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381.
北极海洋沉积物中可培养细菌及其多样性分析 总被引:2,自引:1,他引:1
利用Zobell 2216E培养基和涂布平板法对北极海洋沉积物中可培养细菌进行分离纯化,并利用16SrRNA基因进行分子鉴定与系统发育分析。根据菌落形态学特征,从59个站点的沉积物样品中共分离纯化获得570株细菌;基于16SrRNA基因的分子鉴定与系统发育分析表明,分离到的可培养细菌分别属于细菌域的4个门,5个纲,12个目,23个科,47个属,102个种,其中γ-Proteobactria占绝大多数;有14株菌株与模式菌株的16SrRNA基因序列相似性小于97%,为6个潜在的新种。北极海域的海洋沉积物中存在着丰富的微生物种质资源,为开发新型生物活性物质和特殊功能基因打下了基础。 相似文献
382.
液N2等气体辅助煤层气压裂的常规机理已较为清楚,但其低温特征对煤层物性的影响以及对压裂效果的改善机理尚未引起重视,缺乏理论认识.归纳总结了低温气体对煤岩的冷冲击作用机制,评价了地层水的结冰条件和低温气体的热物性,通过室内实验和数值模拟等手段验证和预测了液N2对煤岩及近井煤层的冷冲击效果,并进行了冷冲击机理应用潜力分析.研究结果表明,煤层气压裂过程中注入N2等低温气体对煤层进行冷冲击,可引起煤岩基质收缩和地层水结冰膨胀,使煤岩产生大量微裂缝和力学强度降低(10%~30%),有利于实现冰晶暂堵和改善煤层气压裂效果.以沁水盆地樊庄区块3#煤层为例,当液N2注入总量为30~120 m3时,可在近井周围3~5 m内形成低温区(<-20 ℃),煤层孔隙度将平均增大约1.5倍,渗透率增大4倍,还可造成煤岩的拉伸和挤压破坏.利用低温气体的冷冲击机理及其产生的冰晶暂堵可以作为改进煤层气和页岩气压裂工艺的新方向. 相似文献
383.
Risk prediction of low temperature in Nanjing city based on grey weighted Markov model 总被引:1,自引:0,他引:1
In this research, we calculate the days whose temperature is less than or equal to ?5 °C in a year according to the data of the daily minimum temperature in Nanjing city (China) from 1951 to 2011, divide these days into 6 categories according to the number (one, two, three, four, five, six and above) of consecutive low-temperature days, and introduce a annual low-temperature weighted index series. We divide the 61 annual low-temperature weighted indexes of 1951–2011 into five states using the mean standard deviation method. Based on the observation sequence of state of low-temperature in 1951–2009, we simulate the real low-temperature states of 2010 and 2011 by employing both weighted Markov method and grey weighted Markov method. The results of both methods show that the values of simulation (predicted) state agree with those of real state. Based on the state series of low temperature in 1951–2011, we predict the future state of low temperature of Nanjing city in 2012 by utilizing both weighted Markov method and grey weighted Markov method. It is found that the risk of low temperature belongs to the third state when we use weighted Markov method; however, the risk of low temperature belongs to the second state when we use the latter method. Although the states of the risk of low temperature are different because they are predicted by different methods, the two states illustrate that the risk of low temperature of Nanjing city in 2012 is in a normal situation. 相似文献
384.
The black shale samples collected from two Neogene formations in the Klias Peninsula area, West Sabah, have been assessed
and characterized in details by gas chromatography, gas chromatography-mass spectrometry and a variety of organic geochemical
parameters. The aims of this study are to describe the characteristics of organic matter of these sediments in terms of source/type
of the organic matter, assess its thermal maturity and paleoenvironment of deposition, based primarily on biomarker distributions.
The results of both formations do not reveal significant differences within the rock extracts. The gas chromatograms of the
saturated hydrocarbon fractions of the Setap Shale and the Belait formations displayed monomodal n-alkane distributions and
nearly identical regular sterane compositions with a predominance of C27 regular steranes. These are consistent with open marine depositional environments dominated by marine biological matter.
Another related feature of these rock extracts is the presence of a high relative abundance of gammacerane, indicating anoxic
marine hypersaline source depositional environment. The relatively high abundance of common land plant-derived biomarkers,
such as bicadinanes and oleananes, is a clear indication of a major terrigenous input to the source of the extractable organic
matter. The predominance of oleanane biomarkers in both formations is indicative of angiospermis input and Tertiary source
rocks. The high C29/C30 hopane ratios, moderate development of C33–C35 hopanes, high abundance of tricyclic terpanes and a slight predominance of C27 regular sterane over C28 and C29 steranes are characteristic features tending to suggest a significant marine influence on these source rocks, thereby suggesting
a mixed source input. The 22S/(22S+22R)C32 hopane ratio has reached equilibrium, and this is supported by the high maturity level as indicated by the 22S/22SC31–33 extended hopane ratios and 20S/(20S+20R)C29 regular steranes ratios. 相似文献
385.
MM5模式系统常被用在气象科研和天气预报当中,通常运行在商业版本的Unix/Linux系统上,对非商业版本的类Unix系统并不太友好。文章详细介绍了MM5V3.7在高性能免费Unix操作系统FreeBSD 6.0上的移植及其应注意的问题,并通过一个个例分别在FreeBSD 6.0和Red Hat Advanced Server 4(RHAS 4)上的运行来比较其效率。通过对比发现,FreeBSD的性能要比通常所用的Linux系统有较大的提高,这对于改善实际业务中的时间迫切性问题有很大的意义。 相似文献
386.