Perhaps you should try some spelling variations:
"tu sach hay thuat bao thi" » "tu sach hay thuat bai thi", "tu sach hay thuat giao thi", "tu sach hay thuat o thi", "tu sach phau thuat bao thi", "tu sach my thuat bao thi", "tu sach va thuat bao thi", "tu sach han thuat bao thi", "tu sach ha thuat bao thi", "tu sach nay thuat bao thi", "thu sach hay thuat bao thi", "su sach hay thuat bao thi", "te sach hay thuat bao thi", "tu sach hay thuat dao thi", "tu sach hay thuat bao chi", "tu sach hay thuat ban thi"
"tu sai ky thuat co khi" » "tu sai ky thuat o khi", "tu bai ky thuat co khi", "tu san ky thuat co khi", "tu cai ky thuat co khi", "tu sac ky thuat co khi"
"tu bach ki thuat do thi" » "tu bach ki thuat o thi", "vu bach ki thuat do thi", "tu cach ki thuat do thi", "tu bac ki thuat do thi", "tu bach mai thuat do thi"

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("tu sai ky thuat co khi") or ((("tu bach ki thuat do thi") or ("tu sach hay thuat bao thi"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("tu sai ky thuat co khi") OR ((("tu bach ki thuat do thi") OR ("tu sach hay thuat bao thi")))).
• Removing quotes may allow a broader search: (( tu sai ky thuat co khi ) or ((( tu bach ki thuat do thi ) or ( tu sach hay thuat bao thi )))).
• Adding a wildcard symbol may retrieve word variants: (("tu sai ky thuat co khi") or ((("tu bach ki thuat do thi") or ("tu sach hay thuat bao thi"))))*.