Perhaps you should try some spelling variations:
state regulation » voltage regulation (Expand Search), gene regulation (Expand Search), self regulation (Expand Search)
"china–hole state relations OR " » "china–hole states relations OR " (Expand Search), "china–hole strain relations OR " (Expand Search), "china–hole strait relations OR " (Expand Search), "china–hole ststem relations OR " (Expand Search), "china–how state relations OR " (Expand Search), "china–idle state relations OR " (Expand Search)
water relations » states relations (Expand Search), power relations (Expand Search), order relations (Expand Search)

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"china–hole state relations) OR (\"china–hole ((state regulation) OR (water relations))))~".
• Removing quotes may allow a broader search: (( china–hole state relations) OR ( china–hole ((state regulation) OR (water relations))))~.
• Adding a wildcard symbol may retrieve word variants: (("china–hole state relations) OR ("china–hole ((state regulation) OR (water relations))))*.