/mL flusilazole as an internal standard. The triticonazole enantiomers in urine and faeces were determined by using an HPLC/MS–MS after samples preparation. The excreted amounts of enantiomers in the urine showed a significant difference (P?<?0.05) except for 3–6?h. The cumulative excretion rate (Xu0→24) in urine was 26.43?±?0.08% and 37.58?±?0.11% for R-(?)- and S-(+)-triticonazole, respectively, indicating high enantioselectivity (P?<?0.001). The cumulative excretion rate (Xu0→72) in faeces was 6.93?±?0.03% and 6.77?±?0.03% for R-(?)- and S-(+)-triticonazole, respectively, without a difference. The results showed that the total cumulative percentage of triticonazole enantiomers accounted for in urine and faeces was 64.00?±?0.13% and 13.70?±?0.32%, the urinary excretion of R-(?)- and S-(+)-triticonazole were significantly different and S-(+)-triticonazole was preferentially excreted. However, the faecal excretion of the enantiomers showed no difference. 相似文献
132.
The short-stature homeobox-containing gene (SHOX) on chromosome Xp22.3 was recently identified as an important determinant of the stature phenotype. Deletions of the SHOX gene, some of them due to structural chromosome abnormalities, have been described in patients with idiopathic short stature and Leri-Weill syndrome. Additionally, haploinsufficiency of SHOX is a main cause for short stature seen in patients with Turner syndrome. Here we report an unusual X-chromosome abnormality, which was detected during a fetal karyotyping performed because of a previous child with Down syndrome. GTG banding demonstrated an extra chromosome segment on the terminal part of the short arm of chromosome X in the index case (karyotype: 46,X,Xp+). The same chromosomal abnormality was found in the mother and the maternal grandmother. All carriers of this chromosomal abnormality presented with short stature but no other associated symptoms. Whole chromosome painting of X revealed a homogeneous painting of the abnormal X chromosome indicating that no other chromosome was involved. Additional FISH studies with probe DXS1140 (Kallmann probe at Xp22.3), Quint-Essential X-Specific DNA (DMD probe at Xp21.2), XIST (at Xq13.2), and Tel Xq/Yq were performed, and no abnormality was observed in the intensities or the localizations of the probes signals. However, applying a specific SHOX gene probe (derived from cosmid LLNONO3M34F5) showed a loss of signal on the derivative X chromosome. Our results show that the Xp+ generation led to a deletion of the complete SHOX gene and caused short stature in the presented family. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
133.
134.
《International Journal of Sustainable Engineering》2013,6(6):405-416
With the increasing penetration of doubly fed induction generators (DFIGs), the impact of the DFIG on transient stability attracts great attention. Transient stability is largely dominated by generator types in the power system, and the dynamic characteristics of DFIG wind turbines are different from that of the synchronous generators in the conventional power plants. The analysis of the transient stability on DFIG integrated power systems has become a very important issue. This paper reviews the current research on the issue from two aspects. One is to describe the methods to improve the fault ride through capability of DFIG wind turbines and the other is to analyse the impact of the DFIG wind farm on transient stability of power systems. 相似文献
135.
136.
本文用0.3mBenton-34/OV-1短填充柱气相色谱法研究了萘在焚烧炉飞灰上的氯化反直产物,实验表明,飞灰表面性质对氯化有促进作用,这种促进作用与飞灰的来源或表面性质有强烈关系,文中对有关分析方法和萘在焚烧炉飞灰上氯化反应的结果作了讨论。 相似文献
137.
Abstract: The ecological benefits of changing cattle grazing practices in the western United States remain controversial, due in part to a lack of experimentation. In 1997 we initiated an experimental study of two rangeland alternatives, cattle removal and high-impact grazing, and compared grassland community responses with those with more conventional, moderate grazing practices. The study was conducted in a high-elevation, semiarid grassland near Flagstaff, Arizona (U.S.A.). We conducted annual plant surveys of modified Whittaker plots for 8 years and examined plant composition shifts among treatments and years. High-impact grazing had strong directional effects that led to a decline in perennial forb cover and an increase in annual plants, particularly the exotic cheatgrass ( Bromus tectorum L.). A twofold increase in plant cover by exotic species followed a severe drought in the sixth year of the study, and this increase was greatest in the high-impact grazing plots, where native cover declined by one-half. Cattle removal resulted in little increase in native plant cover and reduced plant species richness relative to the moderate grazing control. Our results suggest that some intermediate level of cattle grazing may maintain greater levels of native plant diversity than the alternatives of cattle removal or high-density, short-duration grazing practices. Furthermore, episodic drought interacts with cattle grazing, leading to infrequent, but biologically important shifts in plant communities. Our results demonstrate the importance of climatic variation in determining ecological effects of grazing practices, and we recommend improving conservation efforts in arid rangelands by developing management plans that anticipate this variation. 相似文献
138.
The polymorphic information content (PIC) and the degree of heterozygosity of several polymorphic systems within the phenylalanine hydroxylase (PAH) gene were determined in 85 European Caucasian and 19 Chinese phenylketonuria (PKU) kindreds. The first system examined, a short tandem repeat (STR), had a PIC of 80 and 73 per cent in these Caucasian and Chinese samples, respectively. The degree of heterozygosity actually observed for this system was 81 and 64 per cent in the Caucasian and Chinese PKU families, respectively. Through the addition of a second polymorphism based on a variable number of tandem repeats (VNTR), the PIC was increased to 90 per cent in Caucasians, but only to 75 per cent in Chinese. The degree of heterozygosity observed for this combination was 94 per cent in European PKU families and 67 per cent in Chinese PKU families. The further addition of an Xmnl RFLP increased both the PIC and the level of heterozygosity in Caucasians to 95 per cent, but did not change either of these measures in Chinese. The combined use of these three polymorphisms significantly increases the informativity of prenatal diagnostic and carrier screening procedures in both Caucasian and Chinese PKU kindreds. Furthermore, since each of these polymorphisms can be studied by PCR-based methods, these new tests can be performed more quickly and easily than previous Southern-based procedures. 相似文献
139.
Transcervical cells (TCCs), collected by flushing or aspiration at 8–13 weeks of gestation, were analysed for the presence of fetal-derived DNA sequences. DNA extracted from maternal peripheral blood, TCC samples, and placental tissue was amplified by the polymerase chain reaction (PCR) to detect small tandem repeat (STR) markers specific to chromosome 21. STR products of fetal origin could be clearly observed in four TCC samples. TCC samples collected by flushing or aspiration were also analysed by fluorescent in situ hybridization (FISH) using X and Y probes simultaneously: 46,XY cells could be detected in all TCC samples obtained from mothers with male fetuses. 相似文献
140.
地震前兆数据观测中,经常会遇到数据突然发生变化,遇到这种情况,就要及时进行分析,研究其是否与地震孕育有关,为防震减灾工作提供依据。宿迁地震台的短水准观测数据,在2005年6月底发生了大的突变,对于这次变化,本文从测量测线的布设、地质构造、干扰情况、数据演变等方面进行分析,最后得到这次变化并不是由地震孕育引起的这一结论。 相似文献