全文获取类型
收费全文 | 37149篇 |
免费 | 447篇 |
国内免费 | 510篇 |
专业分类
安全科学 | 1116篇 |
废物处理 | 1726篇 |
环保管理 | 4810篇 |
综合类 | 5623篇 |
基础理论 | 9451篇 |
环境理论 | 15篇 |
污染及防治 | 10098篇 |
评价与监测 | 2664篇 |
社会与环境 | 2364篇 |
灾害及防治 | 239篇 |
出版年
2023年 | 191篇 |
2022年 | 434篇 |
2021年 | 433篇 |
2020年 | 326篇 |
2019年 | 330篇 |
2018年 | 663篇 |
2017年 | 611篇 |
2016年 | 977篇 |
2015年 | 686篇 |
2014年 | 1069篇 |
2013年 | 3141篇 |
2012年 | 1352篇 |
2011年 | 1754篇 |
2010年 | 1466篇 |
2009年 | 1484篇 |
2008年 | 1704篇 |
2007年 | 1811篇 |
2006年 | 1588篇 |
2005年 | 1291篇 |
2004年 | 1258篇 |
2003年 | 1218篇 |
2002年 | 1141篇 |
2001年 | 1421篇 |
2000年 | 1049篇 |
1999年 | 665篇 |
1998年 | 454篇 |
1997年 | 443篇 |
1996年 | 476篇 |
1995年 | 504篇 |
1994年 | 437篇 |
1993年 | 412篇 |
1992年 | 380篇 |
1991年 | 367篇 |
1990年 | 366篇 |
1989年 | 370篇 |
1988年 | 323篇 |
1987年 | 274篇 |
1986年 | 258篇 |
1985年 | 263篇 |
1984年 | 338篇 |
1983年 | 283篇 |
1982年 | 345篇 |
1981年 | 268篇 |
1980年 | 231篇 |
1979年 | 282篇 |
1978年 | 200篇 |
1977年 | 190篇 |
1976年 | 167篇 |
1975年 | 167篇 |
1974年 | 165篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
501.
I. Shagina H. L. Dadali V. P. Sitnikov V. V. Pugachev N. A. Malygina O. V. Evgrafov 《黑龙江环境通报》1995,15(1):27-34
Ninety-two families with spinal muscular atrophy (SMA) applied for genetic counselling and further prenatal diagnosis. To minimize expenses, only one tightly linked informative marker was determined in the course of preliminary examination, and non-radioactive allele detection was preferably used. Four prenatal diagnoses of SMA type I, four of SMA type II, and one of SMA type III were made. This trial programme shows the considerable requirements, importance, and potential effectiveness of prenatal prediction of SMA in Russia. 相似文献
502.
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
503.
504.
505.
506.
Reverse phase HPLC of radioactive globin chains has been compared to classical carboxy methyl cellulose chromatography for the prenatal diagnosis of β thalassaemia. The two methods correlated highly (r = 0.97 p < 0.0005) and provided an identical diagnosis for 40 fetal blood samples of fetuses homozygous or heterozygous for β thalassaemia. The HPLC procedure was much faster and required fewer biochemical steps (no globin preparation). It was at least as accurate and more sensitive than the classical chromatography. A single column can be used for 150 analyses and is always ready to be used. Last but not least it is much less expensive than CMC chromatography. 相似文献
507.
The polymerase chain reaction (PCR) was used on material from a blighted ovum to confirm indirectly the carrier status of a woman with a family history of Becker muscular dystrophy. Conventional testing including creatine kinase levels, muscle biopsy, and EMG had been inconclusive, and on the basis of one elevated creatine kinase level, the woman had been designated a possible carrier. Ultrasound examination at 10 weeks of pregnancy indicated a blighted ovum, from which DNA was subsequently extracted and subjected to PCR testing for determination of sex and genotypic status with respect to the known familial deletion of the dystrophin gene. The blighted ovum was found to have a Y chromosome and also to be deleted for at least exon 6 of the dystrophin gene, indirectly indicating that the mother most likely carried the family mutation for Becker muscular dystrophy. 相似文献
508.
509.
David M. Sherer MD James R. Woods Jr Jacques S. Abramowicz John A. Dipreta Leon A. Metlay Richard Jaffe 《黑龙江环境通报》1993,13(12):1079-1084
Although malignant transformation of fetal cervical teratoma is extremely rare, perinatal morbidity is high and usually related to the size of the tumour, which may compromise fetal swallowing and subsequently lead to upper airway obstruction. We present a case in which mid-trimester serial sonography demonstrated markedly rapid early growth of a lesion of this type between 17 and 19 weeks' gestation indicating the aggressive nature of this tumour, assisting parental decision to terminate the pregnancy. Histopathology confirmed grade 3 immaturity of the lesion. 相似文献
510.
IntroductionFertilizationisessentialforagriculturalproduction ,butunreasonablyapplyingfertilizerscouldresultinseriesofproblemssuchascropqualitydecline,fertilizeruseefficiencydecrease,residualfertilizerspollution groundwaterandriversandnitrogencontented … 相似文献