全文获取类型
收费全文 | 28388篇 |
免费 | 281篇 |
国内免费 | 279篇 |
专业分类
安全科学 | 769篇 |
废物处理 | 1098篇 |
环保管理 | 3524篇 |
综合类 | 5828篇 |
基础理论 | 6916篇 |
环境理论 | 15篇 |
污染及防治 | 7045篇 |
评价与监测 | 1979篇 |
社会与环境 | 1589篇 |
灾害及防治 | 185篇 |
出版年
2022年 | 230篇 |
2021年 | 218篇 |
2020年 | 175篇 |
2019年 | 221篇 |
2018年 | 377篇 |
2017年 | 417篇 |
2016年 | 593篇 |
2015年 | 482篇 |
2014年 | 715篇 |
2013年 | 2264篇 |
2012年 | 868篇 |
2011年 | 1154篇 |
2010年 | 919篇 |
2009年 | 1023篇 |
2008年 | 1122篇 |
2007年 | 1162篇 |
2006年 | 1083篇 |
2005年 | 926篇 |
2004年 | 886篇 |
2003年 | 891篇 |
2002年 | 813篇 |
2001年 | 1066篇 |
2000年 | 744篇 |
1999年 | 466篇 |
1998年 | 323篇 |
1997年 | 330篇 |
1996年 | 353篇 |
1995年 | 382篇 |
1994年 | 369篇 |
1993年 | 318篇 |
1992年 | 356篇 |
1991年 | 347篇 |
1990年 | 349篇 |
1989年 | 298篇 |
1988年 | 291篇 |
1987年 | 218篇 |
1986年 | 256篇 |
1985年 | 274篇 |
1984年 | 271篇 |
1983年 | 265篇 |
1982年 | 261篇 |
1981年 | 262篇 |
1980年 | 224篇 |
1979年 | 228篇 |
1978年 | 192篇 |
1977年 | 188篇 |
1974年 | 195篇 |
1973年 | 156篇 |
1972年 | 180篇 |
1967年 | 169篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
As part of a programme to characterize floating anthropogenic debris in the aquatic environment, the US Environmental Protection Agency (EPA) conducted 18 field surveys in the harbours of major metropolitan cities of the east, west, and Gulf coasts of the United States and the Mid-Atlantic Bight. the surveys were designed to provide information on the types, relative amounts, and distributions of aquatic debris in different geographic regions of the United States. Neuston nets (0.33 mm mesh) were used to collect surface debris during outgoing tides on two or three consecutive days in selected areas of each city. After each net tow, the debris, which ranged in size from small resin pellets to large plastic sheeting pieces, was identified, categorized, and counted. the data are being used to qualitatively characterize aquatic debris in coastal metropolitan areas, to examine potential regional variations, and to tentatively identify potential sources. 相似文献
42.
J. Malczewski R. Moreno-Sanchez L.A. Bojorquez-Tapia E. Ongay-Delhumeau 《Journal of Environmental Planning and Management》1997,40(3):349-374
This paper is concerned with developing a model for group decision making under multiple criteria. The multiple criteria group decision making (MCGDM)problem involves a set of feasible land use patterns that are evaluated on the basis of multiple, conflicting and noncommensurate criteria by a group of individuals. The model integrates the Analytic Hierarchy Process (AHP) and an integer mathematical programming method. The former provides a tool for structuring the decision problem and determining land suitability for different socio-economicactivities (the uses of land), the latter is used to identify the land use pattern that maximizes consensus among interest groups. The model is used to analyze environmental conflict over land resource allocation in the Cape Region of Mexico. 相似文献
43.
44.
Collaborative policy making has become increasingly significant in environmental management, but it is often evaluated by whether or not agreement is reached and implemented. The most important outcomes of such policy dialogues are often invisible or undervalued when seen through the lens of a traditional, modernist paradigm of government and accountability. These dialogues represent a new paradigm of governance that can be best understood in the light of a complex adaptive system model of society. From this perspective collaborative policy making is a way of making a system more flexible, adaptive and intelligent. The authors document such outcomes in three cases of water policy making in California, including the San Francisco Estuary Project, the CALFED Bay-Delta Program and the Sacramento Area Water Forum. The outcomes include social and political capital, agreed-on information, the end of stalemates, high-quality agreements, learning and change, innovation and new practices involving networks and flexibility. 相似文献
45.
E. A. Snegin 《Russian Journal of Ecology》2005,36(1):33-40
The distribution pattern of the gastropod Bradybaena fruticum has been studied in a forest-steppe landscape. Analysis of the frequencies of polymorphic biochemical and conchological characters has yielded preliminary results on the characteristics of the species population structure whose formation was determined by a set of natural and anthropogenic factors.Translated from Ekologiya, No. 1, 2005, pp. 39–47.Original Russian Text Copyright © 2005 by Snegin. 相似文献
46.
Bhopal Gas Tragedy was the worst industrial accident in the world where several thousand persons lost their lives. It occurred at the Union Carbide plant located inside the city of Bhopal and close to the railway station, at midnight of December 2-3, 1984 due to the leakage of MIC gas which took the local sleeping and floating population unawares.
This paper describes the experience of a transit passenger who reached the Bhopal Railway Station by train at about the same time when the deadly gas leakage occurred. 相似文献
47.
We report three siblings from consecutive pregnancies affected with restrictive dermopathy (RD). During the second pregnancy, fetal behavioural development and growth were studied extensively using ultrasound at 1–4 week intervals. Dramatic and sudden changes occurred in fetal body movements and growth but not until the end of the second trimester of pregnancy. Prominent at that time were prolonged periods of fetal quiescence and very low heart rate variability, together with abnormally executed body movements of short duration. Retarded femoral development and jerky abrupt fetal body movements (abnormal movement quality) were already present in the early second trimester of pregnancy. Facial anomalies emerged despite the presence of fetal mouth movements. The clinical features of RD were only partly explained by present knowledge of skin development and the fetal akinesia deformation sequence hypothesis. Quantitative assessment of fetal movements proved to be a poor early marker for antenatal diagnosis of this disorder. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
48.
The amounts of total NH
4
+
detected in the external media in which Phascolosoma arcuatum had been exposed to various periods of anoxia were significantly greater than those in which the worms were exposed to normoxia for a similar period. The increased NH
4
+
production by P. arcuatum during anoxic exposure was unlikely to be due to an increased catabolism of adenine nucleotides or urea. In contrast, there were significant decreases in the concentrations of several free amino acids in the coelomic plasma and body tissues of individuals during the 48 h of anoxic exposure. The amount of NH
4
+
produced by the anoxic P. arcuatum could be accounted for by the decreases in the concentrations of aspartate or glycine. Increases in the catabolism of free amino acids (FAA), leading to the increased production of NH
4
+
, in P. arcuatum during anoxia were supported by the detection of significant changes in the kinetic properties of glutamate dehydrogenase (GDH), in the deaminating direction, from worms exposed to anoxia for 48 h. The apparent increase in the affinity of GDH from the anoxic worm to glutamate would bring about a greater deaminating activity at physiological concentrations of ths substrate. P. arcuatum used in these experiments were collected from the mangrove swamp at Mandai, Singapore between 1990 and 1993. 相似文献
49.
50.