全文获取类型
收费全文 | 1977篇 |
免费 | 123篇 |
国内免费 | 45篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 84篇 |
妇产科学 | 57篇 |
基础医学 | 240篇 |
口腔科学 | 16篇 |
临床医学 | 238篇 |
内科学 | 475篇 |
皮肤病学 | 15篇 |
神经病学 | 107篇 |
特种医学 | 297篇 |
外科学 | 217篇 |
综合类 | 18篇 |
预防医学 | 55篇 |
眼科学 | 11篇 |
药学 | 177篇 |
中国医学 | 1篇 |
肿瘤学 | 131篇 |
出版年
2021年 | 8篇 |
2020年 | 7篇 |
2019年 | 13篇 |
2018年 | 18篇 |
2017年 | 10篇 |
2016年 | 14篇 |
2015年 | 35篇 |
2014年 | 35篇 |
2013年 | 55篇 |
2012年 | 63篇 |
2011年 | 62篇 |
2010年 | 70篇 |
2009年 | 58篇 |
2008年 | 72篇 |
2007年 | 108篇 |
2006年 | 82篇 |
2005年 | 69篇 |
2004年 | 68篇 |
2003年 | 71篇 |
2002年 | 68篇 |
2001年 | 82篇 |
2000年 | 85篇 |
1999年 | 58篇 |
1998年 | 61篇 |
1997年 | 53篇 |
1996年 | 54篇 |
1995年 | 40篇 |
1994年 | 33篇 |
1993年 | 32篇 |
1992年 | 48篇 |
1991年 | 48篇 |
1990年 | 53篇 |
1989年 | 58篇 |
1988年 | 62篇 |
1987年 | 53篇 |
1986年 | 47篇 |
1985年 | 35篇 |
1984年 | 27篇 |
1983年 | 25篇 |
1982年 | 19篇 |
1981年 | 17篇 |
1980年 | 22篇 |
1979年 | 10篇 |
1978年 | 11篇 |
1977年 | 25篇 |
1976年 | 14篇 |
1975年 | 18篇 |
1974年 | 12篇 |
1971年 | 7篇 |
1969年 | 5篇 |
排序方式: 共有2145条查询结果,搜索用时 15 毫秒
1.
2.
Dimmeler Stefanie; Tonn Torsten; Seeger Florian; Zeiher Andreas M. 《European heart journal》2007,28(17):2175
It obviously escaped the notion of Egeland and Brinchman thatthe protocols additionally differ with regard to the washingsteps and buffer components used in the 相似文献
3.
F Reichenberger R Voswinckel B Enke M Rutsch E El Fechtali T Schmehl H Olschewski R Schermuly N Weissmann H A Ghofrani F Grimminger E Mayer W Seeger 《The European respiratory journal》2007,30(5):922-927
For chronic thromboembolic pulmonary hypertension not amenable to pulmonary endarterectomy, effective medical therapy is desired. In an open-label uncontrolled clinical trial, 104 patients (mean +/- sem age 62 +/- 11 yrs) with inoperable chronic thromboembolic pulmonary hypertension were treated with 50 mg sildenafil t.i.d. At baseline, patients had severe pulmonary hypertension (pulmonary vascular resistance 863 +/- 38 dyn.s.cm(-5)) and a 6-min walking distance of 310 +/- 11 m. Eight patients were in World Health Organization functional class II, 76 in class III and 20 in class IV. After 3 months' treatment, there was significant haemodynamic improvement, with reduction of pulmonary vascular resistance to 759 +/- 62 dyn.s.cm(-5). The 6-min walking distance increased significantly to 361 +/- 15 m after 3 months' treatment, and to 366 +/- 18 m after 12 months' treatment. A subset of 67 patients received a single dose of 50 mg sildenafil during initial right heart catheterisation. The acute haemodynamic effect of this was not predictive of long-term outcome. In this large series of patients with inoperable chronic thromboembolic pulmonary hypertension, open-label treatment with sildenafil led to significant long-term functional improvement. The acute effect of sildenafil may not predict the long-term outcome of therapy. 相似文献
4.
5.
6.
Does routine stress-thallium cardiac scanning reduce postoperative cardiac complications? 总被引:2,自引:0,他引:2 下载免费PDF全文
J M Seeger G R Rosenthal S B Self T C Flynn M C Limacher T R Harward 《Annals of surgery》1994,219(6):654-663
OBJECTIVE: Prophylactic cardiac revascularization in patients with ischemic myocardium could reduce postoperative cardiac complications after aortic reconstruction. However, the effectiveness of this approach has not been documented. SUMMARY BACKGROUND DATA: Stress-thallium scanning can identify patients with ischemic myocardium. Morbidity and mortality after aortic reconstruction appears to be largely caused by co-existent coronary artery disease, and patients who have had recent cardiac revascularization have few postoperative cardiac complications. METHODS: Preoperative stress-thallium scanning was evaluated prospectively in 146 patients undergoing aortic reconstruction. Patients with positive studies underwent coronary arteriography and cardiac revascularization, when appropriate. Postoperative cardiac complications and long-term survival in these patients were compared with results from 172 similar patients undergoing aortic reconstruction without stress-thallium scanning. Results also were analyzed to determine predictors of postoperative cardiac events. RESULTS: Forty-one per cent of patients undergoing stress-thallium testing underwent coronary arteriography, and 11.6% had cardiac revascularization. In contrast, 14.7% of patients treated without stress-thallium testing had coronary arteriography, and 4.1% had revascularization (p < 0.01). Despite this, cardiac mortality, serious cardiac complications, and long-term cardiac mortality were similar in both groups. Only advanced age and intraoperative complications (but not a positive stress-thallium test) predicted postoperative cardiac events. CONCLUSIONS: Preoperative stress-thallium testing confirmed a high incidence of significant coronary artery disease in patients undergoing aortic reconstruction, but prophylactic cardiac intervention does not reduce operative or long-term mortality. Thus, the risk and expense of routine stress-thallium testing and subsequent cardiac revascularization cannot be justified. 相似文献
7.
8.
9.
We used arthrotomography to study the glenoid labrum in 114 patients. Sixty-nine of the patients had anatomic instability of the shoulder (including recurrent dislocation and subluxation of the shoulder), and 45 patients had functional instability of the shoulder (denoted by chronic pain, clicking of the joint, and the sensation that an unstable condition exists without the objective signs of it). Labral tears were revealed arthrotomographically in 86% of the patients with anatomic instability, while only 40% of the patients with functional instability had labral abnormalities, and these were primarily of minor severity. Fifty-six patients (44 of whom had anatomic instability; 12, functional instability) required surgery. The surgical findings were correlated with the arthrotomographic findings, and no false-positive results were revealed. However, arthrotomography demonstrated only part of the pathologic condition of two patients. These results confirm that there is a strong correlation between labral pathologic conditions and anatomic instability of the shoulder. Arthrotomographic studies have a great impact on the selection of therapy in cases of both anatomic and functional instability of the shoulder. 相似文献
10.
The influence of exogenously supplied free arachidonic acid (AA) and eicosapentaenoic acid (EPA) on the 5-lipoxygenase metabolism in human neutrophils (PMN) was investigated. Simultaneous application of A23187 with incremental concentrations of free AA caused a dose-dependent augmentation of the ionophore-elicited eicosanoid generation [release of leukotriene B4 and its omega-oxidation products, nonenzymatic hydrolysis products of leukotriene A4, and 5-hydroxyeicosatetraeneoic acid (5-HETE)]. A23187 challenge in the presence of free EPA resulted in the dose-dependent appearance of corresponding n - 3-derived metabolites, parallelled by a decrease in 4-series leukotrienes and 5-HETE. The inflammatory ligands formyl-methionyl-leucyl-phenylalanine and platelet-activating factor evoked no substantial eicosanoid generation in the absence of exogenously supplied polyunsaturated fatty acids (PUFAs). Addition of free AA or EPA in parallel with the ligand challenge evoked exclusive and dose-dependent generation of the respective leukotrienes and 5-HETE or 5-hydroxyeicosapentaenoic acid. Total amounts of 5-lipoxygenase products elicited under these conditions approached those in ionophore-stimulated PMN, with platelet-activating factor challenge surpassing the formyl-methionyl-leucylphenylalanine-evoked effect by approximately 50%. Two thirds of the maximum effect was obtained in the presence of only 10 microM free PUFA. Use of labeled fatty acids suggested exclusive origin of the eicosanoids from the exogenously provided precursor PUFA. Critical dependence on timing was noted; maximum response occurred upon simultaneous application of PUFA and ligand, and only 5 min of delay between AA or EPA addition and ligand challenge sufficed to reduce the formation of respective metabolites to less than 20%. EPA competed with AA and was noted to be the preferred substrate for ligand-evoked eicosanoid synthesis. In contrast to the simultaneous addition of free PUFAs, preloading of PMN with AA or EPA for 60 min revealed only very moderate or even no influence on ionophore- or ligand-evoked eicosanoid synthesis. We conclude that inflammatory ligands induce marked stimulation of PMN eicosanoid synthesis, with critical dependence on the presence of free precursor PUFAs. Preference of EPA over AA is observed under these conditions. 相似文献