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71.
大亚湾养殖水域沉积物-海水界面营养盐扩散通量   总被引:15,自引:1,他引:15  
1998年5月10日和11日分别在大亚湾的大鹏澳和澳头养殖水域现场调查,分析了底层海水、上覆水、沉积物间隙水中营养盐的含量和磷的化学形态。结果表明:大亚湾养殖水域NH,HPO和H4SiO4含量从大至小为:间隙水,上覆水,底层海水;NO和NO含量变化不大。估算了沉积物一海水界面营养盐扩散通量,NH,NO,NO,HPO,H4SiO4平均通量分别为302.0,-0.06,-1.82,2.53,47.96μmol·(m2·d)-1。水体和沉积物中磷的主要化学形态分别为DOP(占TP的54%)和无机态(占总态的60%)。大亚湾养殖水域浮游生物生长由磷控制。沉积物间隙水中NO,NO,HPO,H4SiO4的浓度垂直分布变化不大,而NH的浓度垂直分布呈指数下降特征。  相似文献   
72.
The studied area is a shallow water area that belongs to the East China Sea continent shelf. The distribution of zooplankton biomass is higher inshore than offshore. The maximum abundance is in the inshore edge of the centre of upwelling, which is the superposed area of the salinity front and temperature front, due to the fact that the mixture of three different waters has brought about a concentration of nutrients. The herbivorous Euphausia, Copepoda and Tunicata are the major groups of the abundant area. Tunicata possess the possibility to compete against other kinds of herbivorous zooplankton. This means that there is negative correlation between the distribution of Tunicata and that of Copepoda and Euphausia. The positions of maximum areas of zooplankton biomass, phytoplankton individual and the concentration of phosphates and chlorophyll-a overlap one another. In the centre of upwelling, zooplankton can not adapt itself to the environment of lower temperature and less oxygen even with rich nutrient  相似文献   
73.
王述功  高仰 《海洋科学》1989,13(2):24-27
根据我们实测的水深、重力连续剖面资料,计算了自东海至北斐济盆地的地壳厚度。本文旨在对冲绳海槽至马里亚纳海沟的重力异常和地壳结构进行初步的研究。该地段位于太平洋板块俯冲带以西,构造活动十分复杂、剧烈,并含有多种类型的地壳结构。  相似文献   
74.
Impacts of Coastal SST Variability on the East Asian Summer Monsoon   总被引:4,自引:0,他引:4  
The impacts of the seasonal and interannual SST variability in the East Asia coastal regions (EACRSST) on the East Asian summer monsoon (EASM) have been examined using a regional climate model (PδRCM9) in this paper. The simulation results show that the correlation between the EACRSST and the EASM is strengthened after the mid-1970s and also the variability of the EACRSST forcing becomes much more important to the EASM interannual variability after the mid-1970s. The impacts of the EACRSST on the summer precipitation over each sub-region in the EASM region become weak gradually from south to north, and the temporal evolution features of the summer precipitation differences over North and Northeast China agree well with those of the index of EASM (IEASM) differences.
The mechanism analyses show that different EACRSST forcings result in the differences of sensible and latent heat flux exchanges at the air-sea interface, which alter the heating rate of the atmosphere. The heating rate differences induce low level air temperature differences over East Asia, resulting in the differences of the land-sea thermal contrast (LSTC) which lead to 850 hPa geopotential height changes. When the 850 hPa geopotential height increases over the East Asian continent and decreases over the coast of East China and the adjacent oceans during the weakening period of weakens consequently. On the contrary, the EASM enhances during the strengthening period of the LSTC.  相似文献   
75.
范凯波  高玉春  梁丽 《气象科技》2015,43(5):783-787
随着我国新一代天气雷达(CINRAD)的广泛布网,雷达的维修维护工作显得日益繁重。利用虚拟仪器测试系统对雷达重要参数指标测试是一种便捷有效的方式。本文从发射机射频脉冲包络以及其测量方法的介绍出发,搭建一套基于PXI(PCI eXtensions for Instrumentation)模块化仪器的虚拟仪器系统,采用LabVIEW(Laboratory Virtual Instrument Engineering Workbench)软件编程实现参数测试测量功能,通过实验完成了对脉冲包络的重要参数测试。虚拟仪器测试系统与传统仪器对比测量结果,验证了该测试系统的可靠性。  相似文献   
76.
D. maculates is a kind of specialized Schizothoracinae fish has been locally listed as a protected animal in Xinjiang Province,China. Ili River located in north of Tianshan Mountain and Tarim River located in north of Qinghai-Tibetan Plateau were two main distribution areas of this fish. To investigate the genetic diversity and genetic structure of D. maculates,four populations from Tarim River system and two populations from Ili River system were collected in this study. A 570-bp sequence of the control region was obtained for 105 specimens. Twenty-four haplotypes were detected from six populations,only Kunes River population and Kashi River population shared haplotypes with each other. For all the populations examined,the haplotype diversity(h) was 0.904 8±0.012 6,nucleotide diversity(π) was 0.027 9±0.013 9,and the average number of pairwise nucleotide differences(k) was 15.878 3±7.139 1. The analysis of molecular variance(AMOVA) showed that 86.31% of the total genetic variation was apportioned among populations,and the variation within sampled populations was 13.69%. Genetic differences among sampled populations were highly significant. F st statistical test indicated that all populations were significantly divergent from each other(P 0.01). The largest F st value was between Yurungkash River population and Muzat River population,while the smallest F st value was between Kunes River population and Kashi River population. NJ phylogenetic tree of D-loop haplotypes revealed two main clades. The neutrality test and mismatch distribution analysis suggested that the fish had went through a recent population expansion. The uplift of Tianshan Mountain and movement of Qinghai-Tibetan Plateau might contribute to the wide genetic divergence of D. maculates in northwest China.  相似文献   
77.
In order to test the distribution characteristics of metallogenic elements and the application effectiveness of the traee elements and REE for tracing the source of Geogas anomaly, the distribution characteristics of metallogenetic elements .trace elements and REE in different media of the Jiaolongzhang Pb-Zn deposit underneath the loess have been studied in this paper. Results indicate that the distribution characteristics of Geogas anomalous elements over the concealed orebodies are coincided with those of the enriched elements of ores, while the distribution characteristics of trace elements and REE in background Geogas samples are distinctly different from those of other media, indicating that the source of background Geogas materials is influenced by various factors( geological bodies, lab environment and blank reagent). The similar distribution characteristics of the trace elements in the Geogas samples of anomalous areas and in the ores suggested that Geogas anomaly is affected by concealed orebodies in depth. The difference between REE patterns of the Geogas samples of the anomalous area and those of other solid media might be caused by inadequate analytical precision and low collecting efficiency of the instrument. It is believed that the REE tracing method can provide the information on the source of Geogas anomaly if the analytical precision and collecting efficiency of REE could be constantly increased.  相似文献   
78.
CHANGE OF CLIMATE AND ITS INFLUENCE ON THE CROPPING SYSTEM IN CHINA   总被引:3,自引:0,他引:3       下载免费PDF全文
Tne global change of climate and its influence on the cropping system in China have been investigatedin this paper.It is found that the temperature was increased during the last decade and the precipitationdecreased in northern China and increased in southern China during the last 30 years.The sea level hasbeen rising by about 21—26 cm in the coastal areas south of 30°N in China during the last 100 years.The most of results as simulated by the general circulation models(GCMs)show that the temperature increasewould amount to about 2°—4°C in the most parts of China and precipitation and soil moisture might bedecreased in northern China and increased in sourthern China due to doubling of carbon dioxide(CO_2).The effects of doubled CO_2 on growth period and climatic yield capability in China have been estimatedroughly.It is shown that the regions of the growth period in China would be moved northward about fivedegrees latitude and the climatic yield capability might be increased by about 10% in the most parts of China.  相似文献   
79.
The recently discovered Damoqujia (大磨曲家) gold deposit is a large shear zone-hosted gold deposit of disseminated sulphides located in the north of the Zhaoping (招平) fault zone, Jiaodong (胶东) gold province, China. In order to distinguish the temperature range of cluster inclusions from different mineralization stages and measure their compositions, 16 fluid inclusions and 5 isotopic geochemistry samples were collected for this study. Corresponding to different mineralization stages, the multirange peaks of quartz decrepitation temperature (250-270, 310-360 and 380-430℃(2) indicate that the activity of ore-forming fluids is characterized by multistage. The ore-forming fluids were predominantly of high-temperature fluid system (HTFS) by CO2-rich, and SO2-4-K type magmatic fluid during the early stage of mineralization and were subsequently affected by low-temperature fluid system (LTFS) of CH4-rich, and Cl--Na /Ca2 type meteoric fluid during the late stage of mineralization. Gold is transferred by Au-HS- complex in the HTFS, and Au-Cl- complex can be more important in the LTFS. The transition of fluids from deeper to shallow environments results in mixing between the HTFS and LTFS, which might be one of the most key reasons for gold precipitation and large-scale mineralization. The ore-forming fluids are characterized by high-temperature, strong-activity, and superimposed mineralization, so that there is a great probability of forming large and rich ore deposit in the Damoqujia gold deposit. The main bodies are preserved and extend toward deeper parts, thereby suggesting a great potential in future.  相似文献   
80.
全球增暖的另一可能原因初探   总被引:14,自引:1,他引:14       下载免费PDF全文
太阳是地球流体(大气和海洋等)运动的最终能量源,地球环境,尤其是气候的变化不能不与太阳活动有关.目前,普遍将全球增暖归结为温室气体含量增加所导致的温室效应的加剧,这无疑是有一定依据和有道理的.但从科学上来讲,人类活动所引起温室气体增加的影响,并非是唯一原因.基于已有的一些研究结果,从太阳活动的观点所进行的初步分析表明,太阳活动也可能是引起近世纪全球增暖的另一个重要原因.太阳活动的影响主要包括太阳辐射的直接影响和引发地磁场变化的间接影响两个方面,地球磁场的变化将可通过动力过程和热力过程而影响大气环流和气候的变化.  相似文献   
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