Perhaps you should try some spelling variations:
"portable life support system" » "portable ai support system" (Expand Search), "portable high support system" (Expand Search), "portable low support system" (Expand Search), "portable line supports system" (Expand Search), "portable oxide support system" (Expand Search), "portable aids support system" (Expand Search)
"portable line support system" » "portable single support system" (Expand Search), "portable ai support system" (Expand Search), "portable high support system" (Expand Search), "portable line supports system" (Expand Search), "portable using support system" (Expand Search), "portable oxide support system" (Expand Search)

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("portable life support system") OR ("portable line support system"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"portable life support system\") OR (\"portable line support system\"))".
• Removing quotes may allow a broader search: (( portable life support system ) OR ( portable line support system )).
• Adding a wildcard symbol may retrieve word variants: (("portable life support system") OR ("portable line support system"))*.