Better Search Api Solr score sorting for strict word match in Drupal
Having just worked with Solr myself (for English) text. You need to assure Solr is Configured to search how you want. Out of the box the Solr configuration provides:


a case insensitive, stemmed search (fuzzy, such as "savage" searches for "savage", "savages", "savaged", etc. and the search ignores punctuation. It also supports short phrase searching such as "find me this text" although Search API in 7.x-1.20 has a bug that removes min_length words from quoted strings:
https://www.drupal.org/node/2832196


This issue is resolved in the current -dev release available on 12/09/2016.

You have 2 options


So, if the default stemmed search works for you as-is OK. If you want exact word searching with no stemming you need to alter the Solr schema to index text content differently than it does out of the box.

For non-stemmed, case sensitive searches change the analysis and query and multi-part logic to not use SnowballPorterStemmer and CaseInsenitive.

This is kinda outlined, but out of date for Solr 5x in this drupal issue.
https://www.drupal.org/node/1319516#comment-5158076
Solr 5x depercated enablePositionIncrements=true so don't do that in the comments, and it will work. 
If you like the searching as-is. You can alternatively boost the exact words to score higher than the inexact results. You would do this by:


adding a fake entity property using an alter hook, and copying the text content from your fields into that field.
You would then define a Solr field in the solr schema to use for this drupal entity property field which doesnt use stemming to returned results
include this fake property field in your drupal search api Index.
use an alter hook for the solr query include this field with a boost (&amp;myfield="FOOBAR"^10) in your search query.



Here's how you add a fake entity property to then be boosted:
http://cornel.co/article/add-entity-property-node-which-can-be-used-search-api-index-field

Then it's simply a query alter in your form (here for apachesolr module, but for search API it's the same thing):
https://www.phase2technology.com/blog/techniques-to-improve-your-solr-search-results/

Isn't Solr fun!!! (sigh) it's really cool, but also cumbersome.