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   2409766篇
  免费   197179篇
  国内免费   4327篇
耳鼻咽喉   34752篇
儿科学   73794篇
妇产科学   63598篇
基础医学   339083篇
口腔科学   68159篇
临床医学   219197篇
内科学   475662篇
皮肤病学   48592篇
神经病学   204183篇
特种医学   97295篇
外国民族医学   887篇
外科学   366361篇
综合类   56563篇
现状与发展   1篇
一般理论   1017篇
预防医学   193052篇
眼科学   56087篇
药学   179662篇
  4篇
中国医学   4405篇
肿瘤学   128918篇
  2018年   25071篇
  2017年   19410篇
  2016年   21256篇
  2015年   24081篇
  2014年   34771篇
  2013年   52434篇
  2012年   71312篇
  2011年   74930篇
  2010年   44023篇
  2009年   42181篇
  2008年   71174篇
  2007年   75628篇
  2006年   76522篇
  2005年   74509篇
  2004年   71730篇
  2003年   69215篇
  2002年   68379篇
  2001年   112735篇
  2000年   116721篇
  1999年   98612篇
  1998年   28267篇
  1997年   25848篇
  1996年   25684篇
  1995年   24860篇
  1994年   23397篇
  1993年   21751篇
  1992年   79552篇
  1991年   76539篇
  1990年   73699篇
  1989年   70961篇
  1988年   65983篇
  1987年   64916篇
  1986年   61451篇
  1985年   58513篇
  1984年   44353篇
  1983年   37794篇
  1982年   23058篇
  1981年   20469篇
  1980年   19145篇
  1979年   41371篇
  1978年   29049篇
  1977年   24401篇
  1976年   22868篇
  1975年   23991篇
  1974年   29677篇
  1973年   28060篇
  1972年   26242篇
  1971年   24163篇
  1970年   22757篇
  1969年   21096篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
992.
Arthroscopy in the treatment of young patients with anterior knee pain   总被引:1,自引:0,他引:1  
Arthroscopy plays an important role in diagnosis in the management of anterior knee pain and may be used for treating the underlying pathology.  相似文献   
993.
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   
994.
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   
995.
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   
996.
Obsessive-compulsive disorder is increasingly recognized in patients of different age groups. Serotonergic agents, such as clomipramine, have been recently found to be useful in the management of this condition. However, unexpected side effects, such as dysphoria, aggressiveness, and paranoid ideation, may occur with therapeutic doses of this compound, as evidenced in the cases of two male adolescents presented here. Possible pathogenetic factors, involving serotonin and serotonin-receptor abnormalities are discussed. Management of these side effects is based on adequate dose reduction and monitorization.  相似文献   
997.
There is a large body of evidence for the role of thymosin peptides in immunogenesis and immunity. In this paper we report on the influence of prothymosin alpha 1 (ProT-alpha 1), a hormone-like peptide derived from the calf thymus, on humoral and cellular immune reactions in the rat. Young adults received intraperitoneal injections of ProT-alpha 1 in the periods before and after immunization with cellular and soluble antigens. ProT-alpha-treatment produced a dose-dependent increase of both humoral and cell-mediated immune responses. The thymus weight increased but not that of spleen. Treatment of nonimmunized rats with this polypeptide significantly elevated the number of CD4+ and decreased the number of CD8+ cells in the peripheral blood. The results suggest a potent immunostimulatory activity of ProT-alpha 1 and imply direct action of this polypeptide on T lymphocytes.  相似文献   
998.
999.
1000.
Coexistent primary hyperparathyroidism and monoclonal gammopathy, although rare, has been reported previously by a number of investigators. We report four patients with such an occurrence who were seen between 1976 and 1988. Another patient with primary hyperparathyroidism also had multiple myeloma and was in remission for 12 years. These patients represent approximately 1% of the 386 patients with primary hyperparathyroidism seen during the same 12-year period. Although several mechanisms have been proposed to explain this concurrence, we believe it is the result of a chance occurrence. A review of the literature, an estimate of the chance occurrence of coincidental monoclonal gammopathy, benign or malignant, in patients with primary hyperparathyroidism, and some practical implications of this interesting coexistence are presented.  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