Perhaps you should try some spelling variations:
khong thuoc » khang thuoc, hong phuoc, dong thuoc
nhan khong » nhan thong, nhanh chong, nganh khong
tren nhan » trien nhan, tran nhan, tren phan
sach hoi » sach doi, sach moi, cach thoi
ung tren » dung tren, muong tren, trung tren
thuoc xa » thuoc ma, thuoc va, thuoc la
nhan van » nhan dan, nhan va, phan van
gian dan » gian lang
tu sach » thu sach, su sach, te sach
cuu ung » cuu cong, huu tung, cuu nang

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 trac, nghien cuu ung tren nhan khong thuoc xa hoi va ((nhan van) or (gian dan))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach hoi trac, nghien cuu ung tren nhan khong thuoc xa hoi va ((nhan van) OR (gian dan)).
• Adding a wildcard symbol may retrieve word variants: tu sach hoi trac, nghien cuu ung tren nhan khong thuoc xa hoi va ((nhan van) or (gian dan))*.