全文获取类型
收费全文 | 54092篇 |
免费 | 572篇 |
国内免费 | 486篇 |
专业分类
安全科学 | 1604篇 |
废物处理 | 2188篇 |
环保管理 | 7230篇 |
综合类 | 8757篇 |
基础理论 | 14639篇 |
环境理论 | 35篇 |
污染及防治 | 13800篇 |
评价与监测 | 3601篇 |
社会与环境 | 2906篇 |
灾害及防治 | 390篇 |
出版年
2022年 | 413篇 |
2021年 | 448篇 |
2020年 | 332篇 |
2019年 | 420篇 |
2018年 | 782篇 |
2017年 | 795篇 |
2016年 | 1168篇 |
2015年 | 928篇 |
2014年 | 1334篇 |
2013年 | 4327篇 |
2012年 | 1610篇 |
2011年 | 2261篇 |
2010年 | 1926篇 |
2009年 | 1947篇 |
2008年 | 2296篇 |
2007年 | 2403篇 |
2006年 | 2165篇 |
2005年 | 1820篇 |
2004年 | 1761篇 |
2003年 | 1730篇 |
2002年 | 1645篇 |
2001年 | 2121篇 |
2000年 | 1507篇 |
1999年 | 949篇 |
1998年 | 733篇 |
1997年 | 717篇 |
1996年 | 779篇 |
1995年 | 795篇 |
1994年 | 734篇 |
1993年 | 698篇 |
1992年 | 691篇 |
1991年 | 639篇 |
1990年 | 645篇 |
1989年 | 652篇 |
1988年 | 581篇 |
1987年 | 487篇 |
1986年 | 458篇 |
1985年 | 510篇 |
1984年 | 522篇 |
1983年 | 536篇 |
1982年 | 539篇 |
1981年 | 478篇 |
1980年 | 441篇 |
1979年 | 481篇 |
1978年 | 388篇 |
1977年 | 342篇 |
1976年 | 320篇 |
1974年 | 305篇 |
1973年 | 300篇 |
1972年 | 320篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
821.
822.
B. Sikkema-Raddatz R. H. Sijmons M. B. Tan-Sindhunata A. Y. Van Der Veen R. Brunsting B. De Vries J. R. Beekhuis D. J. Bekedam B. Van Aken B. De Jong 《黑龙江环境通报》1995,15(5):467-473
We report two cases of apparently balanced complex de novo chromosomal rearrangements (BCCR) detected prenatally at 17 weeks and 10 weeks of gestation, respectively. Chromosomes were studied using GTG-banding and fluorescent in situ hybridization (FISH). In one case four chromosomes and in the other case three chromosomes were involved in the rearrangements. One of the pregnancies was terminated and no external or internal abnormalities were detected at autopsy. The other pregnancy continued to term. Level III ultrasound examination showed no abnormalities. The child is now 3 years old and has neither congenital anomalies nor evidence of delayed psychomotor development. 相似文献
823.
Frans J. Los MD PhD Diane Van Opstal Martin P. Schol Johannes L. J. Gaillard Helen Brandenburg Ans M. W. Van Den Ouweland Peter A. In 'T Veld 《黑龙江环境通报》1995,15(12):1155-1159
A prenatally detected case of a rare mosaic tetrasomy 12p/trisomy 12p is reported, presenting as the well-known accessory isochromosome 12p and a supernumerary single 12p marker in 17/24 and 6/24 clones of cultured amniotic fluid cells, respectively. The chromosomal nature of both marker chromosomes was investigated in cultured amniotic fluid cells by fluorescent in situ hybridization with various probes: the 12-centromeric probes pa12H8 and D12Z3, a whole chromosome 12 paint, and the chromosome 12p-specific paint M28. DNA analysis revealed a maternal origin of the extra 12p material. After counselling, the parents requested termination of pregnancy. Inspection and autopsy of the fetus revealed many of the dysmorphisms and internal structural abnormalities of the Pallister–Killian syndrome. 相似文献
824.
Christine Willekes Frans J. M. E. Roumen MD PhD Anne-Marie W. van Elsacker-Niele Harro T. Weiland Christl Vermey-Keers Johan H. J. M. van Krieken Christine E. M. de Die-Smulders Guus J. H. Hamers Gerrie P. M. Vaes-Peters 《黑龙江环境通报》1994,14(3):181-185
In a case of hydrops fetalis, serological examination showed a recent maternal human parvovirus B19 infection. Amniocentesis revealed a unique unbalanced translocation between chromosomes 3 and 11 of the fetus. The mother proved to have a balanced reciprocal translocation between chromosomes 3 and 11. A grossly macerated hydropic male fetus was delivered with a flat nose and low implanted deformed ears. Histopathological examination revealed nuclear inclusion bodies in fetal erythroid cells, confirming human parvovirus B19 infection. Parvovirus B19 DNA was demonstrated by in situ hybridization in the nuclei of heart muscle cells. Our finding of two different disorders in one case illustrates the importance of a complete evaluation of every case of hydrops fetalis, especially concerning counselling on the outcome of future pregnancies. The human parvovirus B19 infection will not recur due to the acquired immunity of the mother, whereas the balanced reciprocal translocation will endanger future pregnancies. 相似文献
825.
A 17-year-old woman was referred for amniocentesis due to a low maternal serum alpha-fetoprotein (AFP) concentration in a voluntary screening test. The fetal karyotype was 48,XXYY, and the pregnancy was terminated. Autopsy of the fetus disclosed agenesis of the corpus callosum and unusual facial features. 相似文献
826.
A simplified method is described for processing both direct preparations and long-term cultures from the same fragment of chorionic villi. Enzyme separation of the outer trophoblast layers (used for direct preparations) from the inner mesenchymal core (used to initiate long-term cultures) facilitates the utilization of the same fragments for the two procedures, without jeopardizing the success of either method. This has proved useful in cases where the sample was so small that only one method of chromosome preparation may have been possible using other techniques. 相似文献
827.
828.
829.
We describe a patient with a significantly elevated serum alphafetoprotein (AFP) concentration at 17 weeks of gestation, who showed only a marginally increased amniotic fluid AFP and lacked the second rapidly migrating band of acetylcholinesterase electrophoresis. Ultrasound examination revealed an encephalocele and ventriculomegaly. Autopsy showed that the encephalocele was not covered by skin. 相似文献
830.