Perhaps you should try some spelling variations:
"bo sach ky thuat quoc khi" » "bo sach ky thuat nuoi khi", "bo sach ky thuat quan khi", "bo sach ky chuan quoc khi", "bo sach ky thuat buoc khoi", "bo sach ky thuat quoc thai", "bo sach ky thuat cuoc khoi", "co sach ky thuat quoc khi", "hoc sach ky thuat quoc khi", "bo sac ky thuat quoc khi", "bo sach ty thuat quoc khi", "bo sach kem thuat quoc khi", "bo sach kmy thuat quoc khi", "bo sach kkxy thuat quoc khi", "bo sach kki thuat quoc khi"
"so cac ky thuat tong khoi" » "so cac ky thuat trong khoi", "so cac ky thuat song khoi", "so cac ky thuat cong khoi", "so cac ky thuat xong khoi", "so cac ky thuat tuong khoa", "so cac ky thuat thong khoa", "so cac kmy thuat tong khoi", "so cac kkxy thuat tong khoi", "so cac kki thuat tong khoi", "sao cac ky thuat tong khoi", "so cap ky thuat tong khoi", "o cac ky thuat tong khoi"
"te sach y thuat do thi" » "te sach y thuat o thi", "toc sach y thuat do thi", "te sach my thuat do thi", "te sach kxy thuat do thi", "te sach ki thuat do thi"

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

• Performing a fuzzy search may retrieve terms with similar spellings: (((("bo sach ky thuat quoc khi") or ("so cac ky thuat tong khoi"))) or ("te sach y thuat do thi"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("bo sach ky thuat quoc khi") OR ("so cac ky thuat tong khoi"))) OR ("te sach y thuat do thi")).
• Removing quotes may allow a broader search: (((( bo sach ky thuat quoc khi ) or ( so cac ky thuat tong khoi ))) or ( te sach y thuat do thi )).
• Adding a wildcard symbol may retrieve word variants: (((("bo sach ky thuat quoc khi") or ("so cac ky thuat tong khoi"))) or ("te sach y thuat do thi"))*.