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   65052篇
  免费   6074篇
  国内免费   4945篇
耳鼻咽喉   642篇
儿科学   721篇
妇产科学   621篇
基础医学   7772篇
口腔科学   1122篇
临床医学   8639篇
内科学   9568篇
皮肤病学   621篇
神经病学   3571篇
特种医学   2610篇
外国民族医学   34篇
外科学   6803篇
综合类   11124篇
现状与发展   16篇
一般理论   1篇
预防医学   4377篇
眼科学   1885篇
药学   6869篇
  52篇
中国医学   3332篇
肿瘤学   5691篇
  2024年   160篇
  2023年   948篇
  2022年   2055篇
  2021年   3393篇
  2020年   2490篇
  2019年   2176篇
  2018年   2311篇
  2017年   2043篇
  2016年   1946篇
  2015年   3109篇
  2014年   3736篇
  2013年   3198篇
  2012年   4972篇
  2011年   5490篇
  2010年   3543篇
  2009年   2617篇
  2008年   3298篇
  2007年   3512篇
  2006年   3374篇
  2005年   3482篇
  2004年   2216篇
  2003年   2105篇
  2002年   1762篇
  2001年   1408篇
  2000年   1583篇
  1999年   1627篇
  1998年   1115篇
  1997年   1039篇
  1996年   789篇
  1995年   729篇
  1994年   699篇
  1993年   412篇
  1992年   481篇
  1991年   436篇
  1990年   379篇
  1989年   330篇
  1988年   256篇
  1987年   231篇
  1986年   171篇
  1985年   122篇
  1984年   69篇
  1983年   62篇
  1982年   48篇
  1981年   38篇
  1980年   22篇
  1979年   23篇
  1976年   7篇
  1975年   9篇
  1973年   8篇
  1958年   14篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Changes in T .lymphocyte subsets after severe traumatic brain inJury   总被引:2,自引:0,他引:2  
BACKGROUND: Besides local changes of cranial parenchymal cells, hemorrhage, etc., severe traumatic brain injuries also cause the changes of total body fluid and various functions, and the changes of lymphocytes and T lymphocyte subsets should be paid more attention to. OBJECTIVE: To reveal the changing laws of T lymphocyte subsets after severe traumatic brain injury, and compare with mild to moderate brain injury. DESIGN: A comparative observation. SETTINGS: Department of Neurosurgery, Longgang District Buji People's Hospital of Shenzhen City; Central Laboratory of Shenzhen Hospital of Prevention and Cure for Chronic Disease. PARTICIPANTS: All the subjects were selected from the Department of Neurosurgery, Longgang District Buji People's Hospital of Shenzhen City from August 2002 to August 2005. Thirty patients with severe brain injury, whose Glasgow coma score (GCS) was ≤ 8 points, were taken as the experimental group, including 21 males and 9 females, aging 16 - 62 years. Meanwhile, 30 patients with mild traumatic brain injury were taken as the control group (GCS ranged 14- 15 points), including 18 males and 12 females, aging 15 -58 years. All the subjects were in admission at 6 hours after injury, without disease of major organs before injury Informed consents were obtained from all the patients or their relatives. METHODS: (1) The T lymphocytes and the subsets in peripheral blood were detected with immunofluorescent tricolor flow cytometry at l, 3, 7 and 14 days after injury in both groups. (2) The conditions of pulmonary infections were observed at 4 days after injury. The differences of measurement data were compared with the t test. MAIN OUTCOME MEASURES: Changes of T lymphocytes subsets at 1 - 14 days after severe and mild or moderate traumatic injury. RESULTS: Finally, 28 and 25 patients with mild to moderate traumatic brain injury, whereas 25 and 21 patients with severe traumatic brain injury were analyzed at 7 and 14 days respectively, and the missed ones died due to the development of disease. (1) Changes of T lymphocyte subsets: At 1 and 3 days after injury, CD3, CD4, CD8, CD4/CD8 began to decrease, whereas CD8 increased in the experimental group, which were very significantly different from those in the control group (t =2.77 - 3.26, P 〈 0.01), and began to recover at 7 days, which were significantly different from those in the control group (t = 2.06 - 2.24, P 〈 0.05), and generally recovered to the normal levels at 14 days (P 〉 0.05). (2) Conditions of pulmonary infections: At 4 days after injury, the rate of pulmonary infection was significantly different between the experimental group and control group [73% (22/30), 0, x2=37.29, P 〈 0.01]. CONCLUSION: Patients with severe traumatic brain injury suffer from damages of cellular immune function at early period (within 7 days), and they are easily to be accompanied by pulmonary infections.  相似文献   
72.
作者用同位数前体参入法及透射与扫描电镜研究了平阳霉素(博莱霉素A_5)对HeLa细胞大分子生物合成及超微结构的影响。结果显示:平阳霉素能抑制HeLa细胞DNA,RNA和蛋白质的生物合成,对DNA的抑制作用强,ID_(50DNA)为42.77μg/ml。表现为:染色质减少,核内电子密度低,核仁分离及“核仁帽”形成,细胞表面微绒毛消失或变形,最终导致质膜破裂等。作者认为,细胞膜是否为此类药物作用的靶位值得进一步研究。  相似文献   
73.
中国传统的礼仪制度是在以身份等级制为内核的社会架构中形成的,同时又对传统的社会形态起着维系的作用。然而,至明代中晚期,婚、丧、冠、寿、社交等礼仪惯制却发生了诸多变异,并在江南地区尤为典型地表现出来。考察并分析当时的礼仪之变,可以发现。婚礼的变古出新,丧礼的淆乱旧制,冠礼的废弛,寿诞礼的盛行,人际交往的尊卑失序。所反映的正是社会的震荡与变迁。  相似文献   
74.
图书馆要做好读者服务工作,只有加强图书馆专业队伍建设,丰富读书活动,优化馆藏结构,创新信息服务,树立“读者第一,服务至上”的理念,才能适应社会的发展,最大限度地满足读者的需求。  相似文献   
75.
淋巴瘤样肉芽肿与韦格内肉芽肿临床特点的比较   总被引:2,自引:0,他引:2  
戚务芳  蒋明  赵岩 《北京医学》2005,27(1):15-17
目的 总结淋巴瘤样肉芽肿病(lym phom atoid granulom atosis,LG)与韦格内肉芽肿( egener granulo Wm atosis,W G)的临床特点,从临床上加以鉴别。 方法 回顾性总结我院与北京协和医院 1989 年以来收治的 6 例 LG和20 例 W G 患者的临床资料,并进行比较。 结果 发热、咳嗽及呼吸困难在 LG 中较常见,流涕、鼻衄及关节痛以W G 为多,肺受累以 LG 为多,耳鼻喉、眼及肾病变在 W G 中明显增多,皮肤受损两者相似。W G 患者常有 c-ANCA 阳性及尿沉渣异常。 LG X 线胸片为双侧多发结节,边界不清,多无肺门、纵隔淋巴结肿大; G 则为双侧多发边界清晰W的结节, 易形成空洞, 肺门和纵隔淋巴结可肿大。LG 病理改变为血管中心性淋巴增生性病变, 浸润的细胞主要是小淋巴细胞和不同数量大的不典型淋巴细胞; 而在 W G 中可见坏死性血管炎及大量中性白细胞、浆细胞及少量嗜酸细胞浸润形成的肉芽肿, 部分有多核巨细胞。W G 经治疗后, 多数患者病情缓解; 则疗效不佳。 结论 LG 和 W G 在临 LG床表现、实验室检查、 影像及病理诸方面的差异有利于两者的鉴别诊断。  相似文献   
76.
周建军  高峰  杜江 《医学影像学杂志》2006,16(12):1293-1293,1301
患者女性,53岁。不能左侧卧位近1月,下蹲时感腹痛、左侧胸闷1周,遂来我院就诊。既往史:1993年外伤致左肱骨骨折。体检:T:37.2℃,P:86次/min,R:22分/次,BP:120/80mmHg,呼吸稍促,左肺呼吸运动度减弱,胸廓无压痛。左下肺叩诊呈浊音,左下肺呼吸音减弱,右肺呼吸正常。心脏无阳性体征。腹平,无胃肠型及蠕动波,腹软,上腹部轻微压痛,无反跳痛及肌紧张,肝脾肋下未触及,移动浊音阴性,肠鸣音弱。实验室检查:血常规:WBC:10.5×109/L,NCU:62.8%,HGB:42g/L,PLT:147×109/L。影像学检查X线示:胸部后前位左下肺可见斑片状密度增高影,左侧膈面上升,…  相似文献   
77.
目的观察纳洛酮合参麦注射液治疗慢性阻塞性肺病合并Ⅱ型呼吸衰竭的效果。方法在常规治疗基础上,治疗组用纳洛酮、参麦注射液治疗本病34例,并设对照组对比。结果治疗组、对照组总有效率分别为85.3%、70.6%,治疗组优于对照组(P<0.05)。治疗组在治疗后各项指标比较均优于对照组(P<0.01或P<0.05)。结论本方法对本病有改善症状,缩短病程的功效。  相似文献   
78.
OBJECTIVE: To examine health care seeking pathways for patients with tuberculosis (TB) and barriers related to these pathways in counties under the National TB Control Programme in rural China. METHODS: A cross-sectional study was conducted in two counties of east China in 2004-2005. A total of 557 TB patients were recruited and interviewed by physicians at the time of TB diagnosis. RESULTS: Of 557 participants, 13.3% had presented to a specialised county TB dispensary (CTD) directly after onset of symptoms, 31.4% had first sought care at a village health station and 51.2% had visited a township or county hospital first. The proportion of referral by a first health care provider to a CTD was highest in county level hospitals (73.5%) and lowest in village health stations (21.7%). The most prompt pathway from first health care seeking to TB diagnosis was to visit a CTD directly, with a median provider's delay of only one day. There was an increase in provider's delay when more health facilities were involved. CONCLUSION: To improve direct referral from general health care providers, especially village health care workers, to TB specialists would significantly shorten the delays in TB diagnosis in rural China.  相似文献   
79.
80.
On genetic studies of bone loss.   总被引:3,自引:0,他引:3  
  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