Perhaps you should try some spelling variations:
"su sach phat khoa than đong luc" » "su sach nha khoa than đong luc", "su sach tham khoa than đong luc", "su cach pha khoa than đong luc", "su sach pham khoa than đong luc", "su sach phap khoa than đong luc", "su sach khat khoa than đong luc", "su sach phat khoa luan đong luc", "su sach phat hoa thai đong luc", "su sach phat hoa tan đong luc", "so sach phat khoa than đong luc", "vu sach phat khoa than đong luc"
"su van nganh co khi đong luc" » "su van ngan co khi đong luc", "su va nganh co khi đong luc", "su vien nganh co khi đong luc", "su van nganh cong khi đong luc", "su van nganh hoa khi đong luc", "su van nganh y khi đong luc", "tu van nganh co khi đong luc", "vu van nganh co khi đong luc"

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: (("su sach phat khoa than đong luc") or ("su van nganh co khi đong luc"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("su sach phat khoa than đong luc") OR ("su van nganh co khi đong luc")).
• Removing quotes may allow a broader search: (( su sach phat khoa than đong luc ) or ( su van nganh co khi đong luc )).
• Adding a wildcard symbol may retrieve word variants: (("su sach phat khoa than đong luc") or ("su van nganh co khi đong luc"))*.