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731.
水平定向钻进管道敷设地层响应实验分析   总被引:1,自引:0,他引:1  
在应用水平定向钻进非开挖技术进行近地表管道敷设时,由于上覆地层厚度(C)、钻孔直径(D)和钻井液压力(p)三者无法准确设计,往往会导致地表的变形,进而形成裂缝通道致使地表发生钻井液的溢流.分析了非黏聚力地层的溢流通道形式,同时推导了极限钻井液压力的计算公式.结合室内外实验及应用情况,得出了实测钻井液压力和计算钻井液压力同C/D值的变化规律,即C/D越大,极限钻井液的压力值也就越高.在同一地层中,一般钻井液压力的峰值出现在水平孔段的中间位置.根据C/D值,在保证钻井液不发生溢流的情况下,得出了不同水平孔径范围所对应的上覆地层最小厚度.  相似文献   
732.
根据重力异常资料、地震资料,综合运用重矿物法、碎屑岩类分析法并结合砂体展布特征,基本明确了黄骅坳陷孔南地区孔店组二段的物源区位置及来源方向。区域布格重力异常场从宏观上勾绘出了孔南地区地势的起伏状况,对物源分析具有重要参考意义。在研究区湖盆周缘都发育砂体,在各物源口的砂体展布规律在平面上表现为呈扇形展布的特征,宏观上指示了物源的涉及范围。盆外下切沟槽能大致确定研究区周缘各物源口位置,前积反射结构也能指示出存在物源供给的地区。重矿物以锆石、电气石、金红石、石榴石、磁铁矿为主,不同的物源区具有不同的重矿组合特征,其变化规律指示了碎屑物质的搬运方向和搬运途径。碎屑岩组分以长石为主,其次为石英,岩屑含量较低,主要为岩浆岩岩屑,岩屑类型指示了物源区母岩类型主要为岩浆岩。该区孔店组二段沉积时期在东南、西南、西北、东北4个方向上都存在物源,进一步可识别出乌马营、叶三拔、舍女寺等10个子物源,它们共同控制了孔南地区孔店组二段沉积时期砂体的形成和分布,形成多物源环湖盆分布的特征。  相似文献   
733.
为了揭示粤北地区岩石圈深部结构、深大断裂性质及花岗岩分布规律等科学问题,布设了乳源-潮州宽频带大地电磁探测剖面。由二维反演得出的电性结构,讨论了粤北地区岩石圈导电性结构特点。沿剖面存在3个花岗岩分布区,呈现不同的类型,可能代表不同的成因模式。沿剖面划分3条北东向断裂带:吉安-四会断裂、赣江断裂于韶关东形成宽度近20km的低阻区域,其间形成断陷盆地;河源-邵武断裂带,其两侧发育壳幔高导层并发育壳幔混合型花岗岩,深部电性结构复杂,可能为壳幔剧烈作用的场所;丽水-海丰断裂带,控制了燕山晚期花岗岩的分布。韶关、连平之间和龙川、丰顺之间50~150km存在2个巨大的低阻体,可能是地幔物质底侵作用的"通道";且底侵方向指向连平和龙川之间的区域,由于底侵作用力贡献,发育了一系列的壳内和上地幔高导层。粤北地区岩石圈从西向东逐渐减薄,从100余km减薄到60km,反映了太平洋板块对欧亚板块的消减作用。潮州100km深度以下的中-低阻特征,推断为太平洋板块俯冲作用留下的"洋壳"物质。  相似文献   
734.
煤矿瓦斯抽放井要求垂直精度高、井径大,通常采用常规钻探工艺时,需进行3-4次扩孔才能达到最终孔径,施工时间较长,钻进效率较低。此次在端氏煤矿施工的大口径瓦斯抽放井,采用了的一次成井钻进技术及工艺方法,钻进口径达到φ660mm,选用了江汉735型和715型系列镶齿牙轮钻头,采用塔式加重钻具控制并保证了钻井的重直度,采用密度较大的化学泥浆和保持大泵量排渣,避免了井底牙轮钻头的重复破碎,确保了钻进效果。与传统的扩孔工艺相比,缩短了施工周期,成井质量高,提高了钻进效率,降低了钻进成本。  相似文献   
735.
A single parameter index method, in which ground temperature and air temperature is the sole input variable, respectively, is used to evaluate and compare the glacial runoff in three typical glacier catchments, Dongkemadi glacier catchment in Tibetan plateau, Koxkar glacier catchment and the headwater catchment of Urumqi River catchment in Tianshan Mountains in West China. The method based on ground temperature is an attempt to evaluate glacier runoff in elevated terrains, as few studies have focused specifically on the association between glacier runoff and ground temperature. The results identify ground temperature versus a certain depth, which is a critical factor that affected glacier hydrological processes and showed that runoff data is much better correlated with ground temperature than air temperature. Especially, at the latter two catchments, the largest coefficients of exponential relationship R 2 between glacier runoff and ground temperature are 0.9 and 0.83, respectively. The accuracy of the method makes it possible to estimate the glacier runoff with a certain depth ground temperature at a certain site, which may provide a new approach to evaluate the glacier runoff for areas where there is a lack of observation data.  相似文献   
736.
A supraglacial lake was surveyed on the Koxkar Glacier in southwest Tianshan from July to September 2007 and July to September 2008, and the temperature variation characteristics of the lake, debris and debris-free ice were analyzed at different depths to determine the thermal regimes. In addition, the discrepancies of temperature variation characteristics were investigated for different geomorphic units of the ablation zone of the Koxkar Glacier. It was found that daily temperature variation curves for deep water are V-shaped because meltwater from the glacier surface at temperatures of around 0°C feeds the lake and mixes with the relatively high-temperature surface water during the day. As the water temperature rises to approximately 4°C, the mixed water sinks and forms a low-temperature trough in the deep water of the lake in the middle of the day. The vertical lapse rate of the lake water temperature against depth (?0.33°C/m) has a magnitude lower than that of the debris (?4.29°C/m) and that of the debris-free ice (?0.38°C/m) in the Koxkar Glacier??s ablation zone. The temperature curve for the surface water largely varied between the temperature curves for the debris at depths of 0.2 and 0.5?m. The surface thermal condition of the ablation zone is significantly affected by the daily weather, and there is a limited influence in debris at a depth of 1?m and in the lake at a depth of 5?m.  相似文献   
737.
国土空间规划"一张图"实施监督信息系统是在国土空间基础信息平台和国土空间规划"一张图"基础上,为国土空间规划编制、审查、实施、监督提供技术支撑的信息化系统.该系统引入一种用于三维可视化的倾斜摄影数据采集方法,构建三维立体"一张图",真实地浏览和展示数据,开发"一键式"综合分析功能,将复杂空间分析步骤高度集成和定制化,建立监测预警大数据平台.该系统可辅助审查及决策,有效提升管理部门办事效率,全面提升国土空间规划动态监测、综合监管及社会公众服务能力,助力自然资源管理及空间治理迈向智慧化.  相似文献   
738.
Han XB  Lei EN  Lam MH  Wu RS 《Marine pollution bulletin》2011,63(5-12):160-165
Polybrominated diphenyl ethers (PBDEs) are now found ubiquitously in the aquatic environment and biota, and there is a growing concern that PBDEs may disrupt endocrine systems, leading to reproductive impairments of aquatic animals. In our study, zebrafish (Danio rerio) were exposed to the 5 ng/L, 1 μg/L and 50 μg/L of DE-71 for the duration of the whole life cycle (120 days, from eggs to adults). The expression of selected genes along the brain-pituitary-gonadal (BPG) axis and liver, and the levels of plasma sex hormones were examined. In male fish, up-regulation of GnRH in brain, FSHβ and LHβ in pituitary, FSH-receptor, LH-receptor, and CYP19a in testis was clearly evident, while down-regulation of CYP11a and 3β-HSD was found in testis. In female fish, a 2.4-fold up-regulation of 3β-HSD was found in ovary upon exposure to 50 μg/L of DE-71. GnRH in brain, FSHβ and LHβ in pituitary were also up-regulated, while ERβ, TH and TPH in brain and GnRH-receptor in pituitary were significantly down-regulated. Hepatic ERα, AR and VTG in males were all down-regulated, while hepatic ERα and AR in female were up-regulated. Serum estradiol (E2) was reduced in both male and female upon exposure to DE-71, while significant increases in serum testosterone (T) and 11-keto-testosterone (11-KT) were only found in male but not female fish. The ratio of T/E2 as well as the ratio of 11-KT/E2 in male fish increased in a dose-dependent manner upon exposure to DE-71. Our overall results showed that whole life exposure of DE-71 altered the expression of regulatory genes and receptors at all three levels of the BPG axis in zebrafish, and the responses are sex dependent. The observed disruption of GnRH and GtHs can be further related to the subsequent disruption in both levels and balance sex steroid hormones.  相似文献   
739.
VTI介质中准P波方程叠前逆时深度偏移   总被引:3,自引:0,他引:3       下载免费PDF全文
根据具有垂直对称轴的横向各向同性(VTI)介质中的一阶准P波方程,导出了该方程在交错网格中逆时延拓的高阶有限差分格式,给出了其稳定性条件,采用完全匹配层吸收边界条件解决边界反射问题,分别应用下行波最大能量法和归一化互相关成像条件, 实现了VTI介质中准P波方程的叠前逆时深度偏移.各向异性Marmousi模型的试算结果表明,VTI介质准P波方程叠前逆时深度偏移算法不受地下构造倾角和介质横向速度变化的限制,对复杂模型具有良好的成像能力;应用归一化互相关成像条件能得到更好的成像效果.对比该模型的各向异性和各向同性逆时偏移剖面表明,在各向异性地区采集的纵波数据用各向异性偏移算法理论上能得到更好的成像结果.   相似文献   
740.
Watershed water quality models are increasingly used in management. However, simulations by such complex models often involve significant uncertainty, especially those for non-conventional pollutants which are often poorly monitored. This study first proposed an integrated framework for watershed water quality modeling. Within this framework, Probabilistic Collocation Method (PCM) was then applied to a WARMF model of diazinon pollution to assess the modeling uncertainty. Based on PCM, a global sensitivity analysis method named PCM-VD (VD stands for variance decomposition) was also developed, which quantifies variance contribution of all uncertain parameters. The study results validated the applicability of PCM and PCM-VD to the WARMF model. The PCM-based approach is much more efficient, regarding computational time, than conventional Monte Carlo methods. It has also been demonstrated that analysis using the PCM-based approach could provide insights into data collection, model structure improvement and management practices. It was concluded that the PCM-based approach could play an important role in watershed water quality modeling, as an alternative to conventional Monte Carlo methods to account for parametric uncertainty and uncertainty propagation.  相似文献   
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