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   57090篇
  免费   4667篇
  国内免费   1608篇
耳鼻咽喉   344篇
儿科学   1424篇
妇产科学   1098篇
基础医学   5713篇
口腔科学   1114篇
临床医学   6274篇
内科学   10610篇
皮肤病学   418篇
神经病学   2750篇
特种医学   970篇
外国民族医学   11篇
外科学   3113篇
综合类   8378篇
现状与发展   9篇
预防医学   6939篇
眼科学   296篇
药学   7065篇
  23篇
中国医学   1879篇
肿瘤学   4937篇
  2024年   93篇
  2023年   829篇
  2022年   1487篇
  2021年   2681篇
  2020年   2071篇
  2019年   1972篇
  2018年   1966篇
  2017年   1973篇
  2016年   2268篇
  2015年   2417篇
  2014年   3966篇
  2013年   4636篇
  2012年   3948篇
  2011年   4161篇
  2010年   3188篇
  2009年   2976篇
  2008年   3084篇
  2007年   3034篇
  2006年   2553篇
  2005年   2194篇
  2004年   1811篇
  2003年   1419篇
  2002年   1157篇
  2001年   1048篇
  2000年   830篇
  1999年   725篇
  1998年   596篇
  1997年   582篇
  1996年   500篇
  1995年   387篇
  1994年   377篇
  1993年   285篇
  1992年   287篇
  1991年   240篇
  1990年   178篇
  1989年   178篇
  1988年   121篇
  1987年   150篇
  1986年   100篇
  1985年   158篇
  1984年   112篇
  1983年   68篇
  1982年   98篇
  1981年   79篇
  1980年   73篇
  1979年   53篇
  1978年   38篇
  1977年   48篇
  1976年   44篇
  1975年   31篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
平阳霉素加地塞米松局部注射治疗婴幼儿血管瘤   总被引:6,自引:0,他引:6  
目的探讨平阳霉素+地塞米松局部注射治疗婴幼儿血管瘤的疗效。方法将平阳霉素8 mg+地塞米松5 mg+2%利多卡因1~2 ml+生理盐水3~8 ml稀释后,行血管瘤内注射至肿胀发白为限,1次平阳霉素用量不超过8 mg。观察2周,视瘤体颜色及硬度决定是否继续用药,直至瘤体开始变硬萎缩为止,平阳霉素注射总量不超过40 mg。近两年来,用该方法治疗1~8个月龄婴幼儿体表增生期血管瘤36例,其中颜面部24例,胸部3例,背部2例,上肢5例,足2例;草莓状血管瘤30例,混合型血管瘤6例。血管瘤最小面积0.6 cm×1.2 cm,最大面积23.0 cm×12.0 cm。结果1次注射治愈2例,2~3次注射治愈25例,4~5次治愈9例,其中局部坏死1例(为足背足底大面积草莓状血管瘤),经换药及手术愈合。随访6~19个月,未见复发,除1例遗留瘢痕外,其余全部无瘢痕愈合。有效率达100%。结论平阳霉素+地塞米松局部注射治疗婴幼儿血管瘤,具有疗效显著、简便易行、安全可靠等优点,是治疗增生期血管瘤首选方法之一,值得推广。  相似文献   
102.
目的 评价耐药对地区肺结核病治疗效果的影响.方法 对上海地区2004年2月-9月新登记敏感及耐药肺结核病人1年治疗转归进行分析和比较.结果 在全市各区(县)结核病定点医院新登记1 597例肺结核病病人中,805例培养阳性,其中731例经菌型鉴定为结核分枝杆菌的病人纳入分析.731例病人的总耐药率为18.7%,耐多药率为6.7%.敏感组治疗成功率达到93.0%,非MDR的耐药病人治疗成功率达到85%以上,MDR组治疗成功率为71.4%.经x2检验,差别有统计学意义(x2=83.996 8,P<0.01).在68例治疗不成功的病人中,耐药病人占38.2%;而在30例治疗失败的病人中,耐药病人占60%.复治敏感病人的治疗成功率(92.0%)与初治敏感病人(93.1%)相当,但是复治耐药病人的治疗成功率远低于初治耐药病人.结论 (1)上海地区肺结核病病人治疗管理效果良好;(2)耐药是肺结核病治疗失败的重要因素,应加强和改进对耐药结核病的治疗措施;(3)耐药和敏感病人治疗效果存在较大差异,应分别评价.  相似文献   
103.
目的:评价乳胶结合实验,检测重症监护病房(ICU)耐甲氧西林金黄色葡萄球菌(MRSA)及其肠毒素(SE),并进行耐药性分析。方法:收集260株金黄色葡萄球菌临床分离株,通过药敏试验将其分为耐甲氧西林金黄色葡萄球菌和甲氧西林敏感金黄色葡萄球菌(MSSA),用反向间接血凝试验(RPHA)检测金黄色葡萄球菌肠毒素。结果:MRSA产肠毒素为134株,MSSA产肠毒素为38株,MRSA产肠毒素率为100%,MSSA产肠毒素率为30%。结论:重症监护病房应重视MRSA的检测和金黄色葡萄球菌肠毒素的检测,合理使用广谱抗菌药物。  相似文献   
104.
目的研制新型加速器放疗网络。方法采用服务器-客户端模式.服务器采用SQL—Server2000为数据库服务软件,客户端使用VC++6.0语言编写.通过RTP—Link以及DICOMRT和新型加速器连接传输病人治疗参数资料。结果成功研锚的新型加速器放疗网络包括病人资料管理模块、定位计划管理模块、定位图像预处理模块、靶区勾画模块、计划设计管理模块(包含MLC(多叶光栅)设计以及低熔点挡铅设计)和治疗参数输出(包括报表打印、连接加速器)。结论网络系统操作简单,适合新型全数字化加速器的常规放射治疗管理.是科室常规放疗治疗的质量保证(QA)和质量控制(QC)的有效工具。  相似文献   
105.
106.
BACKGROUND: Chronic kidney disease patients who are resistant to erythropoietin (EPO) treatment may suffer from malnutrition and/or inflammation. METHODS: In a cross-sectional study of haemodialysis patients, we investigated the relationship between the natural logarithm of the weekly EPO dose normalized for post-dialysis body weight and outcome measures of nutrition and/or inflammation [BMI, albumin and C reactive protein (CRP)] by means of multiple linear regression analysis. On the basis of the decile distribution of weekly EPO doses, we also evaluated four groups of patients: untreated, hyper-responders, normo-responders and hypo-responders. RESULTS: Six hundred and seventy-seven adult haemodialysis patients were recruited from five Italian centres. BMI and albumin were lower in the hypo-responders than in the other groups (21.3+/-3.8 vs 24.4+/-4.7 kg/m(2), P<0.001; and 3.8+/-0.6 vs 4.1+/-0.4 g/dl, P<0.001), whereas the median CRP level was higher (1.9 vs 0.8 mg/dl, P = 0.004). The median weekly EPO dose ranged from 30 IU/kg/week in the hyper-responsive group to 263 IU/kg/week in the hypo-responsive group. Transferrin saturation linearly decreased from the hyper- to hypo-responsive group (37+/-15 to 25+/-10%, P = 0.003), without any differences in transferrin levels. Ferritin levels were lower in the hypo-responsive than in the other patients (median 318 vs 445 ng/ml, P = 0.01). At multiple linear regression analysis, haemoglobin, BMI, albumin, CRP and serum iron levels were independently associated with the natural logarithm of the weekly EPO dose (R(2) = 0.22). CONCLUSIONS: Our findings support a clear association between EPO responsiveness and nutritional and inflammation variables in haemodialysis patients; iron deficiency is still a major cause of hypo-responsiveness.  相似文献   
107.
Summary— To investigate if the functional alterations observed in resistance arteries of spontaneously hypertensive rats (SHRs) were also present at the coronary level, in vitro experiments were performed in mesenteric resistance arteries (MRA) and in right (RIC) and left interventricular coronary (LIC) arteries taken from 15–25-week-old SHR and age-matched Wistar Kyoto rats WKYs. Using a passive extension protocol, internal diameters corresponding to 100 mmHg intraluminal pressure (D100) were determined and vessels were set up to a normalized internal diameter (0.9 D100). SHR mesenteric resistance arteries had a significantly smaller diameter compared to WKY arteries, whereas both types of SHR coronary arteries had a greater diameter compared to those of WKY rats. In arteries in the absence of contracting agonist, nitro-L-arginine (NOLA, 100 μM) induced a progressive rise in basal tone, which could be reversed by subsequent addition of L-arginine (100 μM) but not D-arginine (100 μM). When expressed as percent of maximal contractions induced by agonists (noradrenaline, NA [10 μM] in MRA; serotonin, 5-HT [10 μM], in RIC and LIC), these contractions were significantly stronger in WKY compared to SHR coronary and mesenteric resistance arteries. In NA-precontracted MRA and 5HT-precontracted coronary arteries in the presence of indomethacin (10 μM), the magnitude of acetylcholine-induced maximal relaxations (expressed as percent of maximal contractions induced by agonists) was greater in WKY compared to SHR arteries. After a 30-min incubation period, NOLA (100 μM) completely inhibited relaxations induced by acetylcholine (0.01–10 μM) in all types of precontracted arteries. Subsequent additions of sodium nitroprusside, (SNP, 10 μM) induced complete relaxations in all preparations. These results show that a basal release of NO or NO-like compound by endothelial cells is present in isolated mesenteric resistance and coronary arteries of WKY rats and SHRs. The contribution of endothelium-derived relaxing factor-nitric oxide (EDRF-NO) to arterial tone was lower in MRA compared to coronary arteries in both strains and in SHR compared to WKY arteries. In the SHR preparations, the impaired relaxation induced by acetylcholine appeared to be due to a functional alteration of the endothelium in the presence of normal reactivity of the smooth muscle cells.  相似文献   
108.
赛赓啶对 KBV200细胞多药抗性的逆转作用   总被引:3,自引:0,他引:3  
研究赛赓啶对KBV200细胞多药抗性的逆转作用及逆转机制。在KBV200细胞,采用MTT法,测出赛赓啶对长春新碱、阿霉素和鬼臼乙叉甙耐药的逆转系数分别为5.5,2.0和1.9,而对5-氟尿嘧啶、美法仑的细胞毒性作用无明显影响,表明赛赓啶为多药抗性逆转剂。荧光分光光度法测定表明,赛赓啶可使KBV200细胞内阿霉素蓄积量增加。流式细胞荧光测定显示赛赓啶可增加罗丹明123的蓄积并减慢其外排。免疫细胞化学及狭缝杂交表明赛赓啶不影响KBV200细胞的P-糖蛋白染色深度和 mdr1 RNA 表达水平。以上结果提示赛赓啶的多药抗性逆转机制是抑制P-糖蛋白泵的功能。  相似文献   
109.
Multidrug resistance (MDR) is an important problem in chemotheraphy for neoplastic disease. In humans, MDR is mainly mediated by P-glycoprotein (P-gp), a product of theMDR1 gene, which acts as a transmembrane protein pump and eliminates chemotherapeutic agents from the cells. Expression of P-gp was immunohistochemically studied by using two monoclonal antibodies, JSB-1 and C-219, on paraffin-embedded sections from 55 patients with soft-tissue sarcoma. The histological diagnosis of tumors was malignant fibrous histiocytoma in 24 cases, liposarcoma in 9, synovial sarcoma in 7, malignant neurogenic tumors in 6, leiomyosarcoma in 5, others in 4. The histological grade was determined on the basis of criteria previously proposed by us. Out of 55 cases, 34 (62%) were positive for P-gp expression. There was a significant difference in P-gp expression between high-grade (90%) and intermediate and low-grade tumors (46%) (P<0.005). Tumors expressing P-gp had a less favorable prognosis than P-gp-negative tumors in the high- and intermediate-grade tumors. The current study demonstrated that the estimation of P-gp expression could be used to select appropriate therapeutic modalities.Abbreviations MDR multidrug resistance - P-gp P-glyco-protein  相似文献   
110.
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