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171.

Background

In June 2018, the European Parliament and Council of the European Union adopted a legislative regulation for incorporating greenhouse gas emissions and removals from Land Use, Land Use Change and Forestry (EU-LULUCF) under its 2030 Climate and Energy Framework. The LULUCF regulation aim to incentivise EU Member States to decrease greenhouse gas emissions and increase removals in the LULUCF sector. The regulation, however, does not set a target for increasing the LULUCF carbon sink, but rather includes a ‘no net debit’ target for LULUCF (Forests and Agricultural soils). For Managed Forest Land (MFL) an accounting framework with capped credits for additional mitigation against a set forest reference level (FRL) was agreed for 2021–2030. The FRL gives the projected future carbon sink in the two compliance periods 2021–2025 and 2026–2030 under “continuation of forest management practices as they were in the reference period 2000–2009”. This FRL was disputed by some Member States as it was perceived to put a limit on their future wood harvesting from MFL. Here we simulated with the EFISCEN European forest model the “continuation of forest management practices” and determined the corresponding wood harvest for 26 EU countries under progressing age classes.

Results

The simulations showed that under “continuation of forest management practices” the harvest (wood removals) in the 26 EU countries as a whole can increase from 420 million m3/year in 2000–2009 to 560 million m3/year in 2050 due to progressing age classes. This implies there is a possibility to increase absolute wood harvests without creating debits compared to the forest reference level. However, the manner in which ‘continuation of forest management’ developed with a progressing age class development over time, meant that in some countries the future harvesting exceeded 90% of the increment. Since this generally is considered to be unsustainable we additionally set a harvesting cut-off as max 90% of increment to be harvested for each individual country as a possible interpretation of sustainability criteria that are included in the regulation. Using this additional limit the projected harvest will only increase to 493 million m3/year.

Conclusions

The worry from Member States (MS) that the FRL will prevent any additional harvesting seems unwarranted. Due to differences between Member States concerning the state of their forest resources, the FRL as a baseline for harvesting works out very differently for the different Member States. The FRL may have other unforeseen consequences which we discuss. Under all scenarios the living forest biomass sink shows a decline. This can be counteracted through incentivising measures under Climate Smart Forestry.
  相似文献   
172.
西藏山地淋溶土系列与大骨节病分布的关系   总被引:3,自引:0,他引:3  
通过西藏大骨节病县与非病县棕壤与暗棕壤各土属、土种的分布面积的对比分析对西藏耕型棕壤和暗棕壤分布与西藏大骨节病区分布的关系进行研究.结果表明,西藏大骨节病的分布与棕壤、暗棕壤为主的耕型淋溶土壤的分布有一定的联系,但土壤母质和发育程度不同,对大骨节病的分布影响不同.对于残坡积土壤,病区趋于分布在泥质土壤环境,而麻砂质土壤基本是大骨节病的非病区.同样的母质环境,大骨节病区趋于分布在土壤厚度较小,发育程度较低的地区;就洪积土壤来说,其与大骨节病分布的关系似乎与土壤质地有一定的联系,底部砾石含量高的土壤多集中在大骨节病地区.总体而言,山地棕壤、暗棕壤环境是西藏大骨节病区的主要土壤类型之一,西藏未开发的自然棕壤和暗棕壤环境将是大骨节病潜在危险区,因此系统研究西藏典型大骨节病区的土壤分异对探讨未来西藏大骨节病的分布与流行有重要意义.  相似文献   
173.
Zircon U–Pb dates for felsic and intermediate to mafic dikes intruding into the Ryoke granitoids and metamorphic rocks at selected outcrops in the Takamiyama area of the eastern Kii Peninsula, southwest Japan, were determined along with their geology and petrography to reveal the history of Cretaceous magmatism. At each outcrop, the felsic and intermediate to mafic dikes exhibit specific structures that are indicative of magma intermingling and have coeval intrusion ages of ca. 81–77 Ma. Our zircon U–Pb data complement previously published data, suggesting that the mafic magmatism continued intermittently from 83 to 76 Ma in the Takamiyama area and that magmatism migrated eastward within the Ryoke Belt. A comparison of intrusion ages between a dike and a host Ryoke granitoid at one outcrop indicates that the host rock experienced ductile deformation at ~88 to ~83 Ma. Judging from the small number of zircons and the concordant date distributions, we didn't recognize the evidence suggesting the partial melting of the host rocks, as Nakajima et al. (Journal of the Geological Society of Japan, 2021, 127, 69–78) reported.  相似文献   
174.
Soil erosion has become a major global environmental problem and is particularly acute on the Loess Plateau (LP), China. It is therefore highly important to control this process in order to improve ecosystems, protect ecological security, and maintain the harmonious relationship between humans and nature. We compared the effects of rainfall and land use (LU) patterns on soil erosion in different LP watersheds in this study in order to augment and improve soil erosion models. As most research on this theme has so far been focused on individual study areas, limited analyses of rainfall and LU patterns on soil erosion within different- scale watersheds has so far been performed, a discrepancy which might influence the simulation accuracies of soil erosion models. We therefore developed rainfall and LU pattern indices in this study using the soil erosion evaluation index as a reference and applied them to predict the extent of this process in different-scale watersheds, an approach which is likely to play a crucial role in enabling the comprehensive management of this phenomenon as well as the optimized design of LU patterns. The areas considered in this study included the Qingjian, Fenchuan, Yanhe, and Dali river watersheds. Results showed that the rainfall erosivity factor (R) tended to increase in these areas from 2006 to 2012, while the vegetation cover and management factor (C) tended to decrease. Results showed that as watershed area increased, the effect of rainfall pattern on soil erosion gradually decreased while patterns in LU trended in the opposite direction, as the relative proportion of woodland decreased and the different forms of steep slope vegetation cover became more homogenous. As watershed area increased, loose soil and craggy terrain properties led to additional gravitational erosion and enhanced the effects of both soil and topography.  相似文献   
175.
崔艳  王新平  冯丽  苏延桂 《中国沙漠》2010,30(5):1114-1119
土壤种子库是退化生态系统植被恢复重建的重要基础,研究土壤种子库特征对于阐明退化生态系统受损与恢复机理具有重要的科学意义。通过野外土样采集、野外种子萌发定位跟踪调查和室内周期性种子萌发实验,对腾格里沙漠东南缘人工固沙植被区和天然固定沙地的土壤种子库特征进行了对比研究。结果表明:人工固沙植被区土壤种子库包含21个物种,分属于8科;天然固定沙地土壤种子库有33种植物,属于11科。人工固沙植被区以一年生植物为主,天然固定沙地以多年生植物为主。人工固沙植被区的种子总密度明显低于天然固定沙地,但不同物种种子的密度变化存在显著差异。人工固沙植被区的物种丰富度和多样性指数均较天然固定沙地低。人工固沙植被区和天然固定沙地的土壤种子库与地上植被物种的相似性系数分别为0.73和0.71。尽管人工固沙植被区土壤种子库存在少量多年生植物种子,但仍未发展到以多年生草本植物为主的群落演替阶段,说明人工固沙植被区的植物多样性恢复尚需要漫长的过程。  相似文献   
176.
This paper investigates the influences of atom--field coupling and dipole--dipole coupling for atoms on the entanglement between two atoms by means of concurrence. The results show that the sudden death occurs when the atom--field coupling is strong enough, and the collapse and the revival appear when the dipole--dipole interaction is strong enough.  相似文献   
177.
利用巴丹吉林沙漠北缘拐子湖流沙下垫面2013年7、10月和2014年1、4月的湍流通量资料,计算并分析了研究区近地层湍流强度,同时针对风速分量、温度、水汽和CO2归一化标准差随稳定度的变化关系和总体输送系数等陆面过程特征进行分析。结果表明:(1)风速各分量的湍流强度均随风速的增加逐渐减小,风速处于2 m·s-1以下时湍流发展最为旺盛。湍流强度主要由水平方向风速分量决定,垂直方向风速的作用较小,且近中性和不稳定层结利于湍流的发展。与其他地区相比,平坦且没有建筑物的沙漠地区,机械湍流较弱,湍流强度相应较小。(2)风速各分量的归一化标准差与稳定度(z/L)均满足1/3次方函数规律,其中垂直方向风速分量的拟合曲线方程较好。(3)动量输送系数Cd具有明显的夏季高、冬季低的变化状态且各月的日变化形态均呈夜间低、日间高的循环形态。热量输送系数Ch的不同月份日变化间并没有明显的排列次序,且日出日落前后具有明显的波动。不稳定层结时,CdCh均随风速的增加逐渐减小;稳定层结时,CdCh均随着风速的增加逐渐上升。  相似文献   
178.
基于1997-2010年的统计数据,利用统计分析软件SPSS17.0的主成分分析导出西安城市化水平综合得分,进而运用所建立的回归模型分析了西安城市化与城市用水量、用水效益、人均用水水平之间的定量关系.结果表明:西安城市化发展中,生产用水量随城市化的推进呈三次函数曲线型降低,生活用水量则相反;用水效益与城市化呈线性增长关系;人均生产用水量随城市化水平的提高呈三次函数曲线型降低,人均生活用水量则相反.据此,提出未来西安在城市化推进过程中应重视优化产业结构,发展节水技术,改善用水结构,提高用水效益,实现城市化与水资源、水环境的协调发展.  相似文献   
179.
In this paper, the background of developing GPS Automatic Monitoring System for outside deformation of Geheyan Dam is described concisely. The framework, precision and features of the system are stated in detail. Finally, the prospective application of the system is introduced.  相似文献   
180.
灌木生物量模型是预测灌木生物量最有效的方法。选择腾格里沙漠南缘荒漠生态系统中常见的4种灌木(驼绒藜(Ceratoides latens)、盐爪爪(Kalidium foliatum)、珍珠猪毛菜(Salsola passerina)、红砂(Reaumuria soongarica))为研究对象,以株高(H)和冠幅(C)的复合因子灌木体积(V)为自变量,通过回归分析,分别构建了4种灌木和混合物种的叶、新生枝、老龄枝、地上部分、地下部分和整株生物量的预测模型。通过决定系数(R2)、估计值的标准误(SEE)和回归检验显著水平(p<0.05)筛选出了最优的生物量估测模型。结果显示:4种灌木的生物量模型主要以幂函数W=aVb为最优模型,少数以三次函数W=a+bV+cV2+dV3为最优模型。灌木生物量与V之间呈极显著的相关关系(p<0.001),决定系数较高,分别为:叶片(0.775<R2<0.866),新生枝(0.694<R2<0.840),老龄枝(0.819<R2<0.916),地上部(0.832<R2<0.917),地下部分(0.74<R2<0.808),全株(0.811<R2<0.912),说明预测模型可以应用于此4种灌木的生物量估算。不同物种之间及不同器官之间的生物量模型存在差异,在实际使用中,要根据物种来选择相应的模型。生物量模型的建立有助于全面估算荒漠生态系统的生物量,并进一步评估生态系统不同碳库的碳存储量与碳循环。为有效提高荒漠草地碳储量、合理实施生态系统管理和人为干预提供科学依据。  相似文献   
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