Perhaps you should try some spelling variations:
nghien cac » nghiep cach, nghien cuu, nghiep cay
chuc nganh » chuc nang, hoc nganh, cac nganh
cong chuc » cong thuc, cong cu, cong cua
nganh hoa » thanh hoa, khanh hoa, danh hoa
sach hoc » cach hoc, sach hoi, mach hoc
cac cong » cua cong
nhan tao » nhan tai, nhan dan
tu sach » thu sach, su sach, te sach
hoi van » hoi va, hoi dan, hai van
nhan va » nhan tai, nhan dan, phan 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 hoc tap, nghien cac cong chuc nganh hoa hoc ma hoi van ((nhan va) or (nhan tao))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach hoc tap, nghien cac cong chuc nganh hoa hoc ma hoi van ((nhan va) OR (nhan tao)).
• Adding a wildcard symbol may retrieve word variants: tu sach hoc tap, nghien cac cong chuc nganh hoa hoc ma hoi van ((nhan va) or (nhan tao))*.