This paper deals with some current methods for determing primary production.The principle,advantage,weakness and proper applying conditions of each method is also discussed.
文摘This paper deals with some current methods for determing primary production.The principle,advantage,weakness and proper applying conditions of each method is also discussed.
文摘目的探讨广东顺德地区原发性肝癌发病的危险因素,为预防肝癌发生提供科学依据。方法采用频数匹配的病例-对照研究,在757例原发性肝癌病例及1 061例对照中,应用t检验、χ~2检验和非条件Logistic回归模型分析资料。结果病例组与对照组的年龄和性别分布差异均无统计学意义(均有P>0.05)。多因素分析显示,与肝癌发病风险有统计学关联的因素包括乙型肝炎病毒(hepatitis B virus,HBV)慢性感染(OR=25.82,95%CI:18.11~36.83,P<0.001)、恶性肿瘤家族史(OR=2.58,95%CI:1.72~3.88,P<0.001)、吸烟(OR=2.92,95%CI:2.01~4.26,P<0.001)、饮酒(OR=1.93,95%CI:1.34~2.79,P<0.001)、饮用江河沟塘水(OR=3.82,95%CI:2.72~5.35,P<0.001)、食用鱼生类食物(OR=2.47,95%CI:1.47~4.12,P=0.001)、食用腌制食物(OR=2.57,95%CI:1.86~3.55,P<0.001)、喝茶(OR=0.21,95%CI:0.14~0.30,P<0.001)、职业在岗(OR=0.34,95%CI:0.23~0.50,P<0.001)。结论 HBV慢性感染、有恶性肿瘤家族史、吸烟、饮酒、饮用江河沟塘水、食用鱼生类食物和食用腌制食物是肝癌的危险因素,喝茶和职业在岗可能是肝癌的保护因素。
