The studies compared the blood-thinner unfractionated heparin to a placebo, or low-molecular-weight heparin with a placebo, or both types of heparin with each other.

• 这些研究比较了血液稀释剂普通肝素和安慰剂、低分子肝素和安慰剂或是两种肝素之间的作用比较。