全文获取类型
收费全文 | 2402247篇 |
免费 | 196682篇 |
国内免费 | 4348篇 |
专业分类
耳鼻咽喉 | 34677篇 |
儿科学 | 73393篇 |
妇产科学 | 63427篇 |
基础医学 | 338178篇 |
口腔科学 | 68105篇 |
临床医学 | 218293篇 |
内科学 | 474936篇 |
皮肤病学 | 48278篇 |
神经病学 | 203455篇 |
特种医学 | 97064篇 |
外国民族医学 | 886篇 |
外科学 | 365114篇 |
综合类 | 56374篇 |
现状与发展 | 1篇 |
一般理论 | 992篇 |
预防医学 | 192272篇 |
眼科学 | 55811篇 |
药学 | 179158篇 |
4篇 | |
中国医学 | 4410篇 |
肿瘤学 | 128449篇 |
出版年
2018年 | 25004篇 |
2017年 | 19350篇 |
2016年 | 21171篇 |
2015年 | 23979篇 |
2014年 | 34549篇 |
2013年 | 52267篇 |
2012年 | 70785篇 |
2011年 | 74489篇 |
2010年 | 43767篇 |
2009年 | 42141篇 |
2008年 | 70682篇 |
2007年 | 75097篇 |
2006年 | 75900篇 |
2005年 | 73892篇 |
2004年 | 71041篇 |
2003年 | 68598篇 |
2002年 | 67678篇 |
2001年 | 112666篇 |
2000年 | 116660篇 |
1999年 | 98499篇 |
1998年 | 28173篇 |
1997年 | 25762篇 |
1996年 | 25632篇 |
1995年 | 24777篇 |
1994年 | 23303篇 |
1993年 | 21698篇 |
1992年 | 79467篇 |
1991年 | 76486篇 |
1990年 | 73646篇 |
1989年 | 70905篇 |
1988年 | 65893篇 |
1987年 | 64852篇 |
1986年 | 61381篇 |
1985年 | 58456篇 |
1984年 | 44290篇 |
1983年 | 37726篇 |
1982年 | 22955篇 |
1981年 | 20395篇 |
1979年 | 41328篇 |
1978年 | 29018篇 |
1977年 | 24371篇 |
1976年 | 22848篇 |
1975年 | 23983篇 |
1974年 | 29655篇 |
1973年 | 28055篇 |
1972年 | 26239篇 |
1971年 | 24159篇 |
1970年 | 22762篇 |
1969年 | 21091篇 |
1968年 | 19138篇 |
排序方式: 共有10000条查询结果,搜索用时 15 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.
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
993.
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
994.
R D Alarcon B R Johnson J P Lucas 《Journal of the American Academy of Child and Adolescent Psychiatry》1991,30(6):999-1002
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
995.
D Mari? J Velji? J Ranin B D Jankovi? 《The International journal of neuroscience》1991,59(1-3):135-142
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
996.
997.
998.
D S Rao R Antonelli K R Kane J E Kuhn C Hetnal 《Henry Ford Hospital medical journal》1991,39(1):41-44
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
999.
E J Garland D H Smith 《Journal of the American Academy of Child and Adolescent Psychiatry》1991,30(4):553-555
Concurrent acute onset of night terrors, somnambulism, and spontaneous daytime panic attacks meeting the criteria for panic disorder is reported in a 10-year-old boy with a family history of panic disorder. Both the parasomnias and the panic disorder were fully responsive to therapeutic doses of imipramine. A second case of night terrors and infrequent full symptom panic attacks is noted in another 10-year-old boy whose mother has panic disorder with agoraphobia. The clinical resemblance and reported differences between night terrors and panic attacks are described. The absence of previous reports of this comorbidity is notable. It is hypothesized that night terror disorder and panic disorder involve a similar constitutional vulnerability to dysregulation of brainstem altering systems. 相似文献
1000.
We conducted a randomized, double-blind, crossover trial of two anticholinergic agents--trihexyphenidyl and tridihexethyl chloride (a quaternary anticholinergic that does not cross the blood-brain barrier)--in patients with acquired nystagmus and measured visual acuity and nystagmus before and at the end of 1 month on each medication. Of the 10 patients admitted to the study, only five completed trials of both drugs due to intolerance of medication or intercurrent illness. Of six patients who completed the trial of trihexyphenidyl, only one showed improvement. Of six patients who completed a trial of tridihexethyl chloride, four showed improvement. We conclude that (1) trihexyphenidyl is not a reliable treatment for acquired nystagmus, although occasional patients may benefit; (2) anticholinergic agents may suppress nystagmus by peripheral rather than central mechanisms; and (3) the side effects of anticholinergic agents limit their effectiveness in the treatment of nystagmus. 相似文献