全文获取类型
收费全文 | 1778篇 |
免费 | 160篇 |
国内免费 | 29篇 |
专业分类
耳鼻咽喉 | 7篇 |
儿科学 | 94篇 |
妇产科学 | 58篇 |
基础医学 | 250篇 |
口腔科学 | 66篇 |
临床医学 | 236篇 |
内科学 | 324篇 |
皮肤病学 | 23篇 |
神经病学 | 84篇 |
特种医学 | 165篇 |
外科学 | 184篇 |
综合类 | 61篇 |
一般理论 | 1篇 |
预防医学 | 167篇 |
眼科学 | 51篇 |
药学 | 100篇 |
1篇 | |
肿瘤学 | 95篇 |
出版年
2023年 | 14篇 |
2022年 | 12篇 |
2021年 | 18篇 |
2020年 | 17篇 |
2019年 | 31篇 |
2018年 | 37篇 |
2017年 | 24篇 |
2016年 | 34篇 |
2015年 | 26篇 |
2014年 | 36篇 |
2013年 | 61篇 |
2012年 | 85篇 |
2011年 | 74篇 |
2010年 | 37篇 |
2009年 | 50篇 |
2008年 | 86篇 |
2007年 | 69篇 |
2006年 | 89篇 |
2005年 | 51篇 |
2004年 | 69篇 |
2003年 | 69篇 |
2002年 | 57篇 |
2001年 | 81篇 |
2000年 | 59篇 |
1999年 | 46篇 |
1998年 | 47篇 |
1997年 | 33篇 |
1996年 | 38篇 |
1995年 | 32篇 |
1994年 | 27篇 |
1993年 | 30篇 |
1992年 | 37篇 |
1991年 | 38篇 |
1990年 | 32篇 |
1989年 | 35篇 |
1988年 | 31篇 |
1987年 | 23篇 |
1986年 | 31篇 |
1985年 | 29篇 |
1984年 | 23篇 |
1983年 | 26篇 |
1982年 | 17篇 |
1981年 | 19篇 |
1980年 | 22篇 |
1979年 | 26篇 |
1978年 | 15篇 |
1977年 | 14篇 |
1976年 | 13篇 |
1974年 | 19篇 |
1969年 | 13篇 |
排序方式: 共有1967条查询结果,搜索用时 31 毫秒
1.
2.
Electrophysiologic effects of d-sotalol in humans 总被引:1,自引:0,他引:1
J M McComb B McGovern J B McGowan J N Ruskin H Garan 《Journal of the American College of Cardiology》1987,10(1):211-217
Sotalol is a beta-adrenergic blocking agent that prolongs the duration of the cardiac action potential in humans, without affecting the upstroke velocity of depolarization. The dextrorotatory isomer, d-sotalol, retains these class III effects, but has little beta-blocking activity in vitro. d-Sotalol has not been studied extensively in humans. The electrocardiographic (ECG) and electrophysiologic effects of d- and d,l-sotalol were therefore assessed in a prospective randomized study of 20 patients. Each patient received either d-sotalol (1, 1.5 or 2 mg/kg body weight) or d,l-sotalol (1 mg/kg) by intravenous infusion. The QT and QTc intervals were prolonged and refractoriness increased in the atrium, atrioventricular (AV) node, His-Purkinje system and right ventricle after both d- and d,l-sotalol. After d-sotalol, the increases in both QT and QTc intervals and in atrial and ventricular effective refractory periods were dose dependent. Highly significant linear correlation was demonstrated between the plasma sotalol level and the change in QT (r = 0.86, p = 0.001) and QTc intervals (r = 0.79, p = 0.002), and between the plasma sotalol level and the effective refractory period of the right atrium (r = 0.75, p = 0.005) and ventricle (r = 0.70, p = 0.025). This study confirms that d-sotalol has effects consistent with class III properties. It demonstrates these effects in humans, and suggests that d-sotalol may prove to be a useful antiarrhythmic agent. 相似文献
3.
ZQ Yin MD SG Crewther PhD B Pirie BSc DP Crewther PhD 《Clinical & experimental ophthalmology》1997,25(4):107-109
Purpose: It was investigated whether alterations in neuronal structure and function occasioned by strabismic amblyopia also may be reflected in alterations in the expression on Y type neurons of a Cat-301 antibody sensitive antigen in the lateral geniculate nucleus (LGN) and cortex of our cat model of strabismic amblyopia. Methods/Results: The percentage of positively labelled cells was reduced in LGN laminae that received input from the deviated eye in strabismic amblyopic cats compared with normal cats. In the strabismic cortex, the density of immunopositive neurons was significantly reduced compared with normal, the effect being most pronounced in layer IV Conclusions: Despite previous physiological recordings indicating a decrease in X-cell associated acuity in strabismic amblyopia, the present findings imply that the changes in the early visual experience occasioned by strabismus also produce specific molecular changes in theY neuronal class. 相似文献
4.
5.
6.
OBJECTIVE: The aim of this study was to assess the severity of epilepsy and
its effect on patients lives, and to describe patients' use of and
attitudes to health care. METHOD: A questionnaire was sent to 595 people
with epilepsy identified from 14 general practices in north-west Bristol.
All patients aged 16 years and over receiving anti-epileptic medication for
their epilepsy were included in the study. Areas investigated included
severity of epilepsy and its effect on quality of life, anti-epileptic
medication and its perceived effect, health care utilization and
preferences for health care. RESULTS: Seizure frequency was strongly
associated with adverse effects of epilepsy. Attacks of epilepsy were
experienced at least monthly by 20.4% (95% confidence intervals (Cl)
17.0-23.7%) of patients, 29.4% (25.4-33.4%) took more than one
anti-epileptic drug, 56.1% (50.1-62.2%) reported drug side effects, 74.1%
(70.3-77.8%) would prefer to receive all or most of their epilepsy care in
a general practice setting, and 69.8% (63.5- 76.2%) would like contact with
a primary care-based epilepsy specialist nurse. During the previous year
42.4% (35.9-48.8%) of patients had not seen a doctor about their epilepsy.
Of patients who had attended the general practice only 13.4% (9.6-17.2%)
had regular arrangements to see their GP about epilepsy. Patients receiving
both primary and secondary care had the greatest needs and wants for
improved care. CONCLUSIONS: Structured care, including regular
appointments, co-ordination of primary and secondary care, and increased
monitoring and discussion, may improve the quality of life of people with
epilepsy, but requires evaluation.
相似文献
7.
8.
9.
Duplications of the alimentary tract. Clinical characteristics, preferred treatment, and associated malformations. 总被引:5,自引:0,他引:5
下载免费PDF全文
![点击此处可从《Annals of surgery》网站下载免费的PDF全文](/ch/ext_images/free.gif)
S T Ildstad D J Tollerud R G Weiss D P Ryan M A McGowan L W Martin 《Annals of surgery》1988,208(2):184-189
Duplications of the alimentary tract are unusual congenital anomalies that frequently present a diagnostic as well as therapeutic challenge to the surgeon. Because these lesions occur so infrequently, they are often not suspected until encountered intraoperatively. Due to the complicated anatomy and common blood supply shared between the duplication and associated native bowel, appropriate management requires a familiarity with the anatomy and clinical characteristics of this entity. To better define the range of patient characteristics, clinical presentation, and preferred therapy, 20 enteric duplications were reviewed in 17 patients treated at the Children's Hospital Medical Center from 1956 to 1986. Ages of patients ranged from 1 day to 11 years; 60% were less than 2 years of age at initial presentation. Seven duplications in six patients involved alimentary tract structures of foregut derivation (esophagus, stomach, and Parts I and II of duodenum), with a predominance of girls (4 of 6). Most of these patients (67%) presented with moderate to severe acute respiratory distress and a mass present on chest radiograph. In 67% of the patients, the correct diagnosis was established before operation. None required emergency operative intervention. By contrast, 13 duplications in 11 patients were of midgut or hindgut derivation (Parts III and IV of the duodenum, jejunum, ileum, and colon). In this group of patients, 62% of the duplications involved the cecum, 23% involved the ileum, and 16%, the jejunum. Seventy-eight per cent of the patients were boys. The most common symptoms were nausea and vomiting, and the most common sign was a palpable abdominal mass. Emergency operative intervention was required of eight of 11 patients with duplications involving the small bowel and colon. Three patients presented with an intussusception, four with signs and symptoms consistent with acute appendicitis, one with a small bowel obstruction, and two with gastrointestinal hemorrhage due to the presence of ectopic gastric mucosa within the duplication. It was found that two important points must be considered in regard to the management of enteric duplications: (1) the common blood supply shared between the duplication and native bowel must be carefully protected to avoid undue sacrifice of normal bowel, and (2) the presence of heterotopic gastric mucosa in 35% of patients negates internal drainage.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
10.
A comprehensive anatomic and radiographic analysis of the peribursal fat plane in 12 cadavers confirmed that the fat plane seen on radiographs represents extrasynovial fat lining the subacromial bursa and documented the anatomic relations of the bursa. A three-part retrospective clinical evaluation of rotator cuff tears, calcific tendinitis, and rheumatoid arthritis was performed. Two osteoradiologists blindly graded the appearance of the peribursal fat plane with the shoulder in external versus internal rotation in 21 patients with arthrographically intact rotator cuffs and 21 patients with disrupted rotator cuffs. The peribursal fat plane was seen better with disrupted rotator cuffs. The peribursal fat plane was seen better with the shoulder in internal rotation and was seen in 60% of control subjects but only 21% of patients with rotator cuff tears. Partial or complete obliteration of this fat plane is a sensitive (79%) but less specific (60%) indicator of rotator cuff tears. Obliteration of the peribursal fat plane by inflammatory processes in adjacent tissues, including calcific tendinitis and rheumatoid arthritis, occurred with a high frequency. 相似文献