extensive knowledge vs significant knowledge

Some examples from the web:

• All staff is multi-lingual and has extensive knowledge of Russia.
• Barry Brenner has extensive knowledge and experience selling car insurance.
• He owes his reputation not only to his extensive knowledge of ancient inscriptions, but also to his classical Latinity.
• Working in war zones across the globe has given the ICRC extensive knowledge of medical care for the victims.
• Designing a ramp like that requires extensive knowledge of physics, geometry...
• However, EZTrader forex does not require an extensive knowledge.
• Right. Must have been my extensive knowledge of Disneyland Tokyo.
• She has an extensive knowledge of global arms trafficking networks and all the players involved.
• I put my extensive knowledge of privilege fully at your disposal.
• In addition, many immigrants from Europe brought an extensive knowledge of cheese making.
• Ral possesses an extensive knowledge regarding all types of plants and seeds.
• The descriptive passages are made more credible by Obruchev's extensive knowledge of paleontology.
• The profession of sommelier brings extensive knowledge of wine and a sound education in the hospitality industry.
• Our local experts in Central Florida have extensive knowledge on bass fishing in this destination.
• Our sales team maintains an extensive knowledge of healthcare field, including products and effect.
• A diploma in primary vocational education at the mining and metallurgical school suggested extensive knowledge of the mining industry.
• Our local experts have extensive knowledge in how to catch these species.
• He carries with him extensive knowledge of running schools in Malaysia and Singapore.
• And I wowed her with my extensive knowledge of the legal system.
• With his extensive knowledge of cartography, Su Song was able to settle a heated border dispute between the Song and Liao dynasties.

Some examples from the web:

• Citation: Margaret Franken , (2013) "Significant knowledge transitions and resituation challenges in becoming a researcher: International scholarship students' ...
• Significant Knowledge Gaps About Melanoma Skin Cancer. The Centers for Disease Control and Prevention (CDC) reported today that Americans have a low  ...
• Significant Knowledge Extraction from Association Rules. Cristina Davino. 1. , Dario Bruzzese. 2. 1. Dipartimento di Studi sullo Sviluppo Economico, University  ...
• Birmingham Policy Commission (published online): February 2014. 1. Cultural differences in ageing in the UK - A significant knowledge gap. Author: Sarah- Jane ...