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   1606篇
  免费   173篇
  国内免费   48篇
耳鼻咽喉   5篇
儿科学   25篇
妇产科学   17篇
基础医学   222篇
口腔科学   8篇
临床医学   142篇
内科学   133篇
皮肤病学   14篇
神经病学   439篇
特种医学   22篇
外科学   45篇
综合类   120篇
预防医学   135篇
眼科学   18篇
药学   309篇
中国医学   149篇
肿瘤学   24篇
  2024年   5篇
  2023年   44篇
  2022年   68篇
  2021年   63篇
  2020年   51篇
  2019年   59篇
  2018年   44篇
  2017年   69篇
  2016年   49篇
  2015年   56篇
  2014年   68篇
  2013年   133篇
  2012年   107篇
  2011年   78篇
  2010年   74篇
  2009年   78篇
  2008年   81篇
  2007年   84篇
  2006年   60篇
  2005年   68篇
  2004年   57篇
  2003年   45篇
  2002年   43篇
  2001年   45篇
  2000年   26篇
  1999年   28篇
  1998年   28篇
  1997年   18篇
  1996年   19篇
  1995年   16篇
  1994年   19篇
  1993年   6篇
  1992年   20篇
  1991年   15篇
  1990年   18篇
  1989年   10篇
  1988年   12篇
  1987年   10篇
  1986年   3篇
  1985年   8篇
  1984年   8篇
  1983年   6篇
  1982年   4篇
  1981年   3篇
  1980年   4篇
  1979年   5篇
  1978年   5篇
  1977年   2篇
  1976年   2篇
  1967年   1篇
排序方式: 共有1827条查询结果,搜索用时 15 毫秒
1.

Objective

To examine the experience of interracial anxiety among health professionals and how it may affect the quality of their interactions with patients from racially marginalized populations. We explored the influence of prior interracial exposure—specifically through childhood neighborhoods, college student bodies, and friend groups—on interracial anxiety among medical students and residents. We also examined whether levels of interracial anxiety change from medical school through residency.

Data Source

Web-based longitudinal survey data from the Medical Student Cognitive Habits and Growth Evaluation Study.

Study Design

We used a retrospective longitudinal design with four observations for each trainee. The study population consisted of non-Black US medical trainees surveyed in their 1st and 4th years of medical school and 2nd and 3rd years of residency. Mixed effects longitudinal models were used to assess predictors of interracial anxiety and assess changes in interracial anxiety scores over time.

Principal Findings

In total, 3155 non-Black medical trainees were followed for 7 years. Seventy-eight percent grew up in predominantly White neighborhoods. Living in predominantly White neighborhoods and having less racially diverse friends were associated with higher levels of interracial anxiety among medical trainees. Trainees' interracial anxiety scores did not substantially change over time; interracial anxiety was highest in the 1st year of medical school, lowest in the 4th year, and increased slightly during residency.

Conclusions

Neighborhood and friend group composition had independent effects on interracial anxiety, indicating that premedical racial socialization may affect medical trainees' preparedness to interact effectively with diverse patient populations. Additionally, the lack of substantial change in interracial anxiety throughout medical training suggests the importance of providing curricular tools and structure (e.g., instituting interracial cooperative learning activities) to foster the development of healthy interracial relationships.  相似文献   
2.
从包涵体中纯化重组人幽门螺杆菌热休克蛋白A亚单位   总被引:3,自引:1,他引:2  
目的:建立一种有效从包涵体中纯化重组人幽门螺杆菌热休克蛋白A亚单位HspA的方法。方法:重组基因工程大肠杆菌发酵后,表达的Hp r HspA包涵体经洗涤,变性,复性,采用Q Sepharose High Performance阴离子交换层析和Superdex75凝胶过滤层析分离纯化,使用SDS-PAGE和HPLC检测纯度,选用ELISA和动物实验对纯化蛋白的免疫学活性和生物学活性进行鉴定。结果:Hp的HspA包涵经洗涤和溶解后,Hp的HspA的纯度>60%,包涵体溶解液经阴离子交换层析和凝胶过滤层析后纯度超过95%,Hp的HspA纯品经检测具有良好的免疫学活性和生物学活性。结论:本研究建立的分离纯化方法可从包涵体中获得高纯度的重组HspA蛋白,为进一步的动物实验研究奠定了基础。  相似文献   
3.
目的 寻找质粒 pGH/BL2 1在大肠杆菌中的最佳表达条件。方法 当它在大肠杆菌中表达时 ,考查不同IPTG诱导浓度及不同的诱导时间对表达产物的影响 ,表达产物的量以SDS -PAGE电泳方法分析。结果 该基因的最佳表达条件为 :IPTG诱导浓度 1.0mmol/L ,诱导时间 4h。结论 IPTG对不同的基因在不同的表达体系中需不同的诱导条件 ,只有找到它的最佳诱导条件才能保证终产物的最大产率  相似文献   
4.
5.
维胺酯-β-环糊精包合物的研究   总被引:6,自引:0,他引:6  
应用3因素8水平的均匀设计方法,优化出维胺酯-β-环糊精包合物最佳制备条件,所得包合物的包合率为99.3%,其表观稳定常数为1394M-1.  相似文献   
6.
凋亡相关蛋白Apr-2的克隆、测序及初步表达   总被引:1,自引:0,他引:1  
目的: 从HL-60细胞凋亡模型中克隆凋亡相关蛋白Apr-2编码区基因,并对其进行表达,为进一步研究Apr-2的结构功能及多克隆抗体的制备奠定基础.方法: 建立HL-60细胞凋亡模型,提取HL-60凋亡细胞总RNA,以RT-PCR方法获取Apr-2 cDNA编码区全序列,将其与PGEM-T Easy载体连接,转化E.coli DH5α,构建重组克隆载体PGEM-TEasy/apr-2,测序正确后,将目的片段亚克隆入PGEX-4T-2原核表达载体,并转化大肠杆菌, IPTG诱导重组蛋白质表达,分析蛋白质在细菌中的表达分布,进行凝胶自动扫描分析. 结果:序列分析表明,与GenBank中已登录的Apr-2 cDNA编码区序列比较,完全一致.表达的融合蛋白占菌体总蛋白质的40%以上,主要以包涵体的形式存在. 结论:成功的获得了细胞凋亡模型HL-60中Apr-2 cDNA编码区的克隆及其融合蛋白表达产物.  相似文献   
7.
Background In 1995, an unpublished study (S. Hewson & C. Waters) showed that the community links of residents in 11 local National Health Services (NHS) trust houses were meagre, despite the service's stated commitment to community presence and participation. The 1995 study was repeated for the same 11 houses in 2002 to examine whether any changes had occurred. Method A test–retest design, with repeated measures was used, involving, as closely as possible, the same participants at two time points. Community links referred to the time residents spent outside their house, and the time unpaid visitors spent inside the house in the presence of the residents. Results The community links of the people studied were no better in 2002 than in 1995. Conclusions These findings question whether current service provision can deliver policy objectives for social inclusion for people with intellectual disabilities.  相似文献   
8.
We examined the role of the 20S proteasome in pathologic changes, including abnormal aggregation of phosphorylated neurofilaments, of spinal motor nerve cells from aluminum‐treated rabbits. Immunohistochemistry for the 20S proteasome revealed that many lumbar spinal motor neurons without intracytoplasmic neurofilamentous inclusions or with small inclusions were more intensely stained in aluminum‐treated rabbits than in controls, whereas the immunoreactivity was greatly decreased in some enlarged neurons containing large neurofilamentous inclusions. Proteasome activity in whole spinal cord extracts was significantly increased in aluminum‐treated rabbits compared with controls. Furthermore, Western blot analysis indicated that the 20S proteasome degraded non‐phosphorylated high molecular weight neurofilament (neurofilament‐H) protein in vitro. These results suggest that aluminum does not inhibit 20S proteasome activity, and the 20S proteasome degrades neurofilament‐H protein. We propose that abnormal aggregation of phosphorylated neurofilaments is induced directly by aluminum, and is not induced by the proteasome inhibition in the aluminum‐treated rabbits. Proteasome activation might be involved in intracellular proteolysis, especially in the earlier stages of motor neuron degeneration in aluminum‐treated rabbits.  相似文献   
9.
10.
Summary We describe two patients with sporadic amyotrophic lateral sclerosis (ALS), who had developed progressive external ophthalmoplegia of a predominantly supranuclear type while they survived on respirators, and displayed histopathological abnormalities both typical and atypical of ALS. Patient 1 was a 43-year-old man with ALS of 5-year duration, who had initially exhibited fulminant ALS, and remained on a respirator for 4 years. Patient 2 was a 51-year-old man with ALS of 13-year duration, who remained on a respirator for 8 years. Both patients died in a totally locked-in state. Autopsy of both patients revealed not only histopathological abnormalities consistent with ALS, but also multisystem degeneration which involved the pontine tegmentum, substantia nigra, Clarke's dorsal nuclei and spinocerebellar tracts. In addition, Patient 2 displayed intracyto-plasmic neuronal basophilic inclusion bodies which exhibited marked immunoreactivity to anti-ubiquitin antibodies. Our case reports indicate that the longer survival which is possible through the use of respirators may make one subgroup of ALS patients prone to develop atypical clinical and neuropathological features which are not observed during the natural cours of ALS.Supported by a Grant-in-Aid from the Research Committee of CNS Degenerative Diseases, the Ministry of Health and Welfare of Japan, and by a Grant from Nihon University School of Medicine, Tokyo  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