Perhaps you should try some spelling variations:
phan nghien » phap nghien
thuat sach » thuat lanh, thuat san
thi nghiem » thuc nghiem
sach thi » sach thu, sach tai, sach thieu
nghiem d » nghiem de, nghiem do, nghiem _
su sach » so sach, vu sach
van hoc » van hoa
d hoc » du hoc, ad hoc, de hoc
luan » quan, lan

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( thuat sach thi nghiem d hoc ) or ( su sach ((phan nghien) OR (luan nghien)) van hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( thuat sach thi nghiem d hoc ) OR ( su sach ((phan nghien) OR (luan nghien)) van hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( thuat sach thi nghiem d hoc ) or ( su sach ((phan nghien) OR (luan nghien)) van hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( thuat sach thi nghiem d hoc ) or ( su sach ((phan nghien) OR (luan nghien)) van hoc ))*.