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1.
The counter-gradient terms in the computations of turbulent fluxes of heat and moisture have been included in the PBL parameterization of a regional model for monsoon prediction. Results show that inclusion of counter-gradient terms has a marginal impact in the prediction of large scale monsoon circulation and rainfall rates.  相似文献   
2.
    
The concentrations of copper, zinc, cadmium, selenium and mercury were determined in eggs, muscle, liver, kidney and stomach content of nestilings and adults of the Antarctic petrel, Thalassoica antarctica, and its predator, the south polar skua, Chataracta maccormicki, from Svarthamaren, Dronning Maud Land, Antarctica. The dominant food of the petrels is krill, Euphausia superba. The results show relatively high levels of cadmium in krill, which is assumed to be the main reason for the high levels of cadmium in petrels and skuas. Cadmium is almost absent in eggs, but accumulates very rapidly with age in nestlings. The copper concentrations in livers of nestling petrels reach very high levels during growth. This may be seen in connection with physiological development processes. Mercury seems to be accumulated with age and between trophic levels. Among the nestlings, the mercury levels decrease with increasing age, which may be accomplished by the excretion of mercury through the growth of feathers and as a dilution effect during growth. Selenium and mercury are inversely correlated in nestlings. The levels of zinc were similar for different nestling stages and between nestlings and adults in skuas and petrels.  相似文献   
3.
本文回顾了在苏联所有地震区就地震预报而进行的水文地球化学和流体地球动力学的主要研究成果。从83个台站组成的庞大的观测网收集了大量的资料,这些资料涉及到大约40个水文地球化学和流体地球动力学参数的变化。联系本地区的地震活动对这些资料进行了分析研究。在对常规观测结果进行统计分析的基础上,对水文地球化学前兆进行了分类。指出了由前兆物理化学性质而定的水文地球化学异常的几个特点、给定地区的地质条件和预期地震活动的特点。给出了数据分析的一些复杂的统计方法和根据水文地球化学方法预报的几个地震实例。发现水文地球化学和流体地球动力学前兆对短期预报非常有效。讨论了能引起水文地球化学前兆的可能机制。简短地叙述了苏联用于水文地球化学和流体地球动力学观测的精密自记装置的进展。  相似文献   
4.
Trace element concentrations and contents in gills, gonad, kidneys, mantle, muscle and remainder during the reproductive cycle of female and male spiny and Pacific scallops, from the Strait of Georgia, BC, Canada, were quantified by using ICPMS. The elements investigated were chromium, manganese, iron, cobalt, nickel, selenium, molybdenum, cadmium, tin and mercury. For all ten elements, the tissue distribution was to some extent influenced by species, sex and reproductive status. The implications of the present study in relation to the design of biomonitoring programmes are: (1) care should be taken to ensure an equal/constant sex composition when making interannual comparisons of pooled samples. Preferably the sexes should be monitored separately. (2) the practice of obtaining pooled samples in the interspawn phase is applicable only to monitoring long-term trends in contaminant levels, while the reproductive status should be heeded when studying short-term changes. (3) the present study confirms that direct temporal or spatial comparisons of absolute accumulated element concentrations are only valid intraspecifically.  相似文献   
5.
This study has demonstrated a reliable method of quantifying the total mass of litter on a beach. It was conducted on Ookushi beach, Goto-Islands, Japan, and uses a combination of balloon-assisted aerial photography and in situ mass measurements. The total mass of litter over the beach was calculated to be 716 ± 259 kg. This figure was derived by multiplying the litter-covered area (calculated using balloon-assisted aerial photography) by the mass of litter per unit area. Light plastics such as polyethylene made up 55% of all plastic litter on the beach, although more work is needed to determine whether lighter plastics are transported to beaches more readily by winds and ocean currents compared with heavier plastics, or whether lighter plastics comprise a greater percentage of marine litter. Finally, the above estimates were used to calculate the total mass of metals released into coastal ecosystems via plastic litter on beaches.  相似文献   
6.
1989年不市以东近海海底火山喷发之后,1990 ̄1992年间,日本中部豆半岛东部地区没有观测到显著的震群活动。但1993年1月观测到了1次小的震群活动,并于1993年5 ̄6月又再次观测到了1次引人注目的震群活动。在此次震群活动平静之后几个月,1993年9月 ̄1994年2月,在伊豆半岛内陆地区观测到剧烈的地壳运动变化。当伊豆半岛发生这次地壳运动异常变化时,在一些连续的地磁观测点,几乎同时观测到了具  相似文献   
7.
自中印度洋被确认为是大洋岩石圈活动压缩变形的场所以来,人们已经竭尽全力来确定该地区的缩短量.其目的是了解在很高压应力下的板内变形会对周围板块的运动学起什么作用以及大洋岩石圈的机械反映.使用了下面4种不同的方法来定量分析变形速率:  相似文献   
8.
    
De Lange N 《Erdkunde》1993,47(1):61-74
The reduction of the rate of growth of the Brazilian population from 3% in the 1960s to 2% by 1993 resulted from a significant reduction of fertility. According to the 1986 national maternal-child health and family planning survey (PNSMIPF) results, 43.3% of women were using some type of contraception: 65.6% of married or cohabiting women. Women relied most on sterilization (17.2%), followed by oral contraceptives (OCs) (17%), the rhythm method (2.8%), the condom (1.1%), and others (5.2%). Only in the south was OC use more prevalent (28.5%) than sterilization (12.2%). The proportion of sterilization reached 27.8% in the north/center-east urban regions. In urban areas sterilization averaged 18.7% vs. 12.7% in rural areas. 26.9% of currently married women in the age range of 15-44 years had been sterilized. A 1990 international estimation indicated that the proportion of sterilization amounted to 36.9% in China, 30.95 in India, 29.7% in Brazil, 47.6% in South Korea, 30.4% in Thailand, and 36.5% in the Dominican Republic. The 1986 PNSMIPF survey also indicated that sterilized women were better informed than other women about contraception. 75% of the former had used OCs, 5% had used the diaphragm, 3% the IUD, 30% the condom, and 35% coitus interruptus at one time or other. The sterilized women had an average of 1.7 more children than those who were using other methods of contraception. 48.6% of women were sterilized before the age of 30, when they had had an average of 3.6 children. 66.6% of the sterilized women who had given birth before the age of 20 had 4 or more live births as compared to 5.9% of sterilized women aged 30 with the same number of children. 47% of women without any schooling were using some kind of contraception vs. 77% of those who had completed secondary school. A multivariate analysis also showed that the age of the mother, the number of live births, the educational status of the mother, and family income were positively correlated with sterilization.  相似文献   
9.
地震层析是根据多道地震数据估算速度结构的有效方法。本次研究针对海上科拉拉-康坎(Kerala—Konkan)地区一条以前识别出似海底反射(BSR)的地震测线东段的多道地震数据,采用2D方法得到可能的速度场结构,并推测气体水合物,游离气的存在。层析模拟由反射相识别和不同源-接收器位置的走时拾取组成。利用这些拾取采用射线追踪技术进行正演和反演来得到2D速度场。本次模拟调查区的模型第一次显示出细微速度结构。2D模拟揭示了速度场沿地震线研究段的横向发生的变化。结果表明薄层沉积物盖层(约50—60m)的速度为1770至1850m/s。在海底之下具高P波速度(1980—2100m/s)的沉积物层被解释为水合物层,水合物层的厚度在110—140m之间变化。在水合物层底部有一低速层,速度为1660—1720m/s,被解释为游离气层,厚度在50—100m之间。本次调查表明在海上科拉拉-康坎(Kerala—Konkan)局部地区水合物之下存在游离气。  相似文献   
10.
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