全文获取类型
收费全文 | 25653篇 |
免费 | 1404篇 |
国内免费 | 136篇 |
专业分类
耳鼻咽喉 | 210篇 |
儿科学 | 495篇 |
妇产科学 | 525篇 |
基础医学 | 4181篇 |
口腔科学 | 538篇 |
临床医学 | 2237篇 |
内科学 | 4783篇 |
皮肤病学 | 793篇 |
神经病学 | 2524篇 |
特种医学 | 1974篇 |
外国民族医学 | 2篇 |
外科学 | 3157篇 |
综合类 | 115篇 |
一般理论 | 7篇 |
预防医学 | 1168篇 |
眼科学 | 387篇 |
药学 | 2227篇 |
中国医学 | 31篇 |
肿瘤学 | 1839篇 |
出版年
2022年 | 180篇 |
2021年 | 334篇 |
2020年 | 252篇 |
2019年 | 333篇 |
2018年 | 368篇 |
2017年 | 335篇 |
2016年 | 435篇 |
2015年 | 541篇 |
2014年 | 678篇 |
2013年 | 859篇 |
2012年 | 1350篇 |
2011年 | 1434篇 |
2010年 | 871篇 |
2009年 | 893篇 |
2008年 | 1453篇 |
2007年 | 1545篇 |
2006年 | 1515篇 |
2005年 | 1466篇 |
2004年 | 1446篇 |
2003年 | 1474篇 |
2002年 | 1441篇 |
2001年 | 586篇 |
2000年 | 499篇 |
1999年 | 487篇 |
1998年 | 399篇 |
1997年 | 350篇 |
1996年 | 285篇 |
1995年 | 247篇 |
1994年 | 213篇 |
1993年 | 221篇 |
1992年 | 252篇 |
1991年 | 258篇 |
1990年 | 226篇 |
1989年 | 252篇 |
1988年 | 233篇 |
1987年 | 207篇 |
1986年 | 171篇 |
1985年 | 182篇 |
1984年 | 172篇 |
1983年 | 151篇 |
1982年 | 141篇 |
1981年 | 129篇 |
1980年 | 144篇 |
1979年 | 147篇 |
1978年 | 108篇 |
1977年 | 126篇 |
1976年 | 111篇 |
1975年 | 104篇 |
1974年 | 134篇 |
1973年 | 110篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Ligia Teban Hubert Pehamberger Klaus Wolff Michael Binder Harald Kittler 《Journal der Deutschen Dermatologischen Gesellschaft》2003,1(4):292-296
Background and objectives: The aim of this study was to evaluate the practical value of the dermatoscopic classification of Clark nevi Patients and methods: Dermatoscopic images of 268 lesions clinically and dermatoscopically diagnosed as Clark nevi were presented to 2 dermatologists without knowledge of the histological diagnosis. The dermatologists evaluated the lesions according to a simplified version of the classification scheme for Clark nevi proposed by Hofmann‐Wellenhof and differentiated between 12 different types of Clark nevi. Results: The most common type of Clark nevus was the reticular‐homogenous type (n = 64, 23,9 %), followed by the globular‐homogeneous type (n = 32, 12 %) and by the homogenous type (n = 30, 11,2 %). The overall inter‐rater agreement between the examiners was moderate to good (kappa = 0,58). The highest level of agreement was found for the peripheral hyperpigmented type (kappa = 0,83). Histologically, 17 lesions (6,3 %) were diagnosed as melanomas. The frequency of melanoma was highest among the peripheral‐hyperpigmented type for one observer and among the homogenous type for the other observer. No melanoma was found among the globular, reticular‐globular, and the central‐hyperpigmented types. Conclusions: A dermatoscopic classification of Clark nevi is practically feasible and allows – to some extent – a risk stratification of Clark nevi, which could be useful for clinical management. 相似文献
22.
Conventional radiographs do not always make it possible to confirm a diagnosis of ischemic necrosis of the lunate in the early stages of disease. For these doubtful cases MRI is justifiable in addition, to diagnose or to rule out ischemic necrosis of the lunate. 相似文献
23.
Monitoring left ventricular dilation in mice with PET. 总被引:3,自引:0,他引:3
Lars Stegger Klaus P Sch?fers Ulrich Fl?gel Lefteris Livieratos Sven Hermann Christoph Jacoby Petra Keul Edward M Conway Otmar Schober Jürgen Schrader Bodo Levkau Michael Sch?fers 《Journal of nuclear medicine》2005,46(9):1516-1521
Molecular imaging by small-animal PET is an important noninvasive means to phenotype transgenic mouse models in vivo. When investigating pathologies of the left ventricular (LV) myocardium, the serial assessment of LV volumes is important. By this, the presence of LV dilation as a sign of developing heart failure can be detected. Whereas PET is usually used to derive biochemical and molecular information, functional parameters such as ventricular volumes are generally measured using echocardiography or MRI. In this study, a novel method to monitor LV dilation in mice with PET is presented and evaluated using cardiac MRI. METHODS: A semiautomatic 3-dimensional algorithm was used to delineate the LV myocardial wall on static PET images depicting myocardial glucose metabolism ((18)F-FDG PET) for 20 mice: 10 wild-type and 10 genetically modified littermates designed to develop a dilative cardiomyopathy phenotype (cardiomyocyte-specific knockout of survivin). The volume enclosed by the 3-dimensional midmyocardial contour was calculated as a measure for LV volume for each mouse. Data were compared with ventricular volumes measured by MRI in the same animals. RESULTS: LV volumes obtained by PET and MRI correlated well (R = 0.89) for hearts with small and large left ventricles. In accordance with the hypothesis, the LV volumes were increased significantly for transgenic mice examined at an older age compared with those examined at a younger age (MRI: 160.5 +/- 25.7 microL vs. 114.7 +/- 15.2 microL [P = 0.012]; PET: 129.3 +/- 15.3 microL vs. 73.8 +/- 15.0 microL [P < 0.001], all values shown as mean +/- SD; for MRI, mean of end-diastolic and end-systolic volumes are given), whereas they did not for their wild-type littermates (MRI: 106.2 +/- 12.3 microL vs. 94.7 +/- 14.6 microL [P = 0.214]; PET: 82.6 +/- 20.9 microL vs. 65.0 +/- 16.9 microL [P = 0.185]). CONCLUSION: Evaluation and quantitation of LV dilation in both control and cardiomyopathic mice can be reliably and serially performed using small-animal PET and (18)F-FDG, yielding useful functional information in addition to metabolic data. 相似文献
24.
When arthrodesis of the knee is indicated, the operative procedure selected for fixation depends on the condition of the soft tissues, the bone stock, whether infection is present, and the age of the patient and his or her capacity for partial weight-bearing. In young patients with no infection or soft tissue problems, when adequate bone stock is present compression plating or the use of an intramedullary nail is possible and allows stable fixation. Soft tissue problems with defect(s) or infection are a good indication for the use of an external fixator. The most common indication for knee arthrodesis is a failed total knee prosthesis that has become infected. Deficient bone stock with osteopenic bone or a defect after failed total knee arthroplasty are problems that can be solved by the use of modular fusion nail systems, especially in older patients. These systems are more comfortable for the patient than external fixation devices and allow early full weight-bearing. 相似文献
25.
26.
Sami R Achem MD Alexander Klaus MD Ronald A Hinder MD PhD Kenneth R DeVault MD 《The American journal of medicine》2004,116(10):717-718
27.
Albert B. Zajko M.D. Klaus M. Bron William L. Campbell 《Cardiovascular and interventional radiology》1987,10(1):28-31
Biliary obstruction and multiple hepatic abscesses occurred in a patient after ligation of a segmental branch of the right
hepatic duct. The patient was successfully managed by transhepatic biliary drainage and balloon dilatation of an internal
fistula that developed between the ligated duct and a Roux limb of jejunum. Internal biliary fistulas may be dilated using
interventioanl radiologic techniques to permit nonobstructed bile flow. Implications for the nonsurgical treatment' of biliary
strictures are discussed. 相似文献
28.
Asymmetric Electrophilic α-Amidoalkylation, 4): Generation and Trapping Reactions of Chiral N- Acylpyrrolidiniumions The pyrrole derivatives 1 , 6 , and 10 react in the presence of TiCl4 with the silyl enol ether 3 to form α-substituted pyrrolidine amides steroselectively. 6 and 10 (after HCl-addition = > 11 ) react even at ?78°C, the reaction of 10 exceeds that of 6 in yield and stereoselectivity. 相似文献
29.
30.
Dr Klaus Rieneck 《European journal of haematology》2006,76(5):451-452