全文获取类型
收费全文 | 43258篇 |
免费 | 404篇 |
国内免费 | 332篇 |
专业分类
安全科学 | 1074篇 |
废物处理 | 1686篇 |
环保管理 | 5404篇 |
综合类 | 9040篇 |
基础理论 | 11310篇 |
环境理论 | 10篇 |
污染及防治 | 10533篇 |
评价与监测 | 2584篇 |
社会与环境 | 2116篇 |
灾害及防治 | 237篇 |
出版年
2022年 | 315篇 |
2021年 | 279篇 |
2019年 | 306篇 |
2018年 | 578篇 |
2017年 | 609篇 |
2016年 | 905篇 |
2015年 | 649篇 |
2014年 | 959篇 |
2013年 | 3172篇 |
2012年 | 1259篇 |
2011年 | 1614篇 |
2010年 | 1391篇 |
2009年 | 1416篇 |
2008年 | 1641篇 |
2007年 | 1729篇 |
2006年 | 1544篇 |
2005年 | 1492篇 |
2004年 | 1644篇 |
2003年 | 1515篇 |
2002年 | 1218篇 |
2001年 | 1627篇 |
2000年 | 1129篇 |
1999年 | 682篇 |
1998年 | 518篇 |
1997年 | 525篇 |
1996年 | 539篇 |
1995年 | 621篇 |
1994年 | 626篇 |
1993年 | 508篇 |
1992年 | 562篇 |
1991年 | 533篇 |
1990年 | 587篇 |
1989年 | 558篇 |
1988年 | 444篇 |
1987年 | 426篇 |
1986年 | 405篇 |
1985年 | 416篇 |
1984年 | 442篇 |
1983年 | 436篇 |
1982年 | 439篇 |
1981年 | 433篇 |
1980年 | 356篇 |
1979年 | 395篇 |
1978年 | 318篇 |
1977年 | 312篇 |
1975年 | 283篇 |
1974年 | 306篇 |
1973年 | 305篇 |
1972年 | 297篇 |
1967年 | 265篇 |
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
101.
102.
103.
104.
5p deletion syndrome commonly known as cri du chat is well described in affected neonates with catlike cry and hypotonia. Karyotyping will usually show a deletion of the short arm of one chromosome 5 with variable breakpoints. Only a few cases have been reported prenatally, and the fetal form of the syndrome has not been clearly individualised. We report a new case of 5p deletion syndrome diagnosed prenatally in association with Dandy–Walker syndrome and agenesis of the corpus callosum. Other brain anomalies have been reported previously, but this unusual association suggests the use of a specific probe in the investigation of these malformations. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
105.
New data on the composition of surface assemblages of plant macroremains from soil and swamp samples have been obtained in the study of geomorphologically different localities in the middle reaches of the Nizhnyaya Tunguska River. The results of paleocarpological analysis of forest soil sections supported by relevant palynological and geochronological data are presented. Natural changes of the forest cover over the past 2400 years and quantitative characteristics of the paleoclimate during each stage are described.Translated from Ekologiya, No. 1, 2005, pp. 3–10.Original Russian Text Copyright © 2005 by Koshkarova, Koshkarov. 相似文献
106.
107.
A. Coulomb L'Herminé A. Aboura S. Brisset L. Cuisset V. Castaigne P. Labrune R. Frydman Dr G. Tachdjian 《黑龙江环境通报》2003,23(11):938-943
Prader–Willi syndrome (PWS) results from either paternal deletion of 15q11–q13, or maternal uniparental disomy (UPD) of chromosome 15 or imprinting center mutation. Prenatal diagnosis of PWS is currently indicated for chromosomal parental translocation involving chromosome 15 and for decreased fetal movements during the third trimester of gestation. Here we present the prenatal diagnosis of PWS during the first trimester of gestation and autopsy findings. Chorionic villus sampling (CVS) was performed for advanced maternal age at 13 weeks' gestation. CVS showed mosaicism including cells with a normal karyotype and cells with trisomy 15. Amniocentesis showed cells with a normal karyotype. Molecular analysis demonstrated that the fetus had a typical PWS abnormal methylation profile and maternal disomy for chromosome 15. Fetal ultrasound examination showed slightly enlarged lateral ventricles and hypoplasic male external genitalia without intra-uterine growth retardation. The autopsy showed a eutrophic male fetus with facial dysmorphy, hypoplasic genitalia, abnormal position of both feet and posterior hypoplasia of the corpus callosum. This report points out that in a karyotypically normal fetus with ambiguous male external genitalia and cerebral anomalies, extensive cytogenetic and molecular biology studies are strongly recommended because of risk of PWS. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
108.
109.
110.
Mamoru Morikawa Kazutoshi Cho Soromon Kataoka Emi H. Kato Takashi Yamada Hideto Yamada Hisanori Minakami 《黑龙江环境通报》2005,25(3):250-252
Two cases with a large cystic mass within the placenta are reported. By ultrasonography, it was found that both women had a subchorionic hypoechoic lesion (11.0 × 4.8 × 4.0 cm and 6.6 × 3.7 × 2.2 cm, respectively) at 24 and 35 weeks of gestation, respectively. In both cases, turbulent blood flow generated by a pulsatile jet flow (pulse rate; 40 to 60 beats per minute) into the cystic lesion seen on real-time imaging and lesions being low intensity on T1-weighted and isointensity on T2-weighted magnetic resonance image suggested that they contained fresh maternal blood. In both cases, the sonolucency of the lesions did not change until cesarean deliveries of females, both of whom were small-for-gestational-age infants (1940 g at 37 weeks and 2195 g at 37 weeks, respectively). Biochemical analysis of the fluid in the cystic lesion sampled during the cesarean section in the latter case confirmed that the fluid had originated from the maternal blood. These lesions histologically corresponded to large avillous areas surrounded by normal villi. Thus, a huge placental lake was diagnosed in both cases. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献