The public has a high regard for physicians and for the growing number of nurse practitioners and physicians' assistants. On a scale of A to F, very large majorities of adults who have been to a health care provider within the past year give each an A or a B for both the quality of care and for the medical advice they provide. However, substantially more patients give A's to physicians than to the two other health care professionals.

These are some of the results of The Harris Poll of 2,286 U.S. adults (of whom 1,889 have seen a healthcare professional within the past year) surveyed online between May 14 and 19, 2014. (To see the full results including data tables, click here)

Based on their most recent experiences of being treated by them, most patients give their physicians an A (62%) or a B (29%) for the quality of care they received. Only a few patients give them a C (8%), a D (1%) or an F (Less than 1%). These numbers are almost the same as they were in 2012.

Most patients who have been seen by physicians' assistants give them an A (52%) or a B (35%) for the quality of care, and most patients also give the nurse practitioners who treated them an A (55%) or a B (31%). Hardly anyone gives either of these professions a D or an F (1%).

This Harris Poll also asked the public how much trust they have in the health care advice from a number of different sources.

While a large majority of Americans (70%) have a great deal of trust in the advice given to them by physicians, far fewer have a great deal of trust in the advice given to them by nurse practitioners (34%) or physicians' assistants (32%). Most people say that they have "some" trust in the advice from these two professions.

Among those who have been treated by them, the level of trust in nurse practitioners (51%, a great deal of trust) and in physicians' assistants (43%, a great deal of trust) is somewhat higher but still significantly less than for physicians.

The poll also asked about some other sources of health care advice. It found that fewer Americans have a great deal of trust in the advice of pharmacists (28%) and online health care sources (11%) and even less in the advice of medical media (7%) and general news media (3%).