poll是什么意思

用法例句

Objective:To observe and compare of epidural puncture and the hard-membrane wears out chang to vein-inspiration compound anaesthesia,inspiration anflurane and isoflurane to prevent the headache.

目的:观察硬膜穿破后改用静-吸复合全麻,吸入安氟醚与异氟醚对预防术后头痛的比较。