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101.
InFOCμS is a new generation balloon-borne hard X-ray telescope with focusing optics and spectroscopy. We had a successful 22.5-hour flight from Fort Sumner, NM on September 16,17, 2004. In this paper, we present the performance of the hard X-ray telescope, which consists of a depth-graded platinum/carbon multilayer mirror and a CdZnTe detector. The telescope has an effective area of 49 cm2 at 30 keV, an angular resolution of 2.4 arcmin (HPD), and a field of view of 11 arcmin (FWHM) depending on energies. The CdZnTe detector is configured with a 12 × 12 segmented array of detector pixels. The pixels are 2 mm square, and are placed on 2.1 mm centers. An averaged energy resolution is 4.4 keV at 60 keV and its standard deviation is 0.36 keV over 128 pixels. The detector is surrounded by a 3-cm thick CsI anti coincidence shield to reduce background from particles and photons not incident along the mirror focal direction. The inflight background is 2.9 × 10−4 cts cm−2 sec−1 keV−1 in the 20–50 keV band.  相似文献   
102.
Generally, PT pseudosections for reduced compositional systems, such as K2O–FeO–MgO–Al2O3–SiO2–H2O, Na2O–K2O–FeO–MgO–Al2O3–SiO2–H2O and MnO–K2O–FeO–MgO–Al2O3–SiO2–H2O, are well suited for inferring detailed PT paths, comparing mineral assemblages observed in natural rocks with those calculated. Examples are provided by PT paths inferred for four metapelitic samples from a 1 m2 wide outcrop of the Herbert Mountains in the Shackleton Range, Antarctica. The method works well if the bulk composition used is reconstituted from average mineral modes and mineral compositions (AMC) or when X‐ray fluorescence (XRF) data are corrected for Al2O3 and FeO. A plagioclase correction is suitable for Al2O3. Correction for FeO is dependent on additional microscopic observations, e.g. the kind and amount of opaque minerals. In some cases, all iron can be treated as FeOtot, whereas in others a magnetite or hematite correction yields much better results. Comparison between calculated and observed mineral modes and mineral compositions shows that the AMC bulk composition is best suited to the interpretation of rock textures using PT pseudosections, whereas corrected XRF data yield good results only when the investigated sample has few opaque minerals. The results indicate that metapelitic rocks from the Herbert Mountains of the Northern Shackleton Range underwent a prograde PT evolution from about 600 °C/5.5 kbar to 660 °C/7 kbar, followed by nearly adiabatic cooling to about 600 °C at 4.5 kbar.  相似文献   
103.
We discuss a hard x-ray telescope for the range 25–70 keV based on a one-dimensional lobster-eye telescope and x-ray supermirror coatings. This approach enables wide field-of-view imaging. A telescope suitable for a large balloon payload, with a 50×100 cm frontal area, could have an effective area of 50–100 cm2 and a 100×100 field of view, and thereby detect AGN that are 0.5 milliCrab in the soft x-rays in a 104 second exposure. 29% of the sky could be surveyed to this limit in a 2-week balloon flight, reaching 6 times fainter than the HEAO A-4 all-sky survey.  相似文献   
104.
The sessile and mobile macrobenthos on artificial hard bottoms was studied in 12 stations of the Sacca di Goro lagoon, a brackish, highly stressed water basin in the delta of the river Po, open to the Northwestern Adriatic Sea. Three sampling surveys were carried out in June and September 2000 and June 2001 in order to make three types of temporal comparisons: (i) on a seasonal scale, before and after a summer dystrophic event; (ii) on an annual basis, before and after the works of excavation of a canal through the outer sand bank; (iii) on a multiannual scale, comparing the data with those of a survey carried out in 1988. The biocoenoses did not show large fluctuations after a moderately severe summer dystrophic crisis, while the digging of the canal caused clear changes in the macrobenthos community structure after one year. The long-term comparison showed a shift in the community patterns after a decade.  相似文献   
105.
彭佳  黄春玲  陈旭 《地理研究》2018,37(1):220-230
根据云中湖27 cm长沉积岩芯进行元素、粒度和硅藻多指标分析以及210Pb测年,结合流域气候和人类活动等历史资料,反演1958年以来云中湖在气候变化和人类活动影响下的环境变化。冗余分析结果显示云中湖沉积硅藻组合变化与Al、Fe、Pb和温度四个变量显著相关。硅藻属种聚类分析的结果表明云中湖环境变化经历了两个阶段:1958-1993年间喜碱性水体的Achnanthes minutissimaFragilaria nanana属种大量出现与较高CIA指数响应于气候调控下的流域侵蚀过程;1993年以来气候变暖与旅游发展引起入湖营养盐增加是Cyclotella pseudostelligeraAulacoseira alpigena等中—富营养硅藻种增殖的主要诱因。重建亚高山湖泊在气候变化以及人类活动影响下湖泊生态系统的演化,为保护亚高山湖泊生态环境和改善流域水质提供参考。  相似文献   
106.
贺兰山奥陶系研究的新进展   总被引:5,自引:1,他引:4  
郑昭昌  李玉珍 《现代地质》1991,5(2):119-137
近年来,作者对贺兰山区奥陶系进行了岩石地层及生物地层学的研究,取得了新的进展。确证该区寒武系与奥陶系为连续沉积,对奥陶系进行了合理划分和时代厘定,初步建立了11个化石带或生物组合。该区是华北地台西缘奥陶系发育最好、生物地层研究最清楚的地区。根据沉积物及生物特征,确认本区中奥陶统为大陆边缘斜坡相沉积,浊流特征颇为典型。是研究斜坡沉积作用及其相模式、古构造古地理演化及其含矿性的理想地区。  相似文献   
107.
文蛤MERETRIX MERETRIX LINNAEUS工厂化人工育苗试验   总被引:1,自引:0,他引:1  
文蛤的人工催产、浮游幼虫培育和稚贝水泥池培养试验结果表明:(1)用阴干与流水结合的方法刺激亲贝能获得理想俏产效果。(2)在水温28.0~29.1℃,比重1.0160—1.0187,pH值8.2-8.4条件下,用亚心形扁藻作文蛤D幼的开口饵料和壳顶幼虫饵料,生长快(日增长高达24.5μm)、成活率高(72.3%)、浮游期短(仅5-6天)。(3)文蛤眼点功出水泥池无砂底附苗试验获得成功,且单位面积附苗量高达433.3万颗/m2。(4)室内水泥池铺砂培养文蛤稚贝,前期生长快,但当壳长达300μm后,稚贝分泌一种粘液,生长和成活受到影响。建议定期翻池洗苗,当壳长达500μm后尽早将苗移至池塘内砂滩培养。  相似文献   
108.
通过亲贝促熟、人工催产、幼体培育和采苗等技术环节,初步建立了库页岛厚蛤蜊(Pseudocardium sachalinense)的人工繁育技术。对库页岛厚蛤蜊胚胎发育过程的观察表明,在水温22~24℃,盐度28~30条件下,受精卵经约50min开始卵裂;约20h发育至D形幼体;经约11d的人工培育,幼体出现足和水管原基...  相似文献   
109.
粘性土为主的地基强夯的时效性   总被引:1,自引:0,他引:1  
根据浦东国际机场飞行区跑道地基强夯工程(三标)实测的不同时间的静力触探资料,讨论以粘性土为主的地基强夯强度增长的时效现象,得出:粘性土为主的地基,强夯的加艇具有滞后特性。  相似文献   
110.
The East China Sea Shelf Basin generated a series of back-arc basins with thick successions of marine- and terrestrial-facies sediments during Cenozoic. It is enriched with abundant oil and gas resources and is of great significance to the petroleum exploration undertakings. Therein, the Lishui Sag formed fan delta, fluvial delta and littoral-to-neritic facies sediments during Paleocene–Eocene, and the research on its sedimentary environment and sediment source was controversial. This study analyzed the paleontological combination characteristics, and conducted a source-to-sink comparative analysis to restore the sedimentary environment and provenance evolution of the Lishui Sag during Paleocene–Eocene based on the integration of detrital zircon U-Pb age spectra patterns with paleontological assemblages. The results indicated that Lishui Sag was dominated by littoral and neritic-facies environment during time corroborated by large abundance of foraminifera, calcareous nannofossils and dinoflagellates. Chronological analysis of detrital zircon U-Pb revealed that there were significant differences in sediment sources between the east and west area of the Lishui Sag. The western area was featured by deeper water depths in the Paleocene–Eocene, and the sediment was characterized by a single Yanshanian peak of zircon U-Pb age spectra, and mainly influenced from Yanshanian magmatic rocks of South China Coast and the surrounding paleo-uplifts. However, its eastern area partly showed Indosinian populations. In particular, the upper Eocene Wenzhou sediments were featured by increasingly plentiful Precambrian zircons in addition to the large Indosinian-Yanshanian peaks, indicating a possible impact from the Yushan Low Uplift to the east. Therefore, it is likely that the eastern Lishui Sag generated large river systems as well as deltas during time. Due to the Yuquan Movement, the Lishui Sag experienced uplifting and exhumation in the late stage of the late Eocene and was not deposited with sediments until Miocene. Featured by transitional-facies depositions of Paleocene–Eocene, the Lishui Sag thus beared significant potential for source rock and oil-gas reservoir accumulation.  相似文献   
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