Perhaps you should try some spelling variations:
cong thuoc » dong thuoc, long thuoc, cong thuong
hoc nhanh » hoc nganh, hoc phan
cong thuc » cong tac
sach hoi » sach doi, sach moi, cach thoi
van pham » san pham, van phan, van phat
tu sach » thu sach, su sach, te sach
hoi tai » hoc tai, hoi trac
cuu hoa » cuu khoa, cuu hoan, cau hoa
hoi van » hoi va, hoi dan, hai van
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach hoi tai, nghien cuu hoa hoc nhanh ((cong thuoc) or (cong thuc)) ma hoi van pham van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach hoi tai, nghien cuu hoa hoc nhanh ((cong thuoc) OR (cong thuc)) ma hoi van pham van.
• Adding a wildcard symbol may retrieve word variants: tu sach hoi tai, nghien cuu hoa hoc nhanh ((cong thuoc) or (cong thuc)) ma hoi van pham van*.