首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   6757篇
  免费   501篇
  国内免费   22篇
耳鼻咽喉   22篇
儿科学   252篇
妇产科学   121篇
基础医学   1274篇
口腔科学   77篇
临床医学   758篇
内科学   1356篇
皮肤病学   224篇
神经病学   683篇
特种医学   133篇
外科学   748篇
综合类   37篇
一般理论   2篇
预防医学   360篇
眼科学   74篇
药学   408篇
中国医学   20篇
肿瘤学   731篇
  2023年   40篇
  2022年   59篇
  2021年   98篇
  2020年   97篇
  2019年   122篇
  2018年   154篇
  2017年   114篇
  2016年   141篇
  2015年   166篇
  2014年   184篇
  2013年   289篇
  2012年   470篇
  2011年   514篇
  2010年   279篇
  2009年   293篇
  2008年   459篇
  2007年   541篇
  2006年   468篇
  2005年   507篇
  2004年   468篇
  2003年   434篇
  2002年   403篇
  2001年   69篇
  2000年   39篇
  1999年   68篇
  1998年   80篇
  1997年   83篇
  1996年   71篇
  1995年   65篇
  1994年   57篇
  1993年   36篇
  1992年   31篇
  1991年   28篇
  1990年   24篇
  1989年   29篇
  1988年   32篇
  1987年   26篇
  1986年   16篇
  1985年   20篇
  1984年   19篇
  1983年   16篇
  1982年   22篇
  1981年   8篇
  1980年   21篇
  1979年   9篇
  1978年   9篇
  1977年   8篇
  1975年   9篇
  1974年   9篇
  1971年   8篇
排序方式: 共有7280条查询结果,搜索用时 93 毫秒
11.
12.
BACKGROUND AND OBJECTIVES: Two absorbable polydioxanone threads are compared regarding intraoperative handling qualities, scar dehiscence, and possible side effects. METHODS: In 30 excisions, half of each suture was performed with PDS II (Ethicon GmbH, Norderstedt, Germany), whereas the other half was closed with Serasynth (Serag-Wiessner, Naila, Germany). Clinical evaluation for scar spreading, spitting of the sutures, hypertrophic scarring, or suture granuloma was performed 3 and 6 months after surgery. RESULTS: No significant difference in scar spreading, hypertrophic scarring, or the incidence of suture granuloma was noted. A significantly lower frequency of spitting was seen with Serasynth than with PDS. The handling and suturing properties of SerasynthM were estimated to be slightly superior compared with those of PDS. CONCLUSION: Our study shows that PDS and Serasynth provide equal cosmetic results when applied in an appropriate suturing technique. Possibly owing to its better pliability, the frequency of spitting was lower with Serasynth.  相似文献   
13.
To evaluate the reliability of Doppler ultrasonography (US) in identifying children with renal artery stenosis (RAS) among those with hypertension, we compared Doppler US results in 22 hypertensive children (mean age 8.9±4.3 years), with (13 cases) and without RAS at angiography, and in 33 normotensive children (mean age 8.8±4.7 years). We observed 2 false-negatives and 2 false-positives with Doppler US. Of the 2 false-negative diagnoses, 1 had RAS on an accessory renal artery located behind a normal upper polar artery and the other was observed in a patient with bilateral multiple stenosis of the very distal segments of renal arteries. The 2 false-positive diagnoses were due to sinuous left renal artery and to technical reasons, respectively. In another patient, Doppler US showed a tight RAS, while arteriography was normal. RAS was subsequently confirmed by a second arteriography. Peak systolic velocity values of Doppler US were significantly higher in patients with proven angiographic RAS (3.44±0.66 m/s) than in hypertensive patients with normal renal arteries at angiography (0.99±0.35 m/s, P <0.0001) and normotensive healthy children (1.04±0.23 m/s, P <0.0001). With the use of multiple views, and the experience acquired with practice, false-negatives or false-positives due to the geometry of the renal artery can be avoided. Nevertheless, very distal stenosis can be missed by Doppler US. Received October 30, 1995; received in revised form April 16, 1996; accepted May 14, 1996  相似文献   
14.
15.
16.
OBJECTIVES: The purpose of this study was to evaluate both reliability and validity of the assessment of the shape of the mandibular condyle in panoramic images of the TMJ. STUDY DESIGN: Forty subjects were included and were examined according to the Research Diagnostic Criteria for Temporomandibular Disorders. Panoramic radiographs (PRs) and magnetic resonance images (MRIs) were completed for all subjects. Both MRIs and PRs were rated by raters blinded to the clinical diagnosis. Kappa statistics were used to compare the results of the raters of the PRs. Additionally, the specificity and the sensitivity of the PRs were calculated for 2 scenarios: one with MRI and the other with clinical findings as the gold standard. RESULTS: The sensitivity was 0.94 (specificity = 0.45) for the assumption that MRI is the gold standard and 0.86 (specificity = 0.49) for the assumption that the clinical examination is the gold standard. For reliability, the results for kappa ranged from 0.06 to 0.327. CONCLUSION: It can be concluded that PRs are not a reliable method of accurately judging the shape of the mandibular condyle.  相似文献   
17.
Valproic acid (VPA) is a broad-spectrum antiepileptic drug and is usually well-tolerated. Rare serious complications may occur in some patients, including haemorrhagic pancreatitis, bone marrow suppression, VPA-induced hepatotoxicity and VPA-induced encephalopathy. The typical signs of VPA-induced encephalopathy are impaired consciousness, sometimes marked EEG background slowing, increased seizure frequency, with or without hyperammonemia. There is still no proof of causative effect of VPA in patients with encephalopathy, but only of an association with an assumed causal relation. We report 19 patients with VPA-associated encephalopathy in Germany from the years 1994 to 2003, none of whom had been published previously.  相似文献   
18.
BioArgos (Sanofi Diagnostics Pasteur, Marnes-la-Coquette, France) is a fully automated blood culture system that detects carbon dioxide production by infrared spectroscopy through a glass bottle. This hands-off system was compared with the BACTEC NR-660 system (Becton Dickinson Diagnostic Instrument Systems, Towson, Md.). A total of 336 microorganisms belonging to 74 taxa were tested in simulated blood cultures by both systems. Experimental data showed no significant differences between the two systems. The inclusive detection times (+/- the standard deviations) were 33.2 +/- 28.7 and 35.0 +/- 30.6 h with BioArgos and BACTEC, respectively. Anaerobes were detected earlier with BioArgos, whereas detection of some organisms that need oxygen to grow was slightly delayed. In conclusion, BioArgos is as reliable and accurate as BACTEC NR-660 and shows better practicability owing to noninvasive detection, reduction of vial manipulation, and absence of daily maintenance.  相似文献   
19.
Greim  Brigitte  Engel  Claudia  Apel  Annett  Zettl  Uwe K. 《Journal of neurology》2007,254(2):II102-II106
Journal of Neurology - Fatigue is a widespread symptom in numerous neuroimmunological diseases like multiple sclerosis (MS), myasthenia gravis, morbus Behcet, neurosarcoidosis, neuroborreliosis or...  相似文献   
20.
Aim: There is strong evidence that hepatocellular apoptosis is not only initiated by circulating blood cells which become adherent within the endotoxemic liver, but also contributes to further sustain the inflammatory cell-cell response. Methods: Because previous studies assumed the importance of the role of cellular cross-talk in mediating inflammatory liver injury, we herein examined the activation of Kupffer cells (KCs) and their spatial coincidence with intrahepatic leukocyte adherence and hepatocellular apoptosis at 6 h after intraperitoneal exposure of rats with lipopolysaccharide (10 mg/kg). Results: In vivo multifluorescence microscopy revealed liver injury including nutritive perfusion failure, tissue hypoxia, leukocyte accumulation, as well as KC activation and parenchymal apoptotic cell death. Detailed spatial analysis revealed frequent colocalization of activated KCs with apoptotic hepatocytes. Colocalization was absent in saline-treated controls.Colocalization was confirmed by histochemistry, which showed ED1-positive KCs neighboring and engulfing TUNEL-positive hepatocytes. Colocalization of KCs with leukocytes ranged between 4% and 5% and did not increase in endotoxemic animals. Taken together, the present results indicate that apoptotic cell death of hepatocytes may stimulate phagocytosis by neighboring KCs. Direct KC-leukocyte contact seems not to be mandatory for cellular communication in the process of hepatocellular apoptosis. Conclusion: With respect to the fundamental importance of cell apoptosis, improved knowledge of these cell-cell interactions might allow the development of new therapeutic strategies through the regulation of apoptotic cell death.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号