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101.
Rebecca S. Anderson Lin Huang Richard Iannone Jochen Rudolph 《Journal of Atmospheric Chemistry》2007,56(3):275-291
The carbon kinetic isotope effects (KIEs) in the reactions of several unsaturated hydrocarbons with chlorine atoms were measured
at room temperature and ambient pressure using gas chromatography combustion isotope ratio mass spectrometry (GCC-IRMS). All
measured KIEs, defined as the ratio of the rate constants for the unlabeled and labeled hydrocarbon reaction k
12/k
13, are greater than unity or normal KIEs. The KIEs, reported in per mil according to Cl
ɛ = (k
12/k
13−1) × 1000‰ with the number of experimental determinations in parenthesis, are as follows: ethene, 5.65 ± 0.34 (1); propene,
5.56 ± 0.18 (2); 1-butene, 5.93 ± 1.16 (1); 1-pentene, 4.86 ± 0.63 (1); cyclopentene, 3.75 ± 0.14 (1); toluene, 2.89 ± 0.31
(2); ethylbenzene, 2.17 ± 0.17 (2); o-xylene, 1.85 ± 0.54 (2). To our knowledge, these are the first reported KIE measurements for reactions of unsaturated NMHC
with Cl atoms. Relative rate constants were determined concurrently to the KIE measurements. For the reactions of cyclopentene
and ethylbenzene with Cl atoms, no rate constant has been reported in refereed literature. Our measured rate constants are:
cyclopentene (7.32 ± 0.88) relative to propene (2.68 ± 0.32); ethylbenzene (1.15 ± 0.04) relative to o-xylene (1.35 ± 0.21), all × 10−10 cm3 molecule−1 s−1. The KIEs in reactions of aromatic hydrocarbons with Cl atoms are similar to previously reported KIEs in Cl-reactions of
alkanes with the same numbers of carbon atoms. Unlike the KIEs for previously studied gas-phase hydrocarbon reactions, the
KIEs for alkene–Cl reactions do not exhibit a simple inverse dependence on carbon number. This can be explained by competing
contributions of normal and inverse isotope effects of individual steps in the reaction mechanism. Implications for the symmetries
of the transition state structures in these reactions and the potential relevance of Cl-atom reactions on stable carbon isotope
ratios of atmospheric NMHC are discussed. 相似文献
102.
103.
104.
液化天然气接收站取排水过程的卷载效应、冷冲击效应和余氯效应均会对渔业资源造成一定影响。文章以温州LNG接收站工程为例,根据2017年11月在工程附近海域的渔业资源现状调查资料,定性分析了取排水对渔业资源的影响,并对卷载效应和余氯排放造成的渔业资源损失进行定量估算。温州LNG接收站工程建成投产近期运行期间,将造成鱼卵损失量为1.45×107 ind./a,仔鱼损失量为1.66×107ind./a,鱼类幼体损失量为7.56×104 ind./a,虾类幼体损失量为8.68×104 ind./a,蟹类幼体损失量为0.04×103 ind./a。 相似文献
105.
T. J. Luick R. W. Heckert K. Schulz R. S. Disselkamp 《Journal of Atmospheric Chemistry》1999,32(3):315-325
Infrared spectroscopy has been used to measure the vapor pressure of chlorine containing species generated from H2SO4/HNO3/H2O/HCl solutions at 200 K. The vapor pressure was observed to be a function of solution composition. Two solution compositions were investigated. One solution remained a liquid whereas the second solution was a mixed liquid and solid phase (an ice slurry). The liquid solution had a composition of 64.6 wt.% H2SO4/4.8 wt.% HNO3/30.1 wt.% H2O/0.5 wt.% HCl and produced only vapor phase HCl. The ice slurry solution had a composition of 76.6 wt.% H2SO4/3.0 wt.% HNO3/20.1 wt.% H2O/0.3 wt.% HCl and produced HCl, ClNO, and ClNO2 vapor phase components. The sulfuric acid, nitric acid, and water content of these solutions are representative of those present in polar stratospheric clouds (PSCs), however the HCl concentrations are much higher than present within these clouds. The partitioning of chlorine between vapor phase HCl (50%) and ClNO/ClNO2 (50%) for the ice slurry solution suggests a possible mechanism of halogen activation within PSCs. A reaction mechanism to model the observed chemistry is proposed. 相似文献
106.
To find out the decay character of residual chlorine (RC) in the sea water, the concentration of RC was analyzed by N, N-diethyl-p-phenylenediamine (DPD) method under different simulation experimental conditions, in which salinity, temperature, and Chemical Oxygen Demand (COD) were selected. The water used in the experiment was the mixture of aging ocean water, coastal water and extracting solution of coastal sediment at appropriate level. Results are shown as follows:(1) Piecewise function can well reflect the decay dynamics of RC in the cooling seawater. Concretely, the decay dynamics of first 1 min is too rapid to ascertain using a specific kinetic function, and that of the time from 1 to 30 min is fit for the first-order kinetic model. (2) The results could be the foundation of the chemical behavior of RC in seawater, and be used as not only the guidance of the coastal power plants production and sea water desalting companies, but also the establishment of the correlative trade standard. 相似文献
107.
Autumn photoproduction of carbon monoxide in Jiaozhou Bay,China 总被引:1,自引:0,他引:1
Carbon monoxide(CO) plays a significant role in global warming and atmospheric chemistry. Global oceans are net natural sources of atmospheric CO. CO at surface ocean is primarily produced from the photochemical degradation of chromophoric dissolved organic matter(CDOM). In this study, the effects of photobleaching, temperature and the origin(terrestrial or marine) of CDOM on the apparent quantum yields(AQY) of CO were studied for seawater samples collected from Jiaozhou Bay. Our results demonstrat that photobleaching, temperature and the origin of CDOM strongly affected the efficiency of CO photoproduction. The concentration, absorbance and fluorescence of CDOM exponentially decreased with increasing light dose. Terrestrial riverine organic matter could be more prone to photodegradation than the marine algae-derived one. The relationships between CO AQY and the dissolved organic carbon-specific absorption coefficient at 254 nm for the photobleaching study were nonlinear, whereas those of the original samples were strongly linear. This suggests that: 1) terrestrial riverine CDOM was more efficient than marine algae-derived CDOM for CO photoproduction; 2) aromatic and olefinic moieties of the CDOM pool were affected more strongly by degradation processes than by aliphatic ones. Water temperature and the origin of CDOM strongly affected the efficiency of CO photoproduction. The photoproduction rate of CO in autumn was estimated to be 31.98 μmol m-2 d-1 and the total DOC photomineralization was equivalent to 3.25%- 6.35% of primary production in Jiaozhou Bay. Our results indicate that CO photochemistry in coastal areas is important for oceanic carbon cycle. 相似文献
108.
氧弹燃烧-电位滴定法测定煤中氯 总被引:3,自引:0,他引:3
介绍了氧弹燃烧-电位滴定法测定煤中氯离子含量的方法:将样品于加入已知量的碳酸铵溶液的氧弹内燃烧,释放出的氯被碳酸铵溶液吸收后用0.01mol/L的硝酸银标准溶液进行电位滴定。方法的检出限为0.007mg,回收率为96.4%-101.4%。用于实际样品的测定,准确度和精密度与ISO和国标方法相当,但操作简便、快捷。 相似文献
109.
X射线荧光光谱法测定土壤样品中氯的不确定度评定 总被引:11,自引:7,他引:11
用实例对x射线荧光光谱法测定土壤样品中氯的不确定度进行了评定。测量结果的不确定度由仪器综合稳定性、制样、标准物质、回归工作曲线、重复测量等所引入的不确定度分量组成。在对各个不确定度分量进行量化的基础上,通过合成得到测量结果的标准不确定度,再乘以95%置信概率下的扩展因子2,得到测量结果的扩展不确定度。 相似文献
110.
核反应35Cl(n,γ)36Cl和37Cl(n,γ)38Cl的最终产物36Ar和38Ar,对40Ar-39Ar定年影响不可忽视,尤其是在测定某些含K量低的沉积成因矿物时更为重要。本文介绍含Cl样品的40Ar-39Ar定年技术及全部数据处理步骤,以及ppm级K、Ca、Cl含量的测定及计算方法。 相似文献