榆林港新姿

在我国海南岛的最南端,有一个天然的港口——榆林港,它东南面对西、中、南沙群岛,临近西沙群岛(180海里),与西沙共扼南海西出印度洋及去泰国湾之要冲,西南面对中南半岛,与越南岘港仅距153海里,为北部湾之锁匙,是我国南方最大最优良的军港。榆林港指斩颈角与鹿回头角联线以北的水域,并     

北水南调的宏伟设想

打开中国地图,就可以看到东北地区有两大水系,一条是松花江水系,一条是辽河水系,但这两大水系自古以来互不相通。引松花江水到辽河流域,以解决松辽两个相邻流域水资源的综合开发利用,这就是“北水南调”。“北水南调”工程的设想由来已久。早在清朝康熙二十二年(1683年)就曾提出开掘松辽运河的设想。民国初期,孙中山先生在《建国方略》也对开辟松辽运河做了科学的设想与著述。解放后,在1956～     

Causality of future and spot grain prices between China and the US: Evidence from soybean and corn markets against the surging import pressure

As the boom of the world grain market phases out, the challenge for Chinese government has gradually moved from retarding grain exports to restraining imports. This study tries to examine the causalities of soybean and corn price movement among the United States (US) future market, Chinese domestic future market and Chinese spot markets. We find that the daily prices of all these three types of grains belong to I(1) series, and there are long-run integrations. Also Chinese soybean future prices adjust more quickly than its spot prices, while Chinese corn future prices adjust slower. This paper finds that the soybean price movement originates from the US future market, then passes through Chinese future market, and finally reaches Chinese spot market, while the corn price movement starts in Chinese spot market, then spreads to the future markets in both China and the US. Finally, this paper also provides some policy implications on how to release the pressure from the grain imports.     

海蜇

海蜇,这种低等的海洋生物三十左右年纪的人并不感到陌生。可是,近二十年来,这种美味佳肴几乎在餐桌上消失,更不用说见到它嬉水逐浪、婷婷多姿的游态了。自八十年代初,海蜇在我国沿海又抛头露面。更有趣的是,每到七、八月份,游人观光烟台,站在烟台山那陡峭耸立的惹浪亭上,还可观赏海蜇表演的“赛花会”呢!     

连续压力流率测定在前列腺增生诊断中的应用

目的 探讨前列腺增生症（ＢＰＨ）伴膀胱出口梗阻（ＢＯＯ）患者的逼尿肌收缩状况。方法 采用连续两次压力－流率法检测７１例ＢＰＨ伴ＢＯＯ者，将在第１次压力－流率测定中得Ａ－Ｇ值，按照Ｓｃｈａｆｅｒ氏ＢＯＯ分级把病人分成３组；第１组为ＢＯＯ２级１９例；第２组为ＢＯＯ３－４级２４例，第３组为ＢＯＯ ５￣６级２８例，再将在连续两次尿流率和最大尿流率时的逼尿肌压均比第１次显著下降；第２组中第２次的Ｑｍａｘ和Ｐ