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141.
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引言应用经济模型研究苏联区域发展是非常有效的。计划经济中经济活动的调节、分配制度的显著作用以及产生、区域与国民经济宏观指标的密切关系都有利于这一方法的应用。本文介绍了1981—1983年建立的苏联多区域经济模型 SRM。模型的目标是描述苏联15个共和国的经济增长并预测它们在八十年代的发展。每个共和国分成工业、农林业、运输通信业、建筑业、商业等5个生产部门和服务业1个非生产部门。 相似文献
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Markarian 478是典型的窄线赛弗特I星系之一。本文展示了在 2 0 0 1年 1月利用远紫外光谱探测卫星 (FUSE)观测到的Markarian 478的远紫外光谱。我们的光谱覆盖了 91 5Å ;— 1 1 85Å的波长范围 ,分辨率约为 2 0km/s。我们在连续谱上探测到OⅥλλ1 0 3 2 ,1 0 3 8、NⅢλ989和CⅢλ977强发射线。在高电离双线OⅥ以及Lyβ的蓝端线翼上出现了成协吸收线 ,而在NⅢ和CⅢ发射线上没有出现内禀吸收线。这些吸收线被分解成 5个动力学成分 ,它们相对于系统红移zem=0 .0 774的静止坐标系速度覆盖了从 -2 3 0 0~ 3 70km/s的范围 相似文献
146.
Mahmoudi E Essid N Beyrem H Hedfi A Boufahja F Vitiello P Aissa P 《Marine pollution bulletin》2005,50(11):1197-1204
Anthropogenic inputs of crude and refined petroleum hydrocarbons into the sea require knowledge of the effects of these contaminants on the receiving assemblages of organisms. A microcosm experiment was carried out to study the influence of diesel on a free living nematode community of a Tunisian lagoon. Sediments were contaminated by diesel that ranged in concentration from 0.5 to 20 mg diesel kg−1 dry weight (dw), and effects were examined after 90 days. Gradual changes in community structure were revealed depending on the quantity of diesel administrated. In the medium (1 mg diesel kg−1 and 5 mg diesel kg−1 (dw)) and high (10 mg diesel kg−1, 15 mg diesel kg−1 and 20 mg kg−1 (dw)) treated microcosms, most univariate measures, including diversity and species richness, decreased significantly with increasing level of diesel contamination whereas nematode assemblage from the low treated microcosm (0.5 mg diesel kg−1 (dw)) remained unaffected. Results from multivariate analyses of the species abundance data demonstrated that responses of nematode species to the diesel treatments were varied: Chaetonema sp. was eliminated at all doses tested and seemed to be intolerant species to diesel contamination; Pomponema sp. and Oncholaimus campylocercoïdes were significantly affected at all diesel contamination levels but they were not eliminated, these species were categorized as “diesel-sensitive”; Hypodontolaimus colesi, Daptonema trabeculosum and Daptonema fallax which significantly increased respectively at 0.5, 1 and 5 mg diesel kg−1 (dw) concentrations and appeared to be “opportunistic” species at these doses whereas Marylynnia stekhoveni which increased at all high doses (10, 15 and 20 mg diesel kg−1 (dw)) seemed to be a “diesel-resistant” species. 相似文献
147.
东南亚锡矿带长约3900km,从缅甸和泰国大陆起,一直延伸到印度尼西亚群岛(见图).矿带由东带和西带组成,两带近于平行,局部为断层错开. 在此矿带内,锡矿床与花岗岩伴生,西带虽有些晚期浅成花岗岩,但中成花岗岩占优势,东带则以浅成花岗岩为主.因此,两带花岗岩之间存在着明显的矿物学差异(Hutchison,1975);同时,西带花岗岩中痕量元素的分布模式也与东带截然不同(Yeap,1974).这两个带的花岗岩有着长期而复杂的历史,每个带中都产有时代显然不同的花岗岩.不 相似文献
148.
The influence on solute transport of the small-scale spatial variation of aquifer hydraulic conductivity (K) was analyzed by comparing results from fine-grid (2 m by 2 m) simulations of a synthetic heterogeneous aquifer to those from coarse-grid (8 m by 4 m) simulations of an equivalent homogeneous aquifer. Realizations of the K field of the heterogeneous aquifer were generated, using the Monte Carlo approach, from a lognormal distribution with mean log K of 2 (K in m/d) and three levels of log K variance of 0.1, 0.5, and 1.0. Numerical simulation results show that the average standard deviation of point concentrations increased from 1.21 to 5.78 when the value of log K variance was increased from 0.1 to 1.0. The average discrepancy between modeled concentrations (obtained from a coarse-grid deterministic numerical simulation) and the actual mean point concentrations (obtained from fine-grid Monte Carlo numerical simulations) increased from 0.91 to 4.23 with the increase in log K variance. The results from this study illustrate the uncertainty in predictions from contaminant transport models due to their inability to simulate the effects of heterogeneities at scales smaller than the model grid. 相似文献
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150.
Panigada S Pesante G Zanardelli M Capoulade F Gannier A Weinrich MT 《Marine pollution bulletin》2006,52(10):1287-1298
This paper reviews and analyzes ship collision records for the relatively isolated population of fin whales in the Mediterranean Sea from 1972 to 2001. Out of 287 carcasses, 46 individuals (16.0%) were certainly killed by boats. The minimum mean annual fatal collision rate increased from 1 to 1.7 whales/year from the 1970s to the 1990s. Fatal strike events (82.2%) were reported in or adjacent to the Pelagos Sanctuary, characterized by high levels of traffic and whale concentrations. Among 383 photo-identified whales, 9 (2.4%) had marks that were attributed to a ship impact. The reported rates are unusually high for baleen whales. The high likelihood of unreported fatal strikes combined with other anthropogenic threats suggests an urgent need for a comprehensive, basin-wide conservation strategy, including ship strike mitigation requirements, like real-time monitoring of whale presence and distribution to re-locate ferry routes to areas of lower cetacean density, and reducing ship speed in high cetacean density areas. 相似文献