Perhaps you should try some spelling variations:
"su sach dao thuan bo chi" » "su sach tao thuan bo chi", "su sach dao thanh bo chi", "su sach duc thuan bo chi", "su lanh dao thuan bo chi", "su sach dao thuat bao chi", "su sach dao thuan loi chi", "su sach dao thuat do chi", "so sach dao thuan bo chi", "vu sach dao thuan bo chi", "su sach dao thuan bao chi", "su sach dao thuan ho chi", "su sach dao thuan bo cai"
"tu sai ky thuat doi khi" » "tu sai ky thuat do khi", "tu sai ky thuat di khi", "tu sai ky thuat doc khi", "tu bai ky thuat doi khi", "tu san ky thuat doi khi", "tu cai ky thuat doi khi", "tu sac ky thuat doi khi"
"tu bach my thuat co khi" » "tu bach ki thuat co khi", "tu bach va thuat co khi", "tu bach my thuat do khi", "tu bach my thuat o khi", "vu bach my thuat co khi", "tu cach my thuat co khi", "tu bac my thuat co khi", "tu bach mai thuat co khi", "tu bach mao thuat co khi"

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: (("tu bach my thuat co khi") or ((("su sach dao thuan bo chi") or ("tu sai ky thuat doi khi"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("tu bach my thuat co khi") OR ((("su sach dao thuan bo chi") OR ("tu sai ky thuat doi khi")))).
• Removing quotes may allow a broader search: (( tu bach my thuat co khi ) or ((( su sach dao thuan bo chi ) or ( tu sai ky thuat doi khi )))).
• Adding a wildcard symbol may retrieve word variants: (("tu bach my thuat co khi") or ((("su sach dao thuan bo chi") or ("tu sai ky thuat doi khi"))))*.