全文获取类型
收费全文 | 5131篇 |
免费 | 869篇 |
国内免费 | 2728篇 |
专业分类
安全科学 | 395篇 |
废物处理 | 242篇 |
环保管理 | 400篇 |
综合类 | 4479篇 |
基础理论 | 1674篇 |
环境理论 | 1篇 |
污染及防治 | 1112篇 |
评价与监测 | 281篇 |
社会与环境 | 109篇 |
灾害及防治 | 35篇 |
出版年
2024年 | 9篇 |
2023年 | 101篇 |
2022年 | 182篇 |
2021年 | 246篇 |
2020年 | 194篇 |
2019年 | 261篇 |
2018年 | 317篇 |
2017年 | 300篇 |
2016年 | 360篇 |
2015年 | 401篇 |
2014年 | 467篇 |
2013年 | 546篇 |
2012年 | 592篇 |
2011年 | 600篇 |
2010年 | 474篇 |
2009年 | 536篇 |
2008年 | 361篇 |
2007年 | 378篇 |
2006年 | 415篇 |
2005年 | 307篇 |
2004年 | 240篇 |
2003年 | 240篇 |
2002年 | 193篇 |
2001年 | 174篇 |
2000年 | 154篇 |
1999年 | 122篇 |
1998年 | 92篇 |
1997年 | 82篇 |
1996年 | 84篇 |
1995年 | 75篇 |
1994年 | 47篇 |
1993年 | 44篇 |
1992年 | 40篇 |
1991年 | 25篇 |
1990年 | 15篇 |
1989年 | 9篇 |
1988年 | 10篇 |
1987年 | 8篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有8728条查询结果,搜索用时 468 毫秒
741.
《环境科学学报(英文版)》2023,35(7):152-160
Urea oxidation reaction (UOR) provides a method for hydrogen production besides wastewater treatment, but the current limited catalytic activity has prevented the application. Herein, we develop a novel H2O2 treatment strategy for tailoring the surface oxygen ligand of NiFe-layered double hydroxides (NiFe-LDH). The sample after H2O2 treatment (NiFeO-LDH) shows significant enhancement on UOR efficiency, with the potential of 1.37 V (RHE) to reach a current density of 10 mA/cm2. The boost is attributed to the richness adsorption O ligand on NiFeO-LDH as revealed by XPS and Raman analysis. DFT calculation indicates formation of two possible types of oxygen ligands: adsorbed oxygen on the surface and exposed from hydroxyl group, lowered the desorption energy of CO2 product, which lead to the lowered onset potential. This strategy is further extended to NiFe-LDH nano sheet on Ni foam to reach a higher current density of 440 mA/cm2 of UOR at 1.8 V (RHE). The facile surface O ligand manipulation is also expected to give chance to many other electro-catalytic oxidations. 相似文献
742.
M. Rifé J. Mallolas C. Badenas B. Tazón M. Rodríguez Miguélez T. Pàmpols A. Sànchez M. Milà 《黑龙江环境通报》2002,22(6):459-462
An Erratum has been published for this article in Prenatal Diagnosis 23 (9), 2003, 771. Fragile X syndrome (SFX) is the commonest form of inherited mental retardation. Due to the highly variable phenotype clinical diagnosis is complicated. In nearly all cases, the disorder is caused by expansion of a CGG-repeat in the 5′-untranslated region of the FMR1 (fragile X mental retardation-1) gene. We have evaluated the feasibility, efficiency and costs of two methodologies in order to develop a simple test to screen large populations: PCR and fragile X mental retardation-1 protein (FMRP) immunodetection. We studied 100 newborn males using PCR and immunodetection (26.91 Euro). All but one amplified the CGG repeat of the FMR1 gene within the normal size range. The sample that failed to amplify showed only 28% of FMRP expression by immunodetection study; both results indicated an affected male. A further 100 males were studied only by polymerase chain reaction (PCR) (7.8 Euro); all of them amplified within the normal size range. Both methodologies, PCR and immunodetection, are feasible for screening large populations, PCR being the most suitable, economical and less time-consuming. However, it is advisable to keep slides for immunodetection when PCR fails or the external control shows no amplification. Early detection of SFX-affected individuals would represent a great benefit for their maximum social integration, due to appropriate treatment and early stimulation and would permit a cascade screening in their pedigree. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
743.
744.
745.
Agnès Guichet Stéphane Triau Catherine Lépinard Chantal Esculapavit Florence Biquard Philippe Descamps Férechté Encha-Razavi Dominique Bonneau 《黑龙江环境通报》2004,24(10):828-832
We report an interstitial deletion of chromosome 3q26-q28 in a fetus in which anophthalmia had been detected prenatally. FISH analysis, using BAC clones encompassing the SOX2 locus, showed that SOX2 gene was involved in the chromosomal breakpoint of the deletion. This case confirms that haploinsufficiency for SOX2 plays a crucial role in human eye development and emphasizes the necessity of careful chromosomal analysis, including FISH analysis of the 3q region, in case of prenatal discovery of anophthalmia. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
746.
747.
Mark J. Pettenati Margaret Berry Vandana Shashi J. Hartley Bowen Margaret Harper 《黑龙江环境通报》2001,21(6):435-440
The prenatal diagnosis of a complete trisomy of the long arm of chromosome 1 is reported. Major ultrasound findings included: nuchal thickening, bi-temporal narrowing, a single choroid plexus cyst, andmild ventriculomegaly. There was a mass in the chest and abdomen, pleural effusion, ascites and a hyperechoic bowel. Skin edema was present. The fetus died at 26 weeks' gestation. A literature review is presented of 17 de novo and two inherited cases with only trisomy 1q. Of note is the fact that 3/5 prenatally detected 1q trisomies have teratomas. A review of the literature reveals a dismal outcome fortrisomy 1q cases if the duplication involves bands 1q25→q32. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
748.
S. Cavani C. Perfumo F. Faravelli M. Malacarne M. Sogliani G. Piombo G. Zerega M. Zucca F. Dagna Bricarelli M. Pierluigi 《黑龙江环境通报》2003,23(10):819-823
Here we describe a foetus with intrauterine growth retardation (IUGR), cerebral malformations and a 46,XY,der(1),t(1;6)(p36.3;q25.2) karyotype owing to a familial cryptic translocation segregating in three generations. A balanced translocation was present in the mother, the maternal uncle, the aunt and the grandmother. A female first cousin with dysmorphisms, hydrocephalus and mental retardation was a carrier of a partial trisomy 1p and a partial monosomy 6q. Multiple miscarriages were present in the family pedigree. Parents of the foetus had three other pregnancies: a male with a balanced translocation, and two foetuses with 1p36.3–pter monosomy and 6q25.2–qter trisomy. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
749.
Abstract: Anthropogenic disturbances such as fragmentation are rapidly altering biodiversity, yet a lack of attention to species traits and abundance patterns has made the results of most studies difficult to generalize. We determined traits of extinction‐prone species and present a novel strategy for classifying species according to their population‐level response to a gradient of disturbance intensity. We examined the effects of forest fragmentation on dung beetle communities in an archipelago of 33 islands recently created by flooding in Venezuela. Species richness, density, and biomass all declined sharply with decreasing island area and increasing island isolation. Species richness was highly nested, indicating that local extinctions occurred nonrandomly. The most sensitive dung beetle species appeared to require at least 85 ha of forest, more than many large vertebrates. Extinction‐prone species were either large‐bodied, forest specialists, or uncommon. These explanatory variables were unrelated, suggesting at least 3 underlying causes of extirpation. Large species showed high wing loading (body mass/wing area) and a distinct flight strategy that may increase their area requirements. Although forest specificity made most species sensitive to fragmentation, a few persistent habitat generalists dispersed across the matrix. Density functions classified species into 4 response groups on the basis of their change in density with decreasing species richness. Sensitive and persistent species both declined with increasing fragmentation intensity, but persistent species occurred on more islands, which may be due to their higher baseline densities. Compensatory species increased in abundance following the initial loss of sensitive species, but rapidly declined with increasing fragmentation. Supertramp species (widespread habitat generalists) may be poor competitors but strong dispersers; their abundance peaked following the decline of the other 3 groups. Nevertheless, even the least sensitive species were extirpated or rare on the smallest and most isolated islands. 相似文献
750.
Dr Isabel Lorda-Sánchez Dan Diego-Alvarez Carmen Ayuso Marta Rodríguez de Alba Maria Jose Trujillo Carmen Ramos 《黑龙江环境通报》2005,25(10):934-938
Balanced reciprocal translocation is one of the known causes of recurrent spontaneous abortions. Cytogenetic studies of unbalanced miscarriages are difficult due to the growth failure of early loss and usually macerated abortions. We present a molecular study of an abortion in which the father carries a balanced reciprocal translocation t(2;17)(q32.1;q24.3) using QF-PCR and CGH techniques. DNA analysis showed the presence of a trisomy 2 due to a 3:1 interchange segregation. Recombinant events could also be investigated by comparing DNA samples from the family. We propose QF-PCR in addition to CGH as an efficient diagnostic method to improve our knowledge of unbalanced offspring in balanced translocation carriers. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献