全文获取类型
收费全文 | 562篇 |
免费 | 32篇 |
国内免费 | 2篇 |
专业分类
测绘学 | 28篇 |
大气科学 | 93篇 |
地球物理 | 137篇 |
地质学 | 226篇 |
海洋学 | 27篇 |
天文学 | 47篇 |
综合类 | 3篇 |
自然地理 | 35篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 8篇 |
2020年 | 13篇 |
2019年 | 10篇 |
2018年 | 24篇 |
2017年 | 29篇 |
2016年 | 40篇 |
2015年 | 20篇 |
2014年 | 21篇 |
2013年 | 39篇 |
2012年 | 30篇 |
2011年 | 33篇 |
2010年 | 37篇 |
2009年 | 40篇 |
2008年 | 32篇 |
2007年 | 28篇 |
2006年 | 24篇 |
2005年 | 24篇 |
2004年 | 12篇 |
2003年 | 9篇 |
2002年 | 19篇 |
2001年 | 15篇 |
2000年 | 3篇 |
1999年 | 6篇 |
1998年 | 3篇 |
1997年 | 8篇 |
1996年 | 3篇 |
1995年 | 8篇 |
1994年 | 6篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1978年 | 2篇 |
1977年 | 6篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1965年 | 1篇 |
1961年 | 1篇 |
1960年 | 1篇 |
1958年 | 1篇 |
1953年 | 1篇 |
1951年 | 1篇 |
1950年 | 1篇 |
1948年 | 1篇 |
排序方式: 共有596条查询结果,搜索用时 109 毫秒
591.
The groundwater flow regime at great depth within the Molasse Basin (SW Germany) was studied. Data relevant for a flow model at 600–1,600 m depth are sparse in the western part of the basin. However, temperature measurements are available covering much of the area at a wide range of depths. Therefore, a thermal 3D steady-state model was set up with the aim of comparing modeled with observed subsurface temperatures. Stratigraphic information from many boreholes was also available, but only a few values of rock thermal conductivity and heat-production rate could be obtained. Some strong thermal residual anomalies were identified with respect to the purely conductive model, especially along fault zones, and within stratigraphic layers with high hydraulic conductivity. These anomalies can be explained by various advective heat-transport mechanisms, yet most explanations can be eliminated. The most plausible constellation explaining the major positive thermal anomalies of 10 Kelvin and more is a fault zone of E–W strike, intersected by an aquifer with flow parallel to the fault zone. This concept was investigated by using a simplified type model. In spite of some shortcomings, the method presented here can be used to identify temperature anomalies, and to identify possible explanations. 相似文献
592.
Soil contamination by heavy metals and organic pollutants around industrial premises is a problem in many countries around
the world. Delineating zones where pollutants exceed tolerable levels is a necessity for successfully mitigating related health
risks. Predictions of pollutants are usually required for blocks because remediation or regulatory decisions are imposed for
entire parcels. Parcel areas typically exceed the observation support, but are smaller than the survey domain. Mapping soil
pollution therefore involves a local change of support. The goal of this work is to find a simple, robust, and precise method
for predicting block means (linear predictions) and threshold exceedance by block means (nonlinear predictions) from data
observed at points that show a spatial trend. By simulations, we compared the performance of universal block kriging (UK),
Gaussian conditional simulations (CS), constrained (CK), and covariance-matching constrained kriging (CMCK), for linear and
nonlinear local change of support prediction problems. We considered Gaussian and positively skewed spatial processes with
a nonstationary mean function and various scenarios for the autocorrelated error. The linear predictions were assessed by
bias and mean square prediction error and the nonlinear predictions by bias and Peirce skill scores. 相似文献
593.
Dr. Christoph Hoffmann 《Contributions to Mineralogy and Petrology》1970,27(4):283-320
In the southern Apennin (= northern part of the region dealt with) and the Coasta Chain (= southern part) there are metabasalts wich are classified in the northern part as:
- Glaucophane rocks of the albite-lawsonite-glaucophane-subfacies with the assemblage glaucophane + pumpellyite + lawsonite ±albite ±aragonite ±muscovite (7 rock analyses, 8 mineral analyses). These rocks are conceived as relics of an older burial metamorphism.
- Rocks with pumpellyite and chlorite or also chlorite alone, that are interpreted as reaction rims between the metastable glaucophane rocks and the country rock (phyllites, quartzites). The assemblages pumpellyite + chlorite and chlorite alone are to be found (2 rock analyses and 2 mineral analyses).
- Rocks with lawsonite and/or epidote belong to the same mineral facies as the country rock: a facies similar to the greenschist facies (called “lawsonite-albite-chlorite-subfacies”) which is characterized by the assemblages lawsonite + albite + chlorite ±calcite and also epidote ±lawsonite + albite + chlorite ± muscovite. These types are attributed to a younger dynamo-metamorphism (2 rock analyses).
594.
Christoph Münkel Noora Eresmaa Janne Räsänen Ari Karppinen 《Boundary-Layer Meteorology》2007,124(1):117-128
The Vaisala ceilometers CT25K and CL31 are eye-safe single lens lidar systems reporting attenuated backscatter profiles; they
often operate 24 h a day in fully automated, hands-off operation mode. These profiles can be used for more than just cloud-base
height determination. In dry weather situations, there is a fairly good correlation between the ceilometer near-range backscatter
and in situ PM10 concentration readings. The comparison of mixing height values based on soundings and on ceilometer backscattering
profiles indicates that ceilometers are suitable instruments for determining the convective mixing height. Its enhanced optics
and electronics enables the CL31 ceilometer to detect fine boundary-layer structures whose counterparts are seen in temperature
profiles. 相似文献
595.
596.