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   84255篇
  免费   7113篇
  国内免费   3364篇
耳鼻咽喉   734篇
儿科学   1830篇
妇产科学   1386篇
基础医学   7329篇
口腔科学   1525篇
临床医学   8592篇
内科学   14050篇
皮肤病学   1168篇
神经病学   4946篇
特种医学   3320篇
外国民族医学   2篇
外科学   9552篇
综合类   13057篇
现状与发展   16篇
一般理论   1篇
预防医学   7319篇
眼科学   883篇
药学   8637篇
  63篇
中国医学   4807篇
肿瘤学   5515篇
  2024年   266篇
  2023年   945篇
  2022年   2386篇
  2021年   3281篇
  2020年   2540篇
  2019年   1849篇
  2018年   2072篇
  2017年   2156篇
  2016年   1903篇
  2015年   2938篇
  2014年   3786篇
  2013年   4665篇
  2012年   6477篇
  2011年   6744篇
  2010年   5113篇
  2009年   4639篇
  2008年   5626篇
  2007年   5618篇
  2006年   4801篇
  2005年   4117篇
  2004年   3326篇
  2003年   2893篇
  2002年   2474篇
  2001年   2240篇
  2000年   1974篇
  1999年   1505篇
  1998年   495篇
  1997年   366篇
  1996年   382篇
  1995年   293篇
  1994年   282篇
  1993年   232篇
  1992年   687篇
  1991年   579篇
  1990年   543篇
  1989年   550篇
  1988年   461篇
  1987年   430篇
  1986年   413篇
  1985年   317篇
  1984年   262篇
  1983年   213篇
  1982年   118篇
  1979年   211篇
  1978年   128篇
  1977年   110篇
  1974年   122篇
  1973年   125篇
  1972年   122篇
  1971年   110篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
Cancer cells elaborate metalloproteinases which may play a role in invasion and metastasis. The serum level of the M(r) 72,000 type IV collagenase (MMP-2) was measured in 87 lung cancer patients. Stage IV cancer levels were significantly elevated (P less than 0.0001) compared to normal sera. A significant difference (P less than 0.01) was found between enzyme levels in the presence versus the absence of distant metastasis. For 29 patients treated with combination chemotherapy, a positive relationship was noted between response failure and elevated enzyme levels. Serum metalloproteinase levels may provide information relevant to prognosis as well as treatment decisions.  相似文献   
92.
BACKGROUND: Coronary vasculopathy is the main cause of cardiac graft failure. Because yearly coronary angiography is invasive in children, a non-invasive method for detecting graft vasculopathy is needed. The aim of this study was to test dobutamine-stress echocardiography in a pediatric population to determine its feasibility, safety and reliability in the detection of graft coronary artery disease. METHODS: Eighteen patients, aged 2 days to 16.8 years at transplantation (mean 8.4 years), underwent 44 dobutamine-stress echocardiography (DSE) exams, at a follow-up of 1.1 to 11.8 years (mean 5.1 years). Selective coronary angiography was performed for comparison. Echocardiographic recordings were obtained in 4 standard views of the left ventricle and measurements carried out within the frames of a 16-segment model. Segmental scores of contractility were obtained for each segment and a total segmental contractility index was calculated at each stage. RESULTS: All patients reached the maximum dose stage. Maximum heart rate was 57% to 90% of predicted maximum. Maximum systolic blood pressure reached 190 mmHg. Segmental scores were normal in 37 and abnormal in 7 cases. Echographic results were concordant with angiography in 82% and discordant in 18% of the cases (4 negative DSEs with minor angiographic lesions, 2 positive DSEs with normal angiography), but there was no significant angiographic lesion with normal DSE. CONCLUSIONS: DSE is a safe and highly feasible non-invasive technique in transplanted children. A normal DSE study successfully predicts the absence of significant coronary artery disease in the post-transplant population.  相似文献   
93.
针刀配合膝关节间断主动活动治疗膝关节强直   总被引:1,自引:0,他引:1  
张天民  曹恒君  邵高海 《中国骨伤》2003,16(12):752-753
膝关节强直是膝关节及关节周围创伤、关节炎晚期及手术后的严重并发症,同时伴有髌骨活动度严重减少甚至消失.病理多为髌上囊及两侧沟的广泛粘连,部分患者伴有关节外结构的挛缩.物理治疗几乎无效、开放性手术切开松解及关节镜下松解创伤大,出血多,存在再粘连的可能性,手术并发症多,一次手术失败,没有再次松解的机会.我院自1997年8月-2002年3月,应用针刀闭合松解加关节间断主动活动治疗严重膝关节粘连52例疗效满意.……  相似文献   
94.
超声抽吸法治疗下肢原发性淋巴水肿   总被引:2,自引:0,他引:2  
目的观察超声抽吸法治疗下肢原发性淋巴水肿的疗效。方法为12例患者采用内超声脂肪抽吸机吸除淋巴水肿组织以降低患肢淋巴负荷,抽吸后结合持续弹力袜裤压扎。结果术后2周水肿即时消退明显,术后1年随访水肿消退,复发不明显。结论超声抽吸法治疗原发性淋巴水肿安全简便,结合弹性袜裤压扎可望取得较好的远期疗效。  相似文献   
95.
目的:研究开He患者的舌位置有无特征性变异。方法:利用舌背碘油造影方法,增加头颅侧位定位X线片上舌背的显影效果,在头颅侧位定位X线片上以舌体在固有口腔内的相对位置确定舌体的位置,通过开He与正常He者知位置的团体t检验比较,找出开He患者的舌位置变异特性。结果:开He患者与正常He者比较,舌根部与悬雍垂之间的间隙增大,舌背部与腭表面之间的间隙减小,舌尖部更靠近牙齿,结论:开He个体相对于正常He个体舌位置有向前,向上的变化特点,这可能是开He的病因之一。  相似文献   
96.
目的 探讨参麦注射液对冠心病 (CHD)心绞痛的治疗作用。方法  80例患者分为两组 ,每组 4 0例 ,在常规治疗的基础上 ,对照组应用丹参注射液进行治疗 ,治疗组应用参麦注射液进行治疗。结果 治疗组有效 39例 (97.5 % ) ,心电图改善 38例 (95 .0 % ) ,对照组分别为 31例 (77.5 % )和 2 9例 (72 .5 % ) ,组间比较具有显著性差异 (P <0 .0 1)。结论 参麦注射液对冠心病心绞痛疗效显著 ,且安全、无明显副作用  相似文献   
97.
BACKGROUND: Sodium removal (NaR) may have a major impact on the survival of peritoneal dialysis patients. The dialysate/plasma sodium concentration ratio (D/P(Na)) is an indirect index of transcellular water transport by aquaporin channels, and thus of ultrafiltration. Sodium concentration can be assessed by means of flame photometry (F), and direct (D-ISE) or indirect ion-selective electrodes (I-ISE), but these methods have different properties. I-ISE is being used increasingly in clinical laboratories. The aim of this study was to evaluate NaR and D/P(Na) using the three different measurement methods. METHODS: We performed peritoneal equilibration tests (PETs) in 44 peritoneal dialysis patients and calculated the NaR. We also calculated D/P(Na) during the test; plasma and dialysate sodium concentrations were measured by F, D-ISE and I-ISE. RESULTS: NaR was lower (P<0.001) with D-ISE (69+/-29 mmol) than with F (81+/-29 mmol) or I-ISE (79+/-28 mmol). D/P(Na) was also lower at baseline (0.92+/-0.02 vs 0.95+/-0.02 and 0.95+/-0.02; P<0.001), after 60 min (0.87+/-0.03 vs 0.90+/-0.03 and 0.90+/-0.03; P<0.001) and at the end of PET (0.88+/-0.04 vs 0.92+/-0.04 and 0.92+/-0.04; P<0.001) when measured by D-ISE in comparison with F and I-ISE, respectively. CONCLUSIONS: NaR and D/P(Na) were lower when measured by the D-ISE method compared with the F and I-ISE methods. NaR and D/P(Na) were similar when measured by F or I-ISE. I-ISE can be used reliably in the evaluation of NaR and D/P(Na) in everyday clinical practice of peritoneal dialysis.  相似文献   
98.
目的:探讨应激对下丘脑室旁核中Fos表达的影响,以期揭示应激性溃疡发病的神经内分泌机制。方法:采用SD大鼠冷束缚应激模型,用免疫组织化学方法检测应激前后大鼠下丘脑室旁核Fos的表达。结果:应激后室旁核Fos阳性细胞数量显著增多(t=26.7,P<0.001)。结论:室旁核可能参与了应激性溃疡的病理过程。  相似文献   
99.
100.
A series of 1153 fine-needle aspiration biopsies (FNAB) of breast masses obtained during the period 1985 to 1988 in one institution was examined. The following diagnostic accuracy values were found: sensitivity, 93.0%; specificity, 92.4%; predictive positive value, 93.7%; and efficiency, 92.8%. These results were compared with a previously published series for the period 1976 to 1984. The diagnostic accuracy values did not differ significantly between the two series.  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