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   2392907篇
  免费   186989篇
  国内免费   9814篇
耳鼻咽喉   30647篇
儿科学   78198篇
妇产科学   65443篇
基础医学   339515篇
口腔科学   65911篇
临床医学   225366篇
内科学   474484篇
皮肤病学   52821篇
神经病学   198528篇
特种医学   92312篇
外国民族医学   622篇
外科学   352324篇
综合类   55409篇
现状与发展   3篇
一般理论   838篇
预防医学   200635篇
眼科学   51871篇
药学   172204篇
  11篇
中国医学   4950篇
肿瘤学   127618篇
  2018年   26448篇
  2017年   20384篇
  2016年   23292篇
  2015年   26359篇
  2014年   36595篇
  2013年   55990篇
  2012年   72214篇
  2011年   77255篇
  2010年   46553篇
  2009年   44270篇
  2008年   71243篇
  2007年   75557篇
  2006年   76846篇
  2005年   74261篇
  2004年   70799篇
  2003年   68140篇
  2002年   65351篇
  2001年   109608篇
  2000年   112700篇
  1999年   94591篇
  1998年   28205篇
  1997年   25352篇
  1996年   25946篇
  1995年   25545篇
  1994年   23927篇
  1993年   22426篇
  1992年   77369篇
  1991年   75530篇
  1990年   72885篇
  1989年   69259篇
  1988年   64373篇
  1987年   63093篇
  1986年   59934篇
  1985年   57609篇
  1984年   43897篇
  1983年   37020篇
  1982年   22912篇
  1981年   20462篇
  1980年   19157篇
  1979年   39709篇
  1978年   28768篇
  1977年   23897篇
  1976年   22736篇
  1975年   23472篇
  1974年   28123篇
  1973年   27179篇
  1972年   25117篇
  1971年   23275篇
  1970年   21393篇
  1969年   19808篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
We examined several possible causes for the high incidence of poor sensory acuity in the limbs of 176 patients with moderate to severe peripheral vascular insufficiency. We investigated the relationships of diabetes, alcoholism, and smoking, as well as the severity of peripheral vascular disease, to the integrity of basic sensory modalities such as two-point discrimination and perception of light touch. The presence or absence of diabetes exerted the strongest effect on peripheral sensation. In patients who did not have diabetes, sensation in the limbs was most strongly affected by whether the patient was an alcoholic. Smoking did not have a significant effect on limb sensation. Among nondiabetic, nonalcoholic patients, there was a weak residual effect related to the severity of the peripheral vascular insufficiency. Even among these patients, however, systemic factors predominated in determining the loss of sensation. We also examined the extent to which loss of sensation might be related to the development of ulcers. Among patients who were not diabetic, there was a highly significant relationship between loss of sensation and the presence of limb ulceration. Surprisingly, however, there was no discernable relationship between the presence of ulcers in diabetic patients and the degree of loss of peripheral sensation. This result suggests that a large percentage of ulcers seen in diabetic patients are not of neurogenic origin.  相似文献   
992.
Work therapy and return to work   总被引:2,自引:0,他引:2  
In summary, data were selected for 1 year on patients treated in the Work Tolerance Program at the Hand Rehabilitation Center in Philadelphia. The type of information obtained has been used to obtain a profile of the patient population in the Work Tolerance Program. Statistical analysis was used, not only to formulate patient demographics, but also to evaluate the length of treatment of patients in the Work Tolerance Program. This period averaged 6 weeks. The statistical analysis also revealed there was significant interaction between the type of injury and the patient's diagnosis, and the rate of return to work. The patients with injuries to bone and nerve required longer periods of treatment until they returned to work than did patients with injuries to soft tissue or combination injuries. Our statistical analysis revealed that in 1982, 75 per cent of the patients in the Work Tolerance Program returned to work to regular or modified jobs. The length of time from injury to return to work was 63 per cent longer for patients with Workers' Compensation coverage than for patients with private insurance coverage. Because the statistical analysis that 60 per cent of the patients treated in the Work Tolerance Program were Workers' Compensation insured, and 80 per cent of the patients treated in the Work Tolerance Program were secondarily referred, it should be recognized that all patients with severe hand injuries would benefit from an immediate referral to a Hand Rehabilitation Center of excellence to facilitate their therapeutic management and expedite their recovery from time of injury to return to work. This study was restricted to the analysis of length of treatment and rate of return to work. Future studies should study the effect of early referral and the application of specific treatments.  相似文献   
993.
994.
995.
Survey involved 84 workers matched for age, socio-occupational and families status and divided into 3 groups : A : 27 shift workers on 3 days rotating shift, B : 47 shift workers on 5 days rotating shift, C : 20 days workers. Each subject was submitted to dietary survey by means of 24 hours recall, realised 3 times for shift workers and once for control. All workers were interviewed about caloric intake of the preceding day off caloric intake. Annual weight gain was studied through the use of occupational health service records. There was no significant difference between the 3 groups for working day caloric intake. Day-off intake was lower (p less than 0.05) in group A (day-off any day of the week). Annual weight gain was not different between the 3 groups. Shift workers with faster weight gain had a higher caloric intake on day-off and after evening meal.  相似文献   
996.
997.
998.
999.
Leuko-araiosis.   总被引:1,自引:0,他引:1  
Leuko-araiosis is an unspecific radiologic sign, seen with CT scan or with MRI. It can be found as well in normal elderly persons as in pathological conditions. For the sake of clarity, CT scan and MRI images have to be distinguished. CT leuko-araiosis is linked with vascular risk factors and with age. The situation is more complex for MRI leuko-araiosis (likely on account of the higher sensitivity of MRI). Some images (caps and rims), frequently seen in normal, even young, individuals, are more frequent in aging. On the contrary, abnormal images at a distance from the ventricle are more difficult to interpret. Some of them are due to pathological well defined conditions (small infarcts, Binswanger's disease, cysts, plaques). Others may be secondary to remote pathologies (such as infarcts). Others are due to little specific conditions, such as perivascular dilatations ('état criblé' due to brain vasogenic edema, or to brain atrophy whatever its cause, and more frequently seen in the elderly). Other changes, such as incomplete infarction or myelin pallor with gliosis, have been described. At last, in some cases, no clearcut pathological lesion could be found. Leuko-araiosis may be present in primary degenerative dementia of the Alzheimer type, but it is neither necessary nor sufficient to establish the diagnosis of Alzheimer's disease, and it does not seem more frequent than in elderly controls. The mechanism of leuko-araiosis in Alzheimer's disease is likely multifactorial (for example, cerebral atrophy, amyloid angiopathy, associated hypertensive arteriolosclerosis could be involved). The relationship between leuko-araiosis, myelin pallor and white matter atrophy is poorly understood, and remains to be studied.  相似文献   
1000.
Others have reported that spinal cord transection non-uniformly affects the activities of the cardiac, renal and splenic nerves. We were unable to confirm this finding while recording the wide band (1-1000 Hz) discharges of these sympathetic nerves in baroreceptor-denervated, chloralose-anesthetized cats. Most of the power in nerve discharges was below 6 Hz. There was high coherence between the low frequency discharges of different nerves, and power below 15 Hz was essentially eliminated by spinal transection. Evidence is presented that the disparities between this and past studies are, in part, due to the use of a 30-Hz high-pass filter in the earlier studies.  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