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861.
华北陆块南缘(河南段)出露的富碱侵入岩类集中分布于卢氏-确山一线。岩石类型主要分为三大类:①碱性岩类,即含有似长石或碱性暗色矿物的正长岩类;②碱性花岗岩类,包括钠铁闪石花岗岩以及孪生的钾长花岗岩类;③石英正长岩类,包括碱性长石为主的石英正长岩、英碱正长岩和花岗正长(斑)岩类。在空间上构成一条富碱岩浆岩带,据岩石组合自北而南划为三个亚带:北部碱性岩亚带、中部碱性花岗岩类亚带和南部石英正长(斑)岩亚带。在形成时间上富碱岩浆活动集中于晚元古代末期(700Ma±)和海西晚期(300Ma±)。  相似文献   
862.
Ancient town Dali is located in northwest Yunnan Province. With its ancient history and natural scenery, it is preserved as one of the first 24 historical and cultural towns in China. Dali has become one of the most popular attractions for foreign tourists since it had its first foreign visitors in 1983. As a result, English came into the life of the local people. This paper presents and explains the results of questionnaires and interviews about Dali people’s attitude toward learning English. Three types of questionnaires were designed to local businessmen, local residents and foreign tourists. Interviews were also given whenever possible. In this study, businessmen in Dali were divided into two distinct groups. One group had their business in “Foreigners’ Street”, which was in front of Hongshancha Hotel where many foreign tourists stayed. Another group had business in Fuxin Street, which was vertically across “Foreigners’ Street”. The 41 shops and restaurants in “Foreigners’ Street” served mainly foreign visitors, and most of them had English names and advertisements. The 353 shops and restaurants in Fuxin Street mainly catered for domestic visitors but also served more and more overseas ones. Subjects from local residents were mostly young people because aging ones were apparently not much affected by English. The results of the study showed that the oral English levels became lower from “Foreigners’ Street” to Fuxin Street to local residents, due to declining frequency of contact with foreign people. There were also distinct differences in general English level, the understanding of the importance of English, the purposes of communicating with foreign tourists, the willingness and purposes of going on learning English between businessmen in “Foreigners’ Street” and Fuxin Street: people in “Foreigners’ Street” had more positive feedback than those in Fuxin Street because their constant contact with foreigners required them to speak better English which enabled them to exchange with foreigners in many aspects, which in turn help them to know more about other cultures. On the other hand, Fuxin Street businessmen would catch up with more and more prospective contact with overseas people. Though local residents had nothing to do with foreign tourists, they met them in the street every day and might have to talk with them in unexpected ways. They lived in a place where they saw English advertisement every day. Accordingly, study results showed that they were very much motivated to learn English. They showed even stronger desire to learn more English than businessmen in “Foreigners’ Street”, though many of them were too young to tell why English was so important for them. This is an indication that English has become part of the necessary education for young people in Dali. With the development of tourism, Dali is gradually becoming a place where Chinese culture and western culture meet and coexist. This project was supported by National Natural Science Foundation of China.  相似文献   
863.
HAPI-1是我国第一个用于空间高能天文观测的硬X射线望远镜系统,由面积145cm~2厚0.5cm的CsI(T1)主探测晶体及其下部厚5cm的NaI(T1)反符合晶体构成复合晶体探测器,采用脉冲形状甄别技术区分两种晶体的输出信号,多种物质构成的夹层式屏蔽筒和准直器使望远镜具有约4°视场角(HWHM),电子学、姿态控制和数据获取系统使望远镜具有对20—200keV能区高能光子到达时刻和能量进行空间定向观测的能力。本文介绍HAPI-1的构成和主要性能,以及1984年5月利用该望远镜在我国高空科学气球上对蟹状星云脉冲星的观测结果。  相似文献   
864.
黄土高原黄土物源区的同位素证据   总被引:2,自引:0,他引:2       下载免费PDF全文
系统采集了黄土高原马兰黄土、河西走廊和青藏高原东北部黄土、河床沙和湖泥样品。用酸淋洗去除方解石后,黄土高原马兰黄土εNd(0)值从-9.2到-11.3,87Sr/86Sr比值从0.71784到0.71944,都落在同位素B区内,与青藏高原东北部、巴丹吉林沙漠和腾格里沙漠的值一致。黄土高原马兰黄土白云石的δ13C值从1.2‰到1.5‰,与青藏高原东北部和河西走廊黄土,巴丹吉林沙漠的白云石的值类似。这些表明青藏高原东北部、巴丹吉林沙漠和腾格里沙漠可能是黄土高原黄土的源区,从而排除了其他沙漠(古尔班通古特沙漠、塔克拉玛干沙漠、毛乌素沙漠、库布齐沙漠、浑善达克沙地、科尔沁沙地和呼伦贝尔沙地)作为黄土物源区的可能性。同位素研究结果和野外调查进一步揭示,黄土高原黄土、巴丹吉林沙漠和腾格里沙漠物质可能最终都是来源于青藏高原东北部。  相似文献   
865.
INTRODUCTIONAtpresentgiantfreshwaterprawn (Macrobrachiumrosenbergii) ,Chineseshrimp (Penaeuschinensis)andgianttigerprawn (P .monodon)arethemainshrimpsforcultureinChina.Asweknow ,feedstuffcostisamajorexpenseiteminculturepractice.Overfeedingwillnotonlywastefee…  相似文献   
866.
郭炳跃  王毅  戴俊成 《江苏地质》2021,45(3):327-334
长江中下游地区沿江丘陵平原地貌分布广泛且地质背景相似,开展单个地区的工程地质分区方法研究,对同类区域具有一定的借鉴意义。以安庆地区为例,提出一级分区以地貌类型,二级分区以岩土体类型、结构和重要工程地质层分布为划分原则的工程地质分区方法,将该区划分为5个工程地质区和14个工程地质亚区,并对各分区工程地质特性进行论述,旨在为同类区域水工环地质调查、城市地质调查研究提供参考。  相似文献   
867.
针对目前地震会商现场缺乏交互性与数据分析的动态性,提出地震会商会议发起人-参与者的应用模式。会商期间,通过在广播端实时广播操作消息、运用网络实时推送技术,使各地参与的信息节点会商资料内容一致,同时接收端实时接收并执行操作消息,从而同步显示广播计算机的操作画面,最终达到模拟广播视频的效果。该系统增强了地震会商在线动态数据分析的真实性与实时交互性。  相似文献   
868.
计算并分析了2011年1月19日安庆M4.8地震和2011年9月10日瑞昌-阳新M4.6地震前后震中周边主要地磁台站地磁转换函数参数的变化特征,总结了安庆地震前华东片主要地磁台站地磁资料垂直分量的变化特征。结果表明:在两次中强地震前,武汉、泾县、金寨三个地磁台的转换函数的部分参数出现了不同程度的异常变化;安庆地震前,中国大陆东部地磁低点时间出现位移,地磁日变形态亦发生了明显的畸变。  相似文献   
869.
In a two-dimensional and linear framework, a transformation was developed to derive eigensolutions of internal waves over a subcritical hyperbolic slope and to approximate the continental slope and shelf. The transformation converts a hyperbolic slope in physical space into a flat bottom in transform space while the governing equations of internal waves remain hyperbolic. The eigensolutions are further used to study the evolution of linear internal waves as it propagates to subcritical continental slope and shelf. The stream function, velocity, and vertical shear of velocity induced by internal wave at the hyperbolic slope are analytically expressed by superposition of the obtained eigensolutions. The velocity and velocity shear increase as the internal wave propagates to a hyperbolic slope. They become very large especially when the slope of internal wave rays approaches the topographic slope, which is consistent with the previous studies.  相似文献   
870.
为了提高GPS软件接收机信号捕获的速度,提出了一种GPS卫星C/A码信号捕获的新方法(这种方法具有Gold码的性质)。并证明了多颗卫星信号的相关性可以在同一次相关性计算过程中同时处理完成,在一次捕获卫星信号过程中可同时捕获多颗卫星信号。  相似文献   
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