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   251篇
  免费   17篇
  国内免费   86篇
耳鼻咽喉   1篇
儿科学   14篇
妇产科学   3篇
基础医学   20篇
口腔科学   4篇
临床医学   72篇
内科学   61篇
皮肤病学   4篇
神经病学   4篇
特种医学   18篇
外科学   27篇
综合类   23篇
预防医学   1篇
眼科学   11篇
药学   77篇
中国医学   1篇
肿瘤学   13篇
  2023年   1篇
  2022年   2篇
  2021年   7篇
  2020年   6篇
  2019年   7篇
  2018年   5篇
  2017年   6篇
  2016年   7篇
  2015年   4篇
  2014年   10篇
  2013年   17篇
  2012年   5篇
  2011年   4篇
  2010年   9篇
  2009年   12篇
  2008年   9篇
  2007年   63篇
  2006年   4篇
  2005年   16篇
  2004年   1篇
  2002年   6篇
  2001年   7篇
  2000年   3篇
  1999年   3篇
  1998年   23篇
  1997年   16篇
  1996年   19篇
  1995年   12篇
  1994年   13篇
  1993年   9篇
  1992年   7篇
  1991年   7篇
  1990年   8篇
  1989年   8篇
  1988年   6篇
  1986年   1篇
  1985年   2篇
  1984年   3篇
  1983年   1篇
  1978年   1篇
  1976年   1篇
  1971年   1篇
  1969年   1篇
  1968年   1篇
排序方式: 共有354条查询结果,搜索用时 15 毫秒
61.
中国羊踯躅花化学成分研究   总被引:6,自引:0,他引:6  
从国产杜鹃花科植物羊踯躅(Rhododendron molle G.Don)的花中分离得到两种有药理活性的成分。经光谱(IR,MS,1HNMR,13CNMR,1H-1H COSY,1H-1H NOESY,13C-1H COSY)等分析证明其中一种为新的四环二萜类化合物。命名为羊踯躅素Ⅲ(rhodomollein Ⅲ)(1)。  相似文献   
62.
以不同电性的基团取代顺-3-甲基芬太尼中4-N-丙酰基上的乙基,合成某些顺-3-甲基芬太尼的结构类似物。药理试验结果表明,所合成的化合物均有典型的吗啡样作用。化合物3的镇痛活性略强于顺-3-甲基芬太尼。应用半经验的INDO方法对4个代表化合物进行了量子化学计算,讨论了电子结构与镇痛活性间的关系,化合物3由于氯乙烯基的引入具有与顺-3-甲基芬太尼不同的电子结构特征,氯乙烯基可能作为电子接受体参与了与受体的作用。  相似文献   
63.
64.
柏亚玲  娄皓  马春燕  董燕 《医学争鸣》2005,26(21):2005-2005
1 临床资料 2000-12/2005-01进行人工耳蜗植入手术的深度双耳感音神经性耳聋患者62(男37,女25)例,年龄1.2~21.0岁;语前聋60例,语后聋2例;先天性27例(其中用药17例,患腮腺炎2 例,原因不明25例),术前常规行颞骨薄层CT,部分患者行MRI扫描;术中面神经监测,所有患者经听力学评估均行右侧人工耳蜗植入.  相似文献   
65.
OBJECTIVE The aim of this study was to provide a comprehensive benchmark of 30-day ventriculoperitoneal(VP)shunt failure rates for a single institution over a 5-year study period for both adult and pediatric patients,to compare this with the results in previously published literature,and to establish factors associated with shunt failure.METHODS A retrospective database search was undertaken to identify all VP shunt operations performed in a single,regional neurosurgical unit during a 5-year period.Data were collected regarding patient age,sex,origin of hydrocephalus,and whether the shunt was a primary or secondary shunt.Operative notes were used to ascertain the type of valve inserted,which components of the shunt were adjusted/replaced(in revision cases),level of seniority of the most senior surgeon who participated in the operation,and number of surgeons involved in the operation.Where appropriate and where available,postoperative imaging was assessed for grade of shunt placement,using a recognized grading system.Univariate and multivariate models were used to establish factors associated with early(30-day)shunt failure.RESULTS Six hundred eighty-three VP shunt operations were performed,of which 321 were pediatric and 362 were adult.The median duration of postoperative follow-up for nonfailed shunts(excluding deaths)was 1263 days(range 525-2226 days).The pediatric 30-day shunt failure rates in the authors'institution were 8.8%for primary shunts and 23.4%for revisions.In adults,the 30-day shunt failure rates are 17.7%for primary shunts and 25.6%for revisions.In pediatric procedures,the number of surgeons involved in the operating theater was significantly associated with shunt failure rate.In adults,the origin of hydrocephalus was a statistically significant variable.Primary shunts lasted longer than revision shunts,irrespective of patient age.CONCLUSIONS A benchmark of 30-day failures is presented and is consistent with current national databases and previously published data by other groups.The number of surgeons involved in shunt operations and the origin of the patient's hydrocephalus should be described in future studies and should be controlled for in any prospective work.The choice of shunt valve was not a significant predictor of shunt failure.Most previous studies on shunts have concentrated on primary shunts,but the high rate of early shunt failure in revision cases(in both adults and children)is perhaps where future research efforts should be concentrated.  相似文献   
66.
67.
Hepatocellular carcinoma(HCC) is the second most common cause of death from cancer worldwide. Standard potentially curative treatments are either resection or transplantation. The aim of this paper is to provide an overview of the surgical management of HCC, as well as highlight current issues in hepatic resection and transplantation. In summary, due to the relationship between HCC and chronic liver disease, the management of HCC depends both on tumourrelated and hepatic function-related considerations. As such, HCC is currently managed largely through nonsurgical means as the criteria, in relation to the above considerations, for surgical management is still largelyrestrictive. For early stage tumours, both resection and transplantation offer fairly good survival outcomes(5 years overall survival of around 50%). Selection therefore would depend on the level of hepatic function derangement, organ availability and local expertise. Patients with intermediate stage cancers have limited options, with resection being the only potential for cure. Otherwise, locoregional therapy with transarterial chemoembolization or radiofrequency ablation are viable options. Current issues in resection and transplantation are also briefly discussed such as laparoscopic resection, ablation vs resection, anatomical vs non-anatomical resection, transplantation vs resection, living donor liver transplantation and salvage liver transplantation.  相似文献   
68.
69.

Background  

Neuromyelitis optica spectrum disorders (NMOSD) are severe central nervous system inflammatory demyelinating disorders (CNS IDD) characterized by monophasic or relapsing, longitudinally extensive transverse myelitis (LETM) and/or optic neuritis (ON). A significant proportion of NMOSD patients are seropositive for aquaporin-4 (AQP4) autoantibodies. We compared the AQP4 autoantibody detection rates of tissue-based indirect immunofluorescence assay (IIFA) and cell-based IIFA.  相似文献   
70.
AIM: To study the effects of Tetramethylpyrazine (TMP) on retinal pigment epithelium (RPE) degeneration, choroidal blood flow and oxidative stress of RPE cells. METHODS: The 35mg/kg NaIO3-induced RPE degeneration rat eyes was given 25μg 1% TMP eye drops 3 times a day for 7 days before NaIO3 injection, and then 2 to 4 weeks after NaIO3 injection. RPE function was measured with c-wave of electroretinogram (ERG). Colored microsphere technique was used for in vivo experiments to determine the choroidal blood flow in ocular hypertensive (40mmHg) rabbit eyes. Methylthiazoltetrazolium (MTT) assay was used to study in vitro effect of TMP on various oxidants induced injury in the hRPE (ARPE-19 (ATCC, Manassas, VA, USA)) . RESULTS: Two weeks after NaIO3 injection, the amplitude of ERG c-wave fell markedly in NaIO3 group to 36% of control group(P <0.01). No apparent difference was observed in TMP+NaIO3 group. Four weeks later, the NaIO3 group fell to 46% of control group (P<0.01), while the TMP+NaIO3 group fell to only 77% of control group (P<0.01). There was a 67% reversal of the ERG c-wave by TMP as compared to NaIO3 group(P<0.01). The choroidal blood flow was significantly increased at all time points (at 30, 60 and 120 minutes after TMP instillation) as compared with corresponding controls. TMP had no effect on hypoxia-(1%O2), t-BHP- and H2O2-induced damage in RPE cells. 10(g/mL TMP could reverse 1 and 3mM NaN3-induced loss of viability of RPE by 18.5% (P <0.01) and 23% (P<0.01), respectively. 30μg/mL TMP could reverse 30 and 100mM NaIO3 induced loss of viability of RPE by 18.1% (P <0.05) and 16.8% (P <0.01), respectively. CONCLUSION: TMP can significantly protect RPE from NaIO3 induced degeneration in vivo and oxidative stress in vitro and can increase choroidal blood flow markedly in vivo.  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