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   2451篇
  免费   276篇
  国内免费   12篇
耳鼻咽喉   16篇
儿科学   106篇
妇产科学   60篇
基础医学   387篇
口腔科学   152篇
临床医学   337篇
内科学   539篇
皮肤病学   52篇
神经病学   281篇
特种医学   89篇
外国民族医学   7篇
外科学   154篇
综合类   9篇
一般理论   2篇
预防医学   221篇
眼科学   39篇
药学   168篇
中国医学   11篇
肿瘤学   109篇
  2023年   24篇
  2022年   20篇
  2021年   82篇
  2020年   82篇
  2019年   93篇
  2018年   81篇
  2017年   73篇
  2016年   90篇
  2015年   97篇
  2014年   106篇
  2013年   144篇
  2012年   201篇
  2011年   213篇
  2010年   104篇
  2009年   93篇
  2008年   134篇
  2007年   145篇
  2006年   144篇
  2005年   129篇
  2004年   113篇
  2003年   87篇
  2002年   97篇
  2001年   16篇
  2000年   23篇
  1999年   13篇
  1998年   20篇
  1997年   11篇
  1996年   10篇
  1995年   10篇
  1994年   12篇
  1993年   12篇
  1992年   11篇
  1991年   14篇
  1990年   10篇
  1989年   11篇
  1988年   14篇
  1987年   8篇
  1986年   10篇
  1985年   11篇
  1984年   7篇
  1983年   15篇
  1981年   13篇
  1980年   11篇
  1979年   10篇
  1978年   9篇
  1977年   15篇
  1976年   7篇
  1975年   9篇
  1974年   7篇
  1973年   9篇
排序方式: 共有2739条查询结果,搜索用时 203 毫秒
1.
The repetitive structure of compact virus-like particles (VLPs) provides high density displays of antigenic sequences, which trigger key parts of the immune system. The hepatitis B virus (HBV) and human papilloma virus (HPV) vaccines exploit the assembly competence of structural proteins, which are the effective immunogenic components of the prophylactic HBV and HPV vaccines, respectively. To optimize vaccine designs and to promote immune responses against protective epitopes, the “Asp-Ala-Asp-Pro” (NANP)-repeat from the Plasmodium falciparum circumsporozoite protein (CSP) was expressed within the exposed, main antigenic site of the small HBV envelope protein (HBsAgS); this differs from the RTS,S vaccine, in which CSP epitopes are fused to the N-terminus of HBsAgS. The chimeric HBsAgS proteins are assembly competent, produce VLPs, and provide a high antigenic density of the NANP repeat sequence. Chimeric VLPs with four or nine NANP-repeats (NANP4 and NANP9, respectively) were expressed in mammalian cells, the HBsAgS- and CSP-specific antigenicity of the VLPs was determined, and the immunogenicity of the VLPs assessed in relation to the induction of anti-HBsAgS and anti-CSP antibody responses. The chimeric VLPs induced high anti-CSP titres in BALB/c mice independent of the number of the NANP repeats. However, the number of NANP repeats influenced the activity of vaccine-induced antibodies measured by complement fixation to CSP, one of the proposed effector mechanisms for Plasmodium neutralization in vivo. Sera from mice immunized with VLPs containing nine NANP repeats performed better in the complement fixation assay than the group with four NANP repeats. The effect of the epitope-specific density on the antibody quality may instruct VLP platform designs to optimize immunological outcomes and vaccine efficacy.  相似文献   
2.
Soils can be contaminated with substances arising from anthropogenic sources, but also with natural bioactive compounds produced by plants, such as terpenes and flavonoids. While terpenes and flavonoids have received much less attention from research studies than metals, the effects that phytocompounds can have on soil organisms such as beneficial microorganisms should not be neglected. Herein we report the sole and combined exposure of Rhizobium to cadmium, to the monoterpene alpha-pinene and to the flavanol quercetin. A range of environmentally relevant concentrations of the phytocompounds was tested. Physiological (growth, protein content and intracellular Cd concentration), oxidative damage (lipid peroxidation, protein carbonylation) and antioxidant mechanisms (superoxide dismutase, catalase, glutathione, glutathione-S-transferases, protein electrophoretic profiles) were assessed. Results suggest that exposure to both phytocompounds do not influence Rhizobium growth, but for combined exposure to phytocompounds and Cd, different responses are observed. At low concentrations, phytocompounds seem to relieve the stress imposed by Cd by increasing antioxidant responses, but at high concentrations this advantage is lost and membrane damage may even be exacerbated. Thus, the presence of bioactive phytocompounds in soil may influence the tolerance of microorganisms to persistent toxicants, and may change their impact on the environment.  相似文献   
3.
4.
5.
Background: Before implementation of the new scale, the Swedish modified version of the Postural Assessment Scale for Stroke Patients (SwePASS), to clinical practice, it is fundamental to analyze its measurement properties.Objective: To examine the inter-rater reliability of the SwePASS in the acute phase after stroke.

Methods: Day 3 to day 7 after admission to a stroke unit, 64 persons with stroke were assessed twice, using the SwePASS, by two physiotherapists. Inter-rater reliability was determined using percentage-agreement and the rank-invariant method: relative position, relative concentration, and relative rank variance.

Results: The raters showed a percentage agreement of ≥75% in the assessments using the SwePASS. For 9 of the 12 items, the percentage agreement was >80%. For 8 of the 12 items, there was a statistically significant change in position, revealed in relative position values between 0.08 and 0.15. Three items had statistically significant positive relative concentration values between ?0.11 and 0.10. Except for a statistically significant negligible relative variance value of 0.01 for the items 1 and 8, there was no relative variance.

Conclusions: The SwePASS shows an acceptable inter-rater reliability, albeit with potential for improvement. The reliability can be improved by a consensus how to interpret the scale between the raters prior to implementation in the clinic.  相似文献   

6.
Cardiovascular disease (CVD) is the leading cause of death worldwide and is particularly frequent among those with severe renal impairment. Early diagnosis and therapeutic intervention may help alleviate the burden of cardiovascular complication within this population. In the last years, advances have been made toward developing noninvasive imaging techniques that could offer better insight into the cardiac involvement in end‐stage renal disease (ESRD). Conventional transthoracic echocardiography remains the first‐line investigation used to assess cardiac function, but encompassing in our daily practice, the newer approaches such as speckle‐tracking imaging, cardiac computed tomography, or cardiac magnetic resonance can guide us to a more comprehensive understanding of CVD in ESRD. Given that patients with chronic kidney disease may not present with typical CVD symptoms, the amount of information brought by newer imaging techniques is crucial for an accurate diagnosis, risk stratification, and further management. The purpose of this review is to briefly summarize the specific applications of standard cardiac imaging techniques in patients with ESRD and to offer insight into the novel imaging modalities, highlighting the newest research in this field. By doing so, we aim to identify the most important imaging predictors of clinical outcomes in this population.  相似文献   
7.
8.
9.
10.
The Enhanced Recovery After Surgery Program aims to transfer much of the responsibility for postoperative recovery to the patient and their next of kin. The aim of the study was to identify and describe women's experiences of care within this program in relation to gynecological abdominal surgery. A qualitative approach was used where 16 women were interviewed within 1 to 2 weeks of their surgery. A thematic analysis focusing on interpretation of latent content was performed. Three themes were identified: Empowerment, Self‐care, and Participation. Empowerment represents aspects of the recovery program that strengthen self‐efficacy, such as being seen, being given information, and continuity of care. Self‐care identifies the practical implications of empowerment, namely internal resources, knowledge, and external resources. These two themes were identified as separate but interlinked through the theme Participation. Preoperative information, postoperative encouragement, and follow‐up empowered the women in their recovery. Early discharge from hospital was beneficial for recovery if accompanied by social support and sufficient self‐care ability. A desire for a person‐centered approach in the preoperative meeting and in postoperative care was identified.  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