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961.
962.
中国内陆河流域植被对气候变化的敏感性差异(英文) 总被引:1,自引:0,他引:1
Terrestrial ecosystem and climate system are closely related to each other. Faced with the unavoidable global climate change, it is important to investigate terrestrial ecosystem responding to climate change. In inland river basin of arid and semi-arid regions in China, sensitivity difference of vegetation responding to climate change from 1998 to 2007 was analyzed in this paper. (1) Differences in the global spatio-temporal distribution of vegetation and climate are obvious. The vegetation change shows a slight degradation in this whole region. Degradation is more obvious in densely vegetated areas. Temperature shows a gen-eral downward trend with a linear trend coefficient of -1.1467. Conversely, precipitation shows an increasing trend with a linear trend coefficient of 0.3896. (2) About the central tendency response, there are similar features in spatial distribution of both NDVI responding to precipitation (NDVI-P) and NDVI responding to AI (NDVI-AI), which are contrary to that of NDVI responding to air temperature (NDVI-T). Typical sensitivity region of NDVI-P and NDVI-AI mainly covers the northern temperate arid steppe and the northern temperate desert steppe. NDVI-T typical sensitivity region mainly covers the northern temperate desert steppe. (3) Regarding the fluctuation amplitude response, NDVI-T is dominated by the lower sensi-tivity, typical regions of the warm temperate shrubby, selui-shrubby, bare extreme dry desert, and northern temperate meadow steppe in the east and temperate semi-shrubby, dwarf ar-boreous desert in the north are high response. (4) Fluctuation amplitude responses between NDVI-P and NDVI-AI present a similar spatial distribution. The typical sensitivity region mainly covers the northern temperate desert steppe. There are various linear change trend re-sponses of NDVI-T, NDVI-P and NDVI-AI. As to the NDVI-T and NDVI-AI, which are influ-enced by the boundary effect of semi-arid and semi-humid climate zones, there is less cor-relation of their linear change tendency along the border. There is stronger correlation in other regions, especially in the NDVI-T in the northern temperate desert steppe and NDVI-AI in the warm temperate shrubby, selui-shrubby, bare, extreme and dry desert. 相似文献
963.
秦岭地区秋季降水的气候特征分析 总被引:5,自引:1,他引:4
利用1961-2005年观测资料和NCEP/NCAR再分析资料, 对秦岭邻近地区秋季(9-10月) 降水的气候特征及其与大气环流关系进行分析,结果表明:秦岭地区秋季降水具有明显年代际变化特征, 1960s后期、1970s和1980s初秋季多雨,而1950s和1960s初前期、1980s中后期和1990s秋少雨, 2000年以后秋季降水略有增多.秦岭地区秋季雨涝年环流特征是高原北侧高空西风急流偏强,乌拉尔山长波脊稳定,西大平洋副热带高压位置偏西,强度偏强,对流层低层东南风气流和西南风气流为秦岭地区输送了大量水汽;而少雨干旱年则高空高原北侧西风急流偏弱,秦岭地区受青藏高压控制或西北气流控制,与东亚冬季风相联系的偏北气流阻断了偏南气流的水汽输送. 相似文献
964.
965.
Phosphorus speciation and availability in intertidal sediments of the Yangtze Estuary,China 总被引:1,自引:0,他引:1
In order to better understand P cycling and bioavailability in the intertidal system of the Yangtze Estuary, both surface (0–5 cm) and core (30 cm long) sediments were collected and sequentially extracted to analyze the solid-phase reservoirs of sedimentary P: loosely sorbed P; Fe-bound P; authigenic P; detrital P; and organic P. The total sedimentary P in surface and core sediments ranged from 14.58–36.81 μmol g−1 and 17.11–24.55 μmol g−1, respectively, and was dominated by inorganic P. The average percentage of each fraction of P in surface sediments followed the sequence: detrital P (54.9%) > Fe-bound P (23.7%) > organic P (14.3%) > authigenic P (6.3%) > loosely sorbed P (0.8%), whereas in core sediments it followed the sequence: detrital P (61.7%) > Fe-bound P (17.0%) > authigenic P (13.1%) > organic P (7.5%) > loosely sorbed P (0.7%). Post-depositional reorganization of P was observed in both surface and core sediments, converting organic P and Fe-bound P to authigenic P. The accumulation rates and burial efficiencies of the total P in the intertidal area ranged from 118.70–904.98 μmol cm−2 a−1 and 80.29–88.11%, respectively. High burial efficiency of the total P is likely related to the high percentage of detrital P and the high sediment accumulation rate. In addition, the bioavailable P represented a significant proportion of the sedimentary P pool, which on average accounted for 37.4% and 25.1% of the total P in surface and core sediments, respectively. This result indicates that the tidal sediment is a potential internal source of P for this P-limiting estuarine ecosystem. 相似文献
966.
四川盆地西缘分为龙门山分区和四川盆地分区。已有的地层区划方案均对两大分区采用一条绝然的界限,忽略了盆地西缘原地地层系统与外来地层系统之间不同的沉积环境及构造演化模式。认为在两个分区之间并没有绝然的界线,而是以组成龙门山的三个主要推覆体东缘的断裂为主要界线,但将该界线以东中小飞来峰地层系统归属于龙门山分区,而将介于该界线与中小飞来峰之间的由于飞来峰与主体脱离而暴露的原地地层系统归属于四川盆地分区。龙门山分区可进一步划分为三个小区,分别包含一个大型推覆体及若干中小推覆体或飞来峰,反映了龙门山各段不同的隆升时间及沉积特征。将四川盆地分区进一步划分为西南小区和西北小区,主要以上白垩统及其以上地层是否发育相区别。 相似文献
967.
陕西八卦庙金矿床1290m标高以上矿体为层状、似层状、透境状,单矿体最大厚度70.3m,金品位≥3×10^-6。62-72线长200m,宽200m范围内金品位≥2×10^-6,形状完整。从1290m标高以下矿体均分支为单脉体,厚度2~10m,地质品位≥3×10^-6,矿体形态上,下部与深部变化较大。 相似文献
968.
保护生态环境、防治矸石灾害 总被引:2,自引:0,他引:2
我国是世界上唯一以煤炭为基本能源的大国,在一次能源消费中,煤炭占57%以上。随着经济的发展,煤炭资源的开采日益加强,煤矸石的产量亦日趋增多,然而对煤矸石的随意堆存和缺乏有效管理,不但占用了土地资源,而且对生态和人文环境均造成了一定的危害。本文较详细地论述了对煤矸石的不合理堆放给人类生存环境带来的一些常见危害以及如何充分利用煤矸石,使之变“废”为“宝”。文章最后,作者提出了一些合理化切实可行的防治对策和管理措施。 相似文献
969.
The world is marching into a new development period when the digital technology, physical technology, and biological technology have achieved an unprecedented development respectively in their own fields, and at the same time their applications are converging greatly. These are the three major technological drivers for the Fourth Industrial Revolution. This paper discusses the specific technology niches of each kind technological driver behind the Fourth Industrial Revolution, and then evaluates impacts of the Fourth Industrial Revolution on global industrial, economic, and social development. At last this paper proposes possible measures and policies for both firms and governments to cope with the changes brought by the Fourth Industrial Revolution. 相似文献
970.
Sediment samples obtained from the South Mid-Atlantic Ridge were analyzed for the major and trace elements by inductively coupled plasma atomic emission spectroscopy and inductively coupled plasma mass spectrometry. Results revealed that the contents of elements (e.g., Fe, Mn, Cu, Zn, V, Co) were high in samples 22V-TVG10 and 26V-TVG05 from the sites near the hydrothermal areas, and low in sample 22V-TVG14, which was collected far from the hydrothermal areas. The contents of Ca, Sr and Ba in the samples showed opposite trends. A positive correlation between the concentrations of metallic elements (Cu, Zn, Co, Ni, Pb, V) and Fe in the samples were observed. These results are consistent with chemical evolution of the dispersing hydrothermal plume. 相似文献