Twenty One

Known as: 21, Twenty-One 
A natural number greater than twenty and less than twenty-two and the quantity that it denotes.
National Institutes of Health

Papers overview

Semantic Scholar uses AI to extract papers important to this topic.
Highly Cited
2007
Highly Cited
2007
Context The expected survival of HIV-infected patients has been difficult to measure by comparing selected HIV samples and… (More)
  • table 1
  • table 2
  • table 3
  • table 4
Is this relevant?
Highly Cited
2004
Highly Cited
2004
BACKGROUND Postoperative chemoradiotherapy is the recommended standard therapy for patients with locally advanced rectal cancer… (More)
  • table 1
  • table 2
  • table 3
  • table 4
  • table 5
Is this relevant?
Highly Cited
1999
Highly Cited
1999
BACKGROUND We studied the incidence, prevalence, and radiographic progression of symptomatic adjacent-segment disease, which we… (More)
  • table I
  • figure 1
  • figure 2
  • figure 3
  • table II
Is this relevant?
Highly Cited
1998
Highly Cited
1998
Three experiments examined the conditions under which infants acquiring English succeed in mapping novel adjectives, applied… (More)
  • table 1
  • table 2
  • figure 1
  • figure 2
  • table 3
Is this relevant?
Highly Cited
1997
Highly Cited
1997
There are two cultivated and twenty-one wild species of genus Oryza. O. sativa, the Asian cultivated rice is grown all over the… (More)
  • table 1
  • figure 1
  • table 2
  • table 2
  • table 3
Is this relevant?
Highly Cited
1996
Highly Cited
1996
We evaluated the results of treatment for ninety-seven patients (106 infections in ninety-eight hips) who had had either an… (More)
Is this relevant?
Highly Cited
1992
Highly Cited
1992
We measured the dimensions of the humeral and glenoid articular surfaces in 140 shoulders that were representative of a given… (More)
Is this relevant?
Highly Cited
1981
Highly Cited
1981
We evaluated 121 patients who had had slipped capital femoral epiphysis (149 involved hips) twenty-one to forty-seven years after… (More)
Is this relevant?
Highly Cited
1966
Highly Cited
1966
1. Spatial summation within cat retinal receptive fields was studied by recording from optic-tract fibres the responses of… (More)
  • figure 1
  • figure 2
  • figure 3
  • figure 4
  • figure 5
Is this relevant?
Highly Cited
1959
Highly Cited
1959
In the central nervous system the visual pathway from retina to striate cortex provides an opportunity to observe and compare… (More)
  • figure 2
  • figure 3
  • figure 5
  • figure 6
  • figure 7
Is this relevant?