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71.
太平洋东南海域表层地转流场的季节及年际变化特征 总被引:1,自引:0,他引:1
利用1992~2001年Topex/Poseidon卫星高度计遥感资料分析了太平洋东南海域(5°~55°S,70°~120°W)表层流场的季节及年际变化特征。结果表明,南赤道流的季节变化主要体现在流速上,而秘鲁海流和西风漂流主要体现在流轴位置的移动上。表层流场的年际变化受El Nino影响,在El Nino期间,南赤道流和秘鲁海流均发生流向偏转现象,大部分海区流场被削弱(除低纬度海区外),而在其后的1998年La Nina期间,流场则重新被加强,西风漂流无明显的年际变化。 相似文献
72.
Kunimitsu Ishida Kay I. Ohshima Takashi Yamanouchi Hiroshi Kanzawa 《Journal of Oceanography》1999,55(3):417-426
Meso- or submeso-scale features of the Antarctic sea ice are investigated using the MOS-1/1b MESSR Images (spatial resolution of approximately 50 m) received at Syowa Station. Particular attention is paid to the ice bands and ice streamers in coastal polynyas. In the Antarctic Ocean, ice bands can be often seen not only at the ice edge but also in the ice interior zone throughout the year and they extend for hundreds of kilometers in the latitudinal direction. It is found that the width and spacing of ice bands tend to decrease from winter to summer. The width of ice band is about 2–6 km in August and September, and 0.1–0.7 km in December. The spacing of ice bands is about 3–10 km in August and September, and 0.1–2 km in December. In coastal polynyas, ice streamers, which are composed of new ice, are sometimes observed. In general, the row of the streamers is spaced at 0.5–2 km with a width of 0.1–1.0 km. 相似文献
73.
Seawater samples were collected in the North Pacific along 175°E during a cruise of the Northwest Pacific Carbon Cycle Study (NOPACCS) program in 1994. Many properties related to the carbonate system were analyzed. By using well-known ratios to correct for chemical changes in seawater, the CO2 concentration at a given depth was back calculated to its initial concentration at the time when the water left the surface in winter. We estimated sea-surface CO2 and titration alkalinity (TA) in present-day winter, from which we evaluated the degree of air-sea CO2 disequilibrium in winter was. Using a correction factor for air-sea CO2 disequilibrium in winter, we reconstructed sea-surface CO2 in pre-industrial times. The difference between the back-calculated initial CO2 and sea-surface CO2 in pre-industrial times should correspond to anthropgenic CO2 input. Although the mixing of different water masses may cause systematic error in the calculation, we found that the nonlinear effect induced by the mixing of different water masses was negligible in the upper layer of the North Pacific subtropical gyre along 175°E. The results of our improved method of assessing the distribution of anthropogenic CO2 in that region show marked differences from those obtained using the previous back-calculation method. 相似文献
74.
75.
南北半球副热带高压对赤道东太平洋海温变化的响应 总被引:16,自引:0,他引:16
本文利用1974年1月到1996年12月重分析(NOAANCEP-NCARCDAS-1)全球500hPa位势高度场资料,及同期赤道太平洋各海区SST资料,研究了南北半球副热带高压的变化特征及其对赤道东太平洋SST变化的响应。结果表明,全球副热带高压的变化及对SST的响应,在南北两个半球有很好的一致性。全球副热带高压强度的变化与超前3个月SST的正相关最为显着。对SST响应最强烈的区域主要在南北纬30°之间的低纬,低纬地区局地SST对副热带高压也有强烈的影响。从10°到30°纬度,对SST的响应分别落后于赤道2~9个月。在中、高纬大气环流的响应表现为波列特征,对暖SST及冷SST的响应波列基本相反,但对暖SST的响应更为显着。海温和副热带高压的月际持续性有明显的季节变化,副热带高压9-10月的相关障碍可能与NinoC区SST8-9月的相关障碍低点有关。 相似文献
76.
印太交汇区海洋生物多样性中心形成演化机制研究进展与展望 总被引:1,自引:0,他引:1
印太交汇区是当前全球海洋生物多样性的中心,中心的形成演化是地质历史、气候、海洋环境和生命过程协同作用的结果.本文从印太交汇区海洋生物多样性分布格局、形成演化、成因假说与环境驱动机制等角度,概述了相关研究进展,并梳理了研究存在的问题.迄今对印太交汇区多样性中心形成的关键过程和机制的认识仍相当有限.基于近岸浅海研究判定的全... 相似文献
77.
长鳍金枪鱼(Thunnusalalunga)是主要的经济性金枪鱼鱼种之一,其空间分布与环境因子存在着密切联系。利用2012—2019年印度洋长鳍金枪鱼生产数据和海洋环境数据,包括海表面温度(sea surface temperature, SST)、叶绿素浓度(chlorophyll a, chl a)和海表面盐度(sea surface salinity, SSS)构建印度洋长鳍金枪鱼时空分布神经网络模型。以空间(经度,纬度)、环境因子(SST, chl a, SSS)为解释变量,局部渔获量为因变量,变化隐含层节点数,构建了18个BP空间分布模型,并采用10×10交叉验证模型稳定性,以均方误差(meansquareerror,MSE)、平均相对方差(averagerelativevariance,ARV)以及拟合优度(R~2)作为不同模型精度与稳定性的评判标准,最终选取5-18-1(隐含层节点18)模型为最佳模型,其平均MSE值为0.02232,平均ARV值为0.511。利用最优模型预测结果与同期实际捕捞产量进行叠加对比发现两者具有一致性。环境因子敏感性分析表明海表温度显著影响印度洋长鳍金枪鱼渔场分布,其贡献率达到0.2。印度洋长鳍金枪鱼高精度BP神经网络时空分布模型为其资源的可持续开发与动态管理提供了一种新思路。 相似文献
78.
目的:探讨黄精复方治疗气阴两虚型2型糖尿病的临床疗效。方法:将气阴两虚型2型糖尿病患者64 例随机分为治疗组和对照组,每组各32 例。所有患者均采取饮食、运动等生活方式干预,对照组口服二甲双胍片治疗,治疗组在对照组基础上加用黄精复方治疗,疗程均为12周。观察2组综合疗效及治疗前后中医证候积分、体质量指数(BMI)、空腹血糖(FBG)、餐后2 h血糖(2hPG)、糖化血红蛋白(HbA1c)、空腹胰岛素(FINS)、胰岛素抵抗指数(HOMA-IR)、总胆固醇(TC)、三酰甘油(TG)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)的变化,记录2组不良反应。结果:总有效率治疗组为87.50%(28/32),高于对照组的59.37%(19/32),差异有统计学意义(P<0.05)。2组中医证候积分、BMI、FBG、2hPG、HbA1c、FINS、HOMA-IR、TC、TG、LDL-C、HDL-C治疗前后组内比较及治疗后组间比较,差异均有统计学意义(均P<0.05)。结论:黄精复方治疗气阴两虚型2型糖尿病可以缓解患者的中医证候,降低血糖、血脂,改善胰岛功能,从而提高临床疗效。 相似文献
79.
On 1 December 2007, eight ‘Small Island Developing States’ in the Western and Central Pacific Ocean implemented a management regime restricting the total number of days fished by tuna purse seine vessels within their waters, commonly referred to as the Vessel Day Scheme (VDS). The VDS is seen as one component of management arrangements to reduce fishing mortality on bigeye and yellowfin tuna, constrain fishing effort, and increase the rate of return from access fees by Distant Water Fishing Nations. 相似文献
80.
This is the first regional study of artisanal fisheries in Pacific Island countries and territories that demonstrated that the future of the region's artisanal fishery sector and the livelihood of coastal communities will be highly dependent on alternative subsistence and income sources, which are necessary to reduce fishing pressure to a sustainable level to maintain ecosystem services and food security. The overall objective of this study was to identify socio-economic indicators and drivers to improve the understanding of the dynamics between socio-economic conditions and current exploitation levels of finfish and invertebrates of coastal communities in 17 Pacific Island countries and territories. We showed that exploitation rates and thus possible overexploitation are not solely the consequence of a simple demographic growth process but are in fact a result of the choices people have. Our results confirmed a close relationship between resource exploitation rates and economic development at the national level and the availability of alternative income opportunities at the community level. Multivariate analysis results suggest that communities in countries with somewhat unfavourable conditions and limited access to alternatives and fishing households in communities with overall favourable economic conditions are at highest vulnerability as they have the highest dependence on coastal fisheries resources. Alternative economic opportunities at the national scale and availability of alternative income at the community level vary significantly between cultural groups. Based on our results, the development of management strategies with realistic expectations of ensuring livelihood of coastal communities and sustainable resource use in Pacific Island countries and territories requires a hierarchical and integral approach. Major drivers identified at the regional, cultural and local levels should be used to identify priorities, to assess overall advantages and limitations at the different levels as well as the vulnerability of communities targeted, and to develop strategies accordingly. 相似文献