全文获取类型
收费全文 | 862065篇 |
免费 | 70589篇 |
国内免费 | 1839篇 |
专业分类
耳鼻咽喉 | 12799篇 |
儿科学 | 24635篇 |
妇产科学 | 25099篇 |
基础医学 | 124215篇 |
口腔科学 | 25484篇 |
临床医学 | 75307篇 |
内科学 | 164553篇 |
皮肤病学 | 16974篇 |
神经病学 | 70070篇 |
特种医学 | 35190篇 |
外国民族医学 | 171篇 |
外科学 | 136145篇 |
综合类 | 24604篇 |
现状与发展 | 2篇 |
一般理论 | 263篇 |
预防医学 | 66873篇 |
眼科学 | 20517篇 |
药学 | 64685篇 |
中国医学 | 1594篇 |
肿瘤学 | 45313篇 |
出版年
2018年 | 7346篇 |
2015年 | 7723篇 |
2014年 | 11109篇 |
2013年 | 16782篇 |
2012年 | 22718篇 |
2011年 | 23833篇 |
2010年 | 13866篇 |
2009年 | 13062篇 |
2008年 | 22572篇 |
2007年 | 24617篇 |
2006年 | 24487篇 |
2005年 | 24140篇 |
2004年 | 23704篇 |
2003年 | 22832篇 |
2002年 | 21924篇 |
2001年 | 35822篇 |
2000年 | 36464篇 |
1999年 | 30896篇 |
1998年 | 9221篇 |
1997年 | 8548篇 |
1996年 | 8475篇 |
1995年 | 8006篇 |
1994年 | 7723篇 |
1992年 | 26658篇 |
1991年 | 26098篇 |
1990年 | 25617篇 |
1989年 | 24677篇 |
1988年 | 23219篇 |
1987年 | 22883篇 |
1986年 | 21740篇 |
1985年 | 21097篇 |
1984年 | 16385篇 |
1983年 | 13996篇 |
1982年 | 8854篇 |
1981年 | 8201篇 |
1980年 | 7671篇 |
1979年 | 16736篇 |
1978年 | 12114篇 |
1977年 | 10181篇 |
1976年 | 9328篇 |
1975年 | 10147篇 |
1974年 | 12641篇 |
1973年 | 12136篇 |
1972年 | 11538篇 |
1971年 | 10685篇 |
1970年 | 10218篇 |
1969年 | 9909篇 |
1968年 | 8900篇 |
1967年 | 8230篇 |
1966年 | 7653篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
111.
The efficacy of radiology in evaluating dysphagia was studied in 86 patients by comparison to endoscopic findings. In the 66 patients with endoscopic abnormalities radiology was correct in 54, for a sensitivity of 82%. Sensitivity of radiology improved to 95% if mild esophagitis was excluded. In the 20 patients with normal endoscopy, radiology was normal in 18 (90%). Thus radiology proved to be a reliable means of evaluating the esophagus in patients with dysphagia. 相似文献
112.
P Tugwell L Hart G Kraag A Park C Dok F Bianchi C Goldsmith W W Buchanan 《The Journal of rheumatology》1984,11(4):457-461
A crossover double-blind controlled trial was performed on 36 patients with rheumatoid arthritis to assess the necessity for serum salicylate monitoring in determining optimal dosage. There was no clinically or statistically significant increase in the clinical improvement of patients associated with serum monitoring but potentially toxic serum levels occurred without tinnitus when serum monitoring was not used. 相似文献
113.
114.
Z M Huang D Thewke Q Q Gong D Schlichter W D Wicks 《Brain research. Molecular brain research》1991,11(3-4):309-319
Transient transfection of pLB2CAT constructs bearing short synthetic oligonucleotides derived either from the tyrosine hydroxylase (TH) promoter or other sources was used to examine functional cAMP regulatory element (CRE) activity in a variety of cell lines. The region containing only the putative TH CRE was found to be as or more effective in conferring cAMP responsiveness onto pLB2CAT (which employs the TK promoter) than the immediate 272 bp region of the TH promoter. Increases in CAT activity of 10- to 20-fold were observed in JEG-3 cells with a single insert of the TH CRE region (-31 to -54) in pLB2CAT, and the presence of a second insert generated only a modest further increase. This construct also responded to cAMP in 4 other cell lines tested but the degree of increase was less dramatic. Inserts containing the consensus 8 bp CRE motif embedded in other natural or artificial contexts served generally as weak functional CREs in all cell lines tested. In vitro analysis revealed that a specific protein-DNA complex apparently containing a single protein with a MW of 45-50 kDa was formed equally well with JEG-3 cell nuclear extract and CRE-bearing-TH and other fragments which produced dramatically different cAMP effects in vivo. These results suggest specificity in the effects of cAMP on different CREs which are dictated by contextual differences. 相似文献
115.
116.
Pregnant rats were injected with a single dose of methylazoxymethanol (MAM, 25 mg/kg) on gestational day 14, 15, 16, 17, 18 or 19 and offspring were tested for their physical development, reflex development and spontaneous activity. MAM treatment did not affect gestational and litter parameters at any of the time of administration studied. Treatment at gestational day 14 (GD14) had the most severe effect on functional neurodevelopment until weaning: righting reflex at surface, chimney test, horizontal wire test resulted altered. Administration at GD15, 16, 18, 19 did not affect the performance in these tests. Offspring treated at GD17 showed a delayed eye opening and an impaired performance in the horizontal wire test. When tested at 50 days of age on the rotarod, all the treated groups performed worse than controls with the exception of GD19 treated offspring. Administration at GD14 and GD15 resulted in increased spontaneous activity of the offspring at 21 days but not at 60 days of age. Different degrees of microencephaly were observed for all treated groups. The results indicate that alterations of physical and behavioral development induced by MAM treatment are dependent on the time of MAM administration, and specific behavioral tests are able to detect different abnormalities and differentiate among treatment groups. Some alterations observed in MAM rats undergo to adaptive changes during maturation of the CNS. 相似文献
117.
118.
Although the initial phase of receptor-mediated Ca2+ signaling, involving Ca2+ release from intracellular stores by inositol 1,4,5-trisphosphate, is relatively well characterized, the nature of the organelle releasing Ca2+ is a controversial subject. At issue is the question of whether Ca2+ is released from the endoplasmic reticulum, or from a more specialized organelle called the 'calciosome'. In this review, we attempt to analyse the arguments for and against these two views, and attempt to reconcile some of the apparently conflicting findings by proposing a hypothetical model of the inositol 1,4,5-trisphosphate-sensitive Ca2+ pool. 相似文献
119.
W I Schievink B Mokri V V Michels D G Piepgras 《Stroke; a journal of cerebral circulation》1991,22(11):1426-1430
BACKGROUND AND PURPOSE: The familial occurrence of intracranial aneurysms and cervical artery dissections has been described in different families and supports the hypothesis that a primary arteriopathy may play a role in the pathogenesis of these disorders. Although the basis for this arteriopathy is generally not believed to be similar among cases of intracranial aneurysms and cervical artery dissections, several similarities exist in the epidemiology of these disorders and a common underlying arterial abnormality may be suspected. SUMMARY OF REPORTS: The medical records of all 175 patients with spontaneous dissections of the cervical arteries who were seen at the Mayo Clinic between 1970 and 1989 were reviewed to identify families in which intracranial aneurysms and cervical dissections coexisted. Three families were identified in which intracranial aneurysms and cervical artery dissections were observed among siblings. These families are described in detail. CONCLUSIONS: The familial occurrence of intracranial aneurysms and cervical artery dissections within the same families provides support to the importance of a common underlying arteriopathy in the pathogenesis of both these disorders. The underlying vascular defect may, at least in some cases, be inherited. 相似文献
120.