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991.
在冬春季低水温期,海水网箱养殖的鱼类大批死亡造成了严重的经济损失。本文对死亡的原因进行了初步研究,结果表明:在一定的低水温环境下,这些鱼类虽然因冻伤而造成局部坏死,但维持生命的主要器官的机能仍处于基本正常状态;而患鱼继发感染细菌致病才是其死亡的主要原因。采取适当的越冬防寒措施可提高养殖海鱼在越冬期的成活率。 相似文献
992.
叶澜涛 《广东海洋大学学报》2007,27(2):1-4
从经济运作的方式、历代海洋政策的变迁、古代海洋文学三个方面来分析中国古代南部海洋文化的农业性特征,认为这种特征有别于商业文化的表现形态,它受到中国内陆文化的影响,具有传统性、辅助性和保守性。因此,在考察中国古代海洋文化时,应将中国古代海洋文化作为中国古代农业文化的有机组成部分。 相似文献
993.
本文通过对长城湾表层沉积物中稀土元素的地球化学研究,认为其总量丰度、配分模式、特征参数等,均与菲尔德斯半岛的火山岩相似,因而长城湾沉积物的主要来源似为菲尔德斯半岛基岩的风化产物。 相似文献
994.
本溪系不是岩石地层单位,也不是年代地层单位或生物地层单位,而是历史形成的一种习惯用法。根据地层单位清理的原则,本溪系一名应废弃,置原太原群下部,一并称太原群。辽东地区太原群下部建山城子组、二里河组两个岩石地层单位;辽东半岛南部建山城子组、三棱山组两个岩石地层单位替代原本溪系。华北地台太原群下部(本溪系)海侵方向,根据地层厚度,生物繁衍、迁移路线,地层的空间展布及海相层分析,海水应由北东太子河流域向南西侵进。 相似文献
995.
This study indicates that environmental policy interventions significantly influence the innovation processes for reducing the emissions of marine engine technology. Several different types of interventions have been important and the effect is not directly proportional to the strength or spatial coverage of the intervention. Despite its relative weakness, the MARPOL rule on NOx emissions has contributed to technology development. We also show that the rise of environmental issues in other fields has had a marked effect on the development of the marine sector and that relatively local interventions can influence innovation even in an international sector like marine transport. 相似文献
996.
Ryuichi Wada Joseph M. Beames Andrew J. Orr-Ewing 《Journal of Atmospheric Chemistry》2007,58(1):69-87
An open-path cavity ring-down spectroscopy (CRDS) instrument for measurement of atmospheric iodine monoxide (IO) radicals
has been tested in the laboratory and subsequently deployed in Roscoff on the north-west coast of France as part of the Reactive
Halogens in the Marine Boundary Layer (RHaMBLe) project in September 2006. In situ measurements are reported of local IO mixing
ratios in the marine boundary layer. To obtain these mixing ratios, accurate absorption cross sections of IO are required
at the selected wavelengths used for spectroscopic measurements. Absorption cross sections at the bandheads of the IO A2Π3/2–X2Π3/2 (3,0) and (2,0) vibronic bands were thus verified by a combination of spectral simulation methods, inter-comparison of prior
determinations of cross-sections at high and low spectral resolution, and by measurement of rates of loss of IO by its self-reaction.
The performance of the open-path CRDS instrument was tested by measuring concentrations of NO2 in ambient air, both within and outside the laboratory, with results that were in excellent agreement with a previously validated
continuous wave CRDS apparatus for NO2 detection. During the RHaMBLe campaign, the open-path CRDS instrument was located within a few metres of the shoreline and
operated at wavelengths close to 435 nm to detect the absorption of light by trace levels of IO. The IO mixing ratios were
obtained on two days, peaked close to low tide, and were approximately 5–10 times higher than values calculated from column
densities previously reported by long-path, differential optical absorption spectroscopy (DOAS) in coastal regions. The typical
detection limit of the instrument was estimated to be 10 pptv of IO, with some fluctuation around this value depending on
the conditions of wind and atmospheric aerosol particles, and the total accumulation time was 30 s for each data point. The
observations of relatively high concentration of IO, compared to the values previously reported by DOAS, are consistent with
the concurrent observations using a LIF (Laser induced Fluorescence) instrument (Whalley et al. in press). The first such measurements of localized IO by CRDS and LIF should contribute to an improved understanding of the chemistry
of halogen compounds and the formation of iodine oxide aerosol particles in the marine boundary layer. 相似文献
997.
998.
浪作用下海洋底床动态响应的研究 总被引:4,自引:0,他引:4
有关波浪作用下的底床动态响应越来越引起人们的重视。本文从海洋土的特点出发,针对各向同性底床和各向异性底床,详细论述了在线性波加载下,波浪衰减和底床动态响应这两方面的研究现状,在分析和比较已有研究成果的基础上,对今后的研究方向提出了自己的看法。 相似文献
999.
Preliminary study on responses of marine nematode community to crude oil contamination in intertidal zone of Bathing Beach, Dalian 总被引:1,自引:0,他引:1
This study investigated the responses of marine nematodes to crude oil contamination in polluted and relatively uncontaminated sites in Dalian Xingang, China, 40 days after an oil spill. Samples were taken at different tide levels on the beach and at different positions along the beach. We present the results of a comparison of nematode assemblages from undisturbed sediment from the Xiajiahezi Bathing Beach with those from sediment from the Xinghai Bathing Beach contaminated with crude oil. A total of 1666 nematodes from 26 genera were found in this study. Results showed significant differences in nematode assemblages between samples from undisturbed controls and those from the polluted area. Nematode abundance, number of species, diversity and species richness decreased significantly with increasing levels of crude oil contamination. Fifteen genera were eliminated and seemed to be composed of species intolerant to crude oil contamination; only the abundance of Marylynnia sp. increased slightly. 相似文献
1000.
一次江淮气旋的模拟和海洋敏感试验 总被引:3,自引:2,他引:1
运用中尺度WRFV3.0模式,对2009年4月19日00时-22日00时期间的一次江淮气旋进行了数值模拟(控制试验CTR)研究,得出在CTR中江淮气旋的路径和发展趋势总体上比较理想,为此进一步设计海洋属性敏感试验,探讨海洋属性对江淮气旋的路径和强度的影响.结果表明:当海洋属性修改成陆地属性后,江淮气旋路径向东南偏移,入海后,偏离程度增大;气旋强度在大别山附近稍有增强,入海后强度减弱.气旋中心南侧的偏南气流、气旋前部的水汽辐合区和强对流有效位能,以及气旋中心附近的强潜热能,均有利于江淮气旋发展. 相似文献