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111.
Doreen Y. Tai Kenneth S. Turner Lisa A. Garcia 《Ground Water Monitoring & Remediation》1991,11(1):125-132
A standpipe system was developed for testing the reliability of ground water samplers. The unit consists of a stainless steel pipe 5 inches (13 centimeters) in diameter and 100 feet (30.5 meters) in height. It has 14 sampling ports from which control samples can be withdrawn at the same time and position as the samples are collected by a sampler lowered to that position. Test solutions were made in two mixing tanks, totaling 260 gallons (980 liters), by diluting the concentrate of five volatile chlorohydrocarbons in water at two levels of concentration: 10-to-30 and 100-to-200 parts per billion (micrograms per liter).
A gas chromatograph interfaced with a purge-and-trap system was used to perform the analyses. Comparisons of the control samples with the sampler-collected samples have indicated that the three non-pumping samplers had recoveries in the range of 92.4 to 103.5 percent and the three pumping samplers had recoveries ranging from 97.7 to 101.5 percent. 相似文献
A gas chromatograph interfaced with a purge-and-trap system was used to perform the analyses. Comparisons of the control samples with the sampler-collected samples have indicated that the three non-pumping samplers had recoveries in the range of 92.4 to 103.5 percent and the three pumping samplers had recoveries ranging from 97.7 to 101.5 percent. 相似文献
112.
河北兴隆M111稀有金属花岗岩体地球化学和矿化特征研究 总被引:2,自引:0,他引:2
本文研究河北兴隆一个复式小花岗岩体的岩石地球化学和矿化特征.常量氧化物、Rb-Sr同位素、稀土元素和稀有微量元素的地球化学特点综合表明,该岩体是起源较深的花岗岩浆经过较充分地分异演化的晚阶段产物.岩浆成分向着富钠富钠碱元素富挥发分的方向有规律的分异演化导致Nb,Ta,Li,Be,Rb,Cs等稀有元素富集和矿化.最晚形成的空间上位于岩体较高部位的白色似斑状铁锂云母-钠长石花岗岩,是矿化的有利地段,可作为稀有金属矿床找矿的岩石学标志 相似文献
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本文分析了氧绿线强度剖面的半宽度与氧原子密度剖面的观测值,表明氧绿线强度与氧原子密度的关系,不是如Chapman机制所要求的J∞N3(O),而是J∞N2(O)。 相似文献
115.
Laboratory experiments were conducted to investigate the lethal and sublethal effects of suspended solids on the survival and physiological, behavourial and morphological changes of the green-lipped mussel Perna viridis collected from Tolo Harbour, Hong Kong. Results showed that P. viridis survived in all test conditions of suspended solids from 0 to 1200 mg/l over a period of 96 h. Physiological responses of the green-lipped mussel under 14-d exposure of suspended solids from 0 to 600 mg/l, followed by 14-d recovery in natural seawater, revealed no significant changes (p>0.05) in oxygen consumption and dry gonosomatic index for treatments in different concentrations of suspended solids and exposure time. Changes in clearance rate were only found to be significant (p<0.001) with exposure time. Responses in behavourial and morphological changes of the green-lipped mussel were also studied under similar experimental treatments and exposure time. Byssus production was significantly (p<0.001) related to exposure time. Gill damage, however, was significantly greater in treatments (p<0.001). Present findings suggested that P. viridis could tolerate a high level of suspended solids in the laboratory. There were dose-dependent effects of suspended solids on morphology of gill filaments. Implications of survival and responses of the green-lipped mussel to suspended solids in the marine environment are discussed. 相似文献
116.
最近13万年以来洛川黄土剖面中Porg/Pinorg分布及其古气候指示意义 总被引:2,自引:1,他引:2
对末次间冰期以来洛川黄土进行了有机磷/无机磷(Porg/Pinorg)比值测量。结果表明,黄土中Porg/Pinorg比值的分布主要受降水量和温度的影响,是有机磷和无机磷在不同时期随气候变化相互转化的结果。此指标的变化与黄土—古土壤的变化大致相关,与洛川黄土磁化率曲线相一致,与深海氧同位素可进行很好的对比。此比值与夏季风强弱程度乃至与全球气候变化有密切的联系。Porg/Pinorg比值可作为一种反映古气候环境变迁的新指标。 相似文献
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119.
Chang-Kou Tai 《Dynamics of Atmospheres and Oceans》1983,7(3):147-165
Stability problems involving parallel shear flow are considered in the context of wave-reflection problems. It is found that if an unstable solution exists and its growth rate is sufficiently small, the growth rate can be connected to the reflection coefficient through a formula as if the unstable growth were the direct result of repeated over-reflections. If the stability problem under consideration has time symmetry, then for every growing solution there exists a corresponding decaying solution. It is shown that a consistent formula can also be derived for the decaying solution, and the existence of at least one critical layer in the corresponding wave-reflection problem is needed in order to account for both the growing and decaying solutions. As an application of these concepts, the small-scale non-geostrophic instabilities found by Stone (1970) are identified to be associated with over-reflection of inertia-gravity waves. 相似文献
120.
对2006年4月28日山东省一次飑线天气过程进行诊断分析,应用湿位涡守恒理论研究了飑线的发展机制。结果表明:飑线是由500hPa西风槽影响产生的,为低层增温增湿,高层冷空气南下,低能舌叠加在高能舌之上,导致大气对流性不稳定。850hPa切变线和地面低压槽中的辐合上升运动触发对流不稳定能量释放,产生中尺度对流云团,在热力不稳定和风垂直切变的环境条件下对流云团东移发展,形成飑线。低层大气湿斜压性增强,破坏了地转平衡,倾斜涡度发展,上升运动增强,对流发展;高空高位势涡度下传使得中低层位势涡度增大,导致其垂直涡度增大,有利于对流层低层中尺度涡旋发展,对流增强。较强的上升运动与风垂直切变相互作用,促使对流系统发展形成飑线,产生雷雨大风。 相似文献