Perhaps you should try some spelling variations:
"ki nang quang van hien so" » "ki nang quan van hien so", "ki dang quang van hien so", "ki hang quang van hien so", "ki nang quang ban hien so", "ki nang quang uan hien so", "ki nang quang van hieu so", "ki nang quang van tien so", "ky nang quang van hien so", "ki nang quang van khien so", "ki nang quang van bien so"
"trinh dung quang mai kiem soat" » "trinh dang quang mai kiem soat", "trinh dung quan mai kiem soat", "trinh luong quang mai kiem soat", "trinh dung quang dai kiem soat", "trinh dung quang hai kiem soat", "trinh dung quang ma kiem soat", "trinh dung quang mai kiem toan", "trinh dung quang may kiem soat", "trinh dung quang mang kiem soat", "trinh dung quang mai viet soat"

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: (("ki nang quang van hien so") or ("trinh dung quang mai kiem soat"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("ki nang quang van hien so") OR ("trinh dung quang mai kiem soat")).
• Removing quotes may allow a broader search: (( ki nang quang van hien so ) or ( trinh dung quang mai kiem soat )).
• Adding a wildcard symbol may retrieve word variants: (("ki nang quang van hien so") or ("trinh dung quang mai kiem soat"))*.