Perhaps you should try some spelling variations:
"te sach trien tri" » "te sach tren tri", "te sach thieu tri", "te cach thien tri", "te sach trien thi", "te sach trieu thi", "te sach trien chi"
"toc sach tham tai" » "toc sach nha tai", "hoc sach tham tai", "doc sach tham tai", "thuoc sach tham tai", "toc sach pham tai", "toc sach thai tai", "toc sach thap tai"
"thu sach tien tri" » "thu sach tren tri", "thu sach thieu tri", "tu sach tien tri", "thuat sach tien tri", "thuoc sach tien tri", "thu sach tieng tri", "thu sach kien tri", "thu sach lien tri"

Try widening your search to All Fields.

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("toc sach tham tai") or ((("te sach trien tri") or ("thu sach tien tri"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("toc sach tham tai") OR ((("te sach trien tri") OR ("thu sach tien tri")))).
• Removing quotes may allow a broader search: (( toc sach tham tai ) or ((( te sach trien tri ) or ( thu sach tien tri )))).
• Adding a wildcard symbol may retrieve word variants: (("toc sach tham tai") or ((("te sach trien tri") or ("thu sach tien tri"))))*.