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   1016篇
  免费   63篇
  国内免费   36篇
耳鼻咽喉   13篇
儿科学   84篇
妇产科学   10篇
基础医学   72篇
口腔科学   39篇
临床医学   123篇
内科学   196篇
皮肤病学   21篇
神经病学   39篇
特种医学   76篇
外科学   157篇
综合类   37篇
预防医学   69篇
眼科学   18篇
药学   91篇
中国医学   7篇
肿瘤学   63篇
  2024年   3篇
  2023年   16篇
  2022年   28篇
  2021年   56篇
  2020年   22篇
  2019年   42篇
  2018年   45篇
  2017年   36篇
  2016年   33篇
  2015年   24篇
  2014年   41篇
  2013年   38篇
  2012年   43篇
  2011年   60篇
  2010年   36篇
  2009年   36篇
  2008年   42篇
  2007年   47篇
  2006年   49篇
  2005年   39篇
  2004年   25篇
  2003年   22篇
  2002年   27篇
  2001年   16篇
  2000年   12篇
  1999年   22篇
  1998年   16篇
  1997年   18篇
  1996年   16篇
  1995年   15篇
  1994年   21篇
  1993年   14篇
  1992年   13篇
  1991年   15篇
  1990年   8篇
  1989年   17篇
  1988年   7篇
  1987年   13篇
  1986年   9篇
  1985年   8篇
  1984年   7篇
  1983年   4篇
  1982年   5篇
  1981年   10篇
  1980年   4篇
  1979年   7篇
  1977年   3篇
  1976年   6篇
  1975年   8篇
  1972年   5篇
排序方式: 共有1115条查询结果,搜索用时 0 毫秒
91.
Factors that influence viability and function of cryopreserved peripheral blood mononuclear cells (PBMC) were identified on 54 samples from 27 AIDS Clinical Trial Units. PBMC viability ranged from 1 to 96% with a median of 70%, was higher in laboratories with experienced staff, and was not significantly associated with CD4 cell number. Function of cryopreserved PBMC, measured by lymphocyte proliferation, was associated with viability. Preparations with viability greater than or equal to 70% had consistent proliferative responses and were suitable for functional analyses.  相似文献   
92.
中药贝母类的研究——ⅩⅦ.贝母鳞叶上表皮显微观察   总被引:4,自引:0,他引:4  
本文对浙贝母Fritillaria thunbergii Miq.等20种贝母的鳞叶上(内)表皮进行了显微观察,发现种间在表皮细胞形状、大小和垂周壁部位角质栓(cuticular peg)的形状,大小和排列等方面有一定区别,可作为新的鉴别依据。全文除描述外,列出检索表,并附主要特征图。  相似文献   
93.
硝唑眯(Ⅰ)是六十年代发现的抗曼氏及埃及血吸虫药物。对日本血吸虫也有治疗作用,但毒副反应较大,应用受到限制。考虑到药物分子中氨基经酰化后毒性往往降低的一般规律,我们设计合成了一系列硝唑咪酰化物。  相似文献   
94.
Substance abuse treatment modalities in the age of HIV spectrum disease   总被引:1,自引:0,他引:1  
AMSAODD's Third National Forum on AIDS and Chemical Dependency presented a session about the theory and practicality of combining pharmacologic and nonpharmacologic treatment modalities to maximize the social, psychological, and physical health of patients. Synthesizing methadone maintenance for opioid dependence with abstinence modalities for cocaine dependence and alcoholism was discussed. Chronic adequate methadone treatment allows normalization of neuroendocrine function, is associated with normal natural killer-cell activity, and has proven efficacious in retaining patients in chemical dependence treatment, and thus decreasing the risk for transmission of HIV infection. Individualization of treatment is then exemplified by four clinical vignettes that were discussed by a panel of experts.  相似文献   
95.
96.
Radioimmunoimaging of fresh canine venous thrombi with a murine monoclonal antibody specific for human and dog fibrin has been reported. Successful imaging of canine deep venous thrombi 1, 3, and 5 days old at the time of antibody injection is reported. Images were positive in all dogs, and the uptake of fibrin-specific antibody was equivalent to that of fresh thrombi.  相似文献   
97.
LR Petersen  ; LS Doll 《Transfusion》1991,31(8):698-703
Transmission of human immunodeficiency virus type 1 (HIV-1) by homologous blood transfusion in the United States (US) is minimized by the deferral of potential donors who are at risk for HIV-1 infection and by the screening of all donations for HIV-1 antibody. HIV-1-seropositive donors at 20 blood centers were studied for information to be used in evaluating the safety of the US blood supply and making recommendations to increase that safety. From June 1988 to August 1989, 829 (0.04%) of 2,192,000 donors were found to be seropositive; 512 were interviewed. Of 388 seropositive men, 56 percent had had sex with men, 10 percent had used drugs intravenously, 8 percent had had sex with intravenous drug users, and 27 percent had no identified risk. Of 124 seropositive women, 58 percent had had sex with men at risk for HIV (81% of whom used drugs intravenously), 5 percent had used drugs intravenously, and 41 percent had no identified risk. Racial and ethnic minorities made up 68 percent of seropositive donors (black, 38%; Hispanic, 30%) and approximately 14 percent of all donors. The 157 persons with no identified risk had demographic characteristics and serologic test results for syphilis and hepatitis B that were more similar to those of HIV-1-seropositive donors with recognized risk than to those of seronegative donors. Three health care worker-blood donors (from an estimated 93,100 health care worker-donors) had infection that was probably acquired occupationally.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
98.

Background

Inpatient rehabilitation facilities (IRFs) and skilled nursing facilities (SNFs) represent a significant portion of post-operative expenses of bundled payments for total knee arthroplasty (TKA). Although many surgeons no longer routinely send patients to IRFs or SNFs, some patients are unable to be discharged directly home. This study identified patient factors for discharge to post-acute care facilities with an institutional protocol of discharging TKA patients home.

Methods

A retrospective review of patients undergoing primary unilateral TKA at a single institution from 2012 to 2017 was performed. All surgeons discharged patients home as a routine protocol. An electronic query followed by manual review identified discharge disposition, demographic factors, co-morbidities, and other patient factors. In total, 2281 patients were identified, with 9.6% discharged to SNFs or IRFs and 90.4% discharged home. Univariate and multivariate analyses were conducted to create 2 predictive models for patient discharge: pre-operative visit and hospital course.

Results

Among 43 variables studied, 6 were found to be significant pre-operative risk factors for a discharge disposition other than home. In descending order, age 75 or greater, female, non-Caucasian race, Medicare status, history of depression, and Charlson Comorbidity Index were predictors for patients going to IRFs. In addition, any in-hospital complications led to a higher likelihood of being discharged to IRFs and SNFs. Both models had excellent predictive assessments with area under curve values of 0.79 and 0.80 for pre-operative visit and hospital course.

Conclusion

This study identifies pre-operative and in-hospital factors that predispose patients to non-routine discharges, which allow surgeons to better predict patient post-operative disposition.  相似文献   
99.
100.
目的:认知功能障碍是老年期抑郁症的可逆性症状,试验以认知功能研究为突破口,采用28通道的近红外光谱技术分析处于恢复过程中的老年期抑郁症患者在执行词语流畅性测验时前额叶的激活特点,探讨老年期抑郁症的发病机制。 方法:①分组:患者组为2006~03/12首都医科大学附属北京安定医院收治的12例处于恢复过程中的老年期抑郁症患者,入组时符合DSM-4有关重度和中度抑郁发作或复发的标准诊断,首次发病年龄≥60岁,均服用SSRIs类抗抑郁药物治疗。对照组为12例性别、年龄和教育程度与患者组相匹配的健康志愿者。所有受试者排除脑器质性病变:②试验方法:所有受试者接受近红外光谱测查,在28通道的CW5(TechEnInc.American)NIRS系统上完成。通过近红外光谱系统监测被试者在执行词语流畅性测验任务过程中,前额叶氧合血红蛋白和脱氧血红蛋白浓度的变化,从而反映前额叶认知任务相关的激活效应。采用组块设计的词语流畅性测验作为认知激活任务,任务范式包括词语重复任务和词语流畅性任务两种试验。 结果:24例受试者均进入结果分析。①在健康老年人和处于恢复过程中的老年期抑郁症患者,词语流畅性测验能够激活双侧前额叶.未发现半球单侧化激活效应。②处于恢复过程中的老年期抑郁症患者在词语流畅性测验任务过程中,左侧前额叶激活效应较对照组减弱。③尽管在健康老年人和处于恢复过程中的老年期抑郁症患者,近红外光谱显示了不同的激活模式,但词语流畅性测验的成绩不存在显著性的组间差异(P〉0.05)。 结论:处于恢复过程中的老年期抑郁症患者存在词语流畅性测验相关的功能性左侧前额叶功能减退,微血管功能失调和多巴胺系统异常也许在老年期抑郁症的病理生理学机制中起重要作用。  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