Perhaps you should try some spelling variations:
sach nganh » sach ngan, cac nganh, sach danh
sach tranh » canh tranh
nganh xay » nganh mac, nganh y, nganh ma
huyen van » nguyen van, huyen bao, huyen yen
tranh ky » trinh ky, thanh ky, hanh ky
thuat co » thuat do, thuat o
huyet va » thuyet va, quyet van, thuyet ve
te sach » toc sach

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 tranh ky thuat co hoc ) or ( te sach nganh xay ((huyet va) OR (huyen van)) hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach tranh ky thuat co hoc ) OR ( te sach nganh xay ((huyet va) OR (huyen van)) hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( te sach tranh ky thuat co hoc ) or ( te sach nganh xay ((huyet va) OR (huyen van)) hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( te sach tranh ky thuat co hoc ) or ( te sach nganh xay ((huyet va) OR (huyen van)) hoc ))*.