Perhaps you should try some spelling variations:
kki thuat » ki thuat, khoi thuat, ky thuat
sach kki » sach bai, sach kem, sach doi
thuat co » thuat do, thuat o
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
y thuat » ky thuat, my thuat, kxy thuat
bo khi » bo chi
bo thi » bo thit, do thi, bo tai

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