全文获取类型
收费全文 | 34784篇 |
免费 | 2227篇 |
国内免费 | 147篇 |
专业分类
耳鼻咽喉 | 452篇 |
儿科学 | 680篇 |
妇产科学 | 608篇 |
基础医学 | 5018篇 |
口腔科学 | 1088篇 |
临床医学 | 3409篇 |
内科学 | 7040篇 |
皮肤病学 | 799篇 |
神经病学 | 3409篇 |
特种医学 | 1855篇 |
外国民族医学 | 1篇 |
外科学 | 5209篇 |
综合类 | 286篇 |
一般理论 | 56篇 |
预防医学 | 2225篇 |
眼科学 | 789篇 |
药学 | 2057篇 |
中国医学 | 67篇 |
肿瘤学 | 2110篇 |
出版年
2023年 | 196篇 |
2022年 | 373篇 |
2021年 | 780篇 |
2020年 | 481篇 |
2019年 | 664篇 |
2018年 | 834篇 |
2017年 | 664篇 |
2016年 | 845篇 |
2015年 | 959篇 |
2014年 | 1195篇 |
2013年 | 1739篇 |
2012年 | 2440篇 |
2011年 | 2525篇 |
2010年 | 1488篇 |
2009年 | 1286篇 |
2008年 | 2200篇 |
2007年 | 2347篇 |
2006年 | 2169篇 |
2005年 | 2087篇 |
2004年 | 2015篇 |
2003年 | 1834篇 |
2002年 | 1767篇 |
2001年 | 322篇 |
2000年 | 222篇 |
1999年 | 325篇 |
1998年 | 382篇 |
1997年 | 327篇 |
1996年 | 248篇 |
1995年 | 205篇 |
1994年 | 195篇 |
1993年 | 177篇 |
1992年 | 135篇 |
1991年 | 108篇 |
1990年 | 99篇 |
1989年 | 110篇 |
1988年 | 111篇 |
1987年 | 105篇 |
1986年 | 83篇 |
1985年 | 102篇 |
1984年 | 122篇 |
1983年 | 95篇 |
1982年 | 172篇 |
1981年 | 133篇 |
1980年 | 140篇 |
1979年 | 77篇 |
1978年 | 87篇 |
1977年 | 84篇 |
1976年 | 74篇 |
1974年 | 81篇 |
1973年 | 69篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Increase in the degree of phosphorylation of circulating fibrinogen under thrombolytic therapy with urokinase 总被引:2,自引:0,他引:2
Human fibrinogen is phosphorylated in vivo to an equal extent at two positions, one at Ser 3 located on fibrinopeptide A, the other at Ser 345 of the A alpha-chain. As has been shown previously, the degree of phosphorylation of the circulating fibrinogen pool can be determined in vitro from the ratio between the HPLC peaks formed by phosphorylated and non-phosphorylated fibrinopeptide A which has been cleaved from plasma fibrinogen by thrombin or reptilase. Plasma samples were obtained from patients with venous thrombosis undergoing fibrinolytic therapy with urokinase (n = 8). The degree of phosphorylation increased from about 35% before treatment to values between 50% and 70% within 48 hours. It remained at these high levels as long as urokinase was administered and declined slowly thereafter. This behaviour of the degree of phosphorylation of fibrinogen is explained by a model which assumes that fibrinogen is secreted in the phosphorylated form and then dephosphorylated in the circulation by an up to now unidentified phosphatase by first order kinetics. When this system is in steady state, the degree of phosphorylation is about 25% under normal conditions. If the elimination rate of fibrinogen is greatly enhanced by fibrinogenolysis the system will approach a new steady state with a higher degree of phosphorylation, the magnitude of which will depend on the new ratio of dephosphorylation and elimination. 相似文献
22.
Thomas A. Luger Harald Gollnick Thomas Schwennesen Raphael Bextermller Siegfried Freytag Matthias Brutigam 《Journal der Deutschen Dermatologischen Gesellschaft》2007,5(10):908-914
Background: Pimecrolimus cream 1% has proven to be well‐tolerated and effective in controlled clinical studies in patients with atopic dermatitis (AD). In a 15‐week patient self‐observation study, safety and efficacy was investigated in the daily practice. Patients and methods: 3502 patients with AD (mean age 26.2 ± 18 years, 62% female) received pimecrolimus cream 1% from 810 physicians in the German Federal Republic.The severity of the disease was assessed at baseline, two times during the 15‐week observation period and at the end of treatment.Patients recorded daily the degree of erythema and pruritus. At the end of treatment, safety and efficacy were assessed by the physician based on patient's daily records and by the patient. Results: The percentage of patients with severe or massive AD decreased from 25% to 7%, whereas the percentage of patients without or with mild symptoms increased from 9% to 55%.The efficacy of treatment was rated by physicians as good or very good in 83.5% of cases and by 79% of patients.At baseline 35% of the patients were free of flares as compared to 75% at the end of therapy. Disease control was better in patients who followed the recommended treatment algorithm for pimecrolimus cream.Tolerability was mostly rated as good or very good. Conclusion: Treatment with pimecrolimus cream 1% for patients with AD is well‐tolerated and effective in daily practice. 相似文献
23.
24.
Matthias Thielmann Parwis Massoudy Markus Neuh?user Stephan Knipp Markus Kamler Günter Marggraf Jarowit Piotrowski Heinz Jakob 《European journal of cardio-thoracic surgery》2005,27(5):861-869
OBJECTIVE: Cardiac troponin I (cTnI) is a highly sensitive and specific marker for postoperative prediction of patients outcome after coronary artery bypass surgery (CABG). Whether preoperatively elevated cTnI levels similarly predict the outcome in patients scheduled for elective CABG is currently unknown. METHODS: Therefore, a possible correlation between preoperative cTnI levels and perioperative major adverse events and in-hospital mortality after CABG was investigated. CTnI was measured within 24h before surgery in 1405 out of 3124 consecutive elective CABG patients. Out of these patients, 1178 had a preoperative cTnI level below 0.1ng/ml (group 1), 163 patients had a cTnI level between 0.11 and 1.5ng/ml (group 2), and 64 patients had a cTnI level above 1.5ng/ml (group 3). CTnI levels, electrocardiograms, clinical data, adverse events and in-hospital mortality were recorded prospectively. Patients with ST-elevation myocardial infarction less than 7 days before surgery were excluded from the study. RESULTS: Perioperative myocardial infarction (PMI) occurred in 69/1178 patients (5.9%) in group 1, 14/163 patients (8.6%; odds ratio (OR) 1.5, 95% confidence interval (CI): 0.8-2.8) in group 2, and 11/64 patients (17.2%; OR 3.3, CI: 1.6-7.0) in group 3 (overall: P<0.001, Cochran-Armitage trend test). Low cardiac output syndrome (LCOS) occurred in 19/1178 patients (1.6%), 9/163 (5.5%; OR 3.6, CI: 1.5-8.5), and 7/64 patients (10.9%; OR 7.5, CI: 2.7-19.8) (overall: P<0.001, group 1 vs. group 2: P<0.002), respectively. In-hospital mortality was 1.7% in group 1 and 3.1% in group 2, but 6.3% (OR 3.9, CI: 1.1-12.5) in group 3 (overall: P<0.01, group 1 vs. group 2: P=NS). Intensive care and hospital stay were significantly longer in group 3 compared to groups 1 and 2. Univariate and multivariate logistic regression analysis confirmed the statistically significant relationship between cTnI and PMI, LCOS and in-hospital mortality, respectively (P<0.001). CONCLUSIONS: Risk stratification by measurement of cTnI levels within 24h before elective CABG clearly identifies a subgroup of patients with increased risk for postoperative adverse outcome and in-hospital mortality. 相似文献
25.
Matthias Guckenberger MD Juergen Meyer Juergen Wilbert Kurt Baier Otto Sauer Michael Flentje 《Strahlentherapie und Onkologie》2007,183(6):307-313
PURPOSE: To evaluate the precision of image-guided radiotherapy (IGRT) using cone-beam computed tomography (CB-CT) for volume imaging and a robotic couch for correcting setup errors in six degrees of freedom. PATIENTS AND METHODS: 47 consecutive patients with 372 fractions were classified according to whether a patient fixation device was used (pat(fix): n = 28) or not (pat(non-fix): n = 19). Prior to treatment a CB-CT was acquired and translational and rotational setup errors were corrected online without an action level using a robotic couch (HexaPOD). A second CB-CT was acquired after the correction process and after treatment in 134 and 238 fractions, respectively. RESULTS: In 17 fractions (4.6%) rotational errors > 3 degrees exceeded the motion range of the HexaPOD. Errors (3D vector) after the correction process were significantly smaller for pat(fix) compared to pat(non-fix) (p < 0.001): 0.9 mm +/- 0.5 mm and 1.6 mm +/- 0.8 mm, respectively. For pat(non-fix) the correction of rotational errors resulted in displacements of the patients on the angled couch of 0.6 mm/1 degree. Intrafractional motion further decreased precision in pat(non-fix) but not in pat(fix). CONCLUSION: Very high precision in cranial and extracranial treatment of immobilized patients was demonstrated. Without application of adequate immobilization the correction of rotational errors and intrafractional patient motion significantly decreased the accuracy of the online correction protocol. 相似文献
26.
27.
Carl E Bartecchi 《Journal of the American College of Cardiology》2006,47(7):1498-9; author reply 1499-500
28.
Carl A Kirker-Head David C Van Sickle Steve W Ek John C McCool 《Journal of orthopaedic research》2006,24(5):1095-1108
Focal full-thickness cartilage lesions of the human medial femoral condyle (MFC) can cause pain and functional impairment. Affected middle-aged patients respond unpredictably to existing treatments and knee arthroplasty may be required, prompting risk of revision. This study assesses the safety of, and biological and functional response to, a metallic resurfacing implant which may delay or obviate the need for traditional arthroplasty. The anatomic contour of the surgically exposed MFC of six adult goats was digitally mapped and an 11 mm diameter full-thickness osteochondral defect was created. An anchor-based Co-Cr resurfacing implant, matching the mapped articular contour, was implanted. Each goat's contralateral unoperated femorotibial joint was used as a control. Postoperative outcome was assessed by lameness examination, radiography, arthroscopy, synoviocentesis, necropsy, and histology up to 26 (n = 3) or 52 (n = 3) weeks. By postoperative week (POW) 4, goats demonstrated normal range of motion, no joint effusion, and only mild lameness in the operated limb. By POW 26 the animals were sound with only occasional very mild lameness. Arthroscopy at POW 14 revealed moderate synovial inflammation and a chondral membrane extending centrally across the implant surface. Radiographs at POWs 14 to 52 implied implant stability in the operated joints, as well as subchondral bone remodeling and mild exostosis formation in the operated and contralateral unoperated joints of some goats. By POW 26, histology revealed new trabecular bone abutting the implant. At POWs 26 and 52 MFC cartilage was metachromatic and intact in the operated and unoperated femorotibial joints. Proximal tibiae of some operated and unoperated limbs demonstrated limited subchondral bone remodeling and foci of articular cartilage fibrillation and thinning. The chondral membrane crossing the prosthesis possessed a metachromatic matrix containing singular and clustered chondrocytes. Our data imply the safety, biocompatibility, and functionality of the implant. Focal articular damage was documented in the operated joints at POWs 26 and 52, but lesions were much reduced over those previously reported in untreated defects. Expanded animal or preclinical human studies are justified. 相似文献
29.
30.