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   345篇
  免费   9篇
  国内免费   4篇
耳鼻咽喉   2篇
儿科学   9篇
妇产科学   1篇
基础医学   29篇
口腔科学   42篇
临床医学   25篇
内科学   40篇
神经病学   14篇
特种医学   17篇
外科学   131篇
综合类   15篇
预防医学   6篇
眼科学   5篇
药学   9篇
肿瘤学   13篇
  2018年   4篇
  2015年   9篇
  2014年   11篇
  2013年   24篇
  2012年   20篇
  2011年   12篇
  2010年   15篇
  2009年   6篇
  2008年   11篇
  2007年   3篇
  2006年   6篇
  2005年   4篇
  2004年   5篇
  2003年   3篇
  2002年   5篇
  2000年   2篇
  1999年   6篇
  1998年   4篇
  1997年   11篇
  1996年   4篇
  1995年   8篇
  1994年   3篇
  1993年   4篇
  1992年   6篇
  1991年   4篇
  1990年   8篇
  1989年   7篇
  1988年   3篇
  1987年   4篇
  1986年   7篇
  1985年   4篇
  1984年   4篇
  1983年   3篇
  1982年   2篇
  1981年   3篇
  1979年   2篇
  1978年   5篇
  1977年   11篇
  1976年   13篇
  1975年   13篇
  1974年   10篇
  1973年   11篇
  1972年   13篇
  1971年   8篇
  1970年   11篇
  1969年   4篇
  1967年   3篇
  1966年   3篇
  1965年   4篇
  1964年   3篇
排序方式: 共有358条查询结果,搜索用时 15 毫秒
61.
62.
Our study aimed to evaluate the oral cavity as a reservoir from where Helicobacter pylori may be transmitted. Histology and PCR amplification were performed. Eighty-four percent of the stomach biopsies tested positive; however, H. pylori was not detected in dental samples, indicating the absence of H. pylori within the oral cavity.  相似文献   
63.

Objective

To investigate the antidiabetic properties of aqueous extract of stem bark of Afzelia africana (A. africana) and its beneficial effect on haematological parameters in streptozotocin induced diabetic rats.

Methods

A total of 30 rats including 24 diabetic and 6 normal rats were used for this study. Diabetes was induced in male Wistar rats by intraperitoneal injection of streptozotocin. After being confirmed diabetic, animals were orally treated with distilled water or extracts at 100 or 200 mg/kg body weight daily for 10 days. The haematological parameters including red blood and white blood cells and their functional indices were evaluated in diabetic treated groups compared with the controls.

Results

The extract significantly reduced the blood glucose levels while the best result was obtained at 200 mg/kg body weight. The feed and water intake in diabetic rats were significantly reduced while weight loss was minimized at both dosages. Similarly, the levels of red blood, white blood cells and their functional indices were significantly improved after extract administration at both doses.

Conclusions

It can be concluded that the aqueous extract of bark of A. africana possesses antihyperglycemic properties. In addition, the extract can prevent various complications of diabetes and improve some haematological parameters. Further experimental investigation is needed to exploit its relevant therapeutic effect to substantiate its ethnomedicinal usage.  相似文献   
64.
65.
Recent studies revealed cardiac autonomic dysfunction in patients with acute schizophrenia, which appears to be mainly related to reduced vagal and increased sympathetic modulation. To understand the significance of cardiac autonomic function in patients with schizophrenia, we extended these studies to relatives of patients. In this study, we assessed cardiac autonomic modulation in healthy first-degree relatives of patients with schizophrenia (n = 36) to investigate a putative genetic influence. Data were compared with control subjects matched for age, gender, and physical activity as well as to patients suffering from schizophrenia. First-degree relatives showed an attenuated, yet identical pattern in autonomic dysfunction as patients with decreased vagal modulation of heart rate, decreased baroreflex sensitivity, but no difference in blood pressure variability could be detected. The patients'' relatives also showed a similar pattern in regards to QT variability. In addition, the subgroup comparison of offspring vs. siblings showed a significant difference in heart rate variability suggesting a higher degree of heritability in offspring. In conclusion, the pattern of autonomic dysfunction seen in patients and relatives might indicate underlying disease-inherent genetic vulnerability, especially because autonomic parameters are heritable. In addition, these findings may be of value to identify the high-risk group of patients'' relatives in regards to serious cardiovascular events so that early preventive measures can be taken.  相似文献   
66.
Significant pain can occur after removing transhepatic catheters from biliary access tracks, after percutaneous biliary drainage (PBD) or stenting. We undertook a randomized prospective study to ascertain whether track embolization decreases the amount of pain or analgesic requirement after PBD. Fifty consecutive patients (M:F, 22:28; age range:29–85 years; mean age: 66.3 years) undergoing PBD were randomized to receive track embolization or no track embolization after removal of biliary drainage catheters. A combination of Lipoidol and n-butyl cyanoacrylate were used to embolize transhepatic tracks using an 8F dilator. The patients who did not have track embolization performed had biliary drainage catheters removed over a guide wire. A visual analog scoring (VAS) system was used to grade pain associated with catheter removal, 24 h afterward. A required analgesic score (RAS) was devised to tabulate the analgesia required. No analgesia had a score of 0, oral or rectal nonopiate analgesics had a score of 1, oral opiates had a score of 2, and parenteral opiates had a score of 3. The average VAS and RAS for both groups were calculated and compared. Seven patients were excluded for various reasons, leaving 43 patients in the study group. Twenty-one patients comprised the embolization group and 22 patients comprised the nonembolization group. The mean biliary catheter dwell time was not significantly different (p > 0.05) between the embolization group and nonembolization (mean: 5.4 days vs 6.9 days, respectively). In the nonembolization group, the mean VAS was 3.4. Eight patients required parenteral opiates, three patients required oral opiates, and five patients required oral or rectal analgesics, yielding a mean RAS of 1.6. In the embolization group, the mean VAS was 0.9. No patient required parenteral opiates, six patients required oral opiates, and two patients had oral analgesia. The average RAS was 0.6. Both the VAS and the RAS were significantly lower in the embolization group compared with the nonembolization group (p < 0.0023 and p < 0.002, respectively). No complications were seen related to track embolization. Percutaneous track embolization after removal of biliary drainage catheters decreases patient’s perception of pain and decreases the amount of required analgesia. In particular, the amount of opiate analgesia required is considerably less.  相似文献   
67.
Zusammenfassung Nivellierungsbögen aus verseilten Stahldrähten wurden mit Nickel-Titanium-Drähten der neuen Generation, ausgezeichnet durch Formgedächtnis, Superelastizität und exzellentes Rückstellvermögen, verglichen. Die im Biegeversuch ermittelten Werte wurden statistisch aufbereitet und ergaben eine lineare Kraftweg-Kennlinie der verseilten Stahldrähte. Die Nickel-Titanium-Drähte zeigten aber eine deutliche Abweichung von der Linearität mit kurviger Verlaufsform. Neben der atypischen Kraftweg-Kennlinie mit einer konstanten Kraftabgabe im Mittel der Kurve gaben diese Drähte, unabhängig vom Aktivierungsgrad (das heißt unabhängig davon, ob die Stufe zwischen den Brackets 1 oder 4 mm betrug), dieselbe Kraft ab. Je größer die Aktivierung zwischen den Brackets war, desto länger stellte sich der Bereich der konstanten Kraftabgabe-die Superelastizität-im Diagramm dar. Daher eignen sich die Drähe für große Niveauunterschiede oder Deflektionen. Bei geringer Aktivierung verläuft die Kennlinie sehr steil und annähernd linear. In diesen Fällen ist verseilten Stahldrähten aufgrund ihrer kleineren Federrate und Flexibilität der Vorzug zu geben.
Summary Levelling arches made of stainless-steel wires were compared with nickel-titanium wires of the new generation which are distinguished by their shape memory, superelasticity and their excellent spring-back. The data received from a bending test have been analysed statistically and revealed a linear unloading curve of the twisted stainless-steel wires. The nickel-titanium wires, however, showed a clear deviation form the linearity with a curviform course. Besides the unusual unloading curve with a constant force mechanism in the middle range of deactivation the wires give off the same amount of force irrespective of the degree of activation (that is to say, regardless whether the level difference between the brackets amounts to 1 or to 4 mm). The diagram shows that the greater the activity between the brackets, the longer the period of superelasticity. Therefore the nickel-titanium wires are suited for large level differences or deflections. At a low activation rate the characteristic line takes a very steep and almost linear deactivation curve. In these cases twisted stainless steal wires should be preferred because of their lower load deflection rate and flexibility.

Résumé Les arcs de nivelage de fils d'acier tressés ont été comparés avec les fils nickel-titane de la nouvelle génération, se distinguant par leur mémoire de forme, superélasticité et capacité excellente de rappel. Les valeurs relevées au cours de l'essai de pliage ont été enregistrées statistiquement et ont montré une caractéristique linéaire du tracé de force des fils d'acier tressés. Les fils nickel-titane ont cependant montré une déviation significative en présentant non une linéarité mais un tracé curviligne. A côté de leur caractéristique atypique de leur tracé de force avec un dégagement constant de force au centre de la courbe, ces fils ont produit la même force, indépendamment, du degré d'activation (c.-à-d., indépendamment du fait que l'espace entre les brackets fut de 1 ou 4 mm). Plus l'activation était grande entre les brackets, plus la zone du dégagement de la force constante-la superélasticité, paraissait longue sur le diagramme. C'est pourquoi ces fils sont indiqués pour de fortes différences de niveau ou déflexions importantes. En cas d'activation peu considérable, le tracé est très raide et presque linéaire. Dans ces cas, la préférence doit être accordée aux fils d'acier tressés, en raison de leur force élastique et flexibilité inférieures.
  相似文献   
68.
Zusammenfassung Durch Tierversuche an jungen Beagle-Hunden konnte die normale Entwicklung des Parodontiums nach Zahnkeimtransplantationen histologisch nachgewiesen werden. Die klinisch-röntgenologischen Untersuchungen zeigten keine pathologischen Befunde im Parodontiumbereich nach Zahnkeimtransplantationen beim Menschen. Die transplantierten Zähne können wie die anderen kieferorthopädisch bewegt werden. In diesem Beitrag wird auf die häufigsten Indikationen von Zahnkeimtransplantationen von Molaren, Prämolaren und Eckzähnen hingewiesen.
Summary The normal development of the periodontal structures was confirmed histologically on young Beagle-dogs following tooth-germ transplants. In humans, clinical and radiographic examinations revealed no pathology of the periodontium following transplantation of tooth germs. The grafted teeth could be moved orthodontically in the same way as any other teeth. No precautions need to be taken. This paper describes the most common indications for transplanting the tooth-germs of canines, bicuspids and molars.

Résumé Dans les expérimentations animales chez de jeunes chiens-Beagles, on a prouvé que les structures parodontales sont normalement développées après la transplantation de germes dentaires. Les examens cliniques et radiologiques chez de jeunes sujets d'espèce humaine n'ont pas montré de résultats pathologiques au niveau du parodonte après la greffe de germes dentaires. Les dents transplantées peuvent être déplacées orthodontiquement comme les autres dents sans mesures spéciales. Dans cet article, on a donné les indications concernant les greffes des germes de molaires, prémolaires et canines.
  相似文献   
69.
70.
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