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991.
Linbao Zhang Xiaoli Liu Liping You Di Zhou Junbao Yu Jianmin Zhao Jianghua Feng Huifeng Wu 《洁净——土壤、空气、水》2011,39(11):989-995
Cadmium (Cd) has become an important heavy metal contaminant in the sediment and seawater along the Bohai Sea and been of great ecological risk due to its toxic effects to marine organisms. In this work, the toxicological effects caused by environmentally relevant concentrations (10 and 40 µg L?1) of Cd were studied in the gill tissues of Manila clam Ruditapes philippinarum after exposure for 24, 48, and 96 h. Both low (10 µg L?1) and high (40 µg L?1) doses of Cd caused the disturbances in energy metabolism and osmotic regulation and neurotoxicity based on the metabolic biomarkers such as succinate, alanine, branched chain amino acids, betaine, hypotaurine, and glutamate in clam gills after 24 h of exposure. However, the recovery of toxicological effects of Cd after exposure for 96 h was obviously observed in clam to Cd exposures. Overall, these results indicated that NMR‐based metabolomics was applicable to elucidate the toxicological effects of heavy metal contaminants in the marine bioindicator. 相似文献
992.
The study reports for the first time on the heavy metal contamination of the waters surrounding a shipwreck lying on the sea floor. Square wave anodic stripping voltammetry has been used for a survey of the total and dissolved Cd, Pb and Cu contents of the seawater at the site of the sinking of the Nicole M/V (Coastal Adriatic Sea, Italy). Results show that the hulk has a considerable impact as regards all three metals in the bottom water, especially for the particulate fraction concentrations, which increased by factors of ∼9 (Cd), ∼3 (Pb) and ∼5 (Cu). The contaminated plume extended downstream for about 2 miles. Much lower contamination was observed for dissolved bottom concentrations; nevertheless Pb (0.56 ± 0.03 nmol/L) is higher than the Italian legal limits established for 2015 and Cd (0.23 ± 0.03 nmol/L) is very close the limit of Cd will be exceeded if the hulk is not removed. 相似文献
993.
While much work has been done in investigating determinants of oil spillage attributed to vessel accidents, little research has been conducted on the effectiveness of ship hull design in reducing marine pollution. This paper addresses whether the double-hull requirement reduces vessel-accident oil spillage. The volume of oil spillage due to oil-cargo vessel accidents was investigated using tobit regressions and an empirical data set of individual vessel accident pollution incidents investigated by the US Coast Guard from 2001 to 2008. The results indicate that the double hull design on average reduces the size of oil spills by 20% and 62% in tank barge and tanker ship accidents, respectively. 相似文献
994.
C. Price Y. Yair A. Mugnai K. Lagouvardos M. C. Llasat S. Michaelides U. Dayan S. Dietrich F. Di Paola E. Galanti L. Garrote N. Harats D. Katsanos M. Kohn V. Kotroni M. Llasat-Botija B. Lynn L. Mediero E. Morin K. Nicolaides S. Rozalis K. Savvidou B. Ziv 《Surveys in Geophysics》2011,32(6):733-751
One of the costliest natural hazards around the globe is flash floods, resulting from localized intense convective precipitation over short periods of time. Since intense convective rainfall (especially over the continents) is well correlated with lightning activity in these storms, a European Union FP6 FLASH project was realized from 2006 to 2010, focusing on using lightning observations to better understand and predict convective storms that result in flash floods. As part of the project, 23 case studies of flash floods in the Mediterranean region were examined. For the analysis of these storms, lightning data were used together with rainfall estimates in order to understand the storms?? development and electrification processes. In addition, these case studies were simulated using mesoscale meteorological models to better understand the local and synoptic conditions leading to such intense and damaging storms. As part of this project, tools for short-term predictions (nowcasts) of intense convection across the Mediterranean and Europe, and long-term forecasts (a few days) of the likelihood of intense convection, were developed and employed. The project also focused on educational outreach through a special Web site http://flashproject.org supplying real-time lightning observations, real-time experimental nowcasts, medium-range weather forecasts and educational materials. While flash floods and intense thunderstorms cannot be prevented, long-range regional lightning networks can supply valuable data, in real time, for warning the public, end-users and stakeholders of imminent intense rainfall and possible flash floods. 相似文献
995.
M. Coltorti R. Boraso M. Morsilli A. Riva R. Tassinari G. Di Carlo 《Geochimica et cosmochimica acta》2011,75(9):2271-2294
The regional contribution to the geo-neutrino signal at Gran Sasso National Laboratory (LNGS) was determined based on a detailed geological, geochemical and geophysical study of the region. U and Th abundances of more than 50 samples representative of the main lithotypes belonging to the Mesozoic and Cenozoic sedimentary cover were analyzed. Sedimentary rocks were grouped into four main “reservoirs” based on similar depositional settings and mineralogy. The initial assumption that similar chemico-physical depositional conditions would lead to comparable U and Th contents, was then confirmed by chemical analyses. Basement rocks do not outcrop in the area. Thus U and Th in the upper and lower crust of Valsugana and Ivrea-Verbano areas were analyzed. Irrespective of magmatic or metamorphic origin lithotypes were subdivided into a mafic and an acid reservoir, with comparable U and Th abundances.Based on geological and geophysical properties, relative abundances of the various reservoirs were calculated and used to obtain the weighted U and Th abundances for each of the three geological layers (sedimentary cover, upper and lower crust). Using the available seismic profile as well as the stratigraphic records from a number of exploration wells, a 3D modeling was developed over an area of 2° × 2° down to the Moho depth, for a total volume of about 1.2 × 106 km3. This model allowed us to determine the volume of the various geological layers and eventually integrate the Th and U contents of the whole crust beneath LNGS.On this base the local contribution to the geo-neutrino flux (S) was calculated and added to the contribution given by the rest of the world, yielding a refined reference model prediction for the geo-neutrino signal in the Borexino detector at LNGS: S(U) = (28.7 ± 3.9) TNU and S(Th) = (7.5 ± 1.0) TNU. An excess over the total flux of about 4 TNU was previously obtained by Mantovani et al. (2004) who calculated, based on general worldwide assumptions, a signal of 40.5 TNU. The considerable thickness of the sedimentary rocks, almost predominantly represented by U- and Th-poor carbonatic rocks in the area near LNGS, is responsible for this difference. Thus the need for detailed integrated geological study is underlined by this work, if the usefulness of the geo-neutrino flux for characterizing the global U and Th distribution within the Earth’s crust, mantle and core is to be realized. 相似文献
996.
Stability constants for metal complexation to bidentate ligands containing negatively-charged oxygen donor atoms can be estimated from the following linear free energy relationship (LFER): log KML = χOO(αO log KHL,1 + αO log KHL,2) where KML is the metal-ligand stability constant for a 1:1 complex, KHL,1 and KHL,2 are the proton-ligand stability constants (the ligand pKa values), and αO is the Irving-Rossotti slope. The parameter χOO is metal specific and has slightly different values for five and six membered chelate rings. LFERs are presented for 21 different metal ions and are accurate to within approximately 0.30 log units in predictions of log KML values. Ligands selected for use in LFER development include dicarboxylic acids, carboxyphenols, and ortho-diphenols. For ortho-hydroxybenzaldehydes, α-hydroxycarboxylic acids, and α-ketocarboxylic acids, a modification of the LFER where log KHL,2 is set equal to zero is required. The chemical interpretation of χOO is that it accounts for the extra stability afforded to metal complexes by the chelate effect. Cu-NOM binding constants calculated from the bidentate LFERs are similar in magnitude to those used in WHAM 6. This LFER can be used to make log KML predictions for small organic molecules. Since natural organic matter (NOM) contains many of the same functional groups (i.e. carboxylic acids, phenols, alcohols), the LFER log KML predictions shed light on the range of appropriate values for use in modeling metal partitioning in natural systems. 相似文献
997.
998.
999.
Annamaria Fornelli Antonio Langone Francesca Micheletti Giuseppe Piccarreta 《Mineralogy and Petrology》2011,103(1-4):101-122
The lower crust of the Serre massif (Calabria, southern Italy) provides a window into the mid- to lower crust of the south European Variscan orogenic belt. Previously, zircon U-Pb ages were employed to date high-temperature processes affecting this portion of the Variscan crust. The present paper reports new LA-ICP-MS U-Pb data on the zircon of a deformed quartz-monzodiorite dike and of three mafic granulites sampled at the base of the lower crust section. Determination of trace elements on zircon, including rare earth elements (REE), has been also performed. The end of the Variscan exhumation, dated by anatectic zircon from migmatitic metapelites, and the growth-modification of zircon with respect to the growth of Variscan metamorphic garnet have been assumed as ??time markers??. The concordant zircon ages of the metamorphic basic rocks cover a range from 744?±?20 Ma to 231?±?10 Ma with high age density from 357?±?11?Ma to 279?±?10 Ma, a few ages comprised between 418?±?14 Ma and 483?±?12 Ma and between 505?±?11 Ma and 593?±?14 Ma. Zircon from the deformed quartz-monzodiorite dike evidences a minimum age of emplacement of 323?±?5 Ma. Most of the analysed zircon domains dated between 357?±?11 Ma to 279?±?10 Ma from garnet-bearing metabasic rocks show flat patterns of heavy rare earth elements (HREE), as expected in the case of their simultaneous growth with garnet. This allows to consider (1) zircon domains giving Variscan ages as ??metamorphic?? with specific geological significance, and (2) zircon domains with ages ranging from 564?±?17 Ma to 593?±?14 Ma as dating the emplacement of the magmatic protoliths as shown by internal microtextures, fractionated patterns of HREE and Th/U ratios (0.16?C0.19). The Variscan zircon ages (357?C279?Ma) reflect effects of crustal thickening, peak metamorphism and subsequent multistage Variscan decompression documented by the statistically significant clusters of ages around 347?C340?Ma, 323?C318?Ma, 300?C294?Ma and 279?Ma. The U-Pb zircon ages of the metabasic rocks suggest a period of about 60?C70?Ma for granulite facies metamorphism and anatectic conditions. Literature data indicate that the migmatitic metapelites of the upper part of the Serre crust section also underwent a long period, about 40?Ma, of granulite facies metamorphism and anatectic conditions. A diachronism emerges through the time comparison of the Variscan evolution between the upper and the lower portions of the Serre deep crust. The duration of the Variscan processes defined in Calabria is comparable to that of other south European Variscan blocks. 相似文献
1000.
西藏西部普兰蛇绿岩中的MOR型辉长岩:岩石学和年代学 总被引:10,自引:10,他引:0
西藏普兰蛇绿岩位于雅鲁藏布江缝合带的西段,主要由地幔橄榄岩、辉长岩和玄武岩组成.在拉昂错南侧有一个辉长岩体,面积约1 km2,与其相邻的地幔橄榄岩为侵入接触关系.辉长岩为中细粒辉长结构,块状构造,主要矿物为半自形板柱状基性斜长石和他形-半自形粒状辉石.岩石化学成分显示其具有MOR型岩石特点,表现为中等含量的TiO2(1%~1.77%),低含量的K2O(0.08%~0.21%)和P2O5(0.1%);轻稀土元素(LREE)轻微亏损的近平坦型稀土元素球粒陨石标准化模型,(La/Ce)N、(La/Sm)N和(La/Yb)N等特征比值分别为0.73~0.80、0.44~0.58、0.53~0.65;岩石的高场强元素(HFSE)为相互平行的具有接近1的平坦型分配型式.微量元素的N-MORB标准化图解显示富集大离子亲石元素(LILE)如Rb,高场强元素(HFSE)轻微亏损.辉长岩锆石的LA-ICP-MS U-Pb年龄为130±3Ma,指示了普兰蛇绿岩形成的时代,与邻区休古嘎布、东波蛇绿岩的形成时代相一致. 相似文献