全文获取类型
收费全文 | 28708篇 |
免费 | 257篇 |
国内免费 | 248篇 |
专业分类
安全科学 | 729篇 |
废物处理 | 1011篇 |
环保管理 | 3477篇 |
综合类 | 6964篇 |
基础理论 | 6766篇 |
环境理论 | 17篇 |
污染及防治 | 7199篇 |
评价与监测 | 1724篇 |
社会与环境 | 1190篇 |
灾害及防治 | 136篇 |
出版年
2022年 | 202篇 |
2019年 | 200篇 |
2018年 | 373篇 |
2017年 | 386篇 |
2016年 | 536篇 |
2015年 | 448篇 |
2014年 | 660篇 |
2013年 | 2045篇 |
2012年 | 790篇 |
2011年 | 1106篇 |
2010年 | 832篇 |
2009年 | 945篇 |
2008年 | 1107篇 |
2007年 | 1146篇 |
2006年 | 1028篇 |
2005年 | 858篇 |
2004年 | 836篇 |
2003年 | 846篇 |
2002年 | 797篇 |
2001年 | 1011篇 |
2000年 | 689篇 |
1999年 | 473篇 |
1998年 | 312篇 |
1997年 | 327篇 |
1996年 | 360篇 |
1995年 | 376篇 |
1994年 | 394篇 |
1993年 | 312篇 |
1992年 | 357篇 |
1991年 | 361篇 |
1990年 | 370篇 |
1989年 | 335篇 |
1988年 | 313篇 |
1987年 | 260篇 |
1986年 | 267篇 |
1985年 | 286篇 |
1984年 | 262篇 |
1983年 | 272篇 |
1982年 | 280篇 |
1981年 | 285篇 |
1980年 | 236篇 |
1979年 | 235篇 |
1978年 | 242篇 |
1977年 | 214篇 |
1976年 | 240篇 |
1974年 | 237篇 |
1973年 | 211篇 |
1972年 | 209篇 |
1967年 | 224篇 |
1965年 | 191篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
571.
K. Schmetzer 《Die Naturwissenschaften》1987,74(3):136-137
572.
573.
574.
575.
厦门西港海水质量对鱼卵胚胎发育畸形率的影响 总被引:3,自引:1,他引:3
以养殖场培育的花尾胡椒鲷受精卵为实验材料测试了厦门西域5个站位的表层水水样对花尾胡椒鲷受精卵的胚胎发育毒性,并运用GC-MS手段分析了水样中的美国EPA优控的16PAHs组分的含量。结果表明:3号站位(厦门市工业和生活污水主要排放口的外侧)和4号站位(厦门西港的港区)的水样对鱼卵的胚胎发育的毒性最强。8号站位(位于主航道并濒临嵩屿电厂)的水样对鱼卵胚胎发良的毒性次之,1号站位(湾口)和5号站位(内港)的水样对鱼卵的胚胎发育的毒性较小。水样中的PAHs含量分析结果表明,仅用水样中的PAHs含量不能全面地反映水样对鱼卵胚胎发育的毒性。最后,对本实验方法应用于海洋环境生物监测的有效性进行了探讨。 相似文献
576.
The coastal seawater of Mediterranean of Alexandria receives large amount of discharged waters containing industrial wastes, sewage, and agricultural and domestic drainage. Fluoride and some parameters were(chemical and physical) determined. The data gave indication that the content and the amount of the discharged water largely affect the chemical composition of the coastal water. Stepwise regression analysis was highly significant and the model was very fruitful, where the observed and calculated values were mostly concordant. This may indicated that there was a relation between fluoride content in coastal seawater and its content in the discharged water. 相似文献
577.
W. F. Carey A. Poulos P. Sharp P. V. Nelson E. F. Robertson J. L. Hughes A. Gill 《黑龙江环境通报》1994,14(9):813-819
Variability in the level of expression of very long chain fatty acids (VLCFAs) is documented in cultured chorionic villus (CV) cells derived from two fetuses, one at risk for an unusual peroxisomal fatty acid β-oxidation defect, and the other at risk for the X-linked form of adrenoleucodystrophy (ALD). Cells from early subcultures of chorionic cells from both cases gave normal values for VLCFA ratios. The results for the fetus at risk for the β-oxidation defect were interpreted to indicate that the fetus was not affected; however, at birth, the infant was clinically and biochemically affected. In the case of the fetus at risk for X-linked ALD, although VLCFAs were normal in subculture 1, the levels of these fatty acids increased dramatically in subculture 3, suggesting an abnormal fetus. Termination of the pregnancy and subsequent biochemical and morphological follow-up confirmed that the fetus was indeed affected by ALD. 相似文献
578.
Mr. M. T. Rebello G. Hackett J. Smith F. E. Loeffler S. Robson N. Maclachlan R. W. Beard C. H. Rodeck R. Williamson D. V. Coleman C. Williams 《黑龙江环境通报》1991,11(1):41-46
Ten-ml samples of amniotic fluid were taken from pregnancies being terminated at 8–14 weeks' gestation. DNA was extracted from the amniotic cells by sequential centrifugation and analysed using the polymerase chain reaction (PCR). Fifteen samples were analysed for evidence of maternal contamination using Mfd5 oligo-nucleotide primers for repeat polymorphisms. Ten amniotic fluid samples were tested for the Delta-F508 deletion characteristic of cystic fibrosis to demonstrate a diagnostic application for the technique. In each case, DNA extracted from fetal tissue from the same pregnancy was included in the controls. In 14 of the 15 cases tested with the Mfd5 primers, both the amniotic fluid DNA and the fetal DNA showed no evidence of contaminating DNA. In one case, neither the amniotic fluid cells nor the fetal cells yielded results. In nine of the ten cases tested with the Delta-F508 primers, the amniotic fluid cell DNA provided accurate information about the genetic status of the fetus; in the tenth, the fetal DNA failed to amplify. The results indicate that adequate DNA can be extracted from amniotic fluid from 8 weeks' gestation onward and these samples are suitable for prenatal diagnosis using PCR. 相似文献
579.
The reproductive history of 45 couples at increased risk for neural tube defect (NTD) who came for genetic counselling in 1970 and 1971 were compared with a similar number counselled in 1975 and 1976, when prenatal diagnostic tests were freely offered. They were subsequently interviewed in their homes and had their reproductive history recorded to the end of 1973 and 1978 respectively. Nearly all had a previous child with an NTD and none of the women were pregnant at the time of counselling. The effect of prenatal diagnosis was to speed somewhat the decision about further pregnancies, but the number of couples deciding on no further children and on having further pregnancies were almost identical in the two groups. The average number of pregnancies was 2·8 per family, with only 1·2 surviving children. The pregnancy outcomes are discussed as are the reasons for not attempting further pregnancies in both groups, which included very high risk of recurrence, a surviving spina bifida child, inability to accept the tests or its implications. Ninety per cent of the second group had tests. Their reactions to the tests were favourable but all complained of the waiting time between amniocentesis and obtaining the results. They all would have tests again in any future pregnancy. The reason for women not having prenatal diagnostic tests included inability to accept termination. It is concluded that couples in South Wales decide either to have no more children or to have further pregnancies regardless of tests. but tests speed a decision and enable the women to enjoy the pregnancy after obtaining the results, and that an NTD greatly reduces the number of children per family. A termination for an NTD is much more acceptable to most than an NTD at term. The reasons for this are discussed. 相似文献
580.