Perhaps you should try some spelling variations:
yanling wheat » managing wheat, planting wheat
grains yang » grains dans
wang wang » wang yang, wang liang, wang yan
shang hai » shang kai, dang hai, chang ha
zhang zhi » zhong zhi, wang zhi, zhang wei
yang jin » yang jie, yang jun, ying jin

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

• Performing a fuzzy search may retrieve terms with similar spellings: wang wang yanling wheat grains yang jin ((shang hai) or (zhang zhi)) ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: wang wang yanling wheat grains yang jin ((shang hai) OR (zhang zhi)) ;.
• Adding a wildcard symbol may retrieve word variants: wang wang yanling wheat grains yang jin ((shang hai) or (zhang zhi)) ;*.