全文获取类型
收费全文 | 30817篇 |
免费 | 215篇 |
国内免费 | 165篇 |
专业分类
安全科学 | 568篇 |
废物处理 | 1591篇 |
环保管理 | 3864篇 |
综合类 | 4226篇 |
基础理论 | 8491篇 |
环境理论 | 7篇 |
污染及防治 | 7266篇 |
评价与监测 | 2405篇 |
社会与环境 | 2648篇 |
灾害及防治 | 131篇 |
出版年
2022年 | 170篇 |
2021年 | 200篇 |
2020年 | 135篇 |
2019年 | 195篇 |
2018年 | 1705篇 |
2017年 | 1635篇 |
2016年 | 1610篇 |
2015年 | 453篇 |
2014年 | 553篇 |
2013年 | 1728篇 |
2012年 | 1074篇 |
2011年 | 2118篇 |
2010年 | 1373篇 |
2009年 | 1290篇 |
2008年 | 1764篇 |
2007年 | 2110篇 |
2006年 | 893篇 |
2005年 | 748篇 |
2004年 | 826篇 |
2003年 | 768篇 |
2002年 | 740篇 |
2001年 | 916篇 |
2000年 | 639篇 |
1999年 | 354篇 |
1998年 | 296篇 |
1997年 | 281篇 |
1996年 | 278篇 |
1995年 | 317篇 |
1994年 | 321篇 |
1993年 | 269篇 |
1992年 | 290篇 |
1991年 | 268篇 |
1990年 | 314篇 |
1989年 | 282篇 |
1988年 | 229篇 |
1987年 | 205篇 |
1986年 | 199篇 |
1985年 | 211篇 |
1984年 | 238篇 |
1983年 | 217篇 |
1982年 | 222篇 |
1981年 | 207篇 |
1980年 | 173篇 |
1979年 | 191篇 |
1978年 | 154篇 |
1977年 | 143篇 |
1975年 | 142篇 |
1974年 | 142篇 |
1973年 | 140篇 |
1972年 | 162篇 |
排序方式: 共有10000条查询结果,搜索用时 375 毫秒
231.
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
232.
D. Lemke 《Die Naturwissenschaften》1983,70(11):540-549
Infrared observations with ground-based and balloon-borne telescopes are hampered by thermal background radiation and absorption caused by the earth's atmosphere. A sensitivity gain of up to three orders of magnitude can be obtained under the low photon background conditions of a helium-cooled space telescope. Physical properties of photodetectors and bolometers as well as their application to the new infrared telescopes aboard satellites and Spacelab are discussed. 相似文献
233.
234.
J. Heinze H. Remmert F. L. Boschke D. Reinen L. Jaenicke 《Die Naturwissenschaften》1983,70(11):575-576
235.
236.
Research in molecular neurobiology has recently entered a new phase of rapid development as a result of the application of the techniques of molecular genetics. This is illustrated by recent work on the electric ray (Torpedo marmorata and T. californica), whose electric organ is a rich source of cholinergic synapses. Other examples from recent literature of the application of the recombinant DNA technique to the mammalian central nervous system are given and possible future developments are discussed. 相似文献
237.
238.
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
239.
Ariel Weissman Reuwen Achiron M.D. Jacob Kuint Shlomo Lipitz Shlomo Mashiach Itamar Avigad 《黑龙江环境通报》1994,14(9):888-891
A case of gastric outlet obstruction diagnosed prenatally at 22 weeks' gestation is described. The differential diagnosis and the clinical management of this rare condition are discussed, and an updated literature review is presented. 相似文献
240.
Catherine Donner M.D. Corinne Liesnard Françoise Brancart Frederic Rodesch 《黑龙江环境通报》1994,14(11):1055-1059
Cytomegalovirus (CMV) is the most common cause of intrauterine infection. Recent publications show amniocentesis to have an 81–100 per cent sensitivity in antenatal diagnosis after 21 weeks' gestation. Testing before 21 weeks' gestation is less well documented. We performed 36 amniocenteses between 14 and 20 weeks' gestation. The sensitivity was 45 per cent and the specificity 100 per cent. Implications and possible causes of this low sensitivity are discussed. 相似文献