全文获取类型
收费全文 | 19753篇 |
免费 | 1763篇 |
国内免费 | 69篇 |
专业分类
耳鼻咽喉 | 220篇 |
儿科学 | 573篇 |
妇产科学 | 467篇 |
基础医学 | 2436篇 |
口腔科学 | 436篇 |
临床医学 | 2360篇 |
内科学 | 3484篇 |
皮肤病学 | 210篇 |
神经病学 | 1947篇 |
特种医学 | 595篇 |
外科学 | 2533篇 |
综合类 | 573篇 |
一般理论 | 24篇 |
预防医学 | 2116篇 |
眼科学 | 472篇 |
药学 | 1546篇 |
中国医学 | 15篇 |
肿瘤学 | 1578篇 |
出版年
2021年 | 260篇 |
2020年 | 182篇 |
2019年 | 257篇 |
2018年 | 332篇 |
2017年 | 254篇 |
2016年 | 296篇 |
2015年 | 332篇 |
2014年 | 431篇 |
2013年 | 671篇 |
2012年 | 991篇 |
2011年 | 956篇 |
2010年 | 543篇 |
2009年 | 488篇 |
2008年 | 889篇 |
2007年 | 982篇 |
2006年 | 877篇 |
2005年 | 870篇 |
2004年 | 860篇 |
2003年 | 789篇 |
2002年 | 810篇 |
2001年 | 623篇 |
2000年 | 580篇 |
1999年 | 514篇 |
1998年 | 276篇 |
1997年 | 216篇 |
1996年 | 242篇 |
1995年 | 213篇 |
1994年 | 203篇 |
1993年 | 190篇 |
1992年 | 403篇 |
1991年 | 392篇 |
1990年 | 425篇 |
1989年 | 387篇 |
1988年 | 371篇 |
1987年 | 357篇 |
1986年 | 351篇 |
1985年 | 309篇 |
1984年 | 243篇 |
1983年 | 199篇 |
1982年 | 141篇 |
1981年 | 126篇 |
1979年 | 235篇 |
1978年 | 158篇 |
1977年 | 136篇 |
1976年 | 122篇 |
1975年 | 144篇 |
1974年 | 164篇 |
1973年 | 131篇 |
1972年 | 117篇 |
1968年 | 116篇 |
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
101.
102.
Post-traumatic cerebrospinal fluid (CSF) rhinorrhoea is a well recognized complication of closed head injury. Most cases occur soon after injury and a delay in presentation of more than 1 month is unusual. A case is reported of CSF rhinorrhoea presenting 15 years after initial trauma which was complicated by meningitis after 12 months. The management of this condition is reviewed. 相似文献
103.
104.
105.
BACKGROUND: Parallel comparison studies of cognitive therapy and antidepressant medication have suggested that both treatments are effective. However, we cannot determine from these studies whether cognitive therapy and antidepressant medication are effective for the same populations of depressives. A sequential study in which nonresponders to the first treatment are then treated with the second can address this issue. METHOD: Twenty-seven patients meeting DSM-III criteria for major depression or dysthymic disorder and Columbia criteria for atypical depression received cognitive therapy followed by antidepressant medication for cognitive therapy nonresponders. A response rate with the second treatment equal to that expected with placebo would suggest both treatments target the same depressive population. RESULTS: Of the 25 completers of the study, 14 (56%) were judged responders to cognitive therapy alone. Sixty-nine percent (9/13) of the responders maintained their benefits for 6 months or more. Seven of the 11 cognitive therapy nonresponders (63%) responded to antidepressant medication. These results were compared with those of a concurrent double-blind medication study; both its sample and ours were drawn from the same population at the same time: cognitive therapy and antidepressant medication response rates were higher than expected with placebo (28%). CONCLUSION: The results suggest that (1) cognitive therapy and antidepressant medication are effective treatments for differing populations of depressed patients, as the antidepressant medication response of cognitive therapy nonresponders was greater than expected with placebo, and (2) cognitive therapy has a lasting effect. 相似文献
106.
Ronald B. Stewart Ronald G. Marks Phillip D. Padgett William E. Hale 《Pharmacoepidemiology and drug safety》1994,3(1):23-29
The objective of the work was to identify changes in antidepressant drug use and determine if the prevalence of antidepressant use has changed over 14 years. A longitudinal analysis comparing antidepressant drug use at 14 yearly intervals from 1978–79 to 1991–92 was undertaken using the longitudinal health screening program of ambulatory elderly participants (Florida Geriatric Research Program). Participants included all subjects screened in the Florida Geriatric Research Program from 1 August 1978 to 31 July 1992. The outcome measures were self-reported antidepressant drug use. Approximately 3.0 per cent (range of 2.3 to 3.2 per cent over 14 yearly intervals) of participants in this program reported the use of an antidepressant drug. There was no statistically significant change in antidepressant use between 1978–79 and 1991–92 (p > 0.6630). Across all study intervals women reported more frequent use of antidepressant drugs than men. In 1991–92, amitriptyline and imipramine represented over 50 per cent of all antidepressant drug use in this elderly population. Less than 6 per cent of all antidepressant drug use was for fluoxetine, the newest selective serotonin uptake inhibitor. The majority of elderly patients are receiving older tertiary amine tricyclic antidepressants such as amitriptyline, imipramine and doxepin that are not the preferred drugs for the elderly. Educational programs are needed to improve antidepressant prescribing for geriatric patients. 相似文献
107.
Cardiac conduction abnormalities and rhythm changes after neonatal anatomical correction of transposition of the great arteries. 下载免费PDF全文
S Menahem M S Ranjit C Stewart W J Brawn R B Mee J L Wilkinson 《Heart (British Cardiac Society)》1992,67(3):246-249
Seventy three infants who underwent neonatal anatomical correction for transposition of the great arteries with or without a ventricular septal defect were reviewed for evidence of conduction and rhythm abnormalities on preoperative and postoperative 12 lead electrocardiograms and during 24 hour Holter monitoring. There was a partial right bundle branch block pattern in 47% (29/62) of all patients and in 60% (24/40) of those with simple transposition. Complete right bundle branch block was noted in 21% including 5% with simple transposition. Holter monitoring showed sinus rhythm in all patients except three: one had episodes of supraventricular tachycardia, another an intermittent second degree heart block, and a third a complete heart block. Atrial extrasystoles were noted in 47% (29/62) of patients but were frequent in only three patients. Occasional unifocal ventricular extrasystoles were encountered in 37% (23/62) of patients and were frequent in a further 3% (2/62). Only one patient (2%) developed multifocal ventricular extrasystoles. The frequency of important cardiac arrhythmias after neonatal anatomical correction of transposition of the great arteries was 5%, significantly less than that reported after atrial inflow diversion for the same malformation. 相似文献
108.
109.
Alfred C. Beck E.Stewart Taylor Russell F. Colburn 《American journal of obstetrics and gynecology》1941,41(5):765-775
This investigation has been conducted as two separate studies. Part I consisted of the determination of the prothrombin activity in normal newborn infants together with observations on the alterations in this activity which result from the administration of vitamin K to the mother. Part II was concerned with the practical application of the knowledge gained from the first study. It aimed to show the value of intra-partum vitamin K administration in reducing the incidence of hemorrhage in newborn infants. 相似文献
110.
Lygia Stewart J. McLeod Griffiss Gary A. Jarvis Lawrence W. Way 《Journal of gastrointestinal surgery》2007,11(8):977-984
Objective Gallstone bacteria provide a reservoir for biliary infections. Slime production facilitates adherence, whereas β-glucuronidase
and phospholipase generate colonization surface. These factors facilitate gallstone formation, but their influence on infection
severity is unknown.
Methods Two hundred ninety-two patients were studied. Gallstones, bile, and blood (as applicable) were cultured. Bacteria were tested
for β-glucuronidase/phospholipase production and quantitative slime production. Infection severity was correlated with bacterial
factors.
Results Bacteria were present in 43% of cases, 13% with bacteremia. Severe infections correlated directly with β-glucuronidase/phospholipase
(55% with vs 13% without, P < 0.0001), but inversely with slime production (55 vs 8%, slime <75 or >75, P = 0.008). Low slime production and β-glucuronidase/phospholipase production were additive: Severe infections were present
in 76% with both, but 10% with either or none (P < 0.0001). β-Glucuronidase/phospholipase production facilitated bactibilia (86% with vs 62% without, P = 0.03). Slime production was 19 (±8) vs 50 (±10) for bacteria that did or did not cause bacteremia (P = 0.004). No bacteria with slime >75 demonstrated bacteremia.
Conclusions Bacteria-laden gallstones are biofilms whose characteristics influence illness severity. Factors creating colonization surface
(β-glucuronidase/phospholipase) facilitated bacteremia and severe infections; but abundant slime production, while facilitating
colonization, inhibited detachment and cholangiovenous reflux. This shows how properties of the gallstone biofilm determine
the severity of the associated illness.
Presented at the annual meeting of the Society for Surgery of the Alimentary Tract, held May 20–24, 2006 in Los Angeles, California. 相似文献