Perhaps you should try some spelling variations:
sach nganh » sach ngan, cac nganh, sach danh
sach tranh » canh tranh
thuat quoc » thuat nuoi, thuat quan, chuan quoc
thuat so » thuat do, thuat o, thuat co
sach van » sach han, sach va, bach van
quoc hoc » quoc hoi, duoc hoc, buoc hoc
su sach » so sach, vu sach
so hoc » co hoc, mo hoc, so hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( te ((sach nganh) or (sach tranh)) ky thuat so hoc ) or ( su sach van ky thuat quoc hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te ((sach nganh) OR (sach tranh)) ky thuat so hoc ) OR ( su sach van ky thuat quoc hoc )).
• Adding a wildcard symbol may retrieve word variants: (( te ((sach nganh) or (sach tranh)) ky thuat so hoc ) or ( su sach van ky thuat quoc hoc ))*.