So if you just want to search for all paper that is in HINARI. I would just use example #7 if you want to get everything possible for you. Read examples.

HINARI is treated as a linkout provider as described: http://www.ncbi.nlm.nih.gov/entrez/journals/active_providers.html

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&itool=toolbar

So in PubMed search bar, type:

Example #1:
HIV AND loprovhinari[Filter]

Note, that the term "HIV" is unqualified here so it could refer to a MeSH (highest precedence) or a simple text word. Click on "Details" tab for more information on how the translation file does automatic term mapping.
36919 articles

Example #2:
HIV [Mesh] AND loprovhinari[Filter]

19381 articles

Example #3:
"HIV" [Mesh] AND loprovhinari[Filter]

Note, in example #3, by using the double quotes specifically refer to HIV only, Click on "Details" tab for more information.
14002 articles.

In all the above cases,

loprovhinari[Filter] filters for a specific linkout provider in this case hinari

Here some more useful tips:

So in PubMed, type:

Example #4:

HIV AND free full text[sb]

This should give you all HIV papers (you should click on the "Details" tab to see how "HIV" is translated) whose citations include a link to a free full text article. Often this includes links to the PubMed Central database.
16535 articles.

Example #5:

HIV AND loall[sb]

Citations with LinkOut links in PubMed.
177941 articles.

Example #6:

HIV AND full text[sb]

Citations that include a link to a full text article.
82317 articles. This means both free and paid subscription journals.

Example #7:

HIV AND (free full text[sb] OR loprovhinari[Filter])

47151 articles

So really all the articles that you have access to in Vietnam if you are a HINARI users are:

- all the journals listed as free for HINARI users (assume this means that all articles within that journal is avaiable to HINARI users which may not always be the case)

- All articles aleady marked free full text

- note, there is an overlap in the two sets, so articles in HINARI are considered as free full text, otherwise you would expect 53454 articles.

So, example #7 is a much better choice and more complete. Note the use of the parentheses.