本研究採用同時法與歷時法二種文獻老化研究方法，進行資訊檢索領域下系統研究及使用者研究二種主題文獻之老化研究，主要研究重點有二，一是資訊檢索領域下，系統研究及使用者研究二種不同主題文獻老化現象之差異性；二是同一主題文獻下，同時法與歷時法二種不同老化研究方法之文獻衰退情形是否一致。 同時法研究是針對現時某一特定文獻之引用參考文獻進行分析，並測得其引用年齡中數。本研究自LISA資料庫取得2006年資訊檢索領域下系統研究及使用者研究二種主題之相關文獻，作為同時法研究樣本，並利用T檢定檢測系統研究及使用者研究二種主題文獻老化現象之差異。在同時法研究結果方面，系統研究及使用者研究二種主題文獻之引用年齡中數分別為7.25歲與7.98歲，系統研究主題文獻同時法老化速度快於使用者研究主題文獻，但差異不大，T檢定結果亦顯示同時法系統研究及使用者研究二種主題文獻之老化速度無顯著差異。 歷時法研究是分析過去某特定期間所發表之文獻，其逐年被引用情形，並計算其被引用半衰期。本研究利用LISA資料庫取得1996年資訊檢索領域下系統研究及使用者研究二種主題之相關文獻，作為歷時法研究樣本，並利用WOS資料庫，取得其自1996年至2006年間逐年被引用情形。在歷時法研究結果方面，系統研究及使用者研究二種主題文獻之被引用半衰期分別為5.12歲與4.99歲，系統研究主題文獻之歷時法老化速度較使用者研究主題文獻稍慢，二者差異不大，T檢定結果亦顯示歷時法系統研究及使用者研究二種主題文獻之老化速度無顯著差異。 在同時法與歷時法二種研究方法比較部份，就文獻老化速度而言，同時法之引用參考文獻數量於高峰期後，呈現顯著文獻衰退現象；而歷時法達到被引用次數最高峰後，則未呈現明顯文獻衰退現象，可知同時法文獻老化速度較歷時法文獻老化速度快。在柯史（K-S）檢測方面，檢測結果發現，不論系統研究主題文獻或使用者研究主題文獻，同時法與歷時法之文獻老化現象皆不一致。 因此，本研究重要研究結論有二：一是資訊檢索領域下，不會因主題不同而有顯著差異；二是資訊檢索領域下，同時法所測得之文獻老化現象與歷時法所測得之文獻老化現象不一致。 / This obsolescence study uses two kinds of aging research methods - synchronous approach and diachrinous approach. Analyze two subjects of systems-centered and users-centered in the information retrieval field. The main emphasis of the research is two. First, under information retrieval field, the differences between systems-centered and user-centered in obsolescence study. Second, the difference between synchronous approach and diachrinous approach’s aging phenomenon in the same subject. Synchronous approach is targeted at the present of a particular literature references and calculated median citation age. This study acquired the information retrieval field of systems-centered and user-centered’s sample in 2006 from LISA database, and tested the difference between systems-centered and user-centered literature aging with using t-test. The result of synchronous approach, median citation age of systems-centered literature is 7.25 years and median citation age of user-centered literature is 7.98 years. So systems-centered literature aging is faster than user-centered literature. But the difference is small. T test results also revealed that difference between systems-centered and user-centered of literature aging has not significantly. Diachrinous approach was to analyze a particular during the past published literature and observed the cited times each year, and finally calculated its half-life. This study acquired the information retrieval field of systems-centered and user-centered’s sample in 1996 from LISA database, and acquired the cited times each year during 1996 to 2006 from WOS database.The result of diachrinous approach, cited half-life of system-centered literatures is 5.12 and cited half-life of user-centered literatures is 4.99 years. So user-centered literature aging was faster than system-centered literatures. But the difference was small. T test results also revealed that difference between the system-centered and user-centered of literature aging has not significantly Synchronous approach and diachrinous approach methods of comparison. By the literature on the aging speed, cited reference numbers of synchronous approach reached peak period, and the literature curve showed significant recession; cited times of diachrinous approach reached a peak, and literature curve were not significantly recession. It revealed that aging speed of synchronous approach was faster than aging speed of diachrinous approach. In the K-S test, the results showed that synchronous approach and diachrinous approach were inconsistent, whether systems-centered literatures or users-centered literatures. Therefore, the important conclusion of this study are two : First, in the information retrieval field, even different subject there will be no significant differences on literature aging phenomenon; Second, under the information retrieval field, synchronous approach and diachrinous approach which measured the aging phenomenon of literature are inconsistent.