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   93559篇
  免费   7909篇
  国内免费   4176篇
耳鼻咽喉   1292篇
儿科学   1478篇
妇产科学   540篇
基础医学   6190篇
口腔科学   1344篇
临床医学   13279篇
内科学   8635篇
皮肤病学   372篇
神经病学   8199篇
特种医学   5307篇
外国民族医学   3篇
外科学   19424篇
综合类   17098篇
现状与发展   3篇
一般理论   1篇
预防医学   5918篇
眼科学   1215篇
药学   8234篇
  69篇
中国医学   3988篇
肿瘤学   3055篇
  2024年   333篇
  2023年   1665篇
  2022年   3080篇
  2021年   4225篇
  2020年   4032篇
  2019年   3347篇
  2018年   3325篇
  2017年   3603篇
  2016年   3903篇
  2015年   3707篇
  2014年   6809篇
  2013年   7564篇
  2012年   6189篇
  2011年   6521篇
  2010年   5410篇
  2009年   4941篇
  2008年   4755篇
  2007年   4622篇
  2006年   4241篇
  2005年   3752篇
  2004年   2978篇
  2003年   2645篇
  2002年   2209篇
  2001年   1968篇
  2000年   1643篇
  1999年   1278篇
  1998年   1151篇
  1997年   967篇
  1996年   803篇
  1995年   667篇
  1994年   519篇
  1993年   438篇
  1992年   354篇
  1991年   270篇
  1990年   242篇
  1989年   218篇
  1988年   158篇
  1987年   155篇
  1986年   135篇
  1985年   180篇
  1984年   122篇
  1983年   73篇
  1982年   94篇
  1981年   89篇
  1980年   82篇
  1979年   50篇
  1978年   33篇
  1977年   35篇
  1976年   27篇
  1975年   13篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Prostaglandin E1 (PGE1) was used in renal transplant recipients with living related donors. The drug was given intravenously from day 1 to day 7 after transplantation at a dose of 40 µg/kg twice a day. A total of 45 patients were studied divided into two groups: 25 patients were treated with PGE1 (group B) and the remaining 20 patients did not receive the drug (group A). In group B, 24-h creatinine clearance (Ccr) was 66 ± 12.8 ml/min compared with 40.3 ± 13.4 ml/min in group A on the fifth postoperative day (P < 0.05). Urinary levels of N-acetyl-β-d -glucosaminidase (NAG) and serum levels of platelet factor 4 (PF4) in group B were significantly lower than in group A. On the fourth postoperative day, the urinary excretion of thromboxan B2 (TxB2) in group A was higher than in group B, but not significantly (5.1 ± 3.0 ng/day and 2.8 ± 1.1 ng/day, respectively). Acute rejection occurred in four patients in group B and in 10 patients (40%) in group A. The percentage of Leu2a-positive lymphocytes in group B was higher than in group A. We conclude that postoperative administration of PGE1 improves graft function in kidneys from living related donors.  相似文献   
42.
A lymph node metastasis in the neck or parotid region from an unknown primary melanoma is an uncommon occurrence. Out of a total of 300 patients with head and neck melanoma treated at the Netherlands Cancer Institute between 1976 and 1992, 17 (5.7%) presented in this way. The most common site for metastatic lymph nodes (18 nodes in 17 patients) was level V (n= 7), followed by the parotid region (n= 4), level II (n= 4), level III (n= 2), and level IV (n= 7). Two patients had local excision of the neck node metastasis only, while the remaining 15 patients underwent more extensive surgical treatment. The 5-year disease-specific survival rate in this group was 48%, with a median survival of 36 months, which is more or less similar to the prognosis of stage II melanoma of the head and neck with a known, surgically treated primary tumour. No relation was found between disease-free interval and sex, the number of positive lymph nodes or the duration of symptoms.  相似文献   
43.
格拉斯哥评分的纯数学意义及临床评估价值   总被引:2,自引:0,他引:2  
总结1022例颅脑外伤进行格拉斯哥评分的实践实验,从纯数学意义上评价了评分在临床上的应用价值。指出格拉斯哥评分各参数之间只有15种组合最常见且有临床价值。数学分析表明运动反应最有决定性意义;同时指出格拉斯可评分对患者预后判断有重要评估价值。评分的不足之处在于不能反映瞳孔改变和脑干症状。  相似文献   
44.
Summary A total of 208 multiple trauma patients with head injury (HI) were investigated who had been treated in the period from 1990 to 1995. The average age was 35.2 ± 17.7 years; the injury severity according to ISS was 30.2 ± 8.6 points; 20.5 % died as a result of the HI; the mortality of all patients was 26.5 %. The Glasgow Coma Scale (GCS) was determined at an average of 22 min after trauma (8.0 ± 4.3 points) at the scene of accident. The patients were classified according to GCS into minor HI (group 1: 14–15 points), moderate HI (group 2: 9–13 points) and severe HI (group 3: 3–8 points). Patient outcome was assessed by the Glasgow Outcome Scale (GOS) and was classified as good (GOS 4 and 5) and poor (GOS 1, 2 and 3) outcome. At the latest, 2 h after trauma, a CT scan of the head (CCT) was done. The HI groups are compared regarding frequency of types of injury. In all HI groups the fractures of the bony face occurred at the same frequency (36.0–38.9 %). The frequency of calotte fractures (Kal-Fx) increased from group 1 (8.0 %) to 2 (19.2 %) and 3 (25.6 %); fractures of the skull base significantly differed between group 1 (16.0 %), 2 (7.8 %) and 3 (33.4 %). Epidural hemorrhage (EDB) appeared only in group 2 (7.8 %) and 3 (6.7); subdural hemorrhage was found in group 1 (2.7 %), 2 (7.8 %) and 3 (10.0 %). Subarachnoid hemorrhage (SAB) was significantly more frequently seen, dependent on HI severity, in group 3 (26.7 %) compared to group 2 (11.7 %) and 1 (8.0 %). Intracerebral contusion (ICK) significantly increased from group 1 (12.0 %) to 2 (27.3) and 3 (45.6 %). Brain swelling (BS) also significantly increased from group 1 (8.0 %) to 2 (19.5 %) and 3 (49.0 %) and lesions of ventricles (VL) from group 1 (2.7 %) to 2 (11.7 %) and 3 (20.0 %). Midline shift (13.4 %) and signs of herniation (4.5 %) only occurred in group 3. The analysis of correlation/regression and receiver operating characteristics was able to predict 79 % of patients' outcome accurately using GCS (r 0.54; P < 0.0001) alone, using CCT (r 0.65; P < 0.0001) 87 % were correctly predicted with significant variables Cal-Fx, EDB, SAB and BS. CCT with GCS (r 0.74; P < 0.0001) were able to predict 88 % accurately with significant variables Cal-Fx, EDB, BS and GCS. The combination of CCT with GCS, age and ISS (r 0.78; P < 0.0001) was able to predict only 87 % correctly, although the r value was the highest; significant variables were Kal-Fx, EDB, BS, VL, GCS, age and ISS.   相似文献   
45.
An atypical variant of reflex sympathetic dystrophy (RSD) is presented in a 45 year old female with a vascular malformation of the right arm and chest wall. The mechanism was thought to be compression of the brachial plexus by the malformation. The unique scintigraphic features of this presentation of RSD in the ulnar arterial distribution are illustrated.  相似文献   
46.
Summary A newly designed attachment device of the multipurpose head frame (Sugita) for Neuronavigator (Watanabe) is presented with an illustrative case of glioblastoma in an eloquent area. This has extended the usefulness of the neuronavigator for those who prefer and use the multipurpose head frame, while the requirements for keeping a stereotactic combination and the original concept of the multipurpose head frame, as well as that of the neuronavigator have been kept undisturbed.  相似文献   
47.
Spinal cord injury (SCI) produces an increase in extracellular excitatory amino acid (EAA) concentrations that results in glutamate receptor-mediated excitotoxic events. An important class of these receptors is the metabotropic glutamate receptors (mGluRs). mGluRs can activate a number of intracellular pathways that increase neuronal excitability and modulate neurotransmission. Group I mGluRs are known to modulate EAA release and the development of chronic central pain (CCP) following SCI; however, the role of group II and III mGluRs remains unclear. To begin evaluating group II and III mGluRs in SCI, we administered the specific agonists for group II, APDC, or group III, L-AP4, by interspinal injection immediately following SCI. Contusion injury was produced at spinal segment T10 with a New York University impactor (12.5-mm drop, 10-g rod 2 mm in diameter) in 30 adult male Sprague-Dawley rats (175-200 g). Evoked and spontaneous behavioral measures of CCP, locomotor recovery, changes in mGluR expression, and amount of spared tissue were examined. Neither APDC nor L-AP4 affected locomotor recovery or the development of thermal hyperalgesia; however, L-AP4 and APDC attenuated changes in mechanical thresholds and changes in exploratory behavior indicative of CCP. APDC- and L-AP4-treated groups had higher expression levels of mGluR2/3 at the epicenter of injury on post contusion day 28; however, there was no difference in the amount of spared tissue between treatment groups. These results demonstrate that treatment with agonists to group II and III mGluRs following SCI affects mechanical responses, exploratory behavior, and mGluR2/3 expression without affecting the amount of tissue spared, suggesting that the level of mGluR expression after SCI may modulate nociceptive responses.  相似文献   
48.
参附注射液对肠缺血-再灌注大鼠肿瘤坏死因子α的影响   总被引:5,自引:0,他引:5  
目的观察肿瘤坏死因子α(TNF-α)在大鼠肠缺血-再灌注损伤过程中的作用及参附注射液对TNF-α的影响,探讨参附注射液防治肠缺血-再灌注损伤机制。方法 SD大鼠随机分为肠缺血-再灌注组(IR组)、参附注射液预处理组(SF组)和假手术组(C组)。采用阻断肠系膜上动脉(SMA)的方法制造肠缺血-再灌注模型。分别测定各组动物血浆、肠组织TNF-α含量及血液动力学变化;光镜观察肠粘膜损伤情况。结果IR组再灌注后MAP下降,与C组和SF组比有显著性差异(P<0.01);SF组肠粘膜损伤程度减轻,与IR组比有显著性差异(P<0.01);SF组血浆及肠组织TNF-α水平降低,与IR组比有显著性差异(P<0.01)。结论参附注射液可明显防治大鼠肠缺血-再灌注导致的肠粘膜损伤,这种作用可能是通过抑制TNF-α的释放实现的。  相似文献   
49.
金尔伦治疗急性颅脑损伤的剂量效应研究   总被引:2,自引:1,他引:1  
目的探讨金尔伦(盐酸纳洛酮)在治疗大鼠液压脑损伤后神经功能恢复和病理损害程度的剂量效应.方法将104只SD大鼠随机分为4组,伤后早期分别腹腔注射0.03 mg/Kg(小剂量组)、0.3 mg/Kg(中剂量组)、3 mg/Kg(大剂量组)金尔伦和等量生理盐水(对照组),连续7 d.结果中、大剂量组动物伤后脑神经功能恢复、脑水肿减轻程度及光、电镜检查显著优于对照组及小剂量组.结论伤后早期使用中剂量和大剂量金尔伦(盐酸纳洛酮)对大鼠液压颅脑损伤有明显的治疗效果.  相似文献   
50.
本文根据34例电击伤临床资料,分析早期处理与病人全身情况、局部损伤愈合以及并发症的关系.并讨论间生态组织的处理原则.结果表明:伤后1天内与伤后3天以上就诊的病人比较,前者全身情况良好,创面感染率低,局部损伤用皮瓣或(和)皮片覆盖效果满意,并发症及截肢率均较低  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