全文获取类型
收费全文 | 1184篇 |
免费 | 98篇 |
国内免费 | 100篇 |
专业分类
安全科学 | 178篇 |
废物处理 | 27篇 |
环保管理 | 397篇 |
综合类 | 396篇 |
基础理论 | 112篇 |
环境理论 | 1篇 |
污染及防治 | 63篇 |
评价与监测 | 19篇 |
社会与环境 | 114篇 |
灾害及防治 | 75篇 |
出版年
2023年 | 17篇 |
2022年 | 20篇 |
2021年 | 31篇 |
2020年 | 57篇 |
2019年 | 41篇 |
2018年 | 30篇 |
2017年 | 37篇 |
2016年 | 53篇 |
2015年 | 39篇 |
2014年 | 55篇 |
2013年 | 81篇 |
2012年 | 77篇 |
2011年 | 110篇 |
2010年 | 53篇 |
2009年 | 50篇 |
2008年 | 64篇 |
2007年 | 76篇 |
2006年 | 70篇 |
2005年 | 37篇 |
2004年 | 35篇 |
2003年 | 51篇 |
2002年 | 31篇 |
2001年 | 28篇 |
2000年 | 23篇 |
1999年 | 16篇 |
1998年 | 11篇 |
1997年 | 12篇 |
1996年 | 7篇 |
1995年 | 12篇 |
1994年 | 12篇 |
1993年 | 18篇 |
1992年 | 10篇 |
1991年 | 14篇 |
1990年 | 8篇 |
1989年 | 13篇 |
1988年 | 8篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1973年 | 3篇 |
1972年 | 4篇 |
1971年 | 10篇 |
排序方式: 共有1382条查询结果,搜索用时 390 毫秒
941.
942.
Prenatal diagnosis was requested by a family carrying a 3 base-pair insertion in the dihydropteridine reductase (DHPR) coding region. A chorionic villus sample was obtained and fetal DNA was isolated directly from this. Diagnosis was performed by a polymerase chain reaction (PCR)-based technique, with a simple electrophoretic assay for the insertion. The fetus was found to be heterozygous for the insertion. This is the first time that prenatal diagnosis of DHPR deficiency has been performed by direct detection of the mutation. 相似文献
943.
944.
Exclusion of β-thalassaemia in mice was undertaken by pre-implantation DNA diagnosis. Biopsies of approximately five cells were obtained from mouse pre-embryos. DNA prepared from this material was amplified by the polymerase chain reaction (PCR), enabling identification of the normal β-major globin gene in 11 out of 20 cases where it was known to be present. The expected negative result was obtained in 14 out of 16 homozygous thalassaemic embryos, with two false positives. Results are promptly available following PCR, thereby facilitating re-implantation of embryos which have had homozygous β-thalassaemia excluded. The mouse model illustrates a useful approach to pre-implantation diagnosis of genetic disease in the human. 相似文献
945.
构建绿色城市平台 支持循环经济发展 总被引:3,自引:0,他引:3
论述了厦门市应当利用构建海湾型城市平台的契机,转变传统生产模式,打造产业生态链条,通过发展循环经济,建立循环型社会,走上可持续发展之路。提出了厦门市发展循环经济的对策建议。 相似文献
946.
947.
短缺资源类型与供需趋势分析 总被引:10,自引:0,他引:10
短缺资源是指在一定时空范围和一定技术经济条件下,因需求量大于供给量而产生明显缺口的资源。按照短缺资源的分类,中国战略性短缺资源主要有石油、耕地和淡水,三者对国家安全和社会经济发展具有全局性和长远性影响。中国非战略性短缺资源主要有森林、富铁矿、铬铁矿、铜矿和钾盐等。随着经济的发展,人口的继续增长,从本世纪初到本世纪中叶,上述各种短缺资源的短缺数量增加,短缺程度趋于加剧。解决中国短缺资源的供需矛盾,需要从多种途径综合考虑:①多元化利用国外资源,弥补国内资源短缺;②建立战略资源储备体系,应付突发危机;③节约、替代和综合利用降低资源消耗;④强化资源保护,提高资源再生能力;⑤依靠科技进步,寻求解决短缺资源的新途径。 相似文献
948.
R. G. F. Gray A. Green T. Cole V. Davidson M. Giles R. B. H. Schutgens R. J. A. Wanders 《黑龙江环境通报》1995,15(5):486-490
A case is reported of a male fetus at risk of X-linked adrenoleucodystrophy who showed a normal cultured chorionic villus cell very long chain fatty acid (VLCFA) profile but at birth exhibited grossly abnormal plasma and cultured fibroblast VLCFAs. Maternal contamination or a sample mix-up was excluded by chromosome analysis and analysis of polymorphic markers. This is the second report of a fetus affected with this disorder who showed normal cultured chorionic villus cell VLCFAs. It highlights the importance of a proper audit of all prenatal diagnoses to evaluate method reliability. 相似文献
949.
F. Di Trapani M. Marino E. D'Alcamo I. Abate S. D'Agostino S. Lauricella M. Musicò F. Orlandi P. Sammarco Dr. A. Maggio B. Modell 《黑龙江环境通报》1991,11(12):899-904
Prenatal diagnosis of haemoglobin disorders is accepted to be a useful procedure to avoid births of infants with homozygous diseases. Advances in sampling and molecular techniques, such as polymerase chain reaction (PCR) and chorionic villus sampling (CVS), have made earlier and safer first-trimester prenatal diagnosis possible. However, these procedures need previous studies of at-risk couples, which can be very time-consuming when a number of different β-thalassaemia mutations occur in the region. We describe the possibility of making a first-trimester prenatal diagnosis by cordocentesis and fetal blood analysis at the 12th week of gestation. We found no statistically significant difference (p>0.05) between β/γ values in fetuses at the 12th and 18th weeks of gestation. In seven affected fetuses aborted at the 12th week of gestation, the diagnosis was confirmed in all cases by PCR analysis. These findings suggest that early cordocentesis could be an alternative procedure to CVS and PCR analysis. 相似文献
950.
Before 1970s the Second Songhua River and Ji Canal of China had been polluted seriously by mercury. During peak pollution period, mercury levels in water, sediment and fish body of these rivers were close to or even higher than that of famous Minamata Bay of Japan. Some residents who live near to the polluted rivers were affected and the methyl mercury values in their blood, hair and urine were higher than normal people obviously . Since the fish had decreased even vanished in these rivers, so the food chain that transfers mercury to human also was out off almostly. However, nervous symptoms of Minamata disease were discovered among fisherman who had eaten more fishes. This report relates the stories about the mercury pollution of the Second Songhua River and Ji Canal. 相似文献