求助4篇文献下载，附地址

dulaiyouyu

3篇science: P  ]% |5 r& O& z

, {9 p" E: X; k3 s+ Ghttp://www.sciencemag.org/content/257/5067/201.long
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http://www.sciencemag.org/content/257/5067/206.long% `! y* T. N2 h( [: b9 [0 P

3 T& b8 x$ t- ^* |! O& hhttp://www.sciencemag.org/content/266/5183/291.long8 L% u# X% f1 e& D* j$ y
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1篇Nature7 ~; H/ {/ _% @

. ]% U; d# W9 t6 @9 ^2 P1 Bhttp://www.nature.com/nature/jou ... /full/411309a0.html