全文获取类型
收费全文 | 349篇 |
免费 | 21篇 |
国内免费 | 71篇 |
专业分类
安全科学 | 42篇 |
废物处理 | 12篇 |
环保管理 | 34篇 |
综合类 | 164篇 |
基础理论 | 48篇 |
污染及防治 | 80篇 |
评价与监测 | 14篇 |
社会与环境 | 33篇 |
灾害及防治 | 14篇 |
出版年
2024年 | 3篇 |
2023年 | 9篇 |
2022年 | 13篇 |
2021年 | 13篇 |
2020年 | 12篇 |
2019年 | 13篇 |
2018年 | 19篇 |
2017年 | 23篇 |
2016年 | 31篇 |
2015年 | 21篇 |
2014年 | 15篇 |
2013年 | 14篇 |
2012年 | 17篇 |
2011年 | 13篇 |
2010年 | 14篇 |
2009年 | 11篇 |
2008年 | 19篇 |
2007年 | 16篇 |
2006年 | 9篇 |
2005年 | 10篇 |
2004年 | 11篇 |
2003年 | 5篇 |
2002年 | 11篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 7篇 |
1998年 | 5篇 |
1997年 | 16篇 |
1996年 | 7篇 |
1995年 | 5篇 |
1994年 | 8篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1988年 | 2篇 |
1984年 | 2篇 |
1980年 | 3篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1966年 | 2篇 |
1964年 | 2篇 |
1963年 | 2篇 |
1962年 | 2篇 |
1961年 | 3篇 |
1960年 | 2篇 |
1957年 | 3篇 |
1956年 | 4篇 |
1951年 | 2篇 |
1933年 | 1篇 |
排序方式: 共有441条查询结果,搜索用时 7 毫秒
61.
本文概述了植物的铁素营养、果材缺铁黄化病的诊断治疗方法,论述了高涌液注射法矫治果树缺铁黄化病的理论、假说、树木微型注射器、克黄灵高渗液、树干穴位注射法、树干穴位插管法及其应用前景。 相似文献
62.
63.
Dorothy Lang 《组织行为杂志》1985,6(3):171-182
The study tested predictions derived from Korman (1977) and from Sarason (1977) about factors leading to alienation among occupationally-successful young adults. The sample consisted of 434 college graduates (median age = 29 years), 85 per cent of whom were employed full-time. Respondents completed self-report questionnaires including measures of family and college background; expectations at college graduation for positive outcomes in personal, interpersonal, and work areas; current fulfilment in each of these areas; and alienation (estrangement from self, other people, and occupation or profession). Results of subgroup analysis showed that respondents whose backgrounds included high socio-economic status and graduation from elite colleges were more likely than other subjects to experience alienation when encountering lack of fulfilment. However, moderator regressions failed to show similar moderator effects, indicating that family and college backgrounds may produce discontinuous and qualitatively different subgroup effects. One implication of this study is to suggest more care in selecting individuals for high-risk job assignments with low probability of success. 相似文献
64.
65.
冷媒与空气的反应特征对空调压缩机安全性有重要影响.本文采用最小自由能原理,分别对两种冷媒R407C和R410A与空气的混合气体的爆炸反应参数进行了数值计算,得到了不同初始压力和不同冷媒含量条件下,混合气体爆炸反应温度和压力,分析了混合气体反应压力条件和爆炸极限范围.结果表明:初始压力低于0.2 MPa时,R407C-空气混合气体和R410A-空气混合气体均不会发生爆炸;初始压力超过0.3 MPa时,混合气体能够发生爆炸,爆炸反应温度和压力随着初始压力的升高而升高;R407C和R410A质量分数分别在34%、35%左右,混合气体反应温度和压力达到最大值.R407C和R410A易燃易爆特征相近;但爆炸范围都比氟利昂(R22)气体宽,即同样的条件下更容易发生爆炸.该计算结果能够为新型冷媒R407C和R410A的安全使用提供一定的依据. 相似文献
66.
Extension rate: A primary control on the isotopic composition of West Indian (Jamaican) scleractinian reef coral skeletons 总被引:4,自引:0,他引:4
Large variations in skeletal microarchitecture, and in the carbon and oxygen isotopic composition of the skeleton, exist within single calices and over the surfaces of single colonies of various species of West Indian (Jamaican) scleractinian reef corals. Rapidly extending parts of individual colonies are depleted in both C13 and O18 regardless of the abundance of zooxanthellae in the overlying tissues. We suggest that this relationship is due to active translocation of organic compounds to sites of rapid calcification. Considerable variation in isotopic composition is found in skeletons of different specimens of the same species even when the skeletons are sampled in a consistent manner, come from the same locality and depth, and have a comparable growth history. The isotopic composition of the scleractinian skeleton is vastly more complex than has heretofore been realized. 相似文献
67.
本文论述了我国铅锌矿产资源储量、分布特点和消费现状,并预测了我国铅锌金属的需求量. 相似文献
68.
69.
A thermodynamic sorption model and a diffusion model based on electric double layer (EDL) theory are integrated to yield a surface chemical model that treats porewater chemistry, surface reactions, and the influence of charged pore walls on diffusing ions in a consistent fashion. The relative contribution of Stern and diffuse layer to the compensation of the permanent surface charge represents a key parameter; it is optimized for the diffusion of Cs in Kunipia-F bentonite, at a dry density of 400 kg/m3. The model is then directly used to predict apparent diffusivities (Da) of Cs, Sr, Cl-, I- and TcO4- and corresponding distribution coefficients (Kd) of Cs and Sr in different bentonites as a function of dry density, without any further adjustment of surface chemical and EDL parameters. Effective diffusivities (De) for Cs, HTO, and TcO4- are also calculated. All calculated values (Da, De, Kd) are fully consistent with each other. A comparison with published, measured data shows that the present model allows a good prediction and consistent explanation of (i) apparent and effective diffusivities for cations, anions, and neutral species in compacted bentonite, and of (ii) Kd values in batch and compacted systems. 相似文献
70.
Sources of metals in New York City wastewater 总被引:1,自引:0,他引:1
L A Klein M Lang N Nash S L Kirschner 《Journal - Water Pollution Control Federation》1974,46(12):2653-2662