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   501139篇
  免费   37889篇
  国内免费   10760篇
耳鼻咽喉   6700篇
儿科学   12463篇
妇产科学   8686篇
基础医学   40277篇
口腔科学   13310篇
临床医学   52398篇
内科学   56468篇
皮肤病学   6484篇
神经病学   27142篇
特种医学   12397篇
外国民族医学   40篇
外科学   51891篇
综合类   77866篇
现状与发展   19篇
一般理论   52篇
预防医学   59354篇
眼科学   6646篇
药学   48131篇
  641篇
中国医学   47875篇
肿瘤学   20948篇
  2023年   8325篇
  2022年   13449篇
  2021年   21005篇
  2020年   20124篇
  2019年   24550篇
  2018年   22101篇
  2017年   19005篇
  2016年   16585篇
  2015年   15690篇
  2014年   31707篇
  2013年   33463篇
  2012年   29085篇
  2011年   31212篇
  2010年   25229篇
  2009年   22550篇
  2008年   21544篇
  2007年   21953篇
  2006年   19056篇
  2005年   16368篇
  2004年   13380篇
  2003年   11713篇
  2002年   9214篇
  2001年   8058篇
  2000年   6821篇
  1999年   5785篇
  1998年   4710篇
  1997年   4414篇
  1996年   3756篇
  1995年   3574篇
  1994年   3379篇
  1993年   2788篇
  1992年   2729篇
  1991年   2400篇
  1990年   2122篇
  1989年   1952篇
  1988年   1839篇
  1987年   1601篇
  1986年   1494篇
  1985年   4715篇
  1984年   5757篇
  1983年   4061篇
  1982年   4761篇
  1981年   4129篇
  1980年   3662篇
  1979年   3363篇
  1978年   2886篇
  1977年   2186篇
  1976年   2492篇
  1975年   1844篇
  1974年   1619篇
排序方式: 共有10000条查询结果,搜索用时 968 毫秒
991.
目的 探讨重组大鼠肝再生增强因子(rrALR)对庆大霉素所致急性肾衰竭(ARF)大鼠肾小管上皮细胞及肾功能的保护作用。 方法 雌性Wistar大鼠150只,随机分成5组,每组30只,即健康对照组,ARF模型组,模型+空质粒对照组(空质粒组),模型+rrALR干预组(ALR组):根据给予rrALR的剂量不同分为ALR1组和ALR2组两个亚组。分别于实验的第4、8、12、16和21天每组随机抽取6只大鼠在留取血、尿标本后,处死大鼠并取肾组织标本。常规生化方法检测各组大鼠BUN、Scr和尿N-乙酰-β-D-葡萄糖苷酶(NAG)酶的变化;PAS染色观察各组大鼠肾组织病理学改变;免疫组化法检测大鼠肾组织中ALR和增殖细胞核抗原(PCNA)的表达;Western印迹法检测肾组织中ALR蛋白的表达量。 结果 ARF大鼠各组BUN、Scr及尿NAG酶水平在第4、8、12、16天时均较对照组显著升高(P < 0.05)。与模型组和空质粒组相比,ALR组BUN、Scr及尿NAG酶水平明显降低(P < 0.05);肾组织病理损害程度在各时间点明显减轻;而肾组织的ALR蛋白表达增加(P < 0.05);肾小管上皮细胞增殖活跃;PCNA阳性细胞呈弥漫性分布,增殖指数(PI)明显升高(P < 0.05)。 结论 rrALR对急性损伤的肾小管上皮细胞具有减轻病变和促进再生修复的作用,可明显改善ARF大鼠的肾功能。  相似文献   
992.
比较对新诊断2型糖尿病患者应用瑞格列奈(11例)和迪沙片(10例)治疗4周后空腹血糖(FPG)、餐后2h血糖(2hPG)、晨3点血糖(3aPG),空腹胰岛素(FIns)、餐后2h胰岛素(2hIns),糖化白蛋白的值。结果显示,与迪沙片组相比,瑞格列奈组治疗后空腹血糖、餐后2h血糖的下降幅度更为明显,但低血糖的发生次数反而减少。  相似文献   
993.
994.
目的探讨股骨近端纤维结构不良的手术治疗方式。方法对19例股骨近端纤维结构不良的不同手术治疗方式及术后疗效进行回顾性分析。结果1例术后3d引流管口渗出血清样物质,加强抗感染、营养支持及换药处理后愈合。19例均获随访,时间13—58个月。复查X线片见缺损修复区内有新骨生成改变,骨折处骨愈合;1例术后20个月因外伤致股骨转子下内固定物旁骨折再次手术发现肿瘤复发,行再次刮除植骨内固定术后14个月愈合;除1例未行内固定的病例外,余患者术后患肢功能均得到良好恢复,8—12个月可弃拐行走。结论股骨近端纤维结构不良应积极手术治疗,在彻底刮除病变和充分植骨的基础上,强调内固定的应用。  相似文献   
995.
邻近节指背筋膜(蒂)皮瓣修复手指皮肤软组织缺损   总被引:3,自引:3,他引:0  
目的报道应用手指缺损创面的邻近节指背筋膜(蒂)皮瓣修复手指皮肤组织缺损的方法。方法2004年10月~2006年8月,根据受区皮肤缺损的面积及形状,在供区设计斜形皮瓣修复手指皮肤软组织缺损创面共27例。结果皮瓣全部成活,术后3~20个月随访,皮瓣质地优良,外形与感觉功能恢复满意。结论手指缺损创面的邻近节指背筋膜(蒂)皮瓣手术操作简单、安全可靠,术后治疗、护理容易,外形与功能恢复良好,是手外科修复手指皮肤软组织缺损创面较为理想的方法,值得推广。  相似文献   
996.
Iron deficiency (ID) is one of the most commonly known forms of nutritional deficiencies. Low body iron is thought to induce neurologic defects but may also play a protective role against cancer development by cell growth arrest. Thus, ID may affect cellular pathways controlling cell growth and proliferation, the mechanism of which is still not fully understood. The serine/threonine protein kinase Akt and its downstream target, the mammalian Target of Rapamycin (mTOR), is known to play a crucial role in the regulation of cell growth and survival. Therefore, we hypothesized that Akt/mTOR pathway could be influenced by ID. Three-week-old male Wistar-strain rats were divided into 3 groups and the 2 groups had free access to a control diet (C group) or an iron-deficient diet (D group). The third group (PF group) were pair-fed the control diet to the mean intake of the D group. After 4 weeks, rats were killed and their brains were sampled. In separate experiments, COS-1 cells were cultured with or without the iron chelator deferoxamine. Western blots of brain samples and COS-1 lysates were used to analyze the expression and phosphorylation state of Akt, TSC2, mTOR, and S6 kinase proteins implicated in the Akt/mTOR pathway. Using 2 different ID models, we show for the first time that iron deficiency depresses Akt activity in rats and in COS-1 cells, leading to a decrease in mTOR activity.  相似文献   
997.
奥运志愿者精神是北京奥运会的宝贵精神遗产。充分发挥奥运志愿者精神的社会教育作用,有利于提升当代大学生的奉献精神,激发其创新能力;同时,奥运志愿者精神也是培育大学生党员的重要载体。  相似文献   
998.
Flavocoxid (Limbrel), a proprietary mixture of flavonoid molecules (baicalin and catechin), was tested against a traditional nonsteroidal anti-inflammatory drug, naproxen, for the management of the signs and symptoms of moderate osteoarthritis (OA) in humans. Discomfort and global disease activity were used as the primary end points, and safety assessments were also taken for both treatments as a secondary endpoint. In this double-blind study, 103 subjects were randomly assigned to receive either flavocoxid [500 mg twice daily (BID)] or naproxen (500 mg BID) in a 1-month onset of action trial. Outcome measures included the short Western Ontario and McMaster University Osteoarthritis Index, subject Visual Analogue Scale for discomfort and global response, and investigator Visual Analogue Scale for global response and fecal occult blood. Both flavocoxid and naproxen showed significant reduction in the signs and symptoms of knee OA (P ≤ .001). There were no statistically detectable differences between the flavocoxid and naproxen groups with respect to any of the outcome variables. Similarly, there were no statistically detectable differences between the groups with respect to any adverse event, although there was a trend toward a higher incidence of edema and nonspecific musculoskeletal discomfort in the naproxen group. In this short-term pilot study, flavocoxid was as effective as naproxen in controlling the signs and symptoms of OA of the knee and would present a safe and effective option for those individuals on traditional nonsteroidal anti-inflammatory drugs or cyclooxygenase-2 inhibitors. A low incidence of adverse events was reported for both groups.  相似文献   
999.
目的分析总结外伤性脑疝前驱期特征性临床征象及意义。方法回顾分析我科近5年238例脑疝发生前2h内的临床表现和辅助检查特点,并与同期198例未发生脑疝的重型颅脑损伤患者进行对比分析。结果脑疝组前驱期征象如昏迷加深、烦躁加重、尿失禁、侧脑室和外侧裂受压变窄伴脑基底池受压变窄、生命体征改变具有特征性,其发生率明显高于非脑疝组,两组差异有显著性意义(P〈0.01)。结论颅脑损伤患者出现脑疝前驱期特征性临床征象应作为超早期开颅的重要依据,是特殊的、迫切的手术指征。  相似文献   
1000.
Acute encephalopathy associated with influenza and other viral infections   总被引:7,自引:0,他引:7  
Acute encephalopathy is the most serious complication of pediatric viral infections, such as influenza and exanthem subitum. It occurs worldwide, but is most prevalent in East Asia, and every year several hundreds of Japanese children are affected by influenza-associated encephalopathy. Mortality has recently declined, but is still high. Many survivors are left with motor and intellectual disabilities, and some with epilepsy. This article reviews various syndromes of acute encephalopathy by classifying them into three major categories. The first group caused by metabolic derangement consists of various inherited metabolic disorders and the classical Reye syndrome. Salicylate is a risk factor of the latter condition. The second group, characterized by a systemic cytokine storm and vasogenic brain edema, includes Reye-like syndrome, hemorrhagic shock and encephalopathy syndrome, and acute necrotizing encephalopathy. Non-steroidal anti-inflammatory drugs, such as diclofenac sodium and mephenamic acid, may aggravate these syndromes. Severe cases are complicated by multiple organ failure and disseminated intravascular coagulation. Mortality is high, although methylprednisolone pulse therapy may be beneficial in some cases. The third group, characterized by localized edema of the cerebral cortex, has recently been termed acute encephalopathy with febrile convulsive status epilepticus, and includes hemiconvulsion-hemiplegia syndrome and acute infantile encephalopathy predominantly affecting the frontal lobes. Theophylline is a risk factor of these syndromes. The pathogenesis is yet to be clarified, but an increasing body of evidence points to excitotoxicity and delayed neuronal death.  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