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961.
Introduction of species evolutionary sequence into the quantitative biostratigraphy is a significant work, either for studying biologic evolution or for making stratigraphic correlation and reconstructing geologic history. The quantitative biostratigraphy is to determine biostratigraphic event sequences by using probabilistic analysis. The evolutionary sequence systematics can efficiently ascertain species evolutionary sequences. Two methods have been proposed to determine the sequence of species-disappearance events: (1) species extinction events can be closed by last occurrence events using quantitative biostratigraphic analysis; (2) the duration of a species may be approximately replaced by the duration of its parent species. To combine these two methods for determining the sequence of species disappearance is the best way up to now. A consulting standard sequence that consists of the speciation sequence of Permian waagenophylloid corals and the biostratigraphic event sequence of other important fossils in Permian is used as an example. The group spearman rank-correlation test is used to test the consulting standard sequence by comparing four types of calculations and two kinds of sequences and to find abnormal events. Based on the found abnormal events in the test, the consulting standard sequence is revised to deal with different conditions. Sequences of speciation and species-disappearance, and species duration are determined. Application of species evolutionary sequence to quantitative biostratigraphy can largely improve the quality of biostratigraphic event sequence. In stratigraphic correlation, furthermore, event sequences have higher precision than range biozones.  相似文献   
962.
青田山口叶蜡石传压介质初步研究   总被引:8,自引:0,他引:8  
采用青田山口叶蜡石作为超高压高温合成金刚石的传压介质,分析了其主要化学成分和矿物组成。对青田山叶蜡石粉压块粒度效应进行了研究,确定了该传压介质的粒度组成。超高压高温人造金刚石试验表明,青田山口叶蜡石的传压介质理想,金刚石合成效果较好。  相似文献   
963.
新疆及邻区大地构造编图研究   总被引:21,自引:5,他引:21  
成守德  徐新 《新疆地质》2001,19(1):33-37
新疆及邻区大地构造1150万的编图范围为北纬34°~50°,东经72°~98°,面积约370×10  相似文献   
964.
四川牦牛坪稀土矿床萤石REE配分模式的影响因素   总被引:2,自引:0,他引:2  
四川牦牛坪稀土矿床萤石REE配分模式表现出明显变化的特征,本文从稀土离子半径和温度两个方面分析了影响矿区萤石配分模式的原因。结果表明:矿区萤石中LREE的配分模式主要受温度影响,而MREE、HREE主要受离子半径控制。  相似文献   
965.
In this paper, the definition of latitudinal density and density flattening of the level ellipsoid is given, and integral formulas of latitudinal density for pole gravity and equator gravity are derived. According to the pole gravity condition and equator gravity condition for the level ellipsoid, latitudinal density distribution function of the level ellipsoid is obtained. It is proved mathematically that latitudinal density of the earth’s equator is larger than that of the pole, the earth’s density flattening calculated preliminarily is 1/322, and hypothesis of the earth’s latitudinal normal density is further proposed, so that theoretical preparation for studying the forming cause of the earth gravity in problems such as continent drift, mantle convection, and submarine extension is made well.  相似文献   
966.
导致古森林沉没于海的福建深沪湾古地震研究   总被引:4,自引:2,他引:4  
徐起浩  冯炎基  施建生 《地震地质》2001,23(3):367-380,T001,T002
福建深沪湾海底古森林是强古地震遗迹。研究结果表明 ,全新世早期该处海底古森林生长在由松散的晚更新世含砾砂粘土构成的低凹洼地内。距今 70 0 0a左右的强古地震导致古森林沉没于海并形成泻湖环境 ,约距今 2 0 0 0a的又一次强古地震使海底古森林沉没到更深的海底 ,推测这两次古地震的震级都超过 7级  相似文献   
967.
Abstract: 3–D velocity images of the crust beneath the northern margin of the North China Plate have been constructed using P-wave travel time residuals of the latest earthquakes, with the data supplied by Chinese seismic networks.
The seismic image results indicate that there is a lateral heterogeneity in the crust beneath the northern part of the North China block. The velocity images of the upper crust show features closely related to the tectonic features on the surface. It can be seen from these velocity images of the vertical sections, and from the horizontal slice images at depths of 11 and 16 km that there exist East-West and North-East structures. The images indicate that the juncture zone of basin–and–range terrain is between the blue-colored high–velocity block corresponding to the Yanshan mountain range that developed during the Yanshan period in northwest Beijing and the green low-velocity area corresponding to the North China basin in southeast Beijing (Fig. 5). The juncture zone between high-velocity and low–velocity, and EW and NE fault zones have significant ore-control effects. From the chart of epicenters in the northern region of North China, we find that the epicenters of earthquakes are almost entirely distributed within the NE strip. Almost all major earthquakes took place in the transition strip between the high and low-velocity zones in the crust. The distribution of epicenters also reflects the strikes of known NE–faults. From the image sections along the latitude, we find that in the area between 114.0 E –118.0 E , there is a blue high-velocity block standing upright from the Moho to the upper crust (Fig. 6), from which can be deduced that some materials such as magma moved upward from the upper mantle during the history of its geological development.  相似文献   
968.
大地热流测量数据子库   总被引:6,自引:0,他引:6       下载免费PDF全文
金旭  韩湘君 《地球学报》2001,22(6):521-525
大地热流数据子库是建立在Microsoft Access97基础上,以Microsoft Visual Basic6.0开发,基于Windows平台上的集数据储存,编辑,报表打印输出及基本数据解释处理于一体的数据库管理软件。具有运行速度快,操作简单,易学及可靠性强等优点。特别编制了强大的数据查询系统,提供了各种查询方式,大大方便了用户。  相似文献   
969.
本文利用南京北郊164米气象塔实测资料对一次非降水弱冷锋过程的边界层风场结构一三维风速、横锋向水平散度、湍流通量和能量的时空分布,以及多尺度时空分布进行了计算分析。结果表明,在冷暖空气的过渡区(锋区)风场各参量具有明显的梯度,锋区前线的强上升气流与强冷锋相近,但锋区宽度较强冷锋宽得多,其时间尺度为30分钟,水平距离为35公里。锋面过境对风温场的影响时段为24小时,在这期间,出现阵风浪涌和多种中、小尺度(时间尺度为3-4小时、1-20分钟)的湍涡活动。  相似文献   
970.
首先分析了河套华北地区旱涝的前期异常环流,然后探讨了这种异常环流形成的机制,最后采用了OSU-AGCM作了大西洋地区热源异常强迫的数值试验。结果表明,大西洋地区海温异常强迫激发的定常波向上、下游的能量传播,造成的前期秋冬季环流异常与河套华北地区的夏季旱涝有较好的对应关系。  相似文献   
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