Perhaps you should try some spelling variations:
electronic documents » electronic document, electronic instruments, electronic components
quasar based » pulsar based, laser based, sugar based
documents 1 » documents 12, documents _, documents a
qsar based » sar based, car based, var based
ar based » nmr based
1 curtan » _ curtain, _ cartan, _ curtin

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((((qsar based) OR (quasar based))) or (ar based)) electronic documents 1 curtan-metragem~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((qsar based) OR (quasar based))) OR (ar based)) electronic documents 1 curtan-metragem.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((qsar based) OR (quasar based))) or (ar based)) electronic documents 1 curtan-metragem".
• Adding a wildcard symbol may retrieve word variants: ((((qsar based) OR (quasar based))) or (ar based)) electronic documents 1 curtan-metragem*.