回顧性研究集中於現象的過去趨勢，並將其研究到未來。在進行研究之前，從現

回顧性研究集中於現象的過去趨勢，並將其研究到未來。在進行研究之前，從現有記錄中追溯收集部分數據。

結果 (英文) 1:

A retrospective study focused on the phenomenon of past trends, and to study its future.
Before the study, the data collecting section retroactive from existing records.

結果 (英文) 2:

Retrospective studies focus on past trends in phenomena and study them into the future.
Collect some data retroactively from existing records prior to the study.

結果 (英文) 3:

Retrospective research focuses on the past trend of phenomena and studies it into the future.
Part of the data was collected retroactively from the existing records prior to the study.