全文获取类型
收费全文 | 16953篇 |
免费 | 192篇 |
国内免费 | 333篇 |
专业分类
安全科学 | 425篇 |
废物处理 | 798篇 |
环保管理 | 2072篇 |
综合类 | 2437篇 |
基础理论 | 4411篇 |
环境理论 | 2篇 |
污染及防治 | 4495篇 |
评价与监测 | 1241篇 |
社会与环境 | 1503篇 |
灾害及防治 | 94篇 |
出版年
2023年 | 98篇 |
2022年 | 218篇 |
2021年 | 172篇 |
2020年 | 120篇 |
2019年 | 160篇 |
2018年 | 267篇 |
2017年 | 277篇 |
2016年 | 413篇 |
2015年 | 305篇 |
2014年 | 466篇 |
2013年 | 1389篇 |
2012年 | 543篇 |
2011年 | 770篇 |
2010年 | 638篇 |
2009年 | 696篇 |
2008年 | 807篇 |
2007年 | 817篇 |
2006年 | 692篇 |
2005年 | 613篇 |
2004年 | 579篇 |
2003年 | 630篇 |
2002年 | 557篇 |
2001年 | 785篇 |
2000年 | 511篇 |
1999年 | 301篇 |
1998年 | 207篇 |
1997年 | 207篇 |
1996年 | 232篇 |
1995年 | 271篇 |
1994年 | 208篇 |
1993年 | 176篇 |
1992年 | 197篇 |
1991年 | 195篇 |
1990年 | 206篇 |
1989年 | 193篇 |
1988年 | 152篇 |
1987年 | 158篇 |
1986年 | 110篇 |
1985年 | 148篇 |
1984年 | 149篇 |
1983年 | 138篇 |
1982年 | 132篇 |
1981年 | 131篇 |
1980年 | 107篇 |
1979年 | 113篇 |
1977年 | 86篇 |
1975年 | 81篇 |
1974年 | 80篇 |
1973年 | 95篇 |
1972年 | 88篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
7.
In the diurnal lepidopteran fauna of the northern taiga subzone in the western Russian Plain, the species inhabiting primary biotopic complexes typical of this subzone currently account for slightly more than 60% of the total species richness and abundance. A large part of the fauna is represented by the species of more southern origin, whose expansion to the northern taiga was caused by anthropogenic transformation of landscapes between the 12th and 20th centuries and recent climate warming. 相似文献
8.
Although many conventional physical remediation methods are viewed as proven, they often only relocate wastes to other sites or into the air. How do the emerging biological and chemical in situ methods perform in the same applications? This article reviews their results (much of it in the laboratory) as well as their promise of more complete neutralization of hazardous wastes, lower capital costs, and longer-duration cleanup processes. The optimal method may be a combination of chemical and biological in situ techniques with physical pump-and-treat methods. 相似文献
9.
Dr. J. F. Bruch P. Metezeau N. Garcia-Fonknechten Y. Richard V. Tricottet B.-L. Hsi A. Kitzis C. Julien E. Papiernik 《黑龙江环境通报》1991,11(10):787-798
Three monoclonal antibodies (MAbs) against trophoblast (GB17, GB21, and GB25) and flow cytometry were used to sort trophoblast-like cells (TLCs) from peripheral blood of pregnant women. Sorted TLCs were processed for electron microscopy and fetal DNA amplification of the Y-specific sequences from mothers carrying male fetuses. At the ultra-structural level, most of the nucleated cells had the morphology of leucocytes, suggesting maternal contaminants, and we did not find the characteristic features of the free inter-villous trophoblast cells. Nevertheless, polymerase chain reaction (PCR) analysis showed an amplification of Y-specific sequences in two out of three samples of sorted TLCs. These results suggest that besides the maternal leucocytes, sufficient trophoblast nucleated fetal cells can be obtained using cell enrichment by sorting. This sensitive method holds promise for non-invasive prenatal diagnosis of fetal sex and if sufficient Y(positive) nuclei are found, for the diagnosis of selected numerical chromosome abnormalities. 相似文献
10.
S. Savas S. Eraslan S. Kantarci B. Karaman D. Acarsoz T. Tükel O. Cogulu F. Ozkinay S. Basaran K. Aydınlı M. Yuksel-Apak B. Kirdar 《黑龙江环境通报》2002,22(8):703-709
Childhood-onset spinal muscular atrophy (SMA) is one of the most common neurodegenerative genetic disorders. SMN1 is the SMA-determining gene deleted or mutated in the majority of SMA cases. There is no effective cure or treatment for this disease yet. Thus, the availability of prenatal testing is important. Here we report prenatal prediction for 68 fetuses in 63 Turkish SMA families using direct deletion analysis of the SMN1 gene by restriction digestion. The genotype of the index case was known in 40 families (Group A) but unknown in the remaining 23 families (Group B). A total of ten fetuses were predicted to be affected. Eight of these fetuses were derived from Group A and two of these fetuses were from Group B families. Two fetuses from the same family in Group A had the SMNhyb1 gene in addition to homozygous deletion of the NAIP gene. One fetus from Group A was homozygously deleted for only exon 8 of the SMN2 gene, and further analysis showed the presence of both the SMN1 and SMNhyb1 genes but not the SMN2 gene. In addition, one carrier with a homozygous deletion of only exon 8 of the SMN1 gene was detected to have a SMNhyb2 gene, which was also found in the fetus. To our knowledge, these are the first prenatal cases with SMNhyb genes. Follow-up studies demonstrated that the prenatal predictions and the phenotype of the fetuses correlated well in 33 type I pregnancies demonstrating that a careful molecular analysis of the SMN genes is very useful in predicting the phenotype of the fetus in families at risk for SMA. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献