Perhaps you should try some spelling variations:
"toc sach y thuat bo khi" » "hoc sach y thuat bo khi", "doc sach y thuat bo khi", "thuoc sach y thuat bo khi", "toc sach y thuat bao khi", "toc sach y thuat do khi", "toc sach y thuat so khi", "toc sach my thuat bo khi", "toc sach kxy thuat bo khi", "toc sach ki thuat bo khi", "toc sach y thuat bo chi", "toc sach y thuat bo thi"
"thu hoach ky thuat o khi" » "thu hoach xay thuat o khi", "thu hanh ky thuat o khi", "thu hoa ky thuat o khi", "thu hoach kmy thuat o khi", "thu hoach kkxy thuat o khi", "thu hoach kki thuat o khi", "thu hoach ky thuat do khi"
"thu hoach ky thuat co khi" » "thu hoach xay thuat co khi", "thu hanh ky thuat co khi", "thu hoa ky thuat co khi", "thu hoach ky thuat do khi", "thu hoach kmy thuat co khi", "thu hoach kkxy thuat co khi", "thu hoach kki thuat co khi"

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (("toc sach y thuat bo khi") OR ((("thu hoach ky thuat o khi") OR ("thu hoach ky thuat co khi"))))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"toc sach y thuat bo khi\") or (((\"thu hoach ky thuat o khi\") OR (\"thu hoach ky thuat co khi\"))))~".
• Removing quotes may allow a broader search: (( toc sach y thuat bo khi ) or ((( thu hoach ky thuat o khi ) OR ( thu hoach ky thuat co khi ))))~.
• Adding a wildcard symbol may retrieve word variants: (("toc sach y thuat bo khi") or ((("thu hoach ky thuat o khi") OR ("thu hoach ky thuat co khi"))))*.