全文获取类型
收费全文 | 30125篇 |
免费 | 258篇 |
国内免费 | 195篇 |
专业分类
安全科学 | 765篇 |
废物处理 | 1122篇 |
环保管理 | 3510篇 |
综合类 | 7837篇 |
基础理论 | 6917篇 |
环境理论 | 16篇 |
污染及防治 | 7341篇 |
评价与监测 | 1636篇 |
社会与环境 | 1286篇 |
灾害及防治 | 148篇 |
出版年
2022年 | 230篇 |
2019年 | 212篇 |
2018年 | 407篇 |
2017年 | 386篇 |
2016年 | 558篇 |
2015年 | 454篇 |
2014年 | 631篇 |
2013年 | 2059篇 |
2012年 | 767篇 |
2011年 | 1106篇 |
2010年 | 928篇 |
2009年 | 1049篇 |
2008年 | 1177篇 |
2007年 | 1160篇 |
2006年 | 1020篇 |
2005年 | 906篇 |
2004年 | 868篇 |
2003年 | 845篇 |
2002年 | 840篇 |
2001年 | 1048篇 |
2000年 | 744篇 |
1999年 | 491篇 |
1998年 | 339篇 |
1997年 | 353篇 |
1996年 | 361篇 |
1995年 | 413篇 |
1994年 | 429篇 |
1993年 | 360篇 |
1992年 | 365篇 |
1991年 | 394篇 |
1990年 | 410篇 |
1989年 | 383篇 |
1988年 | 297篇 |
1987年 | 280篇 |
1986年 | 289篇 |
1985年 | 272篇 |
1984年 | 294篇 |
1983年 | 295篇 |
1982年 | 299篇 |
1981年 | 306篇 |
1980年 | 252篇 |
1979年 | 290篇 |
1978年 | 218篇 |
1977年 | 219篇 |
1976年 | 206篇 |
1974年 | 214篇 |
1973年 | 220篇 |
1967年 | 246篇 |
1966年 | 206篇 |
1965年 | 215篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
83.
J. Heinze H. Remmert F. L. Boschke D. Reinen L. Jaenicke 《Die Naturwissenschaften》1983,70(11):575-576
84.
Pheromones — semiochemicals used by insects for intraspecific chemical communication — can be isolated and with special analytical techniques their chemical structure elucidated. With stereoselective synthesis methods, presented by the preparation of sex attractants and aggregating pheromones of moths and beetles, respectively, a synthetic access to compounds is given which can be used for behavior manipulation of insects. Aside the importance of these compounds for investigations of the sensoric process the possibility of their application in an integrated and biological pest control is discussed. 相似文献
85.
86.
Counselling in connection with prenatal diagnosis (PND) is a common task for the obstetrician and the midwife. However, the decision making processes of pregnant women are not completely known, for instance, the questions of women's autonomy, the decision on how to act in the case of an abnormal test, and the partner's participation in the decision. A questionnaire and interview study was carried out among 211 women undergoing PND by amniocentesis or chorionic villus biopsy. Most women in the sample indicated that PND was completely voluntary. However, at the same time almost every woman reported that it was difficult to decline from PND when offered. Even before the visit to register at the antenatal clinic, most of the women (83 per cent) had made up their minds to have PND. At the time of the test, many of the participants (62 per cent) had decided in favour of a legal abortion if the test indicated an abnormality in the fetus. At the same time, however, the data indicate a need for reflection and ambivalence, which the medical staff have to accept. In the questionnaire most of the women stated that they and their partners had similar attitudes towards PND, but when interviewed 38 per cent of the women admitted some differences between their own attitudes and their partners'. Although some women reported considerable deliberation and ambivalence, most of them said that they would undergo PND in another pregnancy. 相似文献
87.
88.
Plasticity of honeybee castes 总被引:1,自引:0,他引:1
89.
Prenatal real-time ultrasonographic diagnosis of microphthalmia is presented. Diagnosis was made at 18 weeks' gestation in a fetus of a patient with a previous infant affected with the syndrome of cryptophthalmia with absence of septum nasi and ambiguous genitalia (Fraser syndrome). Recognition of microphthalmia as a part of Fraser syndrome and the easy visualization of fetal facial bones and orbits in the second trimester made the diagnosis possible. 相似文献
90.
The karyotype of cultured amniotic fluid cells obtained on the indication of advanced maternal age was shown to be a mosaic 45,X/46,X,r(?). The small size and banding pattern made it difficult to determine whether the ring was derived from and X or a Y chromosome, or even from an autosome. By using an X-centromeric probe and fluorescence in situ hybridization (FISH), we demonstrated the ring to have an X centromere. Thus, a more complete genetic counselling was possible. This confirms the usefulness of FISH in identifying and characterizing this and other chromosome rearrangements in prenatal diagnosis. 相似文献