全文获取类型
收费全文 | 7719篇 |
免费 | 507篇 |
国内免费 | 46篇 |
专业分类
耳鼻咽喉 | 27篇 |
儿科学 | 74篇 |
妇产科学 | 74篇 |
基础医学 | 994篇 |
口腔科学 | 95篇 |
临床医学 | 742篇 |
内科学 | 1775篇 |
皮肤病学 | 224篇 |
神经病学 | 572篇 |
特种医学 | 597篇 |
外科学 | 1522篇 |
综合类 | 33篇 |
一般理论 | 2篇 |
预防医学 | 322篇 |
眼科学 | 48篇 |
药学 | 370篇 |
中国医学 | 29篇 |
肿瘤学 | 772篇 |
出版年
2023年 | 49篇 |
2022年 | 77篇 |
2021年 | 164篇 |
2020年 | 117篇 |
2019年 | 155篇 |
2018年 | 187篇 |
2017年 | 155篇 |
2016年 | 207篇 |
2015年 | 202篇 |
2014年 | 267篇 |
2013年 | 366篇 |
2012年 | 512篇 |
2011年 | 571篇 |
2010年 | 358篇 |
2009年 | 349篇 |
2008年 | 520篇 |
2007年 | 514篇 |
2006年 | 541篇 |
2005年 | 555篇 |
2004年 | 463篇 |
2003年 | 467篇 |
2002年 | 437篇 |
2001年 | 94篇 |
2000年 | 77篇 |
1999年 | 79篇 |
1998年 | 108篇 |
1997年 | 97篇 |
1996年 | 61篇 |
1995年 | 47篇 |
1994年 | 32篇 |
1993年 | 23篇 |
1992年 | 26篇 |
1991年 | 24篇 |
1990年 | 22篇 |
1989年 | 25篇 |
1988年 | 21篇 |
1987年 | 28篇 |
1986年 | 29篇 |
1985年 | 19篇 |
1984年 | 22篇 |
1983年 | 13篇 |
1982年 | 11篇 |
1981年 | 19篇 |
1980年 | 16篇 |
1979年 | 11篇 |
1978年 | 9篇 |
1977年 | 6篇 |
1976年 | 13篇 |
1974年 | 7篇 |
1929年 | 5篇 |
排序方式: 共有8272条查询结果,搜索用时 15 毫秒
51.
Peter Albers Roswitha Siener Sabine Kliesch Lothar Weissbach Susanne Krege Christoph Sparwasser Harald Schulze Axel Heidenreich Werner de Riese Volker Loy Erhard Bierhoff Christian Wittekind Rolf Fimmers Michael Hartmann 《Journal of clinical oncology》2003,21(8):1505-1512
PURPOSE: To prospectively assess potential risk factors for relapse in clinical stage I nonseminomatous germ cell tumors of the testis (CS I NSGCT). PATIENTS AND METHODS: From September 1996 to May 2002, 200 patients with CS I NSGCT were prospectively assigned to retroperitoneal lymph node dissection (RPLND), and risk factor assessment was performed within a multicenter protocol. One hundred sixty-five patients had an adequate minimum follow-up of 12 months (mean, 34.5 months) or had pathologic stage II. RESULTS: Pathologic stage II disease was found in 27.9% of patients. Only 0.6% of patients relapsed in the retroperitoneum after confirmation of pathologic stage I disease. With reference pathology, vascular invasion (VI) was most predictive of stage in multifactorial analysis (accuracy, 65.1%). However, the positive predictive value (PPV) of VI to predict patients who have metastatic disease or relapse during follow-up was only 52.7%. With absent VI, low-risk patients had a negative predictive value (NPV) of 76.9%. With a combination of several risk factors, the PPV increased to 63.6% and the negative predictive value increased to 86.5%. CONCLUSION: Even with an optimal combination of prognostic factors and reference pathology, more than one third of patients predicted to have pathologic stage II or relapse during follow-up will not harbor metastatic disease and, therefore, would be overtreated with adjuvant therapy. However, patients at low risk may be predicted at an 86.5% level, and thus, surveillance in highly compliant patients would be a valuable option. For high-risk patients, further reduction of adjuvant treatment is necessary. 相似文献
52.
Cholecystectomy: costs and health-related quality of life: a comparison of two techniques. 总被引:3,自引:0,他引:3
Erik Nilsson Axel Ros Mikael Rahmqvist Karin B?ckman Per Carlsson 《International journal for quality in health care》2004,16(6):473-482
BACKGROUND: Outcomes of previous health economic evaluations comparing minilaparotomy cholecystectomy and laparoscopic cholecystectomy have been inconsistent. OBJECTIVE: To compare costs for minilaparotomy cholecystectomy and laparoscopic cholecystectomy and to study changes in quality of life induced by these operations. DESIGN: Single-blind, randomized controlled trial, run from 1 March 1997 to 30 April 1999. SETTING: One university hospital and four non-university hospitals in Sweden. MAIN MEASURE: : Cost and perceived health estimation according to the global quality of life instrument EuroQol-5D. RESULTS: Of 1719 cholecystectomy patients at five centres, 724 entered the trial and were treated with minilaparotomy cholecystectomy or laparoscopic cholecystectomy, 362 in each group. Total health care costs were less for minilaparotomy cholecystectomy than for laparoscopic cholecystectomy (median values US$2428 for minilaparotomy cholecystectomy versus US$2613 or US$3006 for laparoscopic cholecystectomy with 100 operations per year and reusable trocars or 50 operations per year and disposable trocars, respectively). There was no significant difference in total costs (including costs due to loss of production) between minilaparotomy cholecystectomy and laparoscopic cholecystectomy with 100 operations per year and reusable trocars in laparoscopic cholecystectomy (US$3731 versus US$3649, respectively). However, in calculations assuming 50 operations per year and disposable trocars in laparoscopic cholecystectomy, this technique was more expensive than minilaparotomy cholecystectomy (US$4042 versus US$3731). Health-related quality of life was slightly but significantly lower for the minilaparotomy cholecystectomy group 1 week after surgery. One month and 1 year postoperatively no difference between the randomized groups was found. CONCLUSION: Total costs did not differ between minilaparotomy cholecystectomy and laparoscopic cholecystectomy with high-volume surgery and disposable trocars, whereas laparoscopic cholecystectomy was more expensive with fewer operations and disposable trocars. The gain in health-related quality of life with laparoscopic cholecystectomy compared with minilaparotomy cholecystectomy was small and of limited duration. 相似文献
53.
Axel Müller Johannes Schweizer Detlef Quietzsch Rainer Koch Günther Voigt 《Zeitschrift fur Gesundheitswissenschaften》2004,12(2):111-122
Myocardial infarction has great importance for the populations in industrial countries because of the high morbidity and mortality rates. For research of the epidemiological trends in the 1970s and especially in the 1980s, the World Health Organization (WHO) began registering myocardial infarction throughout the world. The most important aspect was the WHO Monitoring of Trends and Determinants of Cardiovascular Diseases (MONICA) project. From 1974 to 1994 and in 1999 in Chemnitz, Germany, data from patients with acute myocardial infarction were collected for the myocardial infarction register. Despite changes in the event rates from year to year, no decrease in the number of myocardial infarctions in the German population aged 25–64 years was detected, contrary to the trend in the Western industrial states in the period from 1984 to 1994. The event rates in men were significantly higher than in women. In 1999, a significant decrease in the event rates in men and women was found. This may be explained by an incomplete registration of patients with myocardial infarction in 1999 because of the change in the structure of the Public Health System. The highest 28-day fatality rates in men were detected in 1989 and 1990. In women with classic myocardial infarction, a decrease in the 28-day fatality rates after 1993 was recorded, reaching lower rates than those of men. Despite methodological problems, the myocardial infarction register can contribute to a comparison of the morbidity, mortality and case fatality rates of myocardial infarction for a longer period. 相似文献
54.
John Kirkland David Bimler Andrew Drawneek Margaret McKim Axel Sch lmerich 《Early child development and care》2004,174(7):701-719
Attachment Q-Sort (AQS) is a tool for quantifying observations about toddler/caregiver relationships. Previous studies have applied factor analysis to the full 90 AQS item set to explore the structure underlying them. Here we explore that structure by applying multidimensional scaling (MDS) to judgements of inter-item similarity. AQS items are arranged in the MDS solution along three easily interpretable axes: a model that is compatible with but more parsimonious than factor analysis solutions. This geometrical approach suggests ways to modify the AQS—primarily a research tool—to make it more practical for clinical applications. Sets of AQS data are represented and interpreted in the three-dimensional model as vectors. Summaries at a finer-grained level are obtained by finding points in the model where variability across datasets is greatest. We report re-analyses of archival (published) data, and also data collected with streamlined procedures more suitable in the field. Although not reported here, collection and analysis can both be performed online via a website. The general methodology is not restricted to the current application of toddler attachment. 相似文献
55.
针灸的主要作用是促进气血的运行,有理由相信针刺所有的穴位都有这样的功能.本文认为针灸的治疗效应在于针刺部分最为有效的穴位就可以成功治疗任何疾病.理论依据就是气,气分阴阳,分属五行.道生一,一生气,气生阴阳,阴阳生四季和五行,五行创造了人和万物.医生可以根据阴阳五行辨证,也可以根据气辨证.由于气比阴阳五行的层次高,因此在气的水平上选择穴位将优于阴阳辨证.作者把根据其进行辨证成为"气针刺"."气针刺"在4个层面上有不同的取穴策略:时间针刺,基本穴位,远道取穴和局部取穴或阿是穴. 相似文献
56.
Li F Maskey RP Qin S Sattler I Fiebig HH Maier A Zeeck A Laatsch H 《Journal of natural products》2005,68(3):349-353
In our screening of marine Streptomycetes for bioactive principles, two novel antitumor antibiotics designated as chinikomycins A (2a) and B (2b) were isolated together with manumycin A (1), and their structures were elucidated by a detailed interpretation of their spectra. Chinikomycins A (2a) and B (2b) are chlorine-containing aromatized manumycin derivatives of the type 64-pABA-2 with an unusual para orientation of the side chains. They exhibited antitumor activity against different human cancer cell lines, but were inactive in antiviral, antimicrobial, and phytotoxicity tests. 相似文献
57.
58.
Tim Laussmann Ireneus Grzesiak Alexander Krest Kathrin Stirnat Sigrid Meier‐Giebing Uwe Ruschewitz Axel Klein 《Drug testing and analysis》2015,7(1):56-64
The chemical composition of a black powder confiscated by German customs was elucidated. Black powders are occasionally used as a ‘transporter’ for cocaine and are obviously especially designed to cloak the presence of the drug. The material consisting of cocaine, copper, iron, thiocyanate, and graphite was approached by analytical tools and chemical modelling. Graphite is added to the material probably with the intention of masking the typical infrared (IR) fingerprints of cocaine and can be clearly detected by powder X‐ray diffraction (XRD) and Raman spectroscopy. Cu2+ and NCS? ions, when carefully reacted with cocaine hydrochloride, form the novel compound (CocH)2[Cu(NCS)4] (CocH+ = protonated cocaine), which has been characterised by single crystal XRD, IR, NMR, UV/Vis absorption and EPR spectroscopy. Based on some further experiments the assumed composition of the original black powder is discussed. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
59.
J. Axel Zeitler Lynn F. Gladden 《European journal of pharmaceutics and biopharmaceutics》2009,71(1):2-22
Tomographic imaging techniques offer new prospects for a better understanding of the quality, performance and release mechanisms of pharmaceutical solid dosage forms. It is only over the last fifteen years that tomography has been applied for the in-vitro characterisation of dosage forms. This review aims to introduce the concept of tomography in a pharmaceutical context, and describes the current state-of-the-art of the four most promising techniques: X-ray computed microtomography, magnetic resonance imaging, terahertz imaging and optical coherence tomography. The basic working principles of the techniques are introduced and the current pharmaceutical applications of the technologies are discussed, together with a comparison of their specific strengths and weaknesses. Possible future developments in these fields are also discussed. 相似文献
60.
James Larkin Michele Del Vecchio Paolo A Ascierto Ivana Krajsova Jacob Schachter Bart Neyns Enrique Espinosa Claus Garbe Vanna Chiarion Sileni Helen Gogas Wilson H Miller Mario Mandalà Geke A P Hospers Ana Arance Paola Queirolo Axel Hauschild Michael P Brown Lada Mitchell Christian U Blank 《The lancet oncology》2014,15(4):436-444