首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1492篇
  免费   116篇
  国内免费   6篇
耳鼻咽喉   9篇
儿科学   37篇
妇产科学   41篇
基础医学   150篇
口腔科学   13篇
临床医学   164篇
内科学   401篇
皮肤病学   8篇
神经病学   80篇
特种医学   51篇
外科学   161篇
综合类   45篇
预防医学   102篇
眼科学   207篇
药学   87篇
肿瘤学   58篇
  2023年   8篇
  2021年   14篇
  2020年   9篇
  2019年   18篇
  2018年   14篇
  2017年   19篇
  2016年   23篇
  2015年   20篇
  2014年   36篇
  2013年   53篇
  2012年   74篇
  2011年   72篇
  2010年   38篇
  2009年   28篇
  2008年   78篇
  2007年   79篇
  2006年   80篇
  2005年   65篇
  2004年   67篇
  2003年   62篇
  2002年   55篇
  2001年   48篇
  2000年   56篇
  1999年   48篇
  1998年   12篇
  1997年   11篇
  1996年   19篇
  1995年   12篇
  1994年   19篇
  1993年   11篇
  1992年   43篇
  1991年   46篇
  1990年   35篇
  1989年   28篇
  1988年   46篇
  1987年   30篇
  1986年   17篇
  1985年   24篇
  1984年   19篇
  1983年   14篇
  1982年   12篇
  1981年   12篇
  1980年   8篇
  1979年   11篇
  1978年   10篇
  1977年   11篇
  1974年   13篇
  1973年   11篇
  1972年   10篇
  1971年   8篇
排序方式: 共有1614条查询结果,搜索用时 31 毫秒
31.
32.
33.
34.

Background  

The last decade has seen a number of methodological developments in meta-analysis of diagnostic test studies. However, it is unclear whether such developments have permeated the wider research community and on which applications they are being deployed. The objective was to assess the uptake and deployment of the main methodological developments in the meta-analysis of diagnostic tests, and identify the tests and target disorders most commonly evaluated by meta-analysis.  相似文献   
35.
The evaluation of gastrointestinal function in diabetic patients   总被引:2,自引:0,他引:2  
Nowadays,anumberofoptionsareavailablefortheasesmentofgastricmotorfunction.Thus,aglobalevaluationofgastricmotorfunctionmaybeob...  相似文献   
36.
37.
A cardinal clinical feature of Turner syndrome (TS) is linear growth failure resulting in extreme short stature: the median adult height of untreated women with TS is 143 cm, 20 cm (8 in.) below that of the general female population. In the largest multicenter, randomized, long-term, dose-response study conducted in the United States, 232 subjects with TS received either 0.27 or 0.36 mg/kg.wk of recombinant human GH with either low dose ethinyl E2 or oral placebo. The study was placebo-controlled for both GH and estrogen for the first 18 months and remained placebo-controlled for estrogen for its duration. The near-final height of the 99 subjects whose bone age was at least 14 yr was 148.7 +/- 6.1 cm after 5.5 +/- 1.8 yr of GH started at a mean age of 10.9 +/- 2.3 yr; this represents an average increase of 1.3 +/- 0.6 SD scores from baseline (TS standard). Height was greater than 152.4 cm (60 in.) in 29% of subjects compared with the expected 5% of untreated patients. Mean near-final heights of subjects who received the lower GH dose, with or without estrogen, were 145.1 +/- 5.4 and 149.9 +/- 6.0 cm, respectively; those who received the higher GH dose with or without estrogen achieved mean near-final heights of 149.1 +/- 6.0 and 150.4 +/- 6.0 cm, respectively. Factors that most impacted outcome were younger age, lower bone age/chronological age ratio, lower body weight, and greater height SD score at study entry. This study demonstrates significant GH-induced improvement in height SD score, with correction of height to within the normal channels for a significant number of patients, and provides evidence of a GH dose-response effect. These data also indicate that early administration of estrogen, even at relatively low doses, does not improve gain in near-final height in patients with TS.  相似文献   
38.
The molecular basis of androgen insensitivity was investigated in a family with the complete form of the syndrome. Polymerase chain reaction amplification and Southern blot analysis of genomic DNA revealed a deletion of the entire androgen receptor (AR) gene in affected individuals. The carrier status of female members of this family was examined using a HindIII restriction fragment length polymorphism associated with the AR gene. Obligate carriers were hemizygous for one of the two alleles at this locus, while heterozygosity for the polymorphic alleles, implying the presence of two copies of the AR gene, indicated noncarrier status. This conclusion was supported by gene dosage studies using comparative densitometric analysis of Southern blots hybridized simultaneously with an AR cDNA probe and a control cDNA probe from an unrelated gene. Finally, the pattern of inheritance of another X-linked DNA polymorphism allowed us to conclude that the original mutation had occurred in the germ line of the maternal great-grandfather of the index patient. Although rare, complete deletion of the AR gene is of particular importance in terms of correlation between molecular defect and phenotype, as it represents the quintessential form of complete androgen insensitivity, the null phenotype.  相似文献   
39.

Context

The need for hospice and palliative care is growing rapidly as the population increases and ages and as both hospice and palliative care become more accepted. Hospice and palliative medicine (HPM) is a relatively new physician specialty, currently training 325 new fellows annually. Given the time needed to increase the supply of specialty-trained physicians, it is important to assess future needs to guide planning for future training capacity.

Objectives

We modeled the need for and supply of specialist HPM physicians through the year 2040 to determine whether training capacity should continue growing.

Methods

To create a benchmark for need, we used a population-based approach to look at the current geographic distribution of the HPM physician supply. To model future supply, we calculated the annual change in current supply by adding newly trained physicians and subtracting physicians leaving the labor force.

Results

The current U.S. supply of HPM specialists is 13.35 per 100,000 adults 65 and older. This ratio varies greatly across the country. Using alternate assumptions for future supply and demand, we project that need in 2040 will range from 10,640 to almost 24,000 HPM specialist physicians. Supply will range from 8100 to 19,000.

Conclusion

Current training capacity is insufficient to keep up with population growth and demand for services. HPM fellowships would need to grow from the current 325 graduates annually to between 500 and 600 per year by 2030 to assure sufficient physician workforce for hospice and palliative care services given current service provision patterns.  相似文献   
40.
Endogenous opiates modulate pulsatile luteinizing hormone release in humans   总被引:4,自引:0,他引:4  
To test the postulate that endogenous opioid peptides may be involved in the neuroendocrine mechanisms controlling the frequency and amplitude of LH pulses, saline and an opioid receptor antagonist, naloxone, were infused sequentially, each for 6-h intervals, in six normal cycling women during the luteal phase of the menstrual cycle. During naloxone infusion (1.6 mg/h), there was a significant (P less than 0.01) increase in both the frequency and amplitude of LH pulses compared to those in saline controls. FSH pulses were not discernible in individual subjects; however, a significant increment in FSH levels occurred concomitantly with the increase in LH. These data strongly suggest that endogenous opiates, through an inhibition of hypothalamic LRF, participate in the endocrine events leading to the low frequency of episodic LH secretion characteristic of the luteal phase of the human menstrual cycle.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号