全文获取类型
收费全文 | 1252篇 |
免费 | 416篇 |
国内免费 | 959篇 |
专业分类
测绘学 | 18篇 |
大气科学 | 2097篇 |
地球物理 | 134篇 |
地质学 | 138篇 |
海洋学 | 91篇 |
天文学 | 2篇 |
综合类 | 34篇 |
自然地理 | 113篇 |
出版年
2024年 | 15篇 |
2023年 | 31篇 |
2022年 | 51篇 |
2021年 | 66篇 |
2020年 | 68篇 |
2019年 | 100篇 |
2018年 | 76篇 |
2017年 | 59篇 |
2016年 | 60篇 |
2015年 | 87篇 |
2014年 | 127篇 |
2013年 | 124篇 |
2012年 | 125篇 |
2011年 | 123篇 |
2010年 | 103篇 |
2009年 | 111篇 |
2008年 | 163篇 |
2007年 | 131篇 |
2006年 | 133篇 |
2005年 | 128篇 |
2004年 | 93篇 |
2003年 | 88篇 |
2002年 | 60篇 |
2001年 | 66篇 |
2000年 | 66篇 |
1999年 | 63篇 |
1998年 | 51篇 |
1997年 | 52篇 |
1996年 | 54篇 |
1995年 | 40篇 |
1994年 | 32篇 |
1993年 | 34篇 |
1992年 | 9篇 |
1991年 | 14篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 7篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有2627条查询结果,搜索用时 31 毫秒
121.
周海光 《热带气象学报(英文版)》2007,(2)
The three-dimensional wind fields of the heavy rain on 12-13 June 2005 in Guangdong province are retrieved and studied with the volume scan data of the dual-Doppler radar located in the cities of Meizhou and Shantou. It is shown that the meso-β-scale and meso-γ-scale convergence lines located in the convective system at the low and middle layer play an important role in the heavy rainfall. The convergence line is the initiating and maintaining mechanism of the rain. A three dimensional kinematic structure model is also given. 相似文献
122.
123.
介绍自动气象雨量站SL3-1雨量传感器在使用中出现故障现象及改进方法,对台站维护起着参考作用。 相似文献
124.
125.
126.
127.
Yu Xixian 《GeoJournal》1998,45(3):151-158
This paper is translated and consolidated from the following papers: Study on Xu Xia-ke's Records of the Extraordinary Cold Caused by the Heavy Snow in the 17th Century (Geographical Research,
v. 12, no. 3), and A Study on the Extra Long Autumn Rain in the Central Part of Yunnan in 1638 Based on Xu Xia-ke's Travels
(Geographical Research, v. 14, no. 4). The translation and consolidation were done by Wong Yat Loon, Department of Urban and Environment Science, Peking University,
Beijing 100871, China
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
128.
Norimichi Takenaka Tohru Daimon Akihiro Ueda Keiichi Sato Masaru Kitano Hiroshi Bandow Yasuaki Maeda 《Journal of Atmospheric Chemistry》1998,29(2):135-150
Nitrite oxidation in the tropospheric aqueous phase by freezing was evaluated by freezing a field sample. Nitrite oxidation by dissolved oxygen in the freezing process is much faster than by other oxidation processes, such as reactions with ozone, hydrogen peroxide or dissolved oxygen in an aqueous solution at pHs 3 to –6. At pH 4.5 and 25°C, the lifetime of nitrite in the aqueous phase is ca. 1 hr in oxidation by ozone (6×10-10 mol dm-3), ca. 10 hr in oxidation by H2O2 (2×10-4 mol dm-3), and 7.5 hr (Fischer and Warneck, 1996) in photodissociation at midday in summer. Under the same conditions at a temperature below 0°C, the lifetime of nitrite in the freezing process is estimated as ca. 2 sec when the droplets are frozen within a second. The reaction by freezing is affected by the presence of salts, such as NaCl or KCl, or orgnaic compounds, such as methanol or acetone. The results of freezing a field rain or fog sample showed that nitrite oxidation proceeds below pH 6, and the conversion ratio of nitrate from nitrite increases with decreasing pH. The oxidation of nitrite by freezing was also observed in freezing fog particles generated by an ultrasonic humidifier. The ratios of the concentrations of ions in the winter sample to those in the summer sample (or those in the fog sample) were almost the same values. However, the concentration of nitrite in the winter sample was lower than that estimated by the ratios of other ions. From the present study, it seems that the freezing process plays an important role in the nitrite sink process in the tropospheric aqueous phase. 相似文献
129.
130.
从天气形势出发,结合物理量场、卫星云图和雷达回波等演变特征,分析洞庭湖附近生成的两个气旋波东移过程中在九江地区引起的强对流、暴雨天气。 相似文献