全文获取类型
收费全文 | 1741篇 |
免费 | 81篇 |
国内免费 | 43篇 |
专业分类
测绘学 | 59篇 |
大气科学 | 132篇 |
地球物理 | 366篇 |
地质学 | 616篇 |
海洋学 | 120篇 |
天文学 | 419篇 |
综合类 | 13篇 |
自然地理 | 140篇 |
出版年
2024年 | 14篇 |
2023年 | 19篇 |
2022年 | 11篇 |
2021年 | 38篇 |
2020年 | 53篇 |
2019年 | 39篇 |
2018年 | 81篇 |
2017年 | 68篇 |
2016年 | 78篇 |
2015年 | 74篇 |
2014年 | 80篇 |
2013年 | 113篇 |
2012年 | 67篇 |
2011年 | 98篇 |
2010年 | 82篇 |
2009年 | 90篇 |
2008年 | 90篇 |
2007年 | 92篇 |
2006年 | 77篇 |
2005年 | 59篇 |
2004年 | 64篇 |
2003年 | 49篇 |
2002年 | 49篇 |
2001年 | 36篇 |
2000年 | 44篇 |
1999年 | 34篇 |
1998年 | 21篇 |
1997年 | 23篇 |
1996年 | 19篇 |
1995年 | 11篇 |
1994年 | 13篇 |
1993年 | 11篇 |
1992年 | 15篇 |
1991年 | 8篇 |
1990年 | 9篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 12篇 |
1984年 | 7篇 |
1983年 | 9篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 8篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1973年 | 4篇 |
排序方式: 共有1865条查询结果,搜索用时 15 毫秒
171.
Alexander Deutsch Christian Koeberl Joel D. Blum Bevan M. French Billy P. Glass Richard Grieve Peter Horn Elmar K. Jessberger Gero Kurat Wolf Uwe Reimold Jan Smit Dieter Stöffler Stuart Ross Taylor 《地学学报》1994,6(6):644-650
In a recent article in Terra Nova, Kristan-Tollmann and Tollmann (1994) suggested that the Biblical Flood can be explained by seven fragments of a comet that impacted the ocean at seven locations on Earth at 03.00h (C.E.T.) on 23 September, 9545 yr BP. We demonstrate that all the ‘geological proofs’ that allegedly support their conclusions are not supported by the available data on impact cratering. Their hypothesis is based on insufficient and ambiguous data, selective citation, and incomplete comprehension of previous research. 相似文献
172.
The comparison of events that followed the great impact at the Cretaceous/Tertiary boundary with those contained within the Flood myths suggests an analogous cosmic cause. This paper proposes that there is geological evidence to support this thesis which is also indicated by a careful analysis of the natural phenomena described in Flood traditions. The time, the sites, the cause, the detailed course of the events and the consequences of this catastrophe can hope to be reconstructed. 相似文献
173.
Ohne ZusammenfassungMit 2 Textabbildungen. 相似文献
174.
175.
176.
177.
178.
179.
Nicolas C. Jourdain Alexander Sen Gupta Andréa S. Taschetto Caroline C. Ummenhofer Aurel F. Moise Karumuri Ashok 《Climate Dynamics》2013,41(11-12):3073-3102
A large spread exists in both Indian and Australian average monsoon rainfall and in their interannual variations diagnosed from various observational and reanalysis products. While the multi model mean monsoon rainfall from 59 models taking part in the Coupled Model Intercomparison Project (CMIP3 and CMIP5) fall within the observational uncertainty, considerable model spread exists. Rainfall seasonality is consistent across observations and reanalyses, but most CMIP models produce either a too peaked or a too flat seasonal cycle, with CMIP5 models generally performing better than CMIP3. Considering all North-Australia rainfall, most models reproduce the observed Australian monsoon-El Niño Southern Oscillation (ENSO) teleconnection, with the strength of the relationship dependent on the strength of the simulated ENSO. However, over the Maritime Continent, the simulated monsoon-ENSO connection is generally weaker than observed, depending on the ability of each model to realistically reproduce the ENSO signature in the Warm Pool region. A large part of this bias comes from the contribution of Papua, where moisture convergence seems to be particularly affected by this SST bias. The Indian summer monsoon-ENSO relationship is affected by overly persistent ENSO events in many CMIP models. Despite significant wind anomalies in the Indian Ocean related to Indian Ocean Dipole (IOD) events, the monsoon-IOD relationship remains relatively weak both in the observations and in the CMIP models. Based on model fidelity in reproducing realistic monsoon characteristics and ENSO teleconnections, we objectively select 12 “best” models to analyze projections in the rcp8.5 scenario. Eleven of these models are from the CMIP5 ensemble. In India and Australia, most of these models produce 5–20 % more monsoon rainfall over the second half of the twentieth century than during the late nineteenth century. By contrast, there is no clear model consensus over the Maritime Continent. 相似文献
180.
We present a portable elevator-based facility for measuring \(\hbox {CO}_{2}\), water vapour, temperature and wind-speed profiles between the soil surface and the atmospheric surface layer above crop canopies. The end of a tube connected to a closed-path gas analyzer is continuously moved up and down over the profile range (in our case, approximately 2 m) while concentrations are logged at a frequency of \(20 \hbox { s}^{-1}\). Using campaign measurements in winter wheat, winter barley and a catch crop mixture (spring 2015 to autumn 2016) during different stages of crop development and different times of the day, we demonstrate a simple approach to correct for time lags, and the resulting profiles of 30-min mean mole fractions of \(\hbox {CO}_{2}\) and \(\hbox {H}_{2}\hbox {O}\) over height increments of 0.025 m. The profiles clearly show the effects of soil respiration and photosynthetic carbon assimilation, varying both during the diurnal cycle and during the growing season. Profiles of temperature and wind speed are based on a ventilated finewire thermocouple and a hot-wire anemometer, respectively. Measurements over bare soil and a short plant canopy were analyzed in the framework of Monin–Obukhov similarity theory to check the validity of the measurements and raw-data-processing approach. Derived fluxes of \(\hbox {CO}_{2}\), latent and sensible heat and momentum show good agreement with eddy-covariance measurements. 相似文献