Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
khau sach » hau sach, khoa sach, pham sach
thu sach » thuoc sach, thu hoach, theo sach
thuat do » thuat o
tu sach » te sach, tu cach, vu sach
su sach » so sach, vu sach
do khi » doi khi, do thi, 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) OR (su sach))) or (((((thu sach) or (khau sach))) or (thuat sach)))) ky thuat do khi~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((tu sach) OR (su sach))) OR (((((thu sach) OR (khau sach))) OR (thuat sach)))) ky thuat do khi.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((tu sach) OR (su sach))) or (((((thu sach) or (khau sach))) or (thuat sach)))) ky thuat do khi".
• Adding a wildcard symbol may retrieve word variants: ((((tu sach) OR (su sach))) or (((((thu sach) or (khau sach))) or (thuat sach)))) ky thuat do khi*.