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   18785篇
  免费   1517篇
  国内免费   822篇
耳鼻咽喉   58篇
儿科学   140篇
妇产科学   31篇
基础医学   940篇
口腔科学   200篇
临床医学   2262篇
内科学   3419篇
皮肤病学   447篇
神经病学   68篇
特种医学   678篇
外科学   3616篇
综合类   3498篇
预防医学   724篇
眼科学   367篇
药学   2021篇
  22篇
中国医学   1485篇
肿瘤学   1148篇
  2024年   212篇
  2023年   313篇
  2022年   461篇
  2021年   580篇
  2020年   557篇
  2019年   417篇
  2018年   369篇
  2017年   488篇
  2016年   525篇
  2015年   537篇
  2014年   1154篇
  2013年   1367篇
  2012年   1216篇
  2011年   1277篇
  2010年   1079篇
  2009年   971篇
  2008年   975篇
  2007年   956篇
  2006年   941篇
  2005年   880篇
  2004年   676篇
  2003年   591篇
  2002年   523篇
  2001年   555篇
  2000年   475篇
  1999年   387篇
  1998年   347篇
  1997年   330篇
  1996年   262篇
  1995年   221篇
  1994年   210篇
  1993年   161篇
  1992年   156篇
  1991年   131篇
  1990年   127篇
  1989年   103篇
  1988年   111篇
  1987年   84篇
  1986年   62篇
  1985年   63篇
  1984年   43篇
  1983年   29篇
  1982年   25篇
  1981年   27篇
  1980年   28篇
  1979年   24篇
  1978年   26篇
  1977年   23篇
  1976年   19篇
  1975年   11篇
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
21.
Background: Three acid-reducing operations have recently been described for the laparoscopic treatment of peptic ulcer disease. These consist of a posterior truncal vagotomy combined with either (1) an anterior seromyotomy (SERO), (2) an anterior highly selective vagotomy (AHSV), or (3) a linear stapled lesser curvature excision (STAP). The purpose of this study was to investigate the physiologic effects of these procedures in terms of basal and maximal acid outputs. Methods: Fifty New Zealand rabbits were prospectively randomized into five open laparotomy groups (n= 10): a control group without vagal manipulation (CON), a bilateral truncal vagotomy with pyloromyotomy group (VP), a SERO group, an AHSV group, and a STAP group. All animals underwent placement of a gastrostomy tube for subsequent gastric secretory analysis. On postoperative day 6, basal acid outputs (BAO) and maximal acid outputs (MAO) following IV pentagastrin stimulation (30 μg/kg/h) were measured. Results were compared statistically using the ANOVA method. Results: Pentagastrin stimulation was associated with a significant increase in MAO in the CON group (p < 0.05 vs BAO); however, this response was effectively blunted in all the experimental groups. There were no differences in BAO or MAO between any of the vagotomized groups (SERO, HSV, STAP, VP). Conclusions: We conclude that the three acid-reducing procedures modified for laparoscopy are equally efficacious in reducing gastric acid secretion and that they compare favorably with VP. To our knowledge, this is the first report comparing basal and stimulated gastric acid secretion between these new acid-reducing techniques. Received: 27 March 1996/Accepted: 17 July 1996  相似文献   
22.
TheClinicalEfectsofAlantoinPowderforGargleonPeriodontalDiseasesandAphthousUlcerYuWeiyi(俞未一)SunWeibin(孙卫斌)DepartmentofStomatol...  相似文献   
23.
Abstract: A 63-year-old man was hospitalized because of jaundice and anorexia. An upper gastrointestinal series and hypotonic duodenography revealed circumferential sclerosis and stenosis of the duodenal wall. Endoscopic examination disclosed an ulcer, the upper margin of which was located at the papilla of Vater. The papilla was situated in the base of the ulcer. Endoscopic retrograde cholangiopancreatography disclosed mild dilatation of the common bile, intrahepatic bile and pancreatic ducts, but with neither severe stenosis nor occlusion. Nevertheless, there was some degree of circumferential compression and mild stenosis of the terminal portions of the bile and pancreatic ducts, as potential causes of obstructive jaundice in this patient. Computed tomographic examination of the abdomen revealed a tumorous lesion at the duodenal bulb. Because malignancy in the duodenum could not be ruled out, a pancreatoduodenectomy was performed. Histopathological examination showed a postbulbar duodenal ulcer, associated with inflammation of the papillary orifice and fibrosis of the region near the papilla. There was no evidence of a tumorous lesion. In this case, a postbulbar duodenal ulcer may have caused obstructive jaundice.  相似文献   
24.
To evaluate the potential of laser-induced autofluorescence spectroscopy for the detection of premalignant lesions of human stomach, fluorescence properties of stomach tissues have been investigated in vitro and in vivo. A specially made optical fibre probe and the multichannel fluorescence collection system have been used successfully in our research. Paper received 26 June 1997; accepted in revised form 31 October 1997.  相似文献   
25.
We propose a novel technique for laparoscopic treatment of perforated gastroduodenal ulcers. The principle of this procedure involves the closure of the perforated ulcer using the ligamentum teres hepatis (LTH). The LTH is cut near its umbilical end and then dissected up to the site of its hepatic insertion. The umbilical extremity of LTH is grasped with a Dormia noose passed through the ulcerated perforation via a gastroscope. Using the noose, the LTH is pulled through the ulcerated perforation until its volume fits and completely closes the perforation. This laparoscopic technique was performed in 15 patients (12 M, 3 F) with anterior perforated duodenal ulcer revealed within the previous 6 h. The procedure could not be performed in three cases: diameter of the perforation exceeding 1.5 cm (n=1), general purulent peritonitis (n=2). In the other 12 cases, closure of the ulcerated perforation with the LTH was realized without technical difficulty. The postoperative course was uncomplicated. The posttreatment comfort was excellent; the mean period of hospitalization was 10 days (range, 8–14 days). An endoscopic examination carried out following 5 weeks of anti-H2 treatment showed that cicatrization of the ulcer was good and that no pyloric stenosis remained. These initial results suggest that laparoscopic treatment of perforated gastroduodenal ulcer using the LTH is a simple procedure which can be performed with general assurance of success in patients whose perforated ulcers have occurred quite recently. As the laparoscopic procedure is less aggressive than a laparotomy, it enhances the postoperative comfort of patients and prevents the risk of parietal complications. Compared to laparoscopic endosuture this procedure is simple, effective, easier, and particularly adapted to large ulcerated perforation or when an ulcer's edges are tough or friable, tending to tear when knots are tied.Presented at the annual meeting of the Society of American Gastrointestinal Endoscopic Surgeons (SAGES), Nashville, TN, USA, 18–19 April 1994.  相似文献   
26.
用反射光谱法,研究了组胺H_2受体阻断剂Famotidine对急性失血大鼠胃粘膜血液量及血氧饱和度的影响。同时观察了胃液量和酸排出量的变化,并计量了溃疡指数。Famotidine(3mg/kg及8mg/kg,iv)对失血前大鼠胃粘膜血液量和血氧饱和度均未见有影响;对失血后胃粘膜血液量和血氧饱和度的降低有明显保护作用,对胃液量和酸排出量均有显著抑制作用,溃疡指数减小。  相似文献   
27.
28.
We report on a case of a 40-year-old male patient who underwent a gastrectomy because of a biopsy-proven large B-cell lymphoma of the stomach. On surgery, a nodule in the spleen also was noted. Grossly and microscopically, the two lesions were different: the tumor of the stomach appeared white-gray on the cut surface and was a centroblastic variant of diffuse large B-cell lymphoma. Histologically, one perigastric lymph node was involved. Grossly, the splenic nodule was gray-yellow and had a histological appearance of an inflammatory myofibroblastic tumor (IMT). The association between malignant tumor and IMT is rare. In such an association, the latter lesion most often has been reported in the spleen. As EBV may be involved in the genesis of both lymphoma and IMT, we tested both lesions for its presence using in situ hybridization, but the tests were negative. It remains to be verified whether the association between lymphoma and IMT is more than fortuitous.  相似文献   
29.
Zusammenfassung Anhand einer prospektiven, auslesefreien Serie von 22 Patienten mit perforierten Ulcera im Gastroduodenalbereich verweisen wir auf die begrenzte diagnostische Aussagekraft einfacher anamnestischer, klinischer und radiologischer Daten. Lediglich bei acht Patienten (36%) ergaben sich wesentliche Indizien aus Krankengeschichte und Aufnahmebefund. Bei 16 Patienten (73%) verriet die Thoraxübersichtsaufnahme durch Nachweis einer subphrenischen Luftsichel eine Perforation im Magen-Darm-Trakt. Die Ultraschalluntersuchung wird als bedeutungsvolle Ergänzungsmethode vor allem in der diagnostischen Abklärung radiologisch negativer Ulcusperforationen vorgestellt und diskutiert. Dabei werden die sonographisch faßbare flüssigkeitsbedingte Magendistension sowie das Magenwandödem als unspezifische Kriterien gewertet. Der Objektivierung einer pathologischen Magenkokarde kommt bei gleichzeitigem Nachweis freier Luft und/oder extraluminärer Ingesta sowie freier echoloser Transsudatflüssigkeit pathognomonische Beweiskraft zu. Selbige Ultraschallkriterien erlaubten im einschlägigen Krankengut bei 16 Patienten (73%) eine definitive Diagnose und erfaßte 4 Patienten mit negativem Röntgen. Die kombinierte Analyse radiologischer und sonographischer Befunde führte somit bei 20 Patienten (91 %) unverzüglich zur korrekten Diagnose.
Perforated peptic ulcer: Diagnosis and assessment by sonography
Summary In a prospective unselected series of 22 patients with perforated gastroduodenal ulcers the diagnostic efficacy of clinical and radiologic data was modest. In eight patients only (36%), clinical data yielded sufficient evidence; in 16 patients (73%), plain X-ray demonstrated subphrenic gas. Sonography was proven to be a major advance, especially rewarding in the diagnosis of perforations with negative plain X-ray. Gastric distention and stomach wall edema are unspecifc sonographic criteria, whereas objectivation of a pathologic stomach cockade in the presence of free gas, extraluminary ingesta or echofree fluid in the peritoneal cavity are pathognomonic data. These criteria yielded a definite diagnosis in 16 patients (73%) including four patients with negative X-ray. The combined analysis of radiologic and sonographic findings yielded an immediate correct diagnosis in 20 patients (91%).
  相似文献   
30.
糖尿病足溃疡是糖尿病严重的破坏性并发症,致残率及致死率逐年增高,严重威胁人类身心健康。中医药治疗糖尿病足溃疡,注重辨证论治与整体观念相结合,不仅能改善中医证候,更能在加速创面愈合的同时减少创面的复发,一定程度上延缓了糖尿病足溃疡的进一步恶化,降低其致残率及致死率。现代研究发现,糖尿病足溃疡难以愈合与各种细胞因子如炎症因子、生长因子、趋化因子等分布异常密切相关;随着现代医学对中医药研究的不断深入,中药单体及复方调控细胞因子治疗糖尿病足溃疡已成为研究热点,该文通过对目前国内外研究现状进行归纳,得出以下总结:(1)芝麻酚、栀子苷、当归补血汤、紫朱软膏等调节肿瘤坏死因子-α(TNF-α)、白细胞介素(IL)-1、IL-6、IL-10等炎症因子,抑制创面炎症。(2)白芷、丹酚酸B、四效散、壮药拔毒生肌膏等调节血管内皮生长因子(VEGF)、血小板衍生生长因子(PDGF)、转化生长因子(TGF)、表皮生长因子(EGF)等生长因子,促进创面胶原沉积及血管新生。(3)芍药苷、隐丹参酮、蜂毒、回阳生肌汤等调节CXC趋化因子配体(CXCL)1、CXCL2、CC趋化因子配体(CCL)2、CCL3、基质细胞衍生...  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