全文获取类型
收费全文 | 16739篇 |
免费 | 151篇 |
国内免费 | 74篇 |
专业分类
安全科学 | 452篇 |
废物处理 | 628篇 |
环保管理 | 2372篇 |
综合类 | 2714篇 |
基础理论 | 4520篇 |
环境理论 | 4篇 |
污染及防治 | 4306篇 |
评价与监测 | 1011篇 |
社会与环境 | 853篇 |
灾害及防治 | 104篇 |
出版年
2022年 | 115篇 |
2021年 | 134篇 |
2020年 | 124篇 |
2019年 | 180篇 |
2018年 | 226篇 |
2017年 | 224篇 |
2016年 | 359篇 |
2015年 | 256篇 |
2014年 | 367篇 |
2013年 | 1277篇 |
2012年 | 452篇 |
2011年 | 642篇 |
2010年 | 541篇 |
2009年 | 524篇 |
2008年 | 695篇 |
2007年 | 697篇 |
2006年 | 668篇 |
2005年 | 510篇 |
2004年 | 592篇 |
2003年 | 527篇 |
2002年 | 488篇 |
2001年 | 708篇 |
2000年 | 479篇 |
1999年 | 290篇 |
1998年 | 249篇 |
1997年 | 221篇 |
1996年 | 233篇 |
1995年 | 253篇 |
1994年 | 275篇 |
1993年 | 221篇 |
1992年 | 252篇 |
1991年 | 225篇 |
1990年 | 258篇 |
1989年 | 240篇 |
1988年 | 193篇 |
1987年 | 174篇 |
1986年 | 159篇 |
1985年 | 167篇 |
1984年 | 192篇 |
1983年 | 181篇 |
1982年 | 185篇 |
1981年 | 179篇 |
1980年 | 138篇 |
1979年 | 153篇 |
1978年 | 131篇 |
1977年 | 119篇 |
1975年 | 118篇 |
1974年 | 115篇 |
1973年 | 110篇 |
1972年 | 133篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
921.
A pleural effusion associated with congenital pulmonary lymphangiectasia was detected in a fetus in utero but was absent at the time of delivery. The pleural effusion was unilateral although the disease involved both lungs. In this case there was an association between polyhydramnios and congenital pulmonary lymphangiectasia. 相似文献
922.
923.
924.
H. G. Thomas M. Scantlebury D. Swanepoel P. W. Bateman N. C. Bennett 《Die Naturwissenschaften》2013,100(11):1023-1030
Sociality in mole rats has been suggested to have evolved as a response to the widely dispersed food resources and the limited burrowing opportunities that result from sporadic rainfall events. In the most arid regions, individual foraging efficiency is reduced, and energetic constraints increase. In this study, we investigate seasonal differences in burrow architecture of the social Cryptomys hottentotus hottentotus in a mesic region. We describe burrow geometry in response to seasonal weather conditions for two seasons (wet and dry). Interactions occurred between seasons and colony size for the size of the burrow systems, but not the shape of the burrow systems. The fractal dimension values of the burrow systems did not differ between seasons. Thus, the burrow complexity was dependent upon the number of mole rats present in the social group. 相似文献
925.
D. Gerecke 《Die Naturwissenschaften》1970,57(7):360-360
926.
927.
B. Sikkema-Raddatz R. H. Sijmons M. B. Tan-Sindhunata A. Y. Van Der Veen R. Brunsting B. De Vries J. R. Beekhuis D. J. Bekedam B. Van Aken B. De Jong 《黑龙江环境通报》1995,15(5):467-473
We report two cases of apparently balanced complex de novo chromosomal rearrangements (BCCR) detected prenatally at 17 weeks and 10 weeks of gestation, respectively. Chromosomes were studied using GTG-banding and fluorescent in situ hybridization (FISH). In one case four chromosomes and in the other case three chromosomes were involved in the rearrangements. One of the pregnancies was terminated and no external or internal abnormalities were detected at autopsy. The other pregnancy continued to term. Level III ultrasound examination showed no abnormalities. The child is now 3 years old and has neither congenital anomalies nor evidence of delayed psychomotor development. 相似文献
928.
929.
930.
Urban Flood Damage and Greenhouse Scenarios - The Implications for Policy: An Example from Australia
Urban flooding is often used as an illustration of the potentially adverse effects of greenhouse-induced climate change on extreme events. There is however, a paucity of studies that convert climate scenarios into changes in flood damage. This account summarises the use of modelling techniques, for three flood prone urban catchments in south eastern Australia, to assess changes to urban flood losses for the 'most wet' and 'most dry' scenarios for the year 2070. The most wet scenario indicates that annual average flood damage could increase within the range of 2.5 to 10 times, under the most dry scenario flood regimes would be similar to those experienced at present. The socio-economic scenarios based on the changes to flood losses are used to consider policy responses. It is unlikely that many local government authorities will respond because of lack of interest and because of major changes to the climate scenarios proposed over the last decade. Any response is likely to be incremental and accord with the 'no regrets' and the precautionary principle'. 相似文献