Perhaps you should try some spelling variations:
"hoi phap cau." » "thoi phap cau." (Expand Search), "hoi nhap cau." (Expand Search), "hoc phap cau." (Expand Search), "hoi phap ca." (Expand Search), "hoi phap cac." (Expand Search), "hoi phap chu." (Expand Search)
"doi nhan cau." » "hoi nhap cau." (Expand Search), "doi nhan chau." (Expand Search), "doi nhan hau." (Expand Search), "doi nhan chu." (Expand Search)
"hoi nhan cac." » "hoi nhap cac." (Expand Search), "hon nhan cac." (Expand Search), "hoa nhan cac." (Expand Search), "hoi nhan cach." (Expand Search), "hoi ngan cac." (Expand Search), "hoi nhan sac." (Expand Search)
"hoi hat cau." » "hoi phat cau." (Expand Search), "hoi nhap cau." (Expand Search), "hoi hat chau." (Expand Search), "hoi hat ca." (Expand Search), "hoi vat cau." (Expand Search)

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: (((("hoi hat cau.") OR ("hoi phap cau."))) OR ((("doi nhan cau.") OR ("hoi nhan cac."))))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"hoi hat cau.\") OR (\"hoi phap cau.\"))) OR (((\"doi nhan cau.\") OR (\"hoi nhan cac.\"))))".
• Removing quotes may allow a broader search: (((( hoi hat cau. ) OR ( hoi phap cau. ))) OR ((( doi nhan cau. ) OR ( hoi nhan cac. )))).
• Adding a wildcard symbol may retrieve word variants: (((("hoi hat cau.") OR ("hoi phap cau."))) OR ((("doi nhan cau.") OR ("hoi nhan cac."))))*.