全文获取类型
收费全文 | 20447篇 |
免费 | 235篇 |
国内免费 | 187篇 |
专业分类
安全科学 | 634篇 |
废物处理 | 846篇 |
环保管理 | 3173篇 |
综合类 | 2662篇 |
基础理论 | 5368篇 |
环境理论 | 6篇 |
污染及防治 | 5806篇 |
评价与监测 | 1309篇 |
社会与环境 | 923篇 |
灾害及防治 | 142篇 |
出版年
2022年 | 145篇 |
2021年 | 183篇 |
2020年 | 126篇 |
2019年 | 169篇 |
2018年 | 292篇 |
2017年 | 289篇 |
2016年 | 480篇 |
2015年 | 388篇 |
2014年 | 565篇 |
2013年 | 1808篇 |
2012年 | 678篇 |
2011年 | 893篇 |
2010年 | 710篇 |
2009年 | 825篇 |
2008年 | 946篇 |
2007年 | 1009篇 |
2006年 | 870篇 |
2005年 | 702篇 |
2004年 | 752篇 |
2003年 | 694篇 |
2002年 | 688篇 |
2001年 | 800篇 |
2000年 | 595篇 |
1999年 | 350篇 |
1998年 | 263篇 |
1997年 | 253篇 |
1996年 | 306篇 |
1995年 | 313篇 |
1994年 | 289篇 |
1993年 | 264篇 |
1992年 | 225篇 |
1991年 | 211篇 |
1990年 | 235篇 |
1989年 | 208篇 |
1988年 | 205篇 |
1987年 | 192篇 |
1986年 | 182篇 |
1985年 | 167篇 |
1984年 | 206篇 |
1983年 | 200篇 |
1982年 | 193篇 |
1981年 | 188篇 |
1980年 | 149篇 |
1979年 | 176篇 |
1978年 | 118篇 |
1977年 | 108篇 |
1976年 | 96篇 |
1975年 | 98篇 |
1973年 | 97篇 |
1972年 | 105篇 |
排序方式: 共有10000条查询结果,搜索用时 750 毫秒
261.
Howard Cuckle Nicholas Wald Rossana Stone James Densem James Haddow George Knight 《黑龙江环境通报》1988,8(6):439-445
Thyroid antibodies were measured in mid-trimester antenatal serum samples from 77 pregnancies affected by fetal Down's syndrome and 385 unaffected control pregnancies. Using a haemagglutination technique, thyroglobulin antibodies were detected in 5·2 per cent of cases (4) and 2·9 per cent of controls (11), and thyroid microsomal antibodies were detected in 22 per cent (17) and 15 per cent (59), respectively. Using an enzyme-linked immunosorbent assay (ELISA) for thyroglobulin antibodies and a cut-off level of 50 KIU/1, positive results were found in 25 per cent of cases (19) and 22 per cent of controls (84). Using an ELISA for thyroid microsomal antibodies and the same cut-off level, the proportions were 52 per cent (40) and 39 per cent (149), respectively. While not statistically significant, the differences were consistent with the previously reported increased levels of thyroid antibody found in nonpregnant women who had had pregnancies associated with Down's syndrome. 相似文献
262.
A syncytiotrophoblast-associated antigen identified by the monoclonal antibody (McAb) H315 is detectable on the surface of a low proportion of peripheral blood cells in pregnant women, raising the possibility of a new approach to prenatal diagnosis of genetic disorders. We aimed at verifying the trophoblastic origin of H315+ cells and their use for prenatal diagnosis of β-thalassaemia. H315 + cells were separated from the peripheral blood of pregnant women: the DNA obtained from these cells in two selected cases was shown to have genetic markers indistinguishable from those of the mother and definitely different from the fetus. Our results suggest that H315 antigen is expressed by maternal cells and that prenatal diagnosis on peripheral blood of the mother using H315 McAb is not feasible. 相似文献
263.
264.
265.
A de novo paracentric inversion of chromosome 11 identified through antenatal diagnosis is described along with long-term follow-up information on the child and discussion of reported experiences with de novo inversions. 相似文献
266.
Two-dimensional spectrophotometry and pseudo-color representation of chemical reaction patterns 总被引:1,自引:0,他引:1
The formation of spatio-temporal patterns in layers of chemical and biochemical media is observed and quantified by a two-dimensional spectrophotometer based on a computerized video equipment with high spatial, temporal, and intensity resolution. Images are shown, to some extent, in pseudo-colors. The use of pseudo-colors and three-dimensional perspective representations enhances the perception of the information contained in an image and the inherent order of the spatial structures. 相似文献
267.
268.
269.
C. Vaccarino G. Cimino M.M. Tripodo G. Lagan L. Lo Giudice R. Matarese 《Agriculture, ecosystems & environment》1983,10(3):275-283
Necrotic brown lesions developing on leaves and fruits of lemon, and other plants, near fossil-fuel-burning power plants emitting vanadium-rich ash, were reproduced experimentally by inoculating leaves with this type of ash, which is strongly acidic. Comparable lesions were formed when drops of vanadium oxide, dissolved in NaOH, were put on leaves and fruits. Neutralizing, or adding excess H2SO4 (to pH 3), did not alter lesion formation. The histology of these lesions was similar to that of lesions attributed to vanadium-rich ash. 相似文献
270.