Perhaps you should try some spelling variations:
khoang nguoi » khong nguoi, thong nguoi, thang nguoi
nguoi thong » nguoi muong, nguoi thanh, nguoi cong
trong thuoc » trong thuc, trung thuoc, trong thuong
dai khoang » da khoang, dai khong, tao khoang
sach trong » sac trong, sach rong, sanh trong
thuoc sach » hoc sach, nuoc sach, thuat sach
thuat dai » thuat bai, thuat dam, thuat cai
sach khoa » bach khoa, sach nha, anh khoa
pho thong » he thong
ki thuat » ky thuat
khoa pho » khoa phu, khoa khoa, khoa phau
su sach » so sach, vu sach
sach ki » sach kinh, sach bai, sach kem
tu sach » thu sach, te sach, tu cach

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( su sach ki thuat dai khoang nguoi thong ) or ( tu sach trong thuoc sach khoa pho thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( su sach ki thuat dai khoang nguoi thong ) OR ( tu sach trong thuoc sach khoa pho thong )).
• Adding a wildcard symbol may retrieve word variants: (( su sach ki thuat dai khoang nguoi thong ) or ( tu sach trong thuoc sach khoa pho thong ))*.