全文获取类型
收费全文 | 33151篇 |
免费 | 392篇 |
国内免费 | 486篇 |
专业分类
安全科学 | 1060篇 |
废物处理 | 1527篇 |
环保管理 | 4203篇 |
综合类 | 5492篇 |
基础理论 | 8640篇 |
环境理论 | 27篇 |
污染及防治 | 8720篇 |
评价与监测 | 2234篇 |
社会与环境 | 1903篇 |
灾害及防治 | 223篇 |
出版年
2023年 | 148篇 |
2022年 | 336篇 |
2021年 | 346篇 |
2020年 | 255篇 |
2019年 | 312篇 |
2018年 | 546篇 |
2017年 | 538篇 |
2016年 | 809篇 |
2015年 | 637篇 |
2014年 | 957篇 |
2013年 | 2629篇 |
2012年 | 1192篇 |
2011年 | 1597篇 |
2010年 | 1286篇 |
2009年 | 1338篇 |
2008年 | 1582篇 |
2007年 | 1656篇 |
2006年 | 1432篇 |
2005年 | 1229篇 |
2004年 | 1074篇 |
2003年 | 1160篇 |
2002年 | 1044篇 |
2001年 | 1284篇 |
2000年 | 921篇 |
1999年 | 560篇 |
1998年 | 394篇 |
1997年 | 412篇 |
1996年 | 393篇 |
1995年 | 469篇 |
1994年 | 490篇 |
1993年 | 378篇 |
1992年 | 404篇 |
1991年 | 370篇 |
1990年 | 405篇 |
1989年 | 351篇 |
1988年 | 306篇 |
1987年 | 290篇 |
1986年 | 238篇 |
1985年 | 263篇 |
1984年 | 281篇 |
1983年 | 275篇 |
1982年 | 257篇 |
1981年 | 236篇 |
1980年 | 192篇 |
1979年 | 210篇 |
1978年 | 188篇 |
1975年 | 143篇 |
1974年 | 124篇 |
1972年 | 136篇 |
1971年 | 133篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
651.
Guo R Li X Christie P Chen Q Zhang F 《Environmental pollution (Barking, Essex : 1987)》2008,151(3):443-451
Two-year greenhouse cucumber experiments were conducted to investigate seasonal effects on fruit yield, dry matter allocation, and N uptake in a double-cropping system with different fertilizer management. Seasonal effects were much greater than fertilizer effects, and winter-spring (WS) cucumber attained higher fruit yields and N uptake than autumn-winter (AW) cucumber due to lower cumulative air temperatures during fruit maturation in the AW season. Fertilizer N application and apparent N loss under recommended N management (Nmr) decreased by 40-78% and 33-48% without yield loss compared to conventional N management (Nmt) over four growing seasons. However, there were no seasonal differences in N recommendations, taking into consideration seasonal differences in crop N demand, critical nutrient supply in the root zone and N mineralization rate. 相似文献
652.
Peng Lian Andres F. Mejia Zhengdong Cheng M. Sam Mannan 《Journal of Loss Prevention in the Process Industries》2010,23(2):337-345
Accidental release of pressurized high flash point heat transfer fluids can result in fire and explosion hazard scenarios in the process industry. An experimental investigation on ignition of aerosols of a heat transfer fluid is carried out, and characterization of aerosol and its ignition process by non-intrusive laser diffraction technique is reported. Propagation speed of the aerosol combustion flame front as analyzed from the laser diffraction measurement agrees with high-speed visual camera observation. Flammability of the aerosol, which is based on the chances of the global flame appearance in the aerosol, is mainly controlled by aerosol droplet size and the droplet volume concentration. 相似文献
653.
654.
Idiosyncratic deals in contemporary organizations: A qualitative and meta‐analytical review 下载免费PDF全文
Idiosyncratic deals (i‐deals) research focuses on the emergence of customized work arrangements employees negotiate with their employers. This article provides a critical review and synthesis of i‐deals research, combining a qualitative review of i‐deals theory and research with a supplementary meta‐analysis of 23 empirical studies (k = 27 samples, N = 8110 individuals). The qualitative review examines the conceptualization and measurement of i‐deals and identifies patterns and gaps in i‐deals research, while the quantitative meta‐analysis tests the moderating effect of societal cultures on the predictors and consequences of ideals investigated to date. In each section, attention is given to strengths and weaknesses of current approaches to i‐deals theory and research. Future research directions are identified with particular emphasis on the largely unexamined role of i‐deals from a multilevel perspective. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
655.
Affirmative Action Programs (AAPs) are becoming increasingly common in the workplace. Typically their effectiveness has been assessed by the number of women and minorities hired and promoted. A neglected, but important measure of effectiveness is how AAPs are perceived by employees. When employees perceive that AAPs violate notions of fairness, negative attitudes and behaviors may occur and lead to decreased organizational performance. A model of perceived AAP fairness is presented using an organizational justice perspective. An initial (partial) test of the model is conducted and avenues for future research are discussed. 相似文献
656.
657.
In studies of occupational risks, severity, which is a component of the estimation of every risk, appears as a multifaceted entity assessable according to numerous criteria. A method of measuring the degree of severity of the consequences of potentially dangerous events would be of undeniable value to organisations seeking to improve their understanding of the complexity of such events. The need to control severity is highlighted by scientifically acquired improvements in the understanding of occupational risks, by certain new regulatory obligations in Europe, and by some requirements in the financial management of organisations. We put forward a statistical way of integrating several constituent elements of severity and hence of determining a relevant, synthetic, one-dimensional index. This is achieved by means of principal component analysis (PCA), which is used here to calculate a resultant severity, as in some physical measurements. We also investigate how severity may be statistically modelled, with the aim of contributing to the quantitative assessment of occupational risks. The choice of parametric models is detailed and illustrated by the search for a suitable model for workplace accidents in an organisational setting. The practical value of modelling severity is two-fold. First, one is able to study the distribution of the numerical values of severity over a continuum (a theoretically infinite numerical set) rather than through a limited number of arbitrarily defined categories. Second, with a generally applicable parametric model, one can estimate the law of probability of a measurement of severity in a particular situation, notably recent or new. Lastly, the statistical concept of risk curve is defined and discussed. The goal is to incorporate the severity component into the risk assessment in the form of a probability law, thus circumventing the difficulties associated with an analysis of scenarios. 相似文献
658.
V. V. Akatov T. V. Akatova T. G. Eskina N. M. Sazonets S. G. Chefranov 《Russian Journal of Ecology》2013,44(6):445-454
The occurrence of density compensation effect (DCE) has been estimated in areas occupied by synanthropic communities in the Western Caucasus. The density of dominant plant species has been estimated from their coverage, and that of subordinate species, from their frequency in 0.5-m2 squares within 15 (16)-m2 plots, using natural and seminatural communities as a reference standard. The factual material has been analyzed by the method of numerical experiments. The results show that the transformation of natural habitats into anthropogenic ones has led to a decrease in the species diversity of plant communities, but without causing a widespread occurrence of DCE. It is hypothesized that relatively high average values of species frequency in low-diversity synanthropic communities are more likely accounted for by random rather than compensatory processes. 相似文献
659.
Russian Journal of Ecology - Abstract—Long-term observations (1968–2019) on the dynamics of infection by the cestode Eubothrium rugosum in the burbot (Lota lota) have been performed in... 相似文献
660.
Russian Journal of Ecology - The variability of the ecological and morphological characteristics of the field vole was studied on samples collected in its two localities of the Southern Urals and... 相似文献