全文获取类型
收费全文 | 291篇 |
免费 | 1篇 |
专业分类
安全科学 | 5篇 |
废物处理 | 6篇 |
环保管理 | 8篇 |
综合类 | 135篇 |
基础理论 | 43篇 |
污染及防治 | 69篇 |
评价与监测 | 11篇 |
社会与环境 | 12篇 |
灾害及防治 | 3篇 |
出版年
2021年 | 3篇 |
2018年 | 8篇 |
2017年 | 4篇 |
2015年 | 8篇 |
2014年 | 13篇 |
2013年 | 9篇 |
2012年 | 6篇 |
2011年 | 5篇 |
2010年 | 13篇 |
2009年 | 11篇 |
2008年 | 8篇 |
2007年 | 9篇 |
2006年 | 8篇 |
2005年 | 8篇 |
2004年 | 6篇 |
2003年 | 8篇 |
2002年 | 6篇 |
1998年 | 7篇 |
1996年 | 7篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1969年 | 2篇 |
1966年 | 3篇 |
1965年 | 5篇 |
1964年 | 2篇 |
1963年 | 7篇 |
1962年 | 4篇 |
1961年 | 3篇 |
1960年 | 2篇 |
1959年 | 6篇 |
1958年 | 5篇 |
1957年 | 3篇 |
1956年 | 11篇 |
1955年 | 9篇 |
1954年 | 3篇 |
1953年 | 3篇 |
1952年 | 4篇 |
1950年 | 2篇 |
1949年 | 2篇 |
1947年 | 2篇 |
1942年 | 2篇 |
1940年 | 2篇 |
1939年 | 4篇 |
1937年 | 2篇 |
1934年 | 3篇 |
1933年 | 2篇 |
1929年 | 2篇 |
1925年 | 2篇 |
1918年 | 2篇 |
排序方式: 共有292条查询结果,搜索用时 15 毫秒
71.
72.
J. Büsch P. Huber E. Pflüger St. Miltenyi J. Holtz Professor Dr. A. Radbruch 《黑龙江环境通报》1994,14(12):1129-1140
For simple and effective isolation of fetal cells from peripheral maternal blood, we combined depletion of maternal cells and enrichment of fetal cells by high-gradient magnetic cell separation (MACS). First CD45+ and CD14+ cells were depleted from maternal peripheral blood mononuclear cells by MACS. From the depleted fraction, CD71+ erythroid cells were enriched up to 80 per cent by MACS. This ‘double-MACS’ procedure yielded an average depletion rate of 780-fold and an average enrichment rate of 500-fold, with approximate recovery rates of 40–55 per cent. For paternity testing, cells from unseparated blood and the various fractions were analysed for polymorphism of the HLA-DQ-A1 locus and D1S80 locus by the polymerase chain reaction (PCR). In CD45−/CD71+ sorted cells from maternal blood, but not in unfractionated cells from maternal blood or CD45−/CD14− cells, paternal alleles could be detected. In the CD45−/CD71+ fraction, the relative frequency of paternal alleles compared with maternal alleles ranged from 1 in 20 to 1 in 200 (determined by titration and depending on the quality of separation and biological variation). In 7 out of 11 cases, between weeks 12 and 25 of gestation, we could identify paternal alleles by PCR, either HLA-DQ-A1 or D1S80. This double-MACS procedure is simple, fast, efficient, and reliable for non-invasive prenatal diagnosis. 相似文献
73.
DM Peter Lorenz Rainer Bollmann Georg Klaus Hinkel Marco Mächler Gabriele Siegert Gudrun Stamminger Jörg Wendisch Sabine Ziemer 《黑龙江环境通报》1991,11(11):819-825
The study of the fetal platelet count and size can, according to the literature, be used for the prenatal diagnosis of the Wiskott-Aldrich syndrome (WAS). So far, no affected fetuses have been identified by this method. All pregnancies in which this method had been applied to resulted, as correctly predicted, in the birth of normal children. Here we report on a familial case of WAS where the haematological parameters failed to reveal the affected second child. Hence we assume that the platelet count and size of platelets remain normal in fetuses with WAS to the gestational age of 22 weeks and cannot be used for prenatal diagnosis. 相似文献
74.
75.
76.
77.
78.
79.
There is little evidence that nitrogen (N) cycling in the highly weathered, low-phosphorus (P), acidic soils found in Southern Hemisphere continents will differ greatly from that in North America and Europe. Evidence from the 'south' shows: the similarity in forms and temporal patterns in losses of N from different land uses; that the C:N ratios of the forest floor/litter layer from different continents are strongly predictive of a range of processes on a global scale; that generalizations based on Northern Hemisphere experience of the impact of N additions to 'P-limited' ecosystems are likely to fail for southern ecosystems where anatomical and physiological adaptation of native plants to low-P soils makes questionable the concept of 'P-limitation'; that the greatest threats in the 'south' are probably changes in land use that may greatly increase N inputs and turnover; that localized increases in N inputs produce similar effects to those seen in the 'north'. 相似文献
80.
Kosakowski G 《Journal of contaminant hydrology》2004,72(1-4):23-46
Transport experiments with colloids and radionuclides in a shear zone were conducted during the Colloid and Radionuclide Retardation experiment (CRR) at Nagra's Grimsel Test Site. Breakthrough curves of bentonite colloids and uranine, a non-sorbing solute, were measured in an asymmetric dipole flow field. The colloid breakthrough is earlier than that of uranine. Both breakthrough curves show anomalously long late time tails and the slope of the late time tails for the colloids is slightly higher. Anomalous late time tails are commonly associated with matrix diffusion processes; the diffusive interaction of solutes transported in open channels with the adjacent porous rock matrix or zones of stagnant water. The breakthrough curves for different colloid size classes are very similar and show no signs of fractionation due to their (size-dependent) diffusivity. It is proposed that tailing of the colloids is mainly caused by the structure of the flow field and that for the colloid transport, matrix diffusion is of minor importance. This has consequences for the interpretation of the uranine breakthrough. Comparisons of experimental results with numerical studies and with the evaluation of the colloid breakthrough with continuous time random theory imply that the tailing in the conservative solute breakthrough in this shear zone is not only caused by matrix diffusion. Part of the tailing can be attributed to advective transport in fracture networks and advection in low velocity regions. Models based on the advection-dispersion equation and matrix diffusion do not properly describe the temporal and spatial evolution of colloid and solute transport in such systems with a consistent set of parameters. 相似文献