Perhaps you should try some spelling variations:
phan thong » phan thuong, phan hong, phan tong
thuat mach » thuat sach, thuat tach, thuyet mach
mach khoa » bach khoa, anh khoa, may khoa
pho thong » he thong
thuc bach » truc bach, thuc cach, thuoc sach
so thuat » hoc thuat, ky thuat, ki thuat
khoa pho » khoa phu, khoa khoa, khoa phau
sach tri » sach tai, sach tren, sach truc
tri thuc » tri tue
bach hoa » bach khoa, bach ha, cach hoan
hoa phan » hoa dan, co phan
co dinh » do dinh
su sach » so sach, vu sach

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( co dinh so thuat mach khoa pho thong ) or ( su sach tri thuc bach hoa phan thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( co dinh so thuat mach khoa pho thong ) OR ( su sach tri thuc bach hoa phan thong )).
• Adding a wildcard symbol may retrieve word variants: (( co dinh so thuat mach khoa pho thong ) or ( su sach tri thuc bach hoa phan thong ))*.