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401.
“蓝色粮仓”的内涵阐析及其建设设想——以青岛市为例 总被引:1,自引:0,他引:1
基于“蓝色粮仓”基本概念和科学发展观,分析了建设青岛市“蓝色粮仓”的基础条件,如广阔的海域和近岸滩涂面积、丰富的海洋生物资源种类、不断改善的海洋生态环境、雄厚的海洋科技实力等,还分析了建设青岛市“蓝色粮仓”的功能定位.在此基础上提出了建设青岛市“蓝色粮仓”的基本设想,即选择对海水养殖业、资源保护与增殖业、海水种苗业、远洋渔业、海产品加工业、海产品流通与市场等领域进行重点扶持和建设. 相似文献
402.
海岸带蓝碳生态系统已成为应对气候变化重要的基于自然的解决方案。本研究梳理了全球海岸带蓝碳生态系统的分布、碳封存量和封存价值,并根据经济、科技、蓝碳封存量三个指标对各海岸带国家和地区进行分类。海岸带蓝碳生态系统分布最广的国家是澳大利亚、印度尼西亚、墨西哥和美国,而印度尼西亚、澳大利亚、马来西亚和巴西碳埋藏量最高。全球每年蓝碳埋藏价值在碳交易和碳税价格下分别为3.47×109美元和2.35×109美元。中国拥有丰富的海岸带蓝碳资源,生态系统面积排名第10,年封存量排名第21;然而蓝碳自然资源的赋存禀赋与现有碳价格体系下的价值匹配性较差,基于碳交易价格的中国海岸带蓝碳埋藏价值全球排名第27,基于碳税价格仅排名第39。碳价格低迷将会导致在国际蓝碳交易中处于劣势,中国后续应不断完善碳排放交易市场。中国具有在蓝碳研究以及修复投入与实践方面的优势,以及贝藻养殖、海洋牧场等特色蓝碳资源,可结合不同类型的蓝碳国家经济科技条件与自然条件制定多元合作策略。 相似文献
403.
404.
T. Naylor A. Allan K. S. Long 《Monthly notices of the Royal Astronomical Society》2005,361(3):1091-1101
We present a phase-resolved spectroscopic study of the secondary star in the cataclysmic variable (CV) U Gem. We use our data to measure the radial velocity semi-amplitude, systemic velocity and rotational velocity of the secondary star. Combining this with literature data allows us to determine masses and radii for both the secondary star and white dwarf, which are independent of any assumptions about their structure. We use these to compare their properties to those of field stars and find that both components follow field mass–radius relationships. The secondary star has the mass, radius, luminosity and photometric temperature of an M2 star, but a spectroscopic temperature of M4. The latter may well be due to a high metallicity. There is a troubling inconsistency between the radius of the white dwarf inferred from its gravitational redshift and inclination and that inferred from its temperature, flux and astrometric distance.
We find that there are two fundamental limits to the accuracy of the parameters we can derive. First, the radial velocity curve of the secondary star deviates from a sinusoid, in part because of its asphericity (which can be modelled) and in part because the line flux is not evenly distributed over its surface. Secondly, we cannot be certain which spectral type is the best match for the lines of the secondary star, and the derived rotational velocity is a function of the spectral type of the template star used. 相似文献
We find that there are two fundamental limits to the accuracy of the parameters we can derive. First, the radial velocity curve of the secondary star deviates from a sinusoid, in part because of its asphericity (which can be modelled) and in part because the line flux is not evenly distributed over its surface. Secondly, we cannot be certain which spectral type is the best match for the lines of the secondary star, and the derived rotational velocity is a function of the spectral type of the template star used. 相似文献
405.
406.
Darren S. Baskill Peter J. Wheatley Julian P. Osborne 《Monthly notices of the Royal Astronomical Society》2005,357(2):626-644
We present the complete set of 34 ASCA observations of non-magnetic cataclysmic variables. Timing analysis reveals large X-ray flux variations in dwarf novae in outburst (Z Cam, SS Cyg and SU UMa) and orbital modulation in high inclination systems (including OY Car, HT Cas, U Gem, T Leo). We also found episodes of unusually low accretion rate during quiescence (VW Hyi and SS Cyg). Spectral analysis reveals broad temperature distributions in individual systems, with emission weighted to lower temperatures in dwarf novae in outburst. Absorption in excess of interstellar values is required in dwarf novae in outburst, but not in quiescence. We also find evidence for subsolar abundances and X-ray reflection in the brightest systems.
LS Peg, V426 Oph and EI UMa have X-ray spectra that are distinct from the rest of the sample and all three exhibit candidate X-ray periodicities. We argue that they should be reclassified as intermediate polars.
In the case of V345 Pav we found that the X-ray source had been previously misidentified. 相似文献
LS Peg, V426 Oph and EI UMa have X-ray spectra that are distinct from the rest of the sample and all three exhibit candidate X-ray periodicities. We argue that they should be reclassified as intermediate polars.
In the case of V345 Pav we found that the X-ray source had been previously misidentified. 相似文献
407.
408.
Xiao-Bin Zhang Rong-Xian ZhangNational Astronomical Observatories Chinese Academy of Sciences Beijing xzhang@bao. ac. cnCAS-PKU Joint Beijing Astrophysics Center Beijing 《中国天文和天体物理学报》2003,3(4):311-315
Four stars, GSC 1258-0143, GSC 1986-1665, GSC 3045-0892 and GSC 2983-1597 were found to be new variables during a campaign of CCD photometric monitoring of short-period eclipsing binary stars. The variabilities of these new variables are reported. The main characteristics and probable classifications of the variables are discussed through a preliminary analysis on their light curves. Among these stars, GSC 1258-0143 is classified as a RR Lyr star of sub-type a. Its pulsation period is determined to be about 0.5206 days. The other three stars, are definite variables, but their periods and types of light variations remain unknown. 相似文献
409.
Chris Koen 《Monthly notices of the Royal Astronomical Society》2003,346(2):473-482
76 hours of CCD photometry of 11 L dwarfs and one T dwarf is described. Three objects, including the T dwarf ε Indi B, showed convincing evidence for variability. A periodicity of 8 h is clearly visible in the light curve of 2MASS J1155395−372735. 相似文献
410.
Lawson W. A. Cottrell P. L. Gilmore A. C. Kilmartin P. M. 《Journal of Astrophysics and Astronomy》1989,10(2):151-155
SY Hyi is classified as a suspected R Coronae Borealis-type variable star. Photometric and spectroscopic observations of SY
Hyi lead to the star’s reclassification as a semiregular variable of spectral type M5-6. 相似文献