Only two parameters (Lung shadow of X-rays and partial pressure of oxygen in arterial blood) were described clearly,with the investigate case numbe r being 188 (60.6%) and 156(50.3%),respectively.

• 文献中对32项指标作了不同程度的调查描述,描述清楚者仅有X线肺部阴影、动脉血氧分压两项指标的调查例数(分别为188例及156例)超过了调查总例数(310例)的50%25(分别为606%25、503%25)。