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   49518篇
  免费   5143篇
  国内免费   1509篇
耳鼻咽喉   490篇
儿科学   882篇
妇产科学   209篇
基础医学   3589篇
口腔科学   1013篇
临床医学   7161篇
内科学   13192篇
皮肤病学   750篇
神经病学   1841篇
特种医学   824篇
外国民族医学   1篇
外科学   4488篇
综合类   8134篇
现状与发展   11篇
一般理论   3篇
预防医学   3160篇
眼科学   404篇
药学   4383篇
  43篇
中国医学   4317篇
肿瘤学   1275篇
  2024年   194篇
  2023年   1107篇
  2022年   1608篇
  2021年   2421篇
  2020年   2305篇
  2019年   2161篇
  2018年   1971篇
  2017年   2160篇
  2016年   2333篇
  2015年   2363篇
  2014年   3479篇
  2013年   3984篇
  2012年   3021篇
  2011年   3292篇
  2010年   2545篇
  2009年   2311篇
  2008年   2127篇
  2007年   2238篇
  2006年   1970篇
  2005年   1712篇
  2004年   1360篇
  2003年   1176篇
  2002年   1061篇
  2001年   936篇
  2000年   774篇
  1999年   627篇
  1998年   502篇
  1997年   518篇
  1996年   467篇
  1995年   456篇
  1994年   398篇
  1993年   335篇
  1992年   284篇
  1991年   247篇
  1990年   206篇
  1989年   188篇
  1988年   145篇
  1987年   130篇
  1986年   131篇
  1985年   190篇
  1984年   133篇
  1983年   96篇
  1982年   109篇
  1981年   118篇
  1980年   66篇
  1979年   45篇
  1978年   45篇
  1977年   40篇
  1976年   35篇
  1975年   14篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
对老年慢性肾功能衰竭264例患者(男148例,女116例;年龄66±7a)用硝苯啶10mg联合覆醛氧化淀粉5-10mg,tid,po。另设相似88例患者(男48例,女40例;年龄66±7a)单服覆醛氧化淀粉与之对照,用法同前。2组均连服16wk。结果:前者有效216例(81.8%),后者有效49例(56%),组间比较P<0.01。2组副作用相似,均可坚持服药。  相似文献   
102.
Clinical diagnosis of chronic cholecystitis is made based on diffuse hyperechoic thickening of the gallbladder wall as shown by ultrasonographic examination. We herein report three cases of chronic cholecystitis showing localized hypoechoic thickening of the gallbladder wall that mimicked gallbladder cancer by ultrasonography. Histologically, hypertrophy of the muscularis propria was a common characteristic finding in these three patients. A smooth surface of the inner hypoechoic layer of the thickened wall was considered to be a reliable finding in the differential diagnosis between this type of chronic cholecystitis and gallbladder cancer.  相似文献   
103.
目的用缺氧方法制备的肺源性心脏病(肺心病)大鼠为对象,研究肺心病中M2和β1受体抗体的含量及其与疾病的关系。方法选取健康雄性Wistar大鼠36只,随机分为3组:单纯缺氧组,缺氧加注射FeCl3组,健康对照组。SA-酶联免疫吸附测定(ELISA)法检测血清M2和β1受体抗体变化。最后处死大鼠观察心脏指标,并分析它与抗体滴度的相关性。结果血清中M2和β1受体抗体随缺氧时间延长而升高,滴度分别到第3周达高峰M2受体抗体为1∶80(单纯缺氧组)和1∶53(缺氧加注射FeCl3组),β1受体抗体为1∶60(单纯缺氧组)和1∶45(缺氧加注射FeCl3组),并且P/N值从第2周开始有阳性意义,到第3周同样达高峰M2和β1受体抗体分别为2.88(单纯缺氧组)、2.76(缺氧加注射FeCl3组)和3.25(单纯缺氧组)、3.99(缺氧加注射FeCl3组)。而肺心病大鼠心脏指标最终改变为R/(L+S)0.333±0.027(单纯缺氧组),0.348±0.033(缺氧加注射FeCl3组),R/BW×10-30.58±0.13(单纯缺氧组),0.60±0.15(缺氧加注射FeCl3组),(L+S)/BW×10-32.000±0.024(单纯缺氧组),2.081±0.037(缺氧加注射FeCl3组),并且抗体滴度与心脏改变呈正相关。结论M2和β1受体抗体阳性率及抗体滴度在大鼠肺心病模型中明显增高,表明肺心病的发生发展与M2和β1受体的自身抗体密切相关。  相似文献   
104.
To study the cause and mechanism of transplantation vasculopathy which characterized by accelerated graft arteriosclerosis ( AGA), we estabfished a mouse aorta graft model. Methods: A segment of thoracic aortas of B10. A (2R) mice were transplanted to C57BL/10 mice abdominal aorta by end to side anastomoses. The different time point collected grafts were analyzed by morphological, histochemical and electro microscopic methods. Results:Rejection was manifested as a concentric progressive destruction of the smooth muscle cells. In contrast, the endothelial inflammation and subsequent ncointimal proliferation characteristic of AGA was localized to the regions of turbulent flow, i.e. the junction of the graft with the recipient aorta. Conclusion: This model separates the processes of rejec-tion and neointimal formation which usually manifested together in the lesion of AGA, elucidate that different mecha-nisms control vascular rejection and neointimal formation in chronic rejection.  相似文献   
105.
目的研究鼠婴肾组织移植于肾包膜下对促红细胞生成素的调节作用,为临床应用治疗肾性贫血提供理论依据。方法以Wistar雄性大鼠建立慢性肾功能衰竭动物模型为受体,将鼠婴肾组织块多点植入受体肾包膜下。治疗期间用EPO酶联免疫(ELISA)试剂盒测定血清EPO水平;观察肾组织病理改变,用免疫组化方法检测EPO在移植物中的表达。结果①60d时D组血清促红细胞生成素(1.768±0.140)mu/mL高于B组(1.160±0.324)mu/mL(P<0.01),与C组(2.329±0.125)mu/mL也有差异(P<0.05)。②移植后60d,移植物的体积由1mm3增至3-4mm3大小,表面血管网丰富,光镜下见肾小球、肾小管结构正常;③移植物EPO免疫组化,发现移植物EPO着色颗粒主要分布于肾皮质的肾小管,明显多于病例对照组大鼠肾组织(P<0.05)。结论通过对移植物的形态观察和功能测定,证明肾组织移植是一种有效的治疗手段,有可能为慢性肾性贫血提供一种新的途径。  相似文献   
106.
Despite decreasing mortality rates, morbidity is still high after pancreatic head resection. Comparative data in the United States and Europe show a relationship between hospital volume and mortality. Treatment strategies vary frequently, partially because of the lack of evidence-based data. We performed a multi-institutional analysis in Germany evaluating current numbers, indications, techniques, and complication rates of pancreatic head resection. Questionnaires were completed by seven high-volume surgical departments regarding quantitative and qualitative aspects of pancreatic head resections in the period from 1999 to 2004 (five prospective and two retrospective institutional databases). A total of 1454 pancreatic head resections (944 for malignancy) were reported. Mean annual hospital volume ranged from 14 to 52 (10 to 43 in malignancy). Mortality was between 1.1% and 4.8%, morbidity was between 24% and 46%, and pancreatic leakage was between 9% and 20%. In malignant disease, all centers perform standard lymphadenectomy and regard arterial infiltration as a contraindication for resection. However, the rate of portal vein resection varied from 0% to 28%. No consensus is seen on the type of surgery for malignancy and chronic pancreatitis. After resection for pancreatic cancer less than one fourth of the patients receive adjuvant therapy. The results of our analysis in Germany confirm that pancreatic head resection can be performed with low mortality in specialized units. Variations in indications, operative technique, and perioperative care may demonstrate the lack of evidence-based data and/or personal and institutional experience. The low number of patients receiving adjuvant therapy after resection of pancreatic cancer suggests that more efforts must be made to establish novel adjuvant therapies under randomized study conditions. Presented at the Forty-Sixth Annual Meeting of The Society for Surgery of the Alimentary Tract, Chicago, Illinois, May 14–18, 2005 (oral presentation).  相似文献   
107.
Chronic allograft nephropathy (CAN) of renal allografts is still the most important cause of graft loss. A subset of these patients have transplant glomerulopathy (TGP), characterized by glomerular basement membrane (GBM) duplications, but of unknown etiology. Recently, a role for the immune system in the pathogenesis of TGP has been suggested. In 11 of 16 patients with TGP and in 3 of 16 controls with CAN in the absence of TGP we demonstrate circulating antibodies reactive with GBM isolates. The presence of anti-GBM antibodies was associated with the number of rejection episodes prior to diagnosis of TGP. Sera from the TGP patients also reacted with highly purified GBM heparan sulphate proteoglycans (HSPG). Indirect immunofluorescence with patient IgG showed a GBM-like staining pattern and colocalization with the HSPGs perlecan and especially agrin. Using patient IgG, we affinity purified the antigen and identified it as agrin. Reactivity with agrin was found in 7 of 16 (44%) of patients with TGP and in 7 of 11 (64%) patients with anti-GBM reactivity. In conclusion, we have identified a humoral response against the GBM-HSPG agrin in patients with TGP, which may play a role in the pathogenesis of TGP.  相似文献   
108.
The differential diagnoses of persistent nonproductive cough include numerous pulmonary and nonpulmonary organic disorders as well as functional illnesses. Many diseases can cause cough, and several studies have shown asthma among the most common etiologies associated with chronic cough in adult nonsmokers, as well as children. Psychogenic cough and its relationship to asthma and other asthma-like illnesses is complex since distinct maladies with similar features may coexist individually or in combination in any given patient. While chronic cough may occur as a sole presenting manifestation of bronchial asthma in all age groups, recent findings suggest that most children with persistent cough without other respiratory symptoms do not have asthma. Since several organic, as well as functional diseases, may present with persistent cough as their sole manifestation in either adults or children, cough should not be used as a single or major determinant to diagnose and treat asthma, especially when empirically focused therapy trials fail. Given the range of illnesses causing cough, no single management guideline can be expected to be universally effective.  相似文献   
109.
侯江红教授擅长运用调脾和胃法调治处于亚健康状态的小儿,治疗小儿慢性湿疹,注重从“健脾和胃、消食清热”法入手,每获良效。  相似文献   
110.
目的:对42例肺心病慢性呼吸性酸中毒患者的80例次血气测定结果。方法:用不同的酸碱图(卡)及代偿公式进行酸碱类型的初步差别分析。结果:结合临床表现、各种影响因素与治疗反应等作出综合判定。结论:比较二种判定的差异,并提出较为实用、可靠的判断建议,以助于复合型呼吸性酸碱失衡的临床诊断与处理。  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