全文获取类型
收费全文 | 23233篇 |
免费 | 1818篇 |
国内免费 | 713篇 |
专业分类
耳鼻咽喉 | 89篇 |
儿科学 | 587篇 |
妇产科学 | 633篇 |
基础医学 | 1171篇 |
口腔科学 | 412篇 |
临床医学 | 3219篇 |
内科学 | 5297篇 |
皮肤病学 | 103篇 |
神经病学 | 727篇 |
特种医学 | 889篇 |
外国民族医学 | 7篇 |
外科学 | 2996篇 |
综合类 | 3575篇 |
现状与发展 | 1篇 |
预防医学 | 1435篇 |
眼科学 | 52篇 |
药学 | 2453篇 |
40篇 | |
中国医学 | 1096篇 |
肿瘤学 | 982篇 |
出版年
2024年 | 60篇 |
2023年 | 485篇 |
2022年 | 714篇 |
2021年 | 1215篇 |
2020年 | 1028篇 |
2019年 | 946篇 |
2018年 | 863篇 |
2017年 | 892篇 |
2016年 | 939篇 |
2015年 | 907篇 |
2014年 | 1726篇 |
2013年 | 1859篇 |
2012年 | 1467篇 |
2011年 | 1548篇 |
2010年 | 1270篇 |
2009年 | 1124篇 |
2008年 | 1033篇 |
2007年 | 1052篇 |
2006年 | 980篇 |
2005年 | 818篇 |
2004年 | 648篇 |
2003年 | 563篇 |
2002年 | 480篇 |
2001年 | 404篇 |
2000年 | 356篇 |
1999年 | 273篇 |
1998年 | 234篇 |
1997年 | 203篇 |
1996年 | 207篇 |
1995年 | 185篇 |
1994年 | 165篇 |
1993年 | 122篇 |
1992年 | 139篇 |
1991年 | 108篇 |
1990年 | 103篇 |
1989年 | 93篇 |
1988年 | 78篇 |
1987年 | 62篇 |
1986年 | 48篇 |
1985年 | 62篇 |
1984年 | 46篇 |
1983年 | 38篇 |
1982年 | 40篇 |
1981年 | 36篇 |
1980年 | 33篇 |
1979年 | 20篇 |
1978年 | 26篇 |
1977年 | 18篇 |
1976年 | 15篇 |
1975年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
Didier Mathieu Alain Rahmouni Norbert Vasile Nedal Jazaerli Christophe Duvoux Jeanne Tran Van Nhieu Elie Serge Zafrani 《Journal of magnetic resonance imaging : JMRI》1994,4(3):506-508
This case report illustrates atypical magnetic resonance (MR) imaging findings in a liver hemangioma mimicking a malignant lesion—lower signal intensity than cerebrospinal fluid on T2-weighted spin-echo images and lack of early enhancement on dynamic contrast material—enhanced gradient-echo images. Pathologic analysis demonstrated nearly total replacement of the vascular cavities by dense fibrous tissue. In this rare, sclerosed form, this lesion could not be defined as a hemangioma with MR imaging. 相似文献
102.
用免疫细胞化学方法研究人胚胎各时期胃肠胰的D细胞发生及其形态与功能的关系。结果发现:D细胞最早出现于6周零5天胚的十二指肠,7周零3天胚的胰、胃、空肠,7周零6天胚的回肠,8周零4天胎的结肠及10周零5天胎的阑尾;细胞密度在胚期低,胎期逐增,至胎晚期又依次在胰、胃窦、十二指肠、胃体、空肠、回肠、升结肠及阑尾中降低,且肠绒毛顶端可见衰老的D细胞。提示胚胎D细胞的发生与胃肠胰的发育有关。 相似文献
103.
M. Goldschmiedt MD Dr. D. A. Ahlquist M.D H. S. Wieand PhD D. B. McGill MD W. F. Taylor PhD R. D. Ellefson PhD 《Digestive diseases and sciences》1988,33(5):605-608
Hemoglobin-heme is variably converted to porphyrin during enterocolic transit. This intestinal converted fraction, as measured by HemoQuant, was elevated as a predictor of the occult bleeding site in 152 patients with discrete lesions. The intestinal converted fraction, expressed as the percentage of total fecal hemoglobin, was similar with upper gastrointestinal and proximal colon lesions. Within the colon, values trended downward with more distal location: means ± standard deviations were 18±14 proximal colon, 16 ±15 sigmoid, and 10±10 rectum. The amount of fecal blood also affected the intestinal converted fraction; correcting for hemoglobin concentration improved separation by site. Corrected intestinal converted fraction values were significantly lower with rectal (P< 0.0005) and sigmoid (P<0.02) lesions than with proximal colon lesions. Unfortunately, large within-site variation caused considerable overlap between sites. We conclude that the intestinal converted fraction is influenced by the site and amount of bleeding. However, its clinical utility is compromised by substantial individual differences in luminal hemoglobin metabolism.Presented in part at the Annual meeting of the American Gastroenterological Association in San Francisco in May of 1986 (Gastroenterology 90:1431, 1986).Supported by the Mayo Foundation. 相似文献
104.
白术茯苓汤及其配伍对脾虚大鼠胃肠激素的影响 总被引:3,自引:0,他引:3
目的:探讨益气健脾方剂治疗脾虚证的配伍规律。方法:采用苦寒泻下法复制大鼠脾虚模型,运用放射免疫分析法(RIA)检测白术茯苓汤及其与补气药。行气药及除湿药的不同配伍对脾虚大鼠胃泌素(GAS)、胃动素(MTL)及血管活性肠肽(VIP)的含量影响。结果:与正常对照组比较,脾虚模型大鼠GAS、MTL降低(P<0.01),VIP升高(P<0.01);与自然恢复组比较,各治疗组以上部分或全部指标均有不同程度的改善,其中,以综合配伍组改善作用最优。结论:白术茯苓汤的脾虚大鼠胃肠激素的紊乱的某些指标,有一定的改善作用,综合配合组以上指标的改善,优于白术茯苓汤组及其余各配伍组,说明中医关于复方配伍的理论与实践,有其科学价值。 相似文献
105.
上消化道出血798例分析 总被引:33,自引:0,他引:33
目的 探讨上消化道出血的病因和相关因素。方法 回顾性分析我院 8年来 798例上消化道出血病人的临床资料。结果 男性并发上消化道出血占 80 .2 0 %、女性占 19.80 % ,男性明显高于女性 (χ2 =6 .5 6 ,P <0 .0 5 ) ;青年人、中年人及老年人各占 2 7.82 %、5 7.6 1%和 14 .5 7% (P <0 .0 1) ,老年人合并重度上消化道出血多见 ;不同性别、年龄者出血的原因不尽相同。结论 上消化道出血的病人以消化性溃疡、胃癌、急性胃粘膜损害、食道胃底静脉曲张为最常见的病因 ,性别、年龄等均为上消化道出血的相关因素 相似文献
106.
Toshiyuki Matsui Sumio Tsuda Hiroaki Matake Keisuke Ikeda Tsuneyoshi Yao 《Digestive endoscopy》2004,16(Z1):S27-S30
Background: Gastrointestinal strictures are the most often and serious complication in Crohn's disease. Because of the frequent postoperative recurrence in Crohn's disease, endoscopic therapy of gastrointestinal stricture is one of the best therapeutic options. Method: The present study sets out the results from a prospective study of endoscopic dilation therapy on 48 Crohn's disease patients with severe gastrointestinal stenoses. All patients who could not undergo endoscopic balloon dilation therapy (EBD) were operated on. Results: Long‐term success was attained in 32 of the 48 patients; cumulative avoidance of surgery after EBD was 86% at one year and 71% at three. Second, the most hazardous factor was recurrent inflammation causing restenosis. Patients who had strictures with oral luminal dilatation and patients with frequent recurrence had a tendency to be operated on. As a complication, perforation occurred in two cases (3.3%). Conclusions: EBD therapy for Crohn's stricture in the gastrointestinal tract is recommended before surgical intervention. 相似文献
107.
目的探讨原发性胃肠道淋巴瘤的诊治经验。方法回顾性分析12例原发性胃肠道淋巴瘤,均行剖腹探查,其中行根治性切除7例,姑息性手术3例,肿块活检术2例。结果胃淋巴瘤5例,肠淋巴瘤7例。病理分类:弥漫性非何杰金氏淋巴瘤9例,粘膜相关性淋巴瘤2例,高度恶性淋巴瘤1例。Ann Arbor临床分期:ⅡE期3例,ⅢE期7例,ⅣE期2例。平均随访18(6~72)月,6例存活,死亡6例。结论内镜和消化道造影是淋巴瘤主要诊断手段,手术切除为主的综合治疗为最佳治疗方案。 相似文献
108.
Objective: To investigate the clinical efficacy of estrogen or contraceptives in the treatment of acute bleeding of dysfunctional uterine bleeding (DUB) in adolescent patients and the optimal starting dosage of drugs.Methods: The clinical records of 106 girls who with DUB and moderate or severe anemia from February 1990 to July 2005 were analyzed retrospectively.Results: All 106 patients received hormonal therapy. 56 patients were treated with estradiol benzoate(E2), 30 patients with conjugated equine estrogen(CEE) and 20 patients with combined oral contraceptives (COCs). The rates for rapidly controlling bleeding and for rapidly stopping bleeding in E2 group were higher than those in CEE group ,but similar to those in COCs group. The days for controlling and completely stopping bleeding were not significantly different between the starting dosages (≤8 mg/d and >8 mg/d) of E2 groups, and also there were no statistical difference between the starting dosages (<7.5 mg/d and ≥7.5 mg/d) of CEE groups, but during the treatment the rate of increasing the dosage in <7.5 mg/d group was higher than that of ≥7.5 mg/d group(40% vs. 5%),while there were no statistical difference between the starting dosages (≤3 pills/d and >3 pills/d) of COCs groups. Conclusions: The clinical efficiency of E2 treatment on DUB in adolescent patients is similar to that of COCs. And the efficacies of treatment of DUB with E2, CEE and COCs in the different dosages are similar. 相似文献
109.
Ghrelin does not stimulate gastrointestinal motility and gastric emptying: an experimental study of conscious dogs 总被引:4,自引:0,他引:4
t. ohno y. kamiyama r. aihara t. nakabayashi e. mochiki t. asao & h. kuwano 《Neurogastroenterology and motility》2006,18(2):129-135
Ghrelin is a peptide that was discovered in endocrine cells of the stomach. However, its action in regulating the fasted and fed motor activity of the digestive tract is not fully understood. In the present study, we examined the effects of an intravenous (i.v.) injection of canine ghrelin on the physiological fasted and fed motor activities in the stomach, duodenum, jejunum and colon of freely moving conscious dogs. An i.v. injection of canine ghrelin released growth hormone in a dose-dependent manner; however, it did not stimulate the motor activity of the digestive tract in either the fasted or the fed state. Moreover, an i.v. injection of high-dose canine ghrelin significantly reduced the motility index in the gastric body in the fasted state. Ghrelin did not accelerate gastric emptying, either. These results differ from previous reports dealing with rodents. It is significant that such results were obtained in research with dogs, which are larger animals. 相似文献
110.
R. H. Tholen D. C. Hammond W. P. Cooney J. Fisher 《European journal of plastic surgery》1992,15(2):58-62
Summary Over a four year period, thirteen patients over the age of 60 (mean 69 years) underwent reconstruction of lower extremity defects with free tissue transfers. Ten latissimus dorsi, one tensor facia lata, and two rectus abdominus free flaps were used. Despite significant risk factors which included previous tobacco use, hypertension, diabetes mellitus, and angiographic vessel abnormalities, ten of thirteen cases had successful outcomes. There was one acute flap failure secondary to arterial thrombosis. Four flaps had delayed healing, with one patient eventually requiring amputation secondary to persistent pain and wound drainage. This experience demonstrates that free flap reconstruction of lower extremity defects in the elderly patient is a reasonable alternative to amputation when other options are limited.From the Section of Plastic and Reconstructive Surgery at the Mayo Clinic and Mayo Foundation, Rochester, Minnesota, USA
Requests for reprints: J. Fisher, M.D. 相似文献