全文获取类型
收费全文 | 93905篇 |
免费 | 1226篇 |
国内免费 | 1101篇 |
专业分类
安全科学 | 3844篇 |
废物处理 | 3507篇 |
环保管理 | 14377篇 |
综合类 | 21119篇 |
基础理论 | 26742篇 |
环境理论 | 72篇 |
污染及防治 | 16167篇 |
评价与监测 | 5683篇 |
社会与环境 | 4137篇 |
灾害及防治 | 584篇 |
出版年
2022年 | 820篇 |
2021年 | 827篇 |
2020年 | 655篇 |
2019年 | 863篇 |
2018年 | 1224篇 |
2017年 | 1257篇 |
2016年 | 2202篇 |
2015年 | 1836篇 |
2014年 | 2563篇 |
2013年 | 9206篇 |
2012年 | 2365篇 |
2011年 | 2814篇 |
2010年 | 3350篇 |
2009年 | 3497篇 |
2008年 | 2422篇 |
2007年 | 2218篇 |
2006年 | 2537篇 |
2005年 | 2496篇 |
2004年 | 2772篇 |
2003年 | 2611篇 |
2002年 | 2163篇 |
2001年 | 2450篇 |
2000年 | 2041篇 |
1999年 | 1555篇 |
1998年 | 1376篇 |
1997年 | 1370篇 |
1996年 | 1504篇 |
1995年 | 1606篇 |
1994年 | 1486篇 |
1993年 | 1338篇 |
1992年 | 1336篇 |
1991年 | 1310篇 |
1990年 | 1254篇 |
1989年 | 1220篇 |
1988年 | 1065篇 |
1987年 | 1000篇 |
1986年 | 998篇 |
1985年 | 1066篇 |
1984年 | 1163篇 |
1983年 | 1170篇 |
1982年 | 1176篇 |
1981年 | 1099篇 |
1980年 | 938篇 |
1979年 | 935篇 |
1978年 | 830篇 |
1977年 | 721篇 |
1976年 | 639篇 |
1975年 | 610篇 |
1973年 | 652篇 |
1972年 | 648篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
881.
E. S. Zakharov V. M. Safronov L. P. Koryakina N. N. Smetanin 《Russian Journal of Ecology》2016,47(4):392-398
The population of foxes in the central regions of Yakutia has grown by a factor of four to five during the period from 2000 to 2011–2012, following an increase in the abundance of voles from the genus Microtus. A total of 130 carcasses of foxes taken in 2007–2012 have been examined. Age- and sex-related variation in morphological features has been described. The demographic structure of the population has been studied by estimating animal age from annual layers in the recording structures. Changes in female fertility and involvement in reproduction depending on age and feeding conditions have been analyzed. Changes in the composition of fox diet caused by long-term population depression in the mountain hare and their effect on the dynamics of fox abundance have been revealed. Age- and sex-related characteristics of the condition factor in foxes and sex-related differences in their dietary preferences have been demonstrated. 相似文献
882.
D. M. Bezmaternykh 《Russian Journal of Ecology》2016,47(5):480-485
Communities of benthic macroinvertebrates in drainless Lake Chany, the largest lake in Western Siberia, have been analyzed to estimate the effects of basic abiotic ecological factors (hydrophysical and hydrochemical parameters of water and the type of bottom ground) on their composition, structure, and dynamics. It has been shown that the level of development of these communities depends mainly on the water regime of the lake and also on the type of bottom ground, lake depth, and water mineral content. 相似文献
883.
I. V. Blinova 《Russian Journal of Ecology》2016,47(3):234-240
The spatial structure of 10 populations of rare orchid species (Dactylorhiza incarnata, D. traunsteineri, Listera ovata) has been studied in rich fens sporadically occurring in Murmansk oblast. Two levels of plant aggregation within populations have been distinguished: (1) clusters of individuals and (2) isolated population subsets consisting of clusters. General spatial demographic features of orchid populations in the fens are small area (77 m2) and low ecological density (0.009 ind./m2). Characteristics of the population subsets (their number, area, composition, and distance to the neighboring subset) are species-specific and reflect the degree of species rarity in plant communities. 相似文献
884.
V. M. Emets 《Russian Journal of Ecology》2016,47(4):371-375
The role of ecotones with different (sharp or smooth) spatial boundaries between forest and meadow in ant biodiversity preservation was studied at the right-of-way of a power line in the Voronezh Reserve. The ecotone with a sharp boundary between forest and meadow (transitional zone 2 m wide) had higher species richness of ants compared to the ecotones (also 2 m wide) with smooth boundary between forest and meadow. 相似文献
885.
N. P. Korablev M. P. Korablev P. N. Korablev I. L. Tumanov 《Russian Journal of Ecology》2016,47(3):289-295
A comparative analysis of epigenetic variation has been performed in nine European populations and population groups of the American mink. It has been shown that differentiation of samples in nonmetric characters is due mainly to endogenous processes that have occurred in introduced populations in the course of colonization of new territory by the invasive species. Environmental factors have played a secondary role, with the influence of the geographic (latitudinal) origin of a given sample being considerable and stronger than that of macroclimatic factors. 相似文献
886.
V. G. Tereshchenko D. S. Khrystenko G. O. Kotovska L. I. Tereshchenko 《Russian Journal of Ecology》2016,47(4):364-370
The probable source of stone moroko, Pseudorasbora parva (Temminck & Schlegel, 1846), populations in lake- and stream-type Dnieper reservoirs was revealed. The dynamics and specific growth rates of these populations over 20 years were analyzed. The dynamic phase portrait method was used to determine the timing of stages in the process of invader naturalization and the periods when its populations were in equilibrium. The potential growth rates of P. parva populations in the Kremenchug and Dneprodzerzhinsk reservoirs were estimated. 相似文献
887.
888.
Bimal Kumar Mawandiya J. K. Jha Jitesh Thakkar 《International Journal of Sustainable Engineering》2016,9(5):315-328
This paper considers a two-echelon closed-loop supply chain consisting of a manufacturer and a remanufacturer at the upper echelon and a retailer at the lower echelon. The retailer faces a constant demand from customers, which is satisfied through recovered and new products received from the remanufacturer and the manufacturer, respectively. The manufacturer produces the product with finite rate, whereas the recovery of returned product is instantaneous at the remanufacturer. We develop three models to determine the optimal production-inventory policy of the players for minimizing the joint total cost of the system. In the first model, the retailer receives the product in batches from the manufacturer and the remanufacture simultaneously, whereas in the second and third models, the batches are received alternatively. In the third model, however, the procurement of raw material at the manufacturer is also considered. Numerical illustration is presented to examine the impact of certain key parameters. 相似文献
889.
Krishan Kumar Bhatia William T. Riddell 《International Journal of Sustainable Engineering》2016,9(3):215-222
Through a sensitivity analysis, the trade-off between vehicle range and CO2 emissions is investigated as a function of electric emissions coefficient. Various powertrains were analysed for use in a small crossover sport utility vehicle. Gasoline, gasoline electric hybrid, diesel, fuel cell and battery electric vehicles (BEVs) were considered. Using various upstream fuel pathways and a model for vehicle performance, emissions and energy use were estimated. The hydrogen fuel cell vehicle was found preferable to BEVs under conditions of high CO2 emissions per kW-hr and a high vehicle range requirement. The BEV was preferable for all other conditions. 相似文献
890.
S. Alvandi W. Li M. Schönemann C. Herrmann 《International Journal of Sustainable Engineering》2016,9(6):354-362
Value stream mapping (VSM) is a well-accepted tool within lean manufacturing concept which is often used for analysing and designing the flow of materials and information required to manufacture a product. However, the analysis is static and single product oriented, which fails to cope with either the variation of production plan or a multi-product environment. In addition, the environmental impact of a manufacturing system is highly associated with the dynamic consumption of energy and resources. Despite the recent integration of VSM with simulation or environmental studies (in the domain of energy efficiency), still neglected is the dynamic assessment of all the resources involved in a multi-product production environment. This paper presents a methodology for modelling multi-product manufacturing systems with dynamic material, energy and information flows with the aim to generate economic and environmental value stream maps (E2VSM). The proposed methodology is validated with an industrial case. 相似文献