Perhaps you should try some spelling variations:
"do thi trinh vat" » "do tho trinh vat", "do thi thanh vat", "do thi hinh vat", "do thi trinh van", "do thi trinh luat", "do thi sinh vat"
"ho thi minh tai" » "ho chi minh tai", "ho thi bich tai", "ho thi hinh tai", "ho thi minh tri", "ho thi dinh tai", "hoi thi minh tai", "hoa thi minh tai", "ha thi minh tai"
"ho thi hanh tai" » "ho thi thanh tai", "ho thi hang tai", "ho thi han tai", "hoi thi hanh tai", "hoa thi hanh tai", "ha thi hanh tai"
"ho chi danh bat" » "ho chi dan bat", "ho chi anh bat", "ho chi dinh bat", "ho chi doanh bat", "ho chi anh bai", "ho chi dinh ba"

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

• Performing a fuzzy search may retrieve terms with similar spellings: (((((("ho thi minh tai") or ("ho thi hanh tai"))) or ("do thi trinh vat"))) or ("ho chi danh bat"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((((("ho thi minh tai") OR ("ho thi hanh tai"))) OR ("do thi trinh vat"))) OR ("ho chi danh bat")).
• Removing quotes may allow a broader search: (((((( ho thi minh tai ) or ( ho thi hanh tai ))) or ( do thi trinh vat ))) or ( ho chi danh bat )).
• Adding a wildcard symbol may retrieve word variants: (((((("ho thi minh tai") or ("ho thi hanh tai"))) or ("do thi trinh vat"))) or ("ho chi danh bat"))*.