UN databases, like many other databases, vary in capacity. You will find that with some UN databases, you can only find a citation for the document you are looking for and there maybe a link to the full-text of that document, but that is not always the case. The reason for this is that some databases only index documents, meaning they contain records that have the citation and some descriptive information for individual documents, but you need to go to different databases for the full-text.
For example, the UN Digital Library has an index to speeches with links to full-text.