全文获取类型
收费全文 | 3752篇 |
免费 | 338篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 24篇 |
儿科学 | 86篇 |
妇产科学 | 22篇 |
基础医学 | 564篇 |
口腔科学 | 142篇 |
临床医学 | 246篇 |
内科学 | 997篇 |
皮肤病学 | 23篇 |
神经病学 | 371篇 |
特种医学 | 132篇 |
外科学 | 741篇 |
综合类 | 61篇 |
一般理论 | 1篇 |
预防医学 | 253篇 |
眼科学 | 57篇 |
药学 | 192篇 |
中国医学 | 1篇 |
肿瘤学 | 186篇 |
出版年
2021年 | 56篇 |
2020年 | 54篇 |
2019年 | 56篇 |
2018年 | 80篇 |
2017年 | 51篇 |
2016年 | 48篇 |
2015年 | 61篇 |
2014年 | 77篇 |
2013年 | 125篇 |
2012年 | 168篇 |
2011年 | 173篇 |
2010年 | 105篇 |
2009年 | 131篇 |
2008年 | 179篇 |
2007年 | 172篇 |
2006年 | 165篇 |
2005年 | 190篇 |
2004年 | 155篇 |
2003年 | 167篇 |
2002年 | 153篇 |
2001年 | 106篇 |
2000年 | 111篇 |
1999年 | 92篇 |
1998年 | 47篇 |
1997年 | 49篇 |
1996年 | 57篇 |
1995年 | 51篇 |
1994年 | 34篇 |
1993年 | 46篇 |
1992年 | 51篇 |
1991年 | 69篇 |
1990年 | 66篇 |
1989年 | 61篇 |
1988年 | 52篇 |
1987年 | 59篇 |
1986年 | 55篇 |
1985年 | 55篇 |
1984年 | 49篇 |
1983年 | 52篇 |
1982年 | 53篇 |
1981年 | 38篇 |
1980年 | 34篇 |
1979年 | 38篇 |
1977年 | 32篇 |
1976年 | 28篇 |
1975年 | 23篇 |
1974年 | 33篇 |
1973年 | 25篇 |
1971年 | 21篇 |
1970年 | 34篇 |
排序方式: 共有4099条查询结果,搜索用时 15 毫秒
101.
E G Nabel E J Topol A Galeana S G Ellis E R Bates S W Werns J A Walton D W Muller M Schwaiger B Pitt 《Journal of the American College of Cardiology》1991,17(2):467-473
The adjunctive use of intravenous captopril with tissue plasminogen activator early during acute myocardial infarction offers theoretic advantages of diminishing left ventricular volume, preventing ventricular dilation and improving patient survival. To test the safety and efficacy of combined early administration of intravenous captopril and recombinant tissue-type plasminogen activator (rt-PA), 38 patients treated with rt-PA 3 +/- 0.3 h (mean +/- SE) after the onset of myocardial infarction were randomized to intravenous followed by oral captopril or placebo therapy. They underwent cardiac catheterization with measurement of hemodynamic variables and left ventricular function and determination of serum renin, angiotensin and aldosterone levels on days 1 and 7. Oral administration of the selected agent was continued for 3 months along with other antianginal medications, including nonangiotensin-converting enzyme inhibitor vasodilators. Repeat measurements of left ventricular function were obtained before hospital discharge and at 3 months. There were no significant differences in baseline clinical characteristics between groups. One patient in the captopril-treated group became hypotensive during intravenous therapy, requiring discontinuation of treatment. Compared with the placebo-treated group, the captopril-treated group had significant reductions at day 7 in left ventricular end-diastolic pressure (22.5 +/- 1.5 versus 16.3 +/- 1.6 mm Hg, p less than 0.01) and mean systemic arterial pressure (93.6 +/- 3.3 versus 86.2 +/- 2.7 mm Hg, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
102.
Effectiveness of dopamine in patients with cardiogenic shock 总被引:3,自引:0,他引:3
J Holzer J S Karliner R A O'Rourke W Pitt J Ross 《The American journal of cardiology》1973,32(1):79-84
103.
Myocardial imaging with thallium-201: a multicenter study in patients with angina pectoris or acute myocardial infarction 总被引:7,自引:0,他引:7
J L Ritchie B L Zaret H W Strauss B Pitt D S Berman H R Schelbert W L Ashburn H J Berger G W Hamilton 《The American journal of cardiology》1978,42(3):345-350
A multicenter study of rest and exercise thallium-201 myocardial imaging in 190 patients from five centers was performed. Exercise images were obtained after graded treadmill or bicycle stress with use of five different gamma camera models and were interpreted by the originating investigator without knowledge of other clinical data. Of 42 patients with less than 50 percent coronary stenosis, 4 (10 percent) had a resting image defect, 1 (2 percent) a new exercise defect and 5 (12 percent) either a resting or an exercise image defect, or both. Of 148 patients with coronary stenosis of 50 percent or greater, 64, (45 percent) had an image defect in the study at rest, 90 (61 percent) had new or increased defects after exercise, and 115 (78 percent) had resting or exercise defects, or both. New exercise image defects were more common than exercise S-T depression (90 of 148 [61 percent] versus 62 of 148[42 percent]; P less than 0.01). In a second group of 111 patients with acute myocardial infarction studied at three centers, 90 patients (81 percent) had image defects compared with 71 (64 percent) two had new electrocardiographic Q waves (P less than 0.01). Smaller infractions, as assessed with serum enzyme values, and diaphragmatic infarctions were less commonly detected than larger or anterior infarctions. These findings suggest that myocardial imaging complements the electrocardiographic identification of acute myocardial infarction of exericse-induced myocardial ischemia. 相似文献
104.
Jason B. Liu Marshall S. Baker Vanessa M. Thompson E. Molly Kilbane Henry A. Pitt 《HPB : the official journal of the International Hepato Pancreato Biliary Association》2019,21(1):121-131
Background
Whether the choice of antibiotic prophylaxis, the type of incision, or the use of wound protectors decreases surgical site infections (SSIs) in patients undergoing pancreatoduodenectomy (PD) remains unknown.Methods
Patients undergoing open, elective PD between January 1, 2016 and June 30, 2017 were identified from the American College of Surgeons’ National Surgical Quality Improvement Program registry. Multivariable logistic regression models were constructed to determine the association of antibiotic prophylaxis type, incision type, and wound protector use on the incidence of any, superficial, and organ/space SSIs, and to profile hospitals.Results
Overall, 5969 patients were included from 140 hospitals. The overall rate of SSI was 20.3% (n = 1213). Superficial SSIs occurred in 432 (7.2%) patients and organ/space SSIs in 841 (14.1%). Wound protector use was associated with 23% lower odds of experiencing any SSIs (OR 0.77, 95% CI 0.60–0.98), reflective of the decreased odds associated with superficial SSIs (OR 0.65, 95% CI 0.44–0.97), but not organ/space SSIs (OR 0.89, 95% CI 0.68–1.17). Highest-performing hospitals frequently utilized broad-spectrum antibiotics, midline incisions, and wound protectors.Conclusion
Wound protectors reduced superficial, but not organ/space, infections in patients undergoing pancreatoduodenectomy. Routine use of wound protectors in patients undergoing proximal pancreatectomy is recommended. 相似文献105.
106.
Bertram Pitt 《Cardiovascular drugs and therapy / sponsored by the International Society of Cardiovascular Pharmacotherapy》1997,11(1):285-290
ACE inhibitors have been shown to be effective in reducing the morbidity and mortality of patients with left ventricular systolic dysfunction, but their application to clinical practice in this situation is still limited. In part, the failure to prescribe an ACE inhibitor to a patient with left ventricular systolic dysfunction is due to perceptions regarding their side effects, such as cough and renal dysfunction. Relatively few patients with left ventricular systolic dysfunction and a serum creatinine ≥2 mg/dl receive an ACE inhibitor in clinical practice. In this situation one should consider an agent such as fosinopril, which is metabolized by the liver as well as secreted by the kidney. In patients with moderate renal dysfunction, fosinopril has been well tolerated without an increase in serum creatinine. In patients who develope cough due to an ACE inhibitor, consideration should be given to an angiotensin II type 1 receptor blocking agent, such as losartan. The relative safety and efficacy of an ACE inhibitor compared with an angiotensin II type 1 receptor blocking agent is being explored in a prospective randomized trial (Evaluation of Losartan In The Elderly [ELITE]), as well as the safety and pharmacological effectiveness of adding an angiotensin II receptor antagonist to an ACE inhibitor (Randomized Angiotensin receptor antagonists–ACE-inhibitor Study [RAAS]). There may also be a role for the combination of an aldosterone receptor antagonists and an ACE inhibitor in patients with left ventricular systolic dysfunction. Once an ACE inhibitor is administered to a patient with left ventricular systolic dysfunction it should be continued indefinitely. ACE inhibitors may be of value not only in preventing the progression of heart failure but also in reversing endothelial dysfunction and preventing the development of atherosclerosis and its consequences, such as myocardial infarction. 相似文献
107.
Pascu M Müller AR Wiedenmann B Dignass AU 《International journal of colorectal disease》2003,18(3):271-275
BACKGROUND: Toxic megacolon is a life-threatening complication most commonly observed in patients with ulcerative colitis or Crohn's disease that is characterized by total or segmental nonobstructive colonic dilatation of at least 6 cm on plain abdominal films associated with systemic toxicity. CASE REPORT: We report an unusual case of fulminant steroid-refractory ulcerative colitis complicated by toxic megacolon treated successfully with the immunosuppressant tacrolimus. CONCLUSION: Tacrolimus administration induced clinical remission and bridged the time interval, until the standard immunosuppressant azathioprine could maintain clinical remission, thereby avoiding eminent emergency colectomy. 相似文献
108.
Esophageal Involvement in Lymphoma 总被引:1,自引:0,他引:1
Farooq P. Agha M.D. F.A.C.G. Bertram Schnitzer M.D. 《The American journal of gastroenterology》1985,80(6):412-416
Esophageal involvement by lymphoma in three patients, two with non-Hodgkin's lymphoma and one with Hodgkin's lymphoma are reported. In all three patients, there was discrete involvement of the esophagus not directly contiguous with the stomach. Esophageal involvement by lymphoma either as a primary disease or as manifestation of a disseminated disease is distinctly uncommon. 相似文献
109.
Philip J. Currie MBBS Michael J. Kelly FRACP Aubrey Pitt FRACP 《The American journal of cardiology》1983,52(10):1167-1173
Exercise-induced electrocardiographic ST depression was compared during supine and erect graded bicycle exercise in 43 patients with chest pain but no prior myocardial infarct; all had ≥1 mm of ST depression during either erect or supine exercise; 16 had multivessel, 24 had 1-vessel and 3 had no coronary artery disease. Supine exercise used 4 minutes/stage and erect exercise used either 4 minutes or 3 minutes/stage with identical graded work loads for both postures. Chest pain occurred in 31 patients during erect and in 29 during supine exercise. ST depression was ≥1 mm in 28 patients during erect exercise and in all 43 during supine exercise (p <0.001); mean maximal ST depression was 1.3 ± 0.2 mm during erect and 2.6 ± 0.2 mm during supine exercise (p <0.001). Maximal work load was higher during erect than supine exercise (745 ± 32 versus 678 ± 32 kpm/min; p <0.001). The accentuation of ST depression by supine posture was not attributable to the changes in heart rate, rate-pressure product or mean blood pressure during supine versus erect exercise. In the 10 patients who had 2 erect bicycle tests using work load durations of 3 and 4 minutes, the maximal ST depression was not significantly different (erect 3 minutes 1.3 ± 0.5 mm and erect 4 minutes 1.4 ± 0.4 mm). In 7 patients who also had a maximal treadmill exercise test, the maximal ST depression was significantly greater during supine exercise (2.3 ± 0.4 mm) than during either an erect bicycle test (0.6 ± 0.4 mm) or treadmill exercise (0.7 ± 0.4 mm) (p <0.05). Supine posture should be considered as an important potentiator of exercise-induced myocardial ischemia whem comparing indicators such as electrocardiography, radionuclide ventriculography and thallium-201 myocardial perfusion imaging during exercise. 相似文献
110.
Cashin-Hemphill L Holmvang G Chan RC Pitt B Dinsmore RE Lees RS 《The American journal of cardiology》1999,83(1):43-47
Angiotensin-converting enzyme inhibitors have proven to be of clinical benefit in congestive heart failure. Whether they also provide benefit to patients with coronary artery disease in the absence of congestive heart failure via an antiatherosclerotic mechanism is a question the QUinapril Ischemic Event Trial quantitative coronary angiography (QCA) study attempted to answer: 1,750 patients with normal left ventricular function who were undergoing coronary angiography and angioplasty were randomized to 20 mg/day of quinapril versus placebo and followed for 3 years for cardiac end points. A randomly selected subgroup of the total cohort underwent follow-up angiography. The primary QCA end point was the categorical designation of progression versus nonprogression, defined either by QCA or by a cardiac event in patients selected for the QCA trial who had no usable follow-up x-ray film. Secondary end points in patients with 2 angiograms were: new stenosis development, change in minimum lumen diameter index, and change in percent diameter stenosis index. There were 119 progressors among 243 placebo-treated patients (49%) and 111 progressors among 234 quinapril-treated patients (47%) (p = NS). There were 44 patients with new stenosis development in the placebo group (19%) and 50 (22%) in the quinapril group (p = NS). Change in minimum lumen diameter index was -0.21+/-0.03 mm in the placebo group and -0.18+/-0.03 mm in the quinapril group (p = NS). Finally, change in percent diameter stenosis index was +5.1+/-1.0 in the placebo group and +3.5+/-1.0 in the quinapril group (p = NS). Potential confounders of this trial are presented and discussed. 相似文献