全文获取类型
收费全文 | 32114篇 |
免费 | 6093篇 |
国内免费 | 8401篇 |
专业分类
测绘学 | 1926篇 |
大气科学 | 6780篇 |
地球物理 | 8277篇 |
地质学 | 17032篇 |
海洋学 | 4000篇 |
天文学 | 1451篇 |
综合类 | 3514篇 |
自然地理 | 3628篇 |
出版年
2024年 | 185篇 |
2023年 | 671篇 |
2022年 | 1460篇 |
2021年 | 1735篇 |
2020年 | 1450篇 |
2019年 | 1616篇 |
2018年 | 1870篇 |
2017年 | 1683篇 |
2016年 | 1967篇 |
2015年 | 1653篇 |
2014年 | 2044篇 |
2013年 | 1933篇 |
2012年 | 1850篇 |
2011年 | 1866篇 |
2010年 | 1940篇 |
2009年 | 1897篇 |
2008年 | 1764篇 |
2007年 | 1659篇 |
2006年 | 1375篇 |
2005年 | 1176篇 |
2004年 | 1003篇 |
2003年 | 968篇 |
2002年 | 858篇 |
2001年 | 817篇 |
2000年 | 1027篇 |
1999年 | 1487篇 |
1998年 | 1176篇 |
1997年 | 1178篇 |
1996年 | 1051篇 |
1995年 | 923篇 |
1994年 | 848篇 |
1993年 | 721篇 |
1992年 | 562篇 |
1991年 | 453篇 |
1990年 | 331篇 |
1989年 | 312篇 |
1988年 | 275篇 |
1987年 | 180篇 |
1986年 | 149篇 |
1985年 | 117篇 |
1984年 | 72篇 |
1983年 | 60篇 |
1982年 | 70篇 |
1981年 | 56篇 |
1980年 | 30篇 |
1979年 | 31篇 |
1978年 | 10篇 |
1976年 | 7篇 |
1958年 | 28篇 |
1954年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
961.
962.
963.
重庆极端高温的变化特征及其对区域性增暖的响应 总被引:7,自引:0,他引:7
利用重庆1961-2006年31个站逐日最高温度资料,统计出年极端高温发生频次、年极端高温强度、年极端最高温度,分析了它们近46年来的变化情况.结果表明:近46年来重庆年极端高温发生频次呈西减东增的趋势,但增加/减少趋势并不显著.年极端高温的强度和年极端最高气温均在不断增强.年极端高温发生频次的增加对于重庆区域增暖的响应最显著,而年极端最高温度的升高比年极端高温频次的增加对重庆区域性增暖的响应偏弱,但又比年极端高温强度的增强对重庆区域性增暖的响应程度要偏强. 相似文献
964.
通过对云南6个烤烟种植区35 a来烤烟大田生长期气温资料的初步分析发现:云南省6个烤烟生产区烤烟大田生长季平均气温呈明显升高趋势,热量条件有较明显的改善;各烟区烤烟成熟—采烤期气候变暖趋势一致性好、增温最突出、增幅最大,增温幅度达到了0.0155~0.0356℃/a,这在一定程度上缓和了云南省烤烟生产过程中烤烟生长中、后期高温不足这一制约云南烤烟品质提高的气候瓶颈问题,对提高云南省烟叶品质有十分重要的促进作用。 相似文献
965.
1.北方农业低温冷害监测预警技术研究 "北方农业低温冷害监测预警技术研究"2007年在以下4个方面取得了较显著的进展. 相似文献
966.
利用乐山市1971~2005年整编风资料对乐山市各区县地面风场进行了全面分析,并对全市风能资源的分布情况进行了研究,旨在对今后乐山市风的预报及其相关服务有较好的帮助。 相似文献
967.
雷电探测资料在人工影响天气作业中的应用研究 总被引:3,自引:0,他引:3
利用2002~2005年XDD 03A型雷电探测系统的DDW资料,结合广西人影作业资料和其它气象资料,对雷电资料如何在人影作业中的应用进行了分析和探讨。结果表明,雷电系统可以比雷达和卫星探测提前约1h反映对流云的移动,同时在识别过冷层厚度,把握地面增雨防雹作业时机等方面也具有一定的指导作用。 相似文献
968.
In this study, a coupled atmosphere-surface “climate feedback-response analysis method” (CFRAM) was applied to the slab ocean model version of the NCAR CCSM3.0 to understand the tropospheric warming due to a doubling of CO2 concentration through quantifying the contributions of each climate feedback process. It is shown that the tropospheric warming displays distinct meridional and vertical patterns that are in a good agreement with the multi-model mean projection from the IPCC AR4. In the tropics, the warming in the upper troposphere is stronger than in the lower troposphere, leading to a decrease in temperature lapse rate, whereas in high latitudes the opposite it true. In terms of meridional contrast, the lower tropospheric warming in the tropics is weaker than that in high latitudes, resulting in a weakened meridional temperature gradient. In the upper troposphere the meridional temperature gradient is enhanced due to much stronger warming in the tropics than in high latitudes. Using the CFRAM method, we analyzed both radiative feedbacks, which have been emphasized in previous climate feedback analysis, and non-radiative feedbacks. It is shown that non-radiative (radiative) feedbacks are the major contributors to the temperature lapse rate decrease (increase) in the tropical (polar) region. Atmospheric convection is the leading contributor to temperature lapse rate decrease in the tropics. The cloud feedback also has non-negligible contributions. In the polar region, water vapor feedback is the main contributor to the temperature lapse rate increase, followed by albedo feedback and CO2 forcing. The decrease of meridional temperature gradient in the lower troposphere is mainly due to strong cooling from convection and cloud feedback in the tropics and the strong warming from albedo feedback in the polar region. The strengthening of meridional temperature gradient in the upper troposphere can be attributed to the warming associated with convection and cloud feedback in the tropics. Since convection is the leading contributor to the warming differences between tropical lower and upper troposphere, and between the tropical and polar regions, this study indicates that tropical convection plays a critical role in determining the climate sensitivity. In addition, the CFRAM analysis shows that convective process and water vapor feedback are the two major contributors to the tropical upper troposphere temperature change, indicating that the excessive upper tropospheric warming in the IPCC AR4 models may be due to overestimated warming from convective process or underestimated cooling due to water vapor feedback. 相似文献
969.
The North Atlantic oscillation simulated by versions 2 and 4 of IAP/ LASG GOALS Model 总被引:6,自引:0,他引:6
The capabilities of two versions of the Global-Ocean-Atmosphere-Land-System model (i.e. GOALS-2 and GOALS-4) developed at State Key Laboratory of Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), are validated in terms of the simulations of the winter North Atlantic Oscillation (NAO), which is currently the subject of considerable scientific interest. The results show that both GOALS-2 and GOALS-4 exhibit a realistic NAO signal associated with relatively reasonable spatial pat-terns of sea level pressure, surface air temperature, and precipitation. Generally speaking, the associated pat-terns of precipitation in GOALSs match better with the observation in comparison with the case of surface temperature. For the imprint of NAO on the ocean, or perhaps a coupling between the two fluids, the asso-ciated tripole patterns of the North Atlantic SST anomaly are presented distinctly in GOALS-2, for GOALS-4 however, this is not the case. Spatially, the models’ main deficiencies appear to be that the simu-lated Icelandic lows shift northward apparently, which in turn result in the blemish of GOALSs in repro-ducing the accompanied surface wind anomalies. For the interannual and even longer time scale variations of DJF sea level pressure (SLP) over the North Atlantic region. GOALSs reproduce the center with the strongest variability rationally, but the intensities are far weaker than the observation. 相似文献
970.