全文获取类型
收费全文 | 30890篇 |
免费 | 329篇 |
国内免费 | 224篇 |
专业分类
安全科学 | 859篇 |
废物处理 | 1112篇 |
环保管理 | 4115篇 |
综合类 | 5178篇 |
基础理论 | 8771篇 |
环境理论 | 27篇 |
污染及防治 | 8081篇 |
评价与监测 | 1807篇 |
社会与环境 | 1300篇 |
灾害及防治 | 193篇 |
出版年
2022年 | 186篇 |
2021年 | 192篇 |
2019年 | 223篇 |
2018年 | 416篇 |
2017年 | 413篇 |
2016年 | 581篇 |
2015年 | 519篇 |
2014年 | 714篇 |
2013年 | 2208篇 |
2012年 | 867篇 |
2011年 | 1305篇 |
2010年 | 1066篇 |
2009年 | 1073篇 |
2008年 | 1317篇 |
2007年 | 1397篇 |
2006年 | 1238篇 |
2005年 | 1049篇 |
2004年 | 1034篇 |
2003年 | 971篇 |
2002年 | 972篇 |
2001年 | 1277篇 |
2000年 | 888篇 |
1999年 | 567篇 |
1998年 | 439篇 |
1997年 | 444篇 |
1996年 | 453篇 |
1995年 | 491篇 |
1994年 | 455篇 |
1993年 | 405篇 |
1992年 | 418篇 |
1991年 | 381篇 |
1990年 | 383篇 |
1989年 | 418篇 |
1988年 | 352篇 |
1987年 | 301篇 |
1986年 | 282篇 |
1985年 | 311篇 |
1984年 | 299篇 |
1983年 | 326篇 |
1982年 | 332篇 |
1981年 | 284篇 |
1980年 | 249篇 |
1979年 | 273篇 |
1978年 | 235篇 |
1977年 | 201篇 |
1976年 | 210篇 |
1975年 | 200篇 |
1974年 | 180篇 |
1973年 | 178篇 |
1972年 | 206篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
261.
Runar Brännlund Amin Karimu Patrik Söderholm 《Environmental Economics and Policy Studies》2017,19(2):359-390
Environmental Economics and Policy Studies - This paper examines convergence of per capita carbon dioxide (CO2) emission for a panel of 124 countries taking into account the impact of economic... 相似文献
262.
J. Cambrollé S. Redondo-Gómez E. Mateos-Naranjo T. Luque M. E. Figueroa 《Russian Journal of Ecology》2014,45(3):215-222
Glaucium flavum Crantz. is a short-lived perennial herb distributed in coastal zones from the Black Sea to southern, western and north-western Europe. Despite its diminishing area of distribution and potential pharmacological value, little is known about the ecophysiological features of this coastal species. We investigated the photosynthetic performance of G. flavum by measuring gas exchange, chlorophyll fluorescence, photosynthetic pigment concentration and leaf water content over the space of a year in a coastal habitat of SW Spain. We also measured the variation in total concentrations of nitrogen, phosphorus, sulphur, potassium, calcium and magnesium, in the leaves and soil, throughout the study period. G. flavum showed a high resistance to summer drought conditions which appeared to be due to the high degree of stomatal control. The potential photochemical efficiency of photosystem II showed minimum values during the winter, indicating that low temperatures can produce negative effects within the photosynthetic apparatus. However, the marked decline in net photosynthesis during the winter seems to be mainly related to a loss of metabolic activity. Although leaf nutrient concentrations were, in general, within the normal ranges, phosphorus availability seems to be limited by the high calcium concentrations detected in the soil of the study site. Our study points out the efficiency of the different physiological adaptations of this rare and endangered coastal species in coping with the strong seasonal variability of the Mediterranean climate. 相似文献
263.
F. Ravera A. Scheidel J. dell’Angelo G. Gamboa T. Serrano S. Mingorría V. Cabello N. Arizpe P. Ariza 《Environment, Development and Sustainability》2014,16(4):811-820
While rural transformations are nothing new in human history, current processes of rural change occur under multiple forces at an unprecedented pace, involving profound and unexpected changes in land use and users, and rapid transformations in the metabolic patterns of rural systems. The present special section aims to shed light on current drivers and pathways of rural change by analyzing, under a common conceptual and theoretical framework, examples of new ruralities that are emerging as responses across different world regions. Within this context, this introduction presents: (1) common research questions of the six presented cases of rural change; (2) the general theoretical and methodological framework of integrated assessment of societal metabolism adopted to analyze rural systems and (3) the main contributions and conclusions that could be drawn from six context-specific case studies from Asia, Latin America and Europe. 相似文献
264.
Both the ‘cascade model’ of ecosystem service provision and the Driver-Pressure-State-Impact-Response framework individually contribute to the understanding of human–nature interactions in social–ecological systems (SES). Yet, as several points of criticism show, they are limited analytical tools when it comes to reproducing complex cause–effect relationships in such systems. However, in this paper, we point out that by merging the two models, they can mutually enhance their comprehensiveness and overcome their individual conceptual deficits. Therefore we closed a cycle of ecosystem service provision and societal feedback by rethinking and reassembling the core elements of both models. That way, we established a causal sequence apt to describe the causes of change to SES, their effects and their consequences. Finally, to illustrate its functioning we exemplified and discussed our approach based on a case study conducted in the Alpujarra de la Sierra in southern Spain.
Electronic supplementary material
The online version of this article (doi:10.1007/s13280-015-0651-y) contains supplementary material, which is available to authorized users. 相似文献265.
Jay M. Iwasaki Barbara I. P. Barratt Janice M. Lord Alison R. Mercer Katharine J. M. Dickinson 《Ambio》2015,44(7):694-704
The Varroa mite (Varroa destructor) is implicated as a major disease factor in honey bee (Apis mellifera) populations worldwide. Honey bees are extensively relied upon for pollination services, and in countries such as New Zealand and Australia where honey bees have been introduced specifically for commercial pollinator services, the economic effects of any decline in honey bee numbers are predicted to be profound. V. destructor established in New Zealand in 2000 but as yet, Australia remains Varroa-free. Here we analyze the history of V. destructor invasion and spread in New Zealand and discuss the likely long-term impacts. When the mite was discovered in New Zealand, it was considered too well established for eradication to be feasible. Despite control efforts, V. destructor has since spread throughout the country. Today, assessing the impacts of the arrival of V. destructor in this country is compromised by a paucity of data on pollinator communities as they existed prior to invasion. Australia’s Varroa-free status provides a rare and likely brief window of opportunity for the global bee research community to gain understanding of honey bee-native pollinator community dynamics prior to Varroa invasion. 相似文献
266.
267.
S. Heine W. Schmitt G. Görlitz A. Schäffer T. G. Preuss 《Environmental science and pollution research international》2014,21(16):9644-9654
Laboratory toxicity tests are a key component of the aquatic risk assessments of chemicals. Toxicity tests with Myriophyllum spicatum are conducted based on working procedures that provide detailed instructions on how to set up the experiment, e.g., which experimental design is necessary to get reproducible and thus comparable results. Approved working procedures are established by analyzing numerous toxicity tests to find a compromise between practical reasons (e.g., acceptable ranges of ambient conditions as they cannot be kept completely constant) and the ability for detecting growth alterations. However, the benefit of each step of a working procedure, e.g., the random repositioning of test beakers, cannot be exactly quantified, although this information might be useful to evaluate working procedures. In this paper, a growth model of M. spicatum was developed and used to assess the impact of temperature and light fluctuations within the standardized setup. It was analyzed how important it is to randomly reassign the location of each plant during laboratory tests to keep differences between the relative growth rates of individual plants low. Moreover, two examples are presented on how modeling can give insight into toxicity testing. Results showed that randomly repositioning of individual plants during an experiment can compensate for fluctuations of light and temperature. A method is presented on how models can be used to improve experimental designs and to quantify their benefits by predicting growth responses. 相似文献
268.
Adeola A. Adenugba Dena W. Mcmartin Angus J. Beck 《Journal of environmental science and health. Part. B》2013,48(5):410-421
This study reports on the potential for gastrointestinal (GI) mobilization and bioavailability of food-borne PCBs in humans. The development and validation of a GI simulator and operational protocols, developed in compliance with the requirements of German DIN 19738 risk assessment test procedure, are presented. Food, naturally contaminated with PCBs, was homogenized with simulated saliva fluid and shaken in the GI simulator with simulated gastric fluids (containing pepsin, mucine) for 2 h at 37°C. Afterwards, the simulated intestinal fluids (containing pepsin, mucine, trypsin, pancreatin, bile) were added and the mixture shaken for a further 6 h prior to centrifugation and filtration using Buchner funnels to separate the undigested GI residues from GI fluids. PCBs were recovered from GI residues and fluids by Soxhlet and liquid-liquid extraction respectively, cleaned up using silica-SFE, and analyzed by gas chromatography mass spectrometry detection (GC-MSD). Detailed studies with fish indicate variations in mobilization and bioavailability of Σ PCBs (28, 52, 101, 118, 153, 138 and 180). For example, the bioavailable fractions (fractions mobilized) in mackerel, salmon, crab and prawn were 0.77, 0.60, 0.54, and 0.72 respectively of the Σ PCBs initially present in these food samples. The bioavailable fraction was dependent on the physicochemical characteristics of the PCBs. In mackerel bioavailable fractions for individual PCB congeners ranged from 0.47–0.82, from 0.30–0.70 in salmon, 0.44–0.64 in crab and in prawn from 0.47–0.77. Future studies will focus on understanding better, the variability in bioavailable fractions to be expected for different foodstuffs, in addition to tissue culture techniques using human gut cell lines to investigate a simultaneous mobilization and absorption of food-borne PCBs. 相似文献
269.
B. Pandompatam A. J. Liem R. Frenette M. A. Wilson 《Journal of the Air & Waste Management Association (1995)》2013,63(3):310-316
The thermal decomposition of SF6 is known to be oxygen-independent. Nevertheless, because of its high stability, the use of SF6 as a "conservative" surrogate in incinerator performance evaluation has been advocated and researched. This paper shows that refractory decreases markedly the stability of SF6. The resulting increase in SF6 decomposition was from 0 percent to 95 percent at 900°C, and the temperatures at which 90-99 percent decomposition occurred were lowered by 300-150°C. Refractory also decreased the stability of CCl4 and C2Cl4, but to a lesser extent. The difference between the decompositions of C2Cl4 and SF6 was reduced from several orders of magnitude to a factor of 2-4. Such a drastic and adverse change in relative stability could render SF6 unsuitable as a "conservative" surrogate. The requirements for a "conservative" surrogate and the need for caution in its use are discussed, and further research areas are indicated. 相似文献
270.
Zhou YF Haynes RJ Naidu R 《Environmental science and pollution research international》2012,19(4):1260-1270