Perhaps you should try some spelling variations:
"danh bat trung quoc viet nam" » "danh ba trung quoc viet nam", "danh bac trung quoc viet nam", "danh bao trung quoc viet nam", "danh bat trung nuoc viet nam", "danh bat trung hoc viet nam", "danh bat trung ngoc viet nam", "doanh bat trung quoc viet nam", "anh bai trung quoc viet nam", "dinh ba trung quoc viet nam"
"canh tac dung mot viet nam" » "canh tay dung mot viet nam", "canh giac dung mot viet nam", "cong tac dung mot viet nam", "canh sach dung mot viet nam", "canh xay dung mot viet nam", "canh tin dung mot viet nam", "canh tac dung mo viet nam", "canh tac dung moi viet nam", "canh tac dung co viet nam", "canh tac dung mon viet nam", "canh tac dung muoi viet nam"

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: (("canh tac dung mot viet nam") or ("danh bat trung quoc viet nam"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("canh tac dung mot viet nam") OR ("danh bat trung quoc viet nam")).
• Removing quotes may allow a broader search: (( canh tac dung mot viet nam ) or ( danh bat trung quoc viet nam )).
• Adding a wildcard symbol may retrieve word variants: (("canh tac dung mot viet nam") or ("danh bat trung quoc viet nam"))*.