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991.
贡伟亮  赵伟 《矿物学报》1993,13(2):104-108
作者进行了稀土铌钛氢氧化物共沉淀实验,对共沉淀物及其高温灼烧产物进行了XRD、IR、DTA和Raman研究,结合前人高温高压实验结果以及野外地质事实,提出了热液体系复杂氧化物矿物易解石和黑稀金矿的络合物高温水解、氢氧化物共沉淀、脱水去羟、聚合成核和结晶的成因模式。  相似文献   
992.
莫天麟  谢国梁 《气象学报》1981,39(4):460-464
本文介绍了1979年11月至1980年7月期间南京市区降水酸度的测量结果。结果表明:南京市区降水的pH平均值为5.62,变化范围从4.10—7.93,其中,1980年1月份和7月份出现酸雨,pH的月平均值分别达到5.52和5.26。 测量结果还与日本、英国、美国的观测结果作了比较。  相似文献   
993.
强震记录的采样与插值研究   总被引:2,自引:0,他引:2       下载免费PDF全文
本文从频域和时域两方面对强震记录的采样和插值过程进行了研究。研究中将采样与插值当作一个信号转换系统,通过数值计算,求得和各种常用的采样和插值过程相对应的传递函数。通过对传递函数的进一步研究表明:采样和插值方式对强震记录数据处理的结果有重要的影响,发现采样过程相当于一个低通滤波器,可以滤除信号中的某些高频信息,而插值过程犹如一个高频噪声源,会在数字记录中引入某些伪高频分量。分析结果还表明:在相同的采样密度下,不等距采样方式具有较高的精度,而等间距采样方式能给出更宽的平坦的频率特性曲线;抛物线插值给出的传递函数结果要比线性插值的结果更精确,这对恢复数字信号中的高频成分具有重要的意义。  相似文献   
994.
On September 13, 1976, the Qingzhen enstatite chondrite fell near Qingzhen County, Guizhou Province (26°32′N, 106°28′E). The total mass recovered was 2.6 kg. Phenomena of the meteorite fall were recorded as well. In the present paper some of the significant observations are described. X-ray diffraction analyses and petrologic studies revealed that it is mainly composed of enstatite/clinoenstatite, plagioclase, troilite, kamacite, taenite, quartz and oldhamite. X-ray electron microprobe analyses were performed on orthoenstatite and clinoenstatite. Chemical analysis gave: SiO2-36.48; Al2O3-1.64; TiO2-0.08; Cr2O3-0.28; FeO-0.30; MnO-0.25; MgO-18.19; CaO-1.14; Na2O-1.06; K2O-0.11; H2O+-0.47; H2O?-0.10; P2O5-0.39; FeS-13.35; FeO-22.94; Ni-1.81; Co-0.093; C-0.37; Cu-0.022; Zn-0.027; CaS-0.60; total-99.70 (wt.%). This meteorite has been extremely reduced; all iron is present as FeS and metallic Fe-Ni. The Qingzhen enstatite chondrite is characterized by high ratio, Si/Mg as compared with ordinary chondrites, scarcity of olivine, and enrichment in sulfur and iron. In thin sections, it is observed that round chondrules approximately account for 10–15 per cent, being porphyritic, radial, excentroradial, or excentric fan-shaped. Devitrified chondrules composed of pyroxene were also identified. It is postulated from its mineralogy, chemistry and textural characteristics that the Qingzhen meteorite should be assigned toE 4 orEH chondrites.  相似文献   
995.
This paper outlines the recent advances in geochemical exploration in China.The Regional Geochemistry—National Reconnaissance (RGNR) Project first proposed in 1978, continues to be the focus of geochemical exploration activities in China. Several rapid quantitative multi-element analysis systems using conventional equipment available in most Chinese geological laboratories, have been developed. Eight Geochemical Standard Reference Samples of Drainage Sediments were prepared. Large-scale orientation or pilot surveys are being carried out by nearly 2/3 of the provincial geological bureaus in China. Methods of regional and follow up surveys for high and cold mountainous terrain have been worked out.Special attention has been given to the improvement and application of mercury vapour detection techniques. A new sampler was used to enhance anomalous values. A new Zeeman effect mercury detector was constructed and tested in routine analysis of mercury. Experiments of the application of soil gas mercury survey in petroleum and uranium prospecting are briefly described.Some examples of recent geochemical success in China are given.  相似文献   
996.
塔里木克拉通太古宙岩石主要出露在库鲁克塔格、北阿尔金、铁克里克和敦煌等四个边缘基底隆起带。库鲁克塔格地块位于塔里木克拉通东北缘,其中有可靠年代学报道的太古宙岩石主要出露在库尔勒、辛格尔、兴地和帕尔岗塔格四个地区。库鲁克塔格地块的太古宙岩石主要由长英质正片麻岩(含TTG片麻岩)和少量以包体产出的斜长角闪岩组成,真正的太古宙表壳岩较少见。本次研究在库尔勒地区对长英质正片麻岩和石英岩开展锆石SHRIMP U- Pb测年分析,2个长英质正片麻岩样品的年龄分别为2695±9 Ma和2705±8 Ma;石英岩样品中的碎屑锆石核最小年龄峰为2513 Ma,石英岩有可能是太古宙沉积岩;上述岩石样品都经历了古元古代早期 (1. 9~1. 8 Ga)高级变质作用。地球化学分析发现,库鲁克塔格地块新太古代长英质片麻岩的原岩有多种岩石类型,这些长英质岩石都形成于与俯冲作用有关的岛弧构造背景。基性的斜长角闪岩和变质辉长岩可能产出于不同的背景,一部分来源于岛弧地幔楔的部分熔融,另一部分则可能来自于大洋板内,以洋脊玄武岩为主。库鲁克塔格地块太古宙岩石具有2. 7 Ga和2. 5 Ga两个年龄峰值,2. 7 Ga岩浆事件主要发生在库鲁克塔格西部地区,锆石的εHf(t)值既有正值也有负值,表明这一时期地壳生长和改造同时并存;~2. 5 Ga的岩浆活动分布范围较为广泛,全岩εNd(t)和锆石εHf(t)值以正值为主,暗示这一时期可能存在显著的大陆地壳生长。  相似文献   
997.
~~Characteristics of the mantle source region of sodium lamprophyres and petrogenetic tectonic setting in northeastern Hunan,China~~  相似文献   
998.
Maximum rate of food consumption ( Cmax ) was determined for juvenile Sebastodes fuscescens (Houttuyn) at water temperature of 10, 15, 20 and 25℃. The relationships of Cmax to the body weight (W) at each temperature were described by a power equation: lnCmax = a b lnW. Covariance analysis revealed significant interaction of the temperature and body weight. The relationship of adjusted Cmax to water temperature (T) was described by a quadratic equation: Cmax = -0.369 0.456T - 0.0117T^2. The optimal feeding temperature calculated from this equation was 19.5 ℃. The coefficients of the multiple regression estimation relating Cmax to body weight (W) and water temperature (T) were given in the Table 2.  相似文献   
999.
339 gas samples above oceanic surface were collected on the cruise of "Xuelong" expeditionary ship and nitrous oxide concentrations were analyzed in the laboratory. Results showed that Atmospheric average N2O concentration was 309 ±3. 8nL/L above the surface of northern Pacific and Arctic ocean. N2O concentrations were significantly different on the northbound and southbound track in the range of the same latitude, 308.0 ±3.5 nL/L from Shanghai harbor to the Arctic and 311.9 ±2.5 nL/L from the Arctic to Shanghai harbor. N2O concentration had a greater changing magnitude on the mid- and high-latitude oceanic surface of northern Pacific Ocean than in the other latitudinal ranges. The correlation between the concentrations of the compositions in the aerosol samples and atmospheric N2 O showed that continental sources had a great contribution on atmospheric N2 O concentration above the oceanic surface. Atmospheric N2O concentration significantly increased when the expeditionary ship approached Shanghai h  相似文献   
1000.
A new way to predict forecast skill   总被引:1,自引:0,他引:1  
Forecast skill (Anomaly Correlated Coefficient, ACC) is a quantity to show the forecast quality of the products of numerical weather forecasting models. Predicting forecast skill, which is the foundation of ensemble forecasting, means submitting products to predict their forecast quality before they are used.Checking the reason is to understand the predictability for the real cases. This kind of forecasting service has been put into operational use by statistical methods previously at the National Meteorological Center (NMC), USA (now called the National Center for Environmental Prediction (NCEP)) and European Center for Medium-range Weather Forecast (ECMWF). However, this kind of service is far from satisfactory because only a single variable is used with the statistical method. In this paper, a new way based on the Grey Control Theory with multiple predictors to predict forecast skill of forecast products of the T42L9 of the NMC, China Meteorological Administration (CMA) is introduced. The results show: (1) The correlation coefficients between “forecasted“ and real forecast skill range from 0.56 to 0.7 at different seasons during the two-year period. (2) The grey forecasting model GM(1,8) forecasts successfully the high peaks, the increasing or decreasing tendency, and the turning points of the change of forecast skill of cases from 5 January 1990 to 29 February 1992.  相似文献   
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