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   30577篇
  免费   2708篇
  国内免费   1792篇
耳鼻咽喉   286篇
儿科学   343篇
妇产科学   499篇
基础医学   3630篇
口腔科学   483篇
临床医学   3956篇
内科学   4784篇
皮肤病学   244篇
神经病学   1899篇
特种医学   1204篇
外国民族医学   24篇
外科学   3252篇
综合类   4475篇
现状与发展   5篇
一般理论   17篇
预防医学   2144篇
眼科学   709篇
药学   3034篇
  17篇
中国医学   1467篇
肿瘤学   2605篇
  2024年   89篇
  2023年   395篇
  2022年   1020篇
  2021年   1359篇
  2020年   1003篇
  2019年   894篇
  2018年   1020篇
  2017年   888篇
  2016年   909篇
  2015年   1345篇
  2014年   1581篇
  2013年   1420篇
  2012年   2324篇
  2011年   2406篇
  2010年   1592篇
  2009年   1304篇
  2008年   1791篇
  2007年   1818篇
  2006年   1783篇
  2005年   1647篇
  2004年   1304篇
  2003年   1321篇
  2002年   1132篇
  2001年   629篇
  2000年   571篇
  1999年   522篇
  1998年   318篇
  1997年   339篇
  1996年   282篇
  1995年   270篇
  1994年   226篇
  1993年   167篇
  1992年   194篇
  1991年   163篇
  1990年   149篇
  1989年   92篇
  1988年   94篇
  1987年   81篇
  1986年   67篇
  1985年   62篇
  1984年   62篇
  1983年   26篇
  1982年   30篇
  1981年   26篇
  1959年   21篇
  1958年   25篇
  1957年   23篇
  1956年   37篇
  1955年   27篇
  1954年   22篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
报道58例非心脏手术的围手术期心脏起搏临床应用,重点讨论围手术期心脏起搏的方法与适应症。认为经静脉右室起搏疗效恒定可靠,适应症范围广。对伴有缓慢型或快速型心律失常的心脏病或潜在心脏病患者,围手术期心脏起搏适应症可适当放宽,以确保麻醉手术顺利进行  相似文献   
62.
Cancer chemotherapy in the elderly: a series of 51 patients aged>70 years   总被引:1,自引:0,他引:1  
Summary A total of 2,238 new cancer patients were treated in our institution in 1988; among the 423 (18.9%) who were>70 years old, 51 underwent chemotherapy. The median age was 75.8 years, and the Karnofsky performance status (KPS) was 70% for 40 patients. Malignancies were hematopoietic in 24 cases (47%) and digestive in 15 patients (29%), and 12 subjects (24%) had other types of cancers. The first chemotherapy course was given at the full dose to 23/51 (45.1%) patients. The drug dose was reduced for 28/51 (54.9%) patients, due in 25 cases to the subjects being>70 years old. Neither age, KPS, pretreatment assessment, nor cancer extent was correlated with the modifications made to the first cycle. An overall toxicity of grade 3+4 (WHO grading scale) was noted in 10 subjects (19.6%). Although these elderly patients were probably selected, analysis of their charts did not evidence an increase in chemotherapy toxicity, regardless of the dose they received.Presented at the EORTC Pharmacokinetics and Metabolism Group Meeting, Bordeaux, November 1990  相似文献   
63.
The diagnosis of extensive intramural hematoma of the esophagus due to a bicycle trauma was considerably delayed because symptoms did not develop until 6 h after the accident. This report underscores the importance of a barium meal and computed tomographic (CT) scan in cases of unexplained chest pain, even after minor trauma.  相似文献   
64.
1314例育龄妇女缺铁性贫血发病现状调查   总被引:2,自引:0,他引:2  
目的 :研究育龄妇女缺铁性贫血 (IDA)的发病现状及营养状况与IDA的关系。方法 :检测青岛市城市及农村 1314例妊娠期和非妊娠期育龄妇女的外周血红蛋白浓度 (Hb)、平均红细胞体积 (MCV)、平均红细胞血红蛋白量 (MCH)、血清铁蛋白 (SF) ,并进行个人问卷调查 ,应用营养计算软件评价膳食营养。结果 :1314例育龄妇女IDA发病率为 2 0 .4 0 % ,其中非孕妇的发病率高于孕妇。农村育龄妇女的发病率明显高于城市。孕妇中孕≥ 2 8周组发病率最高 (4 0 % ) ,与其他孕周组相比差异有高度显著性 (P <0 .0 1)。营养评价结果显示非孕妇组热量、维生素A、E、B1、B2 、PP、C的缺乏率高于孕妇组(P <0 .0 0 1)。结论 :农村育龄妇女及孕 2 8周以上的孕妇为IDA高发人群。应加强对农村育龄妇女的膳食营养宣教及指导 ,对孕晚期的孕妇及时采取有针对性的干预措施。  相似文献   
65.
Objective The study was to explore the safety, firmness and convenience of the fascia around the ischial spine as a new fixation site for the vaginal fornix. Methods Between June 2007 and January 2008, detailed dissections and related measurements of the regions around the ischial spine were performed on 10 Chinese female cadavers (3 unembalmed and 7 embalmed cadavers). At the same time, the sacrospinous ligament,the fascia on the ischial spine, the iliococcygeus fascia as well as the vaginal fornix were exposed and the pull-out strength sequentially tested using a digital push-pull force gauge. Results The fascia on the ischial spine was firm and strong, with a thickness of 3 about mm. No major vessels or nerves were observed on the ischial spine. The greatest pullout strengths of the sacrospinous ligament,the fascia on the ischial spine, the iliococcygeus fascia as well as the vaginal fornix were (102±26),(64±15),(33±8)and(32±6)N, respectively. Conclusion The fascia at 1 cm from anterior lateral ischial spine, free of major vessels and nerves, is safe and strong and could be used as a new site for suspension in vaginal prolapse.  相似文献   
66.
Regular physical activity promotes cardiorespiratory fitness and has been considered a cornerstone for non-pharmacological treatment of more than 17 million Americans with diabetes mellitus. Physical exercise has been shown to positively affect certain cardiovascular risk factors such as insulin resistance, glucose metabolism, blood pressure and body fat composition, which are closely associated with diabetes and heart disease. With the increasingly sedentary life style in our society, routine daily exercise of moderate intensity is highly recommended to reduce cardiovascular risk, the leading cause of death in diabetic patients. Exercise produces many beneficial effects to the heart function such as reduced incidence of coronary heart disease, attenuated severity of diabetic cardiomyopathy, improved cardiac performance, cardiac reserve and autonomic regulation. Nevertheless, many diabetic patients do not appear to gain much benefit from exercise or may even be at risk of performing physical exercise. This review summarizes the benefit and risk of exercise on diabetic heart function, with a special emphasis on myocardial and autonomic function.  相似文献   
67.
三维适形低分割放射治疗老年非小细胞肺癌疗效观察   总被引:19,自引:1,他引:19  
目的 探讨三维适形低分割放射治疗老年非小细胞肺癌的疗效。方法  4 5例患者均采用低分割治疗 ,处方剂量为 4~ 5Gy,隔日 1次 ,总量 4 8~ 5 5Gy。结果 CR 2 3例 ( 5 1.1% ) ,PR 15例( 33.3% ) ,NC 5例 ( 11.1% ) ,PD 2例 ( 4 .4 % ) ,RR 38例 ( 84 .4 % )。 1、2、3年生存率分别为 6 6 .7%、4 8.9%、39.1%。结论 三维适形放射治疗对于老年非小细胞肺癌是一种反应较小 ,痛苦较轻 ,安全有效的治疗措施  相似文献   
68.
PURPOSE: To evaluate safety and preliminary efficacy of the humanized anti-epidermal growth factor receptor monoclonal antibody h-R3 in combination with radiotherapy (RT) in unresectable head and neck cancer patients. Secondary end points were the measurement of h-R3 serum levels and the assessment of the potential mechanisms of antitumor effect on patient biopsies. Anti-idiotypic response to h-R3 was assessed. To predict pharmacologic effect, a mathematical model for antibodies recognizing antigens expressed in tumors and normal tissues was built. PATIENTS AND METHODS: Twenty-four patients with advanced carcinomas of the head and neck received six once-weekly infusions of h-R3 at four dose levels in combination with RT. Pretreatment tumor biopsies were obtained to evaluate epidermal growth factor receptor expression as an enrollment criterion. Second biopsies were taken to evaluate the proliferative activity and angiogenesis in comparison with the pretreatment samples. Patient serum samples were collected to measure h-R3 levels and anti-idiotypic response. RESULTS: The combination of h-R3 and RT was well tolerated. Antibody-related adverse events consisted in infusion reactions. No skin or allergic toxicity appeared. Overall survival significantly increased after the use of the higher antibody doses. Immunohistochemistry studies of tumor specimens before and after treatment revealed that antitumor response correlated with antiproliferative and antiangiogenic effect. One patient developed antibodies to h-R3. The mathematical model predicted that the maximum difference between the area under the curve in tumors and normal tissues is reached when the antibody has intermediate affinity. CONCLUSION: h-R3 is a well-tolerated drug that may enhance radiocurability of unresectable head and neck neoplasms.  相似文献   
69.
70.
目的 观察单纯疱疹病毒胸苷激酶基因(HSV-tk)-环丙氧苷(GCV)系统在胶质瘤基因治疗过程中,GCV能否诱导转导有HSV-tk基因的胶质瘤细胞凋亡。方法 采用光镜、电镜和荧光显微镜观察转导有HSV-tk基因的大鼠C6/tk胶质瘤细胞形态学的改变,以末转导HSV-tk基因的C6细胞作为对照,并以流式细胞术,DNA凝胶电流分析进一步验证细胞凋亡的发生。结果 在5μg/ml GCV作用72h后,C6  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