Perhaps you should try some spelling variations:
"tu sach kxmky thuat o khi" » "tu sach kxy thuat o khi", "thu sach kxmky thuat o khi", "su sach kxmky thuat o khi", "tu cach kxmky thuat o khi", "tu sach kxmky thuat do khi", "tu sach kxmky thuat bo khi"
"su xac ky thuat bao chi" » "su xac ky thuat bai chi", "su xac ky thuat giao chi", "su xac ky thuat do chi", "su xac ky thuat bao che", "pu xac ky thuat bao chi", "su cac ky thuat bao chi", "su sac ky thuat bao chi", "su bac ky thuat bao chi"
"te sach ky thuat co khi" » "te sach ky thuat do khi", "toc sach ky thuat co khi", "te sac ky thuat co khi", "te sach y thuat co khi", "te sach ty thuat co khi", "te sach ky thuat cbo 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: (("te sach ky thuat co khi") or ((("su xac ky thuat bao chi") or ("tu sach kxmky thuat o khi"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("te sach ky thuat co khi") OR ((("su xac ky thuat bao chi") OR ("tu sach kxmky thuat o khi")))).
• Removing quotes may allow a broader search: (( te sach ky thuat co khi ) or ((( su xac ky thuat bao chi ) or ( tu sach kxmky thuat o khi )))).
• Adding a wildcard symbol may retrieve word variants: (("te sach ky thuat co khi") or ((("su xac ky thuat bao chi") or ("tu sach kxmky thuat o khi"))))*.