全文获取类型
收费全文 | 10372篇 |
免费 | 127篇 |
国内免费 | 102篇 |
专业分类
安全科学 | 298篇 |
废物处理 | 497篇 |
环保管理 | 1345篇 |
综合类 | 1290篇 |
基础理论 | 2814篇 |
环境理论 | 6篇 |
污染及防治 | 2858篇 |
评价与监测 | 750篇 |
社会与环境 | 692篇 |
灾害及防治 | 51篇 |
出版年
2022年 | 105篇 |
2021年 | 87篇 |
2020年 | 75篇 |
2019年 | 84篇 |
2018年 | 158篇 |
2017年 | 160篇 |
2016年 | 257篇 |
2015年 | 188篇 |
2014年 | 259篇 |
2013年 | 790篇 |
2012年 | 334篇 |
2011年 | 478篇 |
2010年 | 387篇 |
2009年 | 428篇 |
2008年 | 495篇 |
2007年 | 494篇 |
2006年 | 444篇 |
2005年 | 384篇 |
2004年 | 335篇 |
2003年 | 390篇 |
2002年 | 338篇 |
2001年 | 511篇 |
2000年 | 336篇 |
1999年 | 203篇 |
1998年 | 143篇 |
1997年 | 141篇 |
1996年 | 142篇 |
1995年 | 170篇 |
1994年 | 127篇 |
1993年 | 108篇 |
1992年 | 127篇 |
1991年 | 124篇 |
1990年 | 132篇 |
1989年 | 132篇 |
1988年 | 96篇 |
1987年 | 87篇 |
1986年 | 70篇 |
1985年 | 92篇 |
1984年 | 89篇 |
1983年 | 87篇 |
1982年 | 86篇 |
1981年 | 77篇 |
1980年 | 64篇 |
1979年 | 70篇 |
1978年 | 47篇 |
1977年 | 53篇 |
1976年 | 49篇 |
1975年 | 53篇 |
1974年 | 54篇 |
1973年 | 53篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
931.
932.
933.
Blake T. Dotta Nirosha J. Murugan Lukasz M. Karbowski Robert M. Lafrenie Michael A. Persinger 《Die Naturwissenschaften》2014,101(2):87-94
During the first 24 h after removal from incubation, melanoma cells in culture displayed reliable increases in emissions of photons of specific wavelengths during discrete portions of this interval. Applications of specific filters revealed marked and protracted increases in infrared (950 nm) photons about 7 h after removal followed 3 h later by marked and protracted increases in near ultraviolet (370 nm) photon emissions. Specific wavelengths within the visible (400 to 800 nm) peaked 12 to 24 h later. Specific activators or inhibitors for specific wavelengths based upon Cosic’s resonant recognition model elicited either enhancement or diminishment of photons at the specific wavelength as predicted. Inhibitors or activators predicted for other wavelengths, even within 10 nm, were less or not effective. There is now evidence for quantitative coupling between the wavelength of photon emissions and intrinsic cellular chemistry. The results are consistent with initial activation of signaling molecules associated with infrared followed about 3 h later by growth and protein-structural factors associated with ultraviolet. The greater-than-expected photon counts compared with raw measures through the various filters, which also function as reflective material to other photons, suggest that photons of different wavelengths might be self-stimulatory and could play a significant role in cell-to-cell communication. 相似文献
934.
T. Colombo R. Santaguida A. Capasso F. Calzolari F. Evangelisti P. Bonasoni 《Atmospheric environment (Oxford, England : 1994)》2000,34(29-30)
The study concerning carbon dioxide measurements taken during the 1997, 1998 and 1999 summer campaigns at two different altitude stations and biospheric conditions are presented. The higher station (Mt. Cimone, 2165 m a.s.l.) is characterised by 360° free horizon and is located on a rocky mountain while the lower (Ninfa lake, 1550 m a.s.l.) is located inside the red spruce and beech forest. The different behaviour of CO2 at the two mountain stations has been registered. It shows the strong effect of nighttime soil emission and vegetation respiration on CO2 mixing ratio increases and of diurnal vegetative activity on CO2 concentration decreases at the lower measurement site. The baseline character of the higher measurement site has been confirmed by comparison of CO2 diurnal amplitudes recorded at the two stations. 相似文献
935.
For this study, field measurements of current profiles, buoy trajectories and the lag of two tidal stations were performed to explore the flow characteristics of Taichung Harbour. in order to distinguish the effects of wind drift current on circulation inside Taichung Harbour, field surveys during both summer and monsoon (winter) season were completed separately. the speed of the drift current was about 3.5% that of the, wind speed, based on the field data. the horizontal dispersion coefficients were close to Bowden's (1965) formula for the tidal current. the water temperature showed a two-layer profile, with the mixing thickness about 4 to 6 metres for the upper layer. the corresponding Richardson number was about 70. the tidal lag between the two tidal stations was 9.68 minutes. All the results agree well with the theoretical results. 相似文献
936.
In recent years, many electronic manufacturing firms have looked upon Cleaner Production (CP) as the means by which they could maintain environmental practice and competitive advantages. CP has been adopted by companies as an important factor in enhancing industrial productivity. Sustainable projects that deal appropriately with environmental and social factors are also more likely to be the most profitable.This paper investigated the criteria and attributes that determine a successful adoption and implementation of CP in reference to PWB manufacture in Taiwan. Fuzzy Analytic Hierarchy Process (FAHP) methodology is used to discuss the different decision criteria that include Organizing, Systems and Technologies, Measurement and Feedback, Working environment and Worker's Culture which are all vital factors in an effective CP implementation. AHP is an efficient tool in controlling the fuzziness of the data involved in choosing the most preferred decision variables. The linguistic level of comparisons produced by the manufacturers and experts are tapped and constructed in a form of triangular fuzzy numbers in order to construct fuzzy pairwise comparison matrices. The implementation of the system is demonstrated by a problem involving three stages of hierarchy which contains different criteria and attributes at a wider perspective within an environmental uncertainty. The findings advocate that these enterprises would need to setup the priorities of the CP implementation. The results suggest a generic hierarchical model of organizations of which the highest level is to be prioritized among the CP implementation factors. 相似文献
937.
The development of brown trout (Salmo trutta f. fario L.) in water of two differently polluted streams and in a control situation was monitored in order to get insights into the impact of anthropogenic chemical stressors on the reproductive success of this fish species indigenous to both streams. The test streams, situated in the south of Stuttgart, Germany, were the complexly polluted K?rsch stream and the less polluted Kr?henbach stream. Bypass systems connected to the streams and a laboratory control system were used for continuous exposure of early brown trout stages shortly after fertilisation up to the end of the embryonic development. Temperature and oxygen conditions were standardised in all test series in order to minimise unspecific effects. The examined endpoints were: (1) mortality, (2) developmental rate, (3) time course of hatching, (4) malformations, and (5) growth. A retarded development, reduced growth rates and higher mortality rates of K?rsch stream water exposed embryos indicated an embryotoxic potential for the more polluted stream. High infection-related mortality rates of embryos suggested the presence of confounding factors also in the less polluted Kr?henbach stream. In parallel to the exposure experiment, physicochemical and limnochemical parameters as well as concentrations of organic contaminants and heavy metals were monitored. Analytical data confirm the different degrees of pollution of both streams. 相似文献
938.
939.
940.