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101.
China is rising and gradually developing into an innovation-oriented economy. This transition is fueled by public and private investment in education and by increasing inputs into science and technology. Little attention, however, has been paid to the great differences in China-specific context peculiarity. Hence, the paper assesses Chinese innovation networks using a comprehensive analytical model that includes network configuration, regional environment, government interference and firm attributes. The empirical analysis examines China’s machinery manufacturing industry to test the determinants of the spatial character of Chinese innovation networks based on questionnaire surveys and illustrative cases. Our study finds that Chinese innovation networks are affected not only by innovation resource endowments and firm attributes, but also by government interference and regional culture. Regarding the influence of regional culture, the typical Northern culture with the importance of guanxi plays an important role in the process of searching for partners and makes the innovation network and interpersonal network interwoven. Firms’ ownership and innovation ability are the two essential variables to determine whether any of the regional elements are of significance.  相似文献   
102.
In this study, we analyzed 100 three-component strong ground motion records observed within 200 km of the causative fault of the 6 February 2023 MW7.8 Pazarcık (Kahramanmaraş) Earthquake in SE Türkiye. The wavelet method was utilized to identify and analyze the characteristics of pulse-like ground motions in the near-fault region, while considering the uncertainty of the pulse orientation during the analysis. Our investigation focused on the effects of the focal mechanism and rupture process on the spatial distribution, pulse orientation, and maximum pulse direction of the observed pulse-like ground motion. We also analyzed the amplitude and period of the observed ground pulses and the effect of long-period amplification on the ground motion response spectra. Our results indicated the following: (1) A total of 21 typical ground velocity pulses were observed during this earthquake, exhibiting complex characteristics due to the influence of the strike-slip mechanism and rupture directivity. Most ground pulses (17 out of 21) were recorded within 20 km of the fault, in a wide range of orientations, including normal and parallel to the fault direction. The waveforms exhibited unidirectional features, indicating the effects of left-lateral fault slip. Distinct pulses observed more than 20 km from the fault were mainly oriented normal to the fault. The waveforms were bidirectional with double- or multi-round trips as a result of rupture directivity. (2) The amplitudes of the observed pulses ranged from 30.5 to 220.0 cm/s, with the largest peak velocity of 220.0 cm/s observed at Station 3138. The pulse periods ranged from 2.3 to 14.5 s, with the longest pulse period of 14.5 s observed at Station 3116. The amplitude and period of the pulses observed during this earthquake were comparable to those of similar-magnitude global earthquakes. The amplitude of the pulses decreased significantly with increasing fault distance, whereas the pulse period was not significantly affected by the fault distance. (3) Compared with non-pulse records, the velocity pulse records had a pronounced amplification effect on the acceleration response spectra near the pulse period, with factors ranging from 2.1 to 5.8. The larger velocity pulses also significantly amplified the velocity response spectra, particularly over the long periods. This significant amplification effect of the pulses on the response spectra leads to empirical models underestimating the long-period earthquake ground motion.  相似文献   
103.
An introduced turbot population was used to establish families and to estimate genetic parameters of the offspring. However, there is a lack of pedigree information, and common environmental effects can be introduced when each full-sib family is raised in a single tank. Therefore, in the genetic evaluation, SSRs(simple sequence repeats) were used to reconstruct the pedigree and to calculate molecular relatedness between individuals, and the early mixed-family culture model was used to remove the impact of the common environmental effects. After100 d of early mixed culture, twenty SSRs were used to cluster 20 families and to calculate paired molecular relationships(n=880). Additive genetic matrices were constructed using molecular relatedness(MR) and pedigree reconstruction(PR) and were then applied to the same animal model to estimate genetic parameters. Based on PR, the heritabilities for body weight and body length were 0.214±0.124 and 0.117±0.141, and based on MR they were 0.101±0.031 and 0.102±0.034, respectively. Cross validation showed that the accuracies of the estimated breeding values based on MR(body weight and body length of 0.717±0.045 and 0.629±0.141, respectively) were higher than those of PR(body weight and body length of 0.692±0.052 and 0.615±0.060, respectively). The MR method ensure availability of all genotyped selection candidates, thereby improving the accuracy of the breeding value estimation.  相似文献   
104.
The migration of groundwater in rock and soil can appear as abnormalities in geoelectric fields. It is therefore important to study the characteristics of seepage in porous media by measuring the geoelectric field signatures. In this study, a physical model with layers of sand and clay was constructed and an electrical resistivity meter was used to examine the changes in the geoelectric field parameters during the infiltration process. The results show that the infiltration could be detected based on the geoelectric signatures including temporal changes through the spontaneous potential, excitation currents, and apparent resistivity. Specifically, the spontaneous potential was reduced by 100 to 200 mV when the water reaches an electrode. During the second water injection in the experiment, the measured spontaneous potential of all the electrodes recovered to the previous extreme values that range from −200 to −550 mV, thus indicating a “memory” effect. With stepwise changes in the excitation current, it was possible to determine the seepage velocity in sand and clay layer. The apparent resistivity is reduced to less than 400 Ωm when the infiltration reaches the electrodes. These results indicate the potential for real-time monitoring of water flow.  相似文献   
105.
Soil freeze-thaw process is closely related to surface energy budget,hydrological activity,and terrestrial ecosystems.In this study,two numerical experiments(including and excluding soil freeze-thaw process)were designed to examine the effect of soil freeze-thaw process on surface hydrologic and thermal fluxes in frozen ground region in the Northern Hemisphere based on the state-of-the-art Community Earth System Model version 1.0.5.Results show that in response to soil freeze-thaw process,the area averaged soil temperature in the shallow layer(0.0175?0.0451 m)decreases by 0.35℃in the TP(Tibetan Plateau),0.69℃in CES(Central and Eastern Siberia),and 0.6℃in NA(North America)during summer,and increases by 1.93℃in the TP,2.28℃in CES and 1.61℃in NA during winter,respectively.Meanwhile,in response to soil freeze-thaw process,the area averaged soil liquid water content increases in summer and decrease in winter.For surface heat flux components,the ground heat flux is most significantly affected by the freeze-thaw process in both summer and winter,followed by sensible heat flux and latent heat flux in summer.In the TP area,the ground heat flux increases by 2.82 W/m2(28.5%)in summer and decreases by 3.63 W/m2(40%)in winter.Meanwhile,in CES,the ground heat flux increases by 1.89 W/m2(11.3%)in summer and decreases by 1.41 W/m2(18.6%)in winter.The heat fluxes in the Tibetan Plateau are more susceptible to the freeze-thaw process compared with the high-latitude frozen soil regions.Soil freeze-thaw process can induce significant warming in the Tibetan Plateau in winter.Also,this process induces significant cooling in high-latitude regions in summer.The frozen ground can prevent soil liquid water from infiltrating to deep soil layers at the beginning of thawing;however,as the frozen ground thaws continuously,the infiltration of the liquid water increases and the deep soil can store water like a sponge,accompanied by decreasing surface runoff.The influence of the soil freeze-thaw process on surface hydrologic and thermal fluxes varies seasonally and spatially.  相似文献   
106.
通过分析2011年8月的出海调查数据,绘制了不同断面上的温度分布图及调查海域底部的温度分布图,基本了解了黄海冷水团西边界的空间分布特征;根据热力学及流体力学的基本理论,在忽略热量传递次要项的前提下,通过计算海水在输运过程中的"冷量"损失,得到了黄海冷水在输运过程中的温度变化情况;进一步结合青岛地区海水源热泵技术的具体应用情况,分析探讨了黄海冷水团的开发利用前景。结果表明:黄海冷水团边缘距离岸边较近,约20~40km,在冷水输运过程中"冷量"损失较小,管道内部末端水温仅升高5℃~6℃,并且青岛地区已经具备相对成熟的海水温差能利用技术,这些都为黄海冷水团的开发利用提供了理论与现实基础。  相似文献   
107.
Wetlands on the Qinghai-Tibetan Plateau (QTP) perform a dazzling array of vital ecological functions and are one of the most fragile ecosystems in the world. Timely and accurate information describing wetland resources and their changes over time is becoming more important in their protection and conservation. By using remote sensing data, this study intended to investigate spatial distribution and temporal variations of wetlands on the QTP at different watershed scales from 1970s to 2010s. Results show that wetlands on the QTP have undergone widespread degradation from 1970s to 2010s, with nearly 6.4% of their area being lost. Areas of freshwater marsh, salt marsh and wet meadow declined by 46.6%, 53.9% and 15.6%, respectively, while lake area increased by 14.6%. The most extensive losses of natural wetlands have occurred in endorheic basins, such as in the Kunlun-Altun-Qilian Drainage Basin and Qiangtang Basin, which shrank by 44.5% and 33.1%, respectively. A pronounced increase in temperature tends to facilitate the evaporation process and reduce water availability for wetlands. One-third of the wetlands on the QTP are under threat of being submerged due to lakes rising in recent years. More research is needed to gain insight into the interaction mechanisms behind observed variations and potential impacts from further warming in the future.  相似文献   
108.
Large oilfields are often coincidentally located in major river deltas and wetlands, and potentially damage the structure, function and ecosystem service values of wetlands during oil exploration. In the present study, the effects of crude oil contamination during oil exploration on soil physical and chemical properties were investigated in marshes of the Momoge National Nature Reserve in Jilin Province, China. The concentrations of total petroleum hydrocarbons in the marsh soil near the oil wells are significantly higher than those in the adjacent control marsh. Soil water contents in oil-contaminated marshes are negatively correlated with soil temperature and are significantly lower than those in the control area, especially in fall. Crude oil contamination significantly increases the soil pH up to 8.0, and reduces available phosphorus concentrations in the soil. The concentrations of total organic carbon are significantly different among sampling sites. Therefore, crude oil contamination could potentially alkalinize marsh soils, adversely affect soil fertility and physical properties, and cause deterioration of the marshes in the Momoge National Nature Reserve. Phyto-remediation by planting Calamagrostis angustifolia has the potential to simultaneously restore and remediate the petroleum hydrocarbon-contaminated wetlands. Crude oil contamination affects the soil physical and chemical properties, so developing an effective restoration program in the Momoge wetland is neccesary.  相似文献   
109.
豫西崤山北部沟壑纵横,第四系黄土广泛覆盖,地表植被发育。为探讨地电化学法在豫西崤山黄土覆盖区寻找金矿的有效性,选择了隐伏于黄土下的石寨沟金矿开展找矿可行性试验,并在其邻区石龙山金多金属矿预查区南部开展地电化学找矿研究。研究发现,石寨沟Au矿床上部发育地电化学综合异常,异常规律明显,元素相关性较好,具有很好的套合和分带关系。对石龙山预查区地电提取的微量元素含量特征(分形、变异系数、地电提取比)进行分析,发现其与石寨沟Au矿床具有相近的地电异常规律。进一步利用Surfer软件绘制等值线异常图,结合前人研究成果在异常套合较好的02号线45~47测点初步经过地表工程验证,确定了一条品位较好的工业金矿体,侧面证明实测、推测断层F1-1和F20确实存在。该成果为石龙山地区深部及石寨沟矿床外围找矿提供地电化学理论基础,也为崤山黄土覆盖区找矿提供了新的思路。  相似文献   
110.
变形石墨对构造- 热过程的定量约束及流变弱化意义   总被引:1,自引:0,他引:1  
曹淑云  吕美霞 《地质学报》2022,96(10):3573-3588
岩石变形过程的精细厘定是构造地质学研究中的难点和重点。石墨是碳的同素异形体,摩擦实验研究表明,增加少量石墨化碳质物能够显著降低岩石的摩擦系数和力学强度,具有固体润滑剂的流变学意义。本研究针对红河- 哀牢山剪切带新生代变形,开展了详细的野外观测和构造解析,针对不同变形- 变质程度的天然含石墨岩石样品,利用光学显微镜、场发射扫描电子显微镜、电子背散射衍射(EBSD)、拉曼光谱方法,开展了详细的显微及亚显微变质与变形构造、矿物晶格优选定向、石墨拉曼地质温度计应用等深入分析。发现深变质岩中,石墨晶体常常与黑云母共生且定向拉伸或生长,呈现出晶质片状、条带状、膝折等变形构造特征;在强烈塑性变形的岩石中,石墨表现出塑性到超塑性流动构造特征;细粒化石墨富集形成微型滑移带/面,承载流变弱化的“干”润滑作用;在低级变质- 弱变形岩石中,石墨有序度低,呈弥散状分布。EBSD组构显示石墨发育柱面、菱面到低温底面晶格滑移系,对应的石墨拉曼地质温度范围为600~500℃、530~460℃、450~400℃。变形石墨的位错滑移系具有与石英位错滑移系类似的演化特征,具有成为变形温度计的潜力。  相似文献   
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