Perhaps you should try some spelling variations:
kxy thuat » ky thuat, my thuat
ki thuat » ky thuat
tu sach » thu sach, su sach, te sach
sach ki » sach kinh, sach bai, sach kem
vu sach » vu bach, su sach, vu khach
ky thua » ky thuat, ky thu, my thuat
bo khi » co khi, bo chi
bo thi » bo thit, do thi, bo tai
o khi » co khi

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 ki thuat ((bo khi) or (bo thi)) ) or ( vu sach ((kxy thuat) OR (ky thua)) o khi ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach ki thuat ((bo khi) OR (bo thi)) ) OR ( vu sach ((kxy thuat) OR (ky thua)) o khi )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu sach ki thuat ((bo khi) or (bo thi)) ) or ( vu sach ((kxy thuat) OR (ky thua)) o khi ))".
• Adding a wildcard symbol may retrieve word variants: (( tu sach ki thuat ((bo khi) or (bo thi)) ) or ( vu sach ((kxy thuat) OR (ky thua)) o khi ))*.