Perhaps you should try some spelling variations:
khong thuoc » khang thuoc, hong phuoc, dong thuoc
nghien thu » nghiem thuc, nghiep thuc, nghien cuu
nhan khong » nhan thong, nhanh chong, nganh khong
toc sach » hoc sach, doc sach, thuoc sach
cong hoa » dong hoa, dong hoc, hang hoa
hoa nhan » hoa phan, hoa han, hoa nhap
thuoc xa » thuoc ma, thuoc va, thuoc la
nhan van » nhan dan, nhan va, phan van
tu sach » thu sach, su sach, te sach
va nhan » van nhan, ca nhan, va phan

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) or (tu sach)) hoc tap, nghien thu cong hoa nhan khong thuoc xa hoi va nhan van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (tu sach)) hoc tap, nghien thu cong hoa nhan khong thuoc xa hoi va nhan van.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (tu sach)) hoc tap, nghien thu cong hoa nhan khong thuoc xa hoi va nhan van*.