Perhaps you should try some spelling variations:
transport systems » transport system
land transfers » funds transfers, cash transfers, land transport
gplpls models » gplpls model, lppls models, llepls models
models land » model land, modeling land, models latent
low road » slow road, new road, low food
vagues » vague, vogues

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (( vagues low road transport systems across ) OR ( gplpls models land transfers _ cao ))~.
• Adding a wildcard symbol may retrieve word variants: (( vagues low road transport systems across ) or ( gplpls models land transfers _ cao ))*.