全文获取类型
收费全文 | 24188篇 |
免费 | 247篇 |
国内免费 | 197篇 |
专业分类
安全科学 | 595篇 |
废物处理 | 1020篇 |
环保管理 | 2950篇 |
综合类 | 4619篇 |
基础理论 | 5955篇 |
环境理论 | 8篇 |
污染及防治 | 6269篇 |
评价与监测 | 1581篇 |
社会与环境 | 1544篇 |
灾害及防治 | 91篇 |
出版年
2022年 | 203篇 |
2021年 | 187篇 |
2019年 | 160篇 |
2018年 | 329篇 |
2017年 | 320篇 |
2016年 | 500篇 |
2015年 | 375篇 |
2014年 | 548篇 |
2013年 | 1717篇 |
2012年 | 658篇 |
2011年 | 984篇 |
2010年 | 773篇 |
2009年 | 875篇 |
2008年 | 1040篇 |
2007年 | 1065篇 |
2006年 | 946篇 |
2005年 | 798篇 |
2004年 | 788篇 |
2003年 | 820篇 |
2002年 | 752篇 |
2001年 | 1034篇 |
2000年 | 670篇 |
1999年 | 462篇 |
1998年 | 300篇 |
1997年 | 323篇 |
1996年 | 336篇 |
1995年 | 362篇 |
1994年 | 341篇 |
1993年 | 302篇 |
1992年 | 297篇 |
1991年 | 303篇 |
1990年 | 307篇 |
1989年 | 292篇 |
1988年 | 249篇 |
1987年 | 233篇 |
1986年 | 211篇 |
1985年 | 227篇 |
1984年 | 247篇 |
1983年 | 244篇 |
1982年 | 243篇 |
1981年 | 210篇 |
1980年 | 182篇 |
1979年 | 187篇 |
1978年 | 167篇 |
1977年 | 159篇 |
1976年 | 146篇 |
1975年 | 150篇 |
1974年 | 165篇 |
1973年 | 141篇 |
1971年 | 132篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Four introduced and one aboriginal species of the genus Pinus L. have been studied in the middle taiga subzone of southern Karelia. Significant interspecific differences in the dates of onset, cessation, and peak of the growth of shoots and needles have been revealed. It has been shown that their annual increment depends on the rate of growth, rather than on its duration. The dynamics of shoot and needle growth in introduced and aboriginal species, though largely similar, differ in some respects. These differences reflect species-specific responses to hydrothermal conditions in a certain growing season. 相似文献
32.
Russian Journal of Ecology - 相似文献
33.
34.
The past two decades have witnessed an increase in the exploration for, and development of, mineral resources at Arctic latitudes. Such effort has resulted in the commencement of production at a number of different localities in close proximity to the ocean. Since proximity to a source of transportation for the conveyance of concentrates to the market is a primary requirement governing the economic decisions for the mine to proceed, it is logical that ore deposits near a coastline are primary targets for development.
Closely tied to coastal mining developments is the need to dispose of tailings and waste rock in the most economical manner. Prior to the advent of heightened public awareness and environmental concern, and the enactment of pollution legislation, disposal practices were largely based upon convenience. Currently, however, proposed disposal and operating practices receive closer scrutiny, with a view to providing adequate protection for aquatic resources and habitat. This paper summarizes some of the features of three Arctic mines, wastes from which enter the marine environment, and compares the disposal practices used at each to measures of environmental change as indicated by metal concentrations in various media. 相似文献
Closely tied to coastal mining developments is the need to dispose of tailings and waste rock in the most economical manner. Prior to the advent of heightened public awareness and environmental concern, and the enactment of pollution legislation, disposal practices were largely based upon convenience. Currently, however, proposed disposal and operating practices receive closer scrutiny, with a view to providing adequate protection for aquatic resources and habitat. This paper summarizes some of the features of three Arctic mines, wastes from which enter the marine environment, and compares the disposal practices used at each to measures of environmental change as indicated by metal concentrations in various media. 相似文献
35.
Thi Binh Minh Nguyen A.T.M. Nurul Amin 《Environment, Development and Sustainability》2002,4(3):279-297
In recent years flows of foreign direct investment (FDI) to developing countries have rapidly been increasing. It is now an important contributor to the national economy and urban growth in scores of developing countries. Rapid urbanization in these countries is leading to many problems in the cities. Existing urban infrastructure and municipal services have been unable to cope with the increased demand arising from growing population and rapid economic growth. Consequently, the environment in these cities has deteriorated alarmingly. This paper assesses the role of FDI in urban environmental management (UEM) by analyzing the linkages between them for Hanoi City in Vietnam. The paper's analysis and findings are presented under three main themes: one, FDI, employment and income; two, FDI and environmental degradation; and three, potential of utilizing FDI for the provision of urban environmental infrastructure and services (UEI&S) in order to improve the urban environment. Both primary and secondary source data have been used. Policy implications of the research findings are drawn from the perspective of sustainable development. 相似文献
36.
Long-term stationary studies on the ecology of the northern mole vole (Ellobius talpinus Pall.), performed by the mark–recapture method from 1985 to 1997, have provided original data on population dynamics and structure. The analysis shows that, to reveal cyclic fluctuations of population size in this species, the period of three years should be taken as a unit of time for estimating the duration of one phase. The 12-year population cycle in E. talpinus has four distinct phases: an increase, a peak, a decline, and a minimum. At each phase, the population is characterized by certain features of family structure, age composition, birth and death rates, and the composition of migrants. 相似文献
37.
We present a case of ultrasonographic prenatal diagnosis at 24 weeks of femur—fibula—ulna (FFU) complex. To our knowledge, this is the first report of an early prenatal diagnosis of FFU. 相似文献
38.
Observations of air temperature changes in a steppe marmot burrow were performed from late July to mid-October. Until early September, temperature in the burrow remained relatively constant, but then it began to decrease rapidly. This occurred after air temperature above the ground became equal to the temperature in the burrow. Supposedly, it is in this particular period that marmots begin to plug the entrance to the burrow with earth, thus reducing heat exchange between the increasingly cold aboveground air and the air in the burrow. 相似文献
39.
Marc Trimborn Rolf-Dieter Wegner Holger Tönnies Nanette Sarioglu Matthias Albig Heidemarie Neitzel 《黑龙江环境通报》2006,26(3):273-276
We describe the first prenatally detected case of a small de novo interstitial duplication of chromosome 16q. This chromosomal aberration is extremely rare. Amniocentesis was indicated by advanced maternal age only. Ultrasound examinations of the foetus showed no abnormalities. Conventional and molecular cytogenetic analyses on cultured amniocytes by comparative genomic hybridisation (CGH) and fluorescence in situ hybridisation (FISH) using partial chromosome paints and a locus-specific YAC clone revealed a de novo direct duplication of the chromosomal region 16q11.2-q13 leading to a partial trisomy 16q (46,XX,dup(16)(q11.2q13)). There are only five postnatal reports of comparable duplications involving this chromosomal region. These patients presented with little or no associated dysmorphic features but with significant neurodevelopmental delay and severe behavioural problems. After genetic counselling, the parents opted for termination of pregnancy. Post-mortem examination showed slight facial dysmorphic signs, minor dysgenesis of the ovaries and an atypical outflow of the arteria thyroidea ima. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
40.
S. Savas S. Eraslan S. Kantarci B. Karaman D. Acarsoz T. Tükel O. Cogulu F. Ozkinay S. Basaran K. Aydınlı M. Yuksel-Apak B. Kirdar 《黑龙江环境通报》2002,22(8):703-709
Childhood-onset spinal muscular atrophy (SMA) is one of the most common neurodegenerative genetic disorders. SMN1 is the SMA-determining gene deleted or mutated in the majority of SMA cases. There is no effective cure or treatment for this disease yet. Thus, the availability of prenatal testing is important. Here we report prenatal prediction for 68 fetuses in 63 Turkish SMA families using direct deletion analysis of the SMN1 gene by restriction digestion. The genotype of the index case was known in 40 families (Group A) but unknown in the remaining 23 families (Group B). A total of ten fetuses were predicted to be affected. Eight of these fetuses were derived from Group A and two of these fetuses were from Group B families. Two fetuses from the same family in Group A had the SMNhyb1 gene in addition to homozygous deletion of the NAIP gene. One fetus from Group A was homozygously deleted for only exon 8 of the SMN2 gene, and further analysis showed the presence of both the SMN1 and SMNhyb1 genes but not the SMN2 gene. In addition, one carrier with a homozygous deletion of only exon 8 of the SMN1 gene was detected to have a SMNhyb2 gene, which was also found in the fetus. To our knowledge, these are the first prenatal cases with SMNhyb genes. Follow-up studies demonstrated that the prenatal predictions and the phenotype of the fetuses correlated well in 33 type I pregnancies demonstrating that a careful molecular analysis of the SMN genes is very useful in predicting the phenotype of the fetus in families at risk for SMA. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献