全文获取类型
收费全文 | 11534篇 |
免费 | 86篇 |
国内免费 | 52篇 |
专业分类
安全科学 | 245篇 |
废物处理 | 503篇 |
环保管理 | 901篇 |
综合类 | 1755篇 |
基础理论 | 2609篇 |
环境理论 | 8篇 |
污染及防治 | 3229篇 |
评价与监测 | 934篇 |
社会与环境 | 1445篇 |
灾害及防治 | 43篇 |
出版年
2023年 | 76篇 |
2022年 | 192篇 |
2021年 | 225篇 |
2020年 | 109篇 |
2019年 | 136篇 |
2018年 | 296篇 |
2017年 | 326篇 |
2016年 | 429篇 |
2015年 | 280篇 |
2014年 | 483篇 |
2013年 | 923篇 |
2012年 | 526篇 |
2011年 | 608篇 |
2010年 | 443篇 |
2009年 | 450篇 |
2008年 | 625篇 |
2007年 | 630篇 |
2006年 | 501篇 |
2005年 | 436篇 |
2004年 | 409篇 |
2003年 | 366篇 |
2002年 | 326篇 |
2001年 | 323篇 |
2000年 | 235篇 |
1999年 | 130篇 |
1998年 | 91篇 |
1997年 | 93篇 |
1996年 | 83篇 |
1995年 | 112篇 |
1994年 | 94篇 |
1993年 | 66篇 |
1992年 | 76篇 |
1991年 | 79篇 |
1990年 | 90篇 |
1989年 | 69篇 |
1988年 | 57篇 |
1987年 | 48篇 |
1986年 | 70篇 |
1985年 | 59篇 |
1984年 | 63篇 |
1983年 | 49篇 |
1982年 | 65篇 |
1981年 | 45篇 |
1980年 | 57篇 |
1979年 | 52篇 |
1978年 | 36篇 |
1975年 | 38篇 |
1973年 | 37篇 |
1972年 | 47篇 |
1969年 | 36篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Pérez-de-Mora A Madejón P Burgos P Cabrera F Lepp NW Madejón E 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):3018-3027
We investigated the efficiency of various by-products (sugarbeet lime, biosolid compost and leonardite), based on single or repeated applications to field plots, on the establishment of a vegetation cover compatible with a stabilization strategy on a multi-element (As, Cd, Cu, Pb and Zn) contaminated soil 4-6 years after initial amendment applications. Results indicate that the need for re-treatment is amendment- and element-dependent; in some cases, a single application may reduce trace element concentrations in above-ground biomass and enhance the establishment of a healthy vegetation cover. Amendment performance as evaluated by % cover, biomass and number of colonizing taxa differs; however, changes in plant community composition are not necessarily amendment-specific. Although the translocation of trace elements to the plant biotic compartment is greater in re-vegetated areas, overall loss of trace elements due to soil erosion and plant uptake is usually smaller compared to that in bare soil. 相似文献
992.
Anne Bado-Nilles Stéphane Betoulle Alain Geffard Jean-Marc Porcher Béatrice Gagnaire Wilfried Sanchez 《Environmental science and pollution research international》2013,20(5):2692-2704
The neutral red retention assay has been proposed to determine the lysosomal membrane stability in immune cells. Nevertheless, this assay implies many examinations under a microscope at short time intervals and therefore the analysis of few samples. The present study proposes two more rapid, efficient, and sensitive sample analyses using flow cytometry method. Lysosomal presence and lysosomal membrane integrity (LMI) were evaluated on the three-spined stickleback, Gasterosteus aculeatus (L.), a well-described model fish species for aquatic ecotoxicology studies. After development of the two biomarkers, they were validated by ex vivo contamination with endosulfan and copper and by in situ sampling. These immunomarkers were clearly modulated by pollutants and their variations seemed to be correlated with leucocyte mortality. Thus, from a practical point of view, lysosomal presence and LMI may provide novel and efficient means of evaluating immune capacities and indicating the toxic effects of environmental pollution. 相似文献
993.
Dry weight (DW), oxygen consumption, ammonia-N excretion, proximate biochemical composition (total protein, carbohydrate,
lipid, water and ash), and energy content (estimated from biochemical composition and by wet combustion) were determined in
early developmental stages of cultured Farfantepenaeus paulensis. Pooled samples from embryonic, larval and postlarval stages (at 26 ± 1 °C and 34 ± 1‰) were used for measurements. The study
focused on physiological and biochemical processes during transitional periods of ontogeny, such as hatching, lecithotrophic
and planktotrophic stages, metamorphosis, and the attainment of a benthic existence in postlarva. DW showed higher increment
between protozoea I (PZ I) and mysis I (M I) than in the next mysid and postlarval stages. Individual rates of oxygen consumption
and ammonia-N excretion increased, while weight-specific rates presented significant reduction throughout development. Higher
weight-specific oxygen consumption was registered in nauplius III (N III) and PZ I, following a decrease in subsequent stages.
Postlarval stages PL V–VI and PL X–XII exhibited the lowest values among the stages studied. Weight-specific excretion was
high in N III and protozoeal stages, with maximum values in PZ II, while the following stages were marked by lower rates.
O:N ratios indicated higher protein catabolism in the stages between egg and M I and a shift to more lipid utilization close
to metamorphosis. Water content was higher in the protozoeal stages and decreased afterwards. Higher percentages of protein,
lipid and carbohydrate (%DW) were observed in egg and nauplius stages. Protein and lipid decreased from the egg through the
naupliar and protozoeal stages, rising again in mysis stages. Lipid content (%DW) decreased in PL V–VI and PL X–XII. Lipid:protein
ratios showed an increase of the importance of lipid between PZ III and M II. Carbohydrates represented a minor fraction of
body composition, and ash percentages increased from egg to a maximum in PZ II, decreasing in subsequent stages. Energy content
determined by wet combustion or calculated by energy equivalents presented the same trend throughout development, varying
similarly to protein. Protein was the main energy contributor to body energy in all stages, while the importance of lipid
was higher in egg and early naupliar stages. Trends observed in metabolic rates and body composition may be associated to
morphological and behavioral changes during the early stages of penaeid development, such as the transition from herbivory
to omnivory, and the adoption of a benthic existence. Different ontogenetic energy strategies contribute to succeed through
such diverse type of development.
Received: 4 July 2000 / Accepted: 6 December 2000 相似文献
994.
Abstract: Nongame bird hunting is a critical activity of the Zuni people of the southwestern United States. To help determine whether their current hunting practices may be negatively affecting bird populations on the Zuni Reservation, we interviewed 98 Zuni hunters. Nongame bird hunting was practiced by a large portion of Zuni males (45%); the most active age group was 20- to 49-year-olds. The rate a species was hunted was not a function of its abundance at Zuni but seemed instead to be related to its cultural demand. Five "species"—bluebirds ( Sialia currucoides , S. mexicana ), Northern Flicker ( Colaptes auratus ), woodpeckers ( Picoides villosus , P. pubescens , Melanerpes lewis ), Steller's Jay ( Cyanocitta stelleri ), and American Kestrel ( Falco sparverius )—made up 77% of all birds taken. The two most heavily hunted species were each taken in numbers> 10,000 individuals per year. Although the greatest number of hunters were active in autumn, 31% hunted in spring, despite discouragement by the tribal government. Habitats favored by hunters were coniferous forests and riparian areas. Rates of hunting of nongame birds at Zuni equaled or exceeded those reported for game birds hunted by indigenous hunters in the Neotropics and New Mexico. The Zuni believe that some heavily hunted species are decreasing in number because of hunting. Although we cannot prove this at present, we suggest measures to mitigate possible overhunting, including the creation of refugia and a reduction of spring hunting. 相似文献
995.
996.
Effects of dissolved ammonium addition and host feeding with Artemia salina on photoacclimation of the hermatypic coral Stylophora pistillata 总被引:6,自引:0,他引:6
E. Titlyanov K. Bil' I. Fomina T. Titlyanova V. Leletkin N. Eden A. Malkin Z. Dubinsky 《Marine Biology》2000,137(3):463-472
Effects of nutrient treatments on photoacclimation of the hermatypic coral Stylophora pistillata (Esper) were studied. Studies on photoacclimation of colonies from different light regimes in the field were evaluated and
used to design laboratory experiments. Coral colonies were collected in the Gulf of Eilat (Israel) from January to March 1993.
Exterior branches of colonies from different depths (1 to 40 m) displayed different trends in production characteristics at
reduced and very low levels of illumination. From 24 ± 3% to 12 ± 2% of incident surface photosynthetic active radiation (PARo), zooxanthella population density and chlorophyll a+c per 106 zooxanthellae increased, a trend seen in the range of light levels optimal for coral growth (90 to 30% PARo). The P
max of CO2 per 106 zooxanthellae decreased, while P
max of CO2 per 103 polyps increased, indicating an increase in zooxanthella population density at low light levels. Proliferous zooxanthella
frequency (PZF, a measure of zooxanthella division) declined significantly at light levels <18 ± 3% PARo. At the lowest levels of illumination (<5% PARo), zooxanthella population density decreased, as did the PZF; chl a+c per 106 zooxanthellae was unchanged. In 28-d experiments, exterior coral branches from the upper surfaces of colonies from 3 m depth
(65 ± 4% PARo) were incubated in aquaria under bright (80 to 90% PARo), reduced (20 to 30% PARo), and extremely low (2 to 4% PARo) light intensities. At each light intensity, the corals were maintained in three feeding treatments: sea water (SW); ammonium
enriched SW (SW + N); SW with Artemia salina nauplii (SW + A). An increase in P
max of CO2 per 103 polyps was found in corals acclimated to reduced light (20 to 30% PARo) in nutrient-enriched SW, while in SW, where the increase in zooxanthella population density was smaller, it did not occur.
Nutrient enrichments (SW + N at 2 to 4% PARo and SW + A at 20 to 30% PARo) increased zooxanthella population density, but had no effect on chl a+c per 106 zooxanthellae. Acclimation for 14 d to reduced (10 to 20% PARo) and extremely low (1 to 3% PARo) light intensities shifted 14C photoassimilation into glycerol and other compounds (probably glycerides), rather than sugars. Both ammonium addition and
feeding with Artemia salina nauplii resulted in an increase in photosynthetic assimilation of 14C into amino acids. We conclude that acclimation to reduced light consists of two processes: an increase in photosynthetic
pigments and in zooxanthella population density. Both processes require nitrogen, the increase in zooxanthella population
density needing more; this adaptation is therefore limited in nitrogen-poor sea water.
Received: 19 June 1998 / Accepted: 13 June 2000 相似文献
997.
The accumulation of lipofuscin, which is an indictor of physiological age, in the brain of juvenile European lobster (Homarus gammarus L.) was monitored for 22 mo in three experimental temperature regimes that simulated seasonal variation in temperature in
the geographic range of this species. Metabolic rate responses to changes in temperature were estimated by measuring the activity
of the electron transport system (ETS) in muscle tissue and in vivo rates of oxygen consumption. Lipofuscin accumulation oscillated
with simulated seasonal changes in temperature and was described by seasonalised von Bertalanffy growth functions. The incremental
accumulation in lipofuscin between sampling dates was linearly related to the number of degree days that accumulated between
dates, irrespective of the amplitude of temperature fluctuation that had occurred. ETS activity increased with acclimation
temperature and was modelled using a polynomial function. This indicated a lower temperature sensitivity in the temperature
mid-range (12 to 16 °C), although the Q10 for this mid-range was 2.1. ETS activity in lobsters acclimated to 8 and 18 °C and assayed at 13 °C was similar, indicating
no compensation for changes in environmental temperature. Oxygen consumption rate was significantly higher at 14 °C than at
10.5 °C and had a Q10 of 3.6, again suggesting no compensation to temperature change. The absence of metabolic compensation in response to temperature
change in H. gammarus is consistent with the predictability of changes in temperature and food availability in the sub-littoral environment of
this species. As lipofuscin accumulates according to metabolic rate, and metabolic rate in H. gammarus is directly correlated with temperature, geographic differences and long-term temporal trends in temperature will need to
be considered when converting physiological age indices, obtained from lipofuscin estimates, to a chronological scale.
Received: 27 April 2000 / Accepted: 21 July 2000 相似文献
998.
Joke Muys Yves Jacquemyn Bettina Blaumeiser Laura Bourlard Nathalie Brison Saskia Bulk Patrizia Chiarappa Anne De Leener Marjan De Rademaeker Julie Désir Anne Destrée Koenraad Devriendt Annelies Dheedene Armelle Duquenne Annelies Fieuw Erik Fransen Jean-Stéphane Gatot Mauricette Jamar Sandra Janssens Jorien Kerstjens Kathelijn Keymolen Damien Lederer Björn Menten Bruno Pichon Sonia Rombout Yves Sznajer Ann Van Den Bogaert Kris Van Den Bogaert Joris Vermeesch Katrien Janssens 《黑龙江环境通报》2020,40(10):1272-1283
999.
1000.