全文获取类型
收费全文 | 12418篇 |
免费 | 148篇 |
国内免费 | 276篇 |
专业分类
安全科学 | 377篇 |
废物处理 | 510篇 |
环保管理 | 1923篇 |
综合类 | 2398篇 |
基础理论 | 2857篇 |
环境理论 | 7篇 |
污染及防治 | 2785篇 |
评价与监测 | 827篇 |
社会与环境 | 1077篇 |
灾害及防治 | 81篇 |
出版年
2023年 | 76篇 |
2022年 | 154篇 |
2021年 | 130篇 |
2020年 | 90篇 |
2019年 | 132篇 |
2018年 | 184篇 |
2017年 | 217篇 |
2016年 | 294篇 |
2015年 | 231篇 |
2014年 | 336篇 |
2013年 | 1168篇 |
2012年 | 413篇 |
2011年 | 542篇 |
2010年 | 426篇 |
2009年 | 476篇 |
2008年 | 550篇 |
2007年 | 596篇 |
2006年 | 438篇 |
2005年 | 410篇 |
2004年 | 413篇 |
2003年 | 416篇 |
2002年 | 375篇 |
2001年 | 400篇 |
2000年 | 289篇 |
1999年 | 164篇 |
1998年 | 151篇 |
1997年 | 132篇 |
1996年 | 168篇 |
1995年 | 227篇 |
1994年 | 205篇 |
1993年 | 169篇 |
1992年 | 163篇 |
1991年 | 153篇 |
1990年 | 146篇 |
1989年 | 124篇 |
1988年 | 137篇 |
1987年 | 127篇 |
1986年 | 104篇 |
1985年 | 108篇 |
1984年 | 101篇 |
1983年 | 107篇 |
1982年 | 114篇 |
1981年 | 111篇 |
1980年 | 73篇 |
1979年 | 79篇 |
1977年 | 68篇 |
1973年 | 58篇 |
1972年 | 64篇 |
1914年 | 71篇 |
1913年 | 107篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
Konstantinos D. Stagiannis Dr Waldo Sepulveda Luca Fusi Christine Garrett Nicholas M. Fisk 《黑龙江环境通报》1995,15(1):70-73
Exencephaly was diagnosed at 17 weeks in a 27-year-old primigravida with abnormalities of the hands and a family history suggestive of autosomal dominant brachydactyly and clinodactyly. In this family there was also a history of ‘anencephaly’. To our knowledge, this is the first report on the association of exencephaly and autosomal dominant brachydactyly. As the relationship between hand and cranial anomalies is well established, we suggest that this association in our case could be due to a defect in the same gene. 相似文献
103.
E. A. Loupian A. A. Mazurov E. V. Flitman D. V. Ershov G. N. Korovin V. P. Novik N. A. Abushenko D. A. Altyntsev V. V. Koshelev S. A. Tashchilin A. V. Tatarnikov I. Csiszar A. I. Sukhinin E. I. Ponomarev S. V. Afonin V. V. Belov G. G. Matvienko T. Loboda 《Mitigation and Adaptation Strategies for Global Change》2006,11(1):113-145
104.
L. V. Mukhortova I. N. Bezkorovainaya 《Mitigation and Adaptation Strategies for Global Change》2006,11(1):191-202
The evaluation of biospheric role of the boreal forests in the accumulation of carbon is connected with the evaluation of
organic matter (OM) pool in soils. The research sites were larch forests, they are situated on Nizhne-Tungusskoe Plateau.
Larch forests of feather-moss and lichen types (110 and 380 years old) were formed on 'ochric podbur' soils. Litter stocks
are 3.5–4.5 kg m− 2 with thickness 10–25 cm. Cryomezomorphic northern taiga soils contains 38–73 t (carbon) ha− 1. Pool of fast mineralized OM has average value 38.1 t (carbon) ha− 1, including 20.5 and 6.4 t (Carbon) ha− 1 of labile compounds on surface and in the soil, and 11.2 t (carbon) ha− 1 of mobile OM. Microbial mass reaches 1.78–3.47 t (carbon) ha− 1, its proportion is 3.6–4.9% of the total OM carbon. Zoomass of feather-moss larch forest is 0.20–0.61 * 10− 2, in lichen larch forest −0.01–0.07 * 10− 2 t (carbon) ha− 1. A pool of resistant to biological decomposition and bonded to mineral soil matrix OM is 17.7 t (carbon) ha− 1 and it varies from 18.6 to 29.0 in feather-moss larch forest, and from 6.4 to 17.0 t (carbon) ha− 1 in lichen larch forest. Two-years field experiment has been performed to determine transformation rates of various plant
litter fractions and to clarify the role of soil biota in these processes. The results showed participation of all biota groups
in the decomposition of plant residues caused weight loss of larch-needles and root mortmass. Isolation of organic matter
from all-size invertebrate groups leads to some decrease of decomposition activity. 相似文献
105.
The Science of Nature - 相似文献
106.
107.
108.
Dr. Waldo Sepulveda Peter Nicolaidis Jean Hollingsworth Nicholas M. Fisk 《黑龙江环境通报》1995,15(2):193-197
The fetal gall bladder can now be easily identified during the second and third trimesters using high-resolution ultrasonography. In this report we present eight fetuses with an enlarged gall bladder detected on prenatal ultrasonography at a mean gestational age of 24.6 weeks (range 19–31 weeks). Additional ultrasonographic findings were present in four cases: fetal anomalies and intrauterine growth retardation in three and polyhydramnios in one. Of those cases associated with fetal anomalies, one woman underwent amniocentesis at 21 weeks revealing trisomy 18. The other two declined prenatal karyotyping; neonatal karyotyping revealed trisomy 13 in one and trisomy 18 in the other. Although an enlarged fetal gall bladder can be a normal variant in the second and third trimesters, the prenatal detection of cholecystomegaly should prompt a search for associated anomalies and other markers of aneuploidy. If found, prenatal karyotyping should be considered. 相似文献
109.
Mary C. Phelan Ph.D. Robert A. Saul Thompson A. Gailey Jr Steven A. Skinner 《黑龙江环境通报》1995,15(3):274-277
Mosaicism for the Wolf-Hirschhorn syndrome, del(4)(p16), is extremely rare and has not been reported in association with a numerical chromosome abnormality. We report the prenatal diagnosis of mosaic del(4)(p16) and non-mosaic trisomy 21 in a 16-week female fetus. The pregnancy ended in spontaneous abortion at 34 weeks secondary to fetal demise. The fetus had features of both 4p – and trisomy 21. 相似文献
110.
Dr Marianne Johansen Marian Knight Edward J. Maher Kim Smith Ian L. Sargent 《黑龙江环境通报》1995,15(10):921-931
Trophoblast deportation is known to occur in normal human pregnancy, but it is not yet clear whether these cells routinely enter the maternal peripheral circulation and are available as a source of fetal DNA for non-invasive prenatal diagnosis of genetic disorders. To resolve this issue requires an efficient method of enriching trophoblast from maternal blood combined with a means to confirm its identity. Five different techniques were tested on ten retroplacental blood samples to determine the most sensitive and operator-efficient method. Lysis of red cells alone gave the best recovery of trophoblast but had to be discounted, together with Ficoll density gradient centrifugation, due to the very low purity and the excessive time required. Fluorescence-activated cell sorting (FACS) of pre-enriched trophoblast resulted in the lowest recovery rate (8 per cent) despite a 3250-fold enrichment and a very high purity. Immunomagnetic beads (Dynabeads) coated with anti-CD 16 antibody proved to be the best method for the subsequent immunocytochemical characterization of deported trophoblast. However, IO beads coated with anti-CD45 antibody may be more useful for isolating trophoblast for prenatal diagnosis due to the high purity, enrichment (32-fold), and recovery rate (78 per cent) obtained with this method. 相似文献