title: Count Frequency of Words in Text and create Plot
body: <p>I have a list of data frame with 40802 gene names and I have data frame with 14000 article information. The article information contains Article, Abstract, Day, Month, Year.</p>
  
  <p>I have transformed the date into normal format, and the abstract as character.</p>
  
  <p>I want to have a plot of X in time, and the frequency of the gene names appears in the abstract.
  EG</p>
  
  <pre><code>| Date       | Gene Name | Frequency |
  |------------|-----------|-----------|
  | 2017-03-20 | GAPDH     | 5         |
  | 2017-03-21 | AKT       | 6         |
  </code></pre>
  
  <p>Basically, I want to know the gene names most frequently published in the last 100 days and have a timeline to see the evolution of said genenames. Something like a trend.</p>
  
  <pre><code>library(RISmed)
  
  ##Research the query - can be anything relevant to protein expression.
  ##Multiple research not tested yet
  
  search_topic &lt;- 'protein expression'
  
  ##Evaluate the query with reldate = days before today, retmax = maximun number of returned results
  
  search_query &lt;- EUtilsSummary(search_topic, retmax=15000, reldate = 100)
  ##explore the outcome
  
  summary(search_query)
  
  ##get the ids for tall the queries to get the articles
  
  QueryId(search_query)
  ##get all the records associated with the ID - THIS TAKES LOOONG TIME
  
  records&lt;- EUtilsGet(search_query)
  
  ##Analyze the structure
  str(records)
  
  summary(records)
  
  ##Create a data frame with article/abstract/date
  
  pubmed_data &lt;- data.frame('Title'=ArticleTitle(records),'Abstract'=AbstractText(records),
                               "Day"=DayPubmed(records), "Month" = MonthPubmed(records), "Year"=YearPubmed(records))
  ##explore the data
  head(pubmed_data,1)
  ##gene names
  genename &lt;- read.csv("genename.csv", header = T, stringsAsFactors = F)
  
  ##remove any NA tittles
  
  pubmed &lt;-pubmed_data[-which(is.na(pubmed_data$Title)), ]
  ##Coerce the date to YYYY-MM-DD
  
  pubmed$Date &lt;- as.Date( paste( pubmed$Day , pubmed$Month , sep = "." )  , format = "%d.%m" )
  </code></pre>
  
  <p>I've read a lot and cannot figure out how to find genemane[1,1] inside <code>pubmed$Abstract</code>, 
   and count the times it appeared by time.
  Making a plot where X is the last 100 days and the line prot would be the frequency of the genenames, 
  And the legend would be the genename. So a trend can be observed.</p>
  
  <p>I would really appreciate any ideas how this can be done.</p>
  
  <p>I have tried <code>tm</code>, and have tried a lot of different things, but still hitting a wall. Is my concept wrong?</p>