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   1260篇
  免费   107篇
  国内免费   8篇
耳鼻咽喉   6篇
儿科学   51篇
妇产科学   20篇
基础医学   233篇
口腔科学   26篇
临床医学   104篇
内科学   254篇
皮肤病学   12篇
神经病学   151篇
特种医学   36篇
外科学   124篇
综合类   4篇
预防医学   170篇
眼科学   7篇
药学   51篇
肿瘤学   126篇
  2024年   3篇
  2023年   36篇
  2022年   65篇
  2021年   98篇
  2020年   71篇
  2019年   65篇
  2018年   91篇
  2017年   41篇
  2016年   63篇
  2015年   60篇
  2014年   55篇
  2013年   73篇
  2012年   101篇
  2011年   97篇
  2010年   61篇
  2009年   46篇
  2008年   52篇
  2007年   55篇
  2006年   52篇
  2005年   36篇
  2004年   31篇
  2003年   36篇
  2002年   21篇
  2001年   6篇
  1999年   5篇
  1998年   4篇
  1997年   4篇
  1996年   5篇
  1995年   6篇
  1992年   2篇
  1982年   2篇
  1981年   2篇
  1964年   1篇
  1959年   1篇
  1947年   1篇
  1942年   1篇
  1939年   2篇
  1938年   1篇
  1935年   1篇
  1933年   2篇
  1932年   1篇
  1930年   1篇
  1925年   2篇
  1920年   1篇
  1918年   1篇
  1914年   1篇
  1912年   1篇
  1911年   1篇
  1910年   2篇
  1904年   1篇
排序方式: 共有1375条查询结果,搜索用时 265 毫秒
51.
52.
53.
Successful visual prostheses require stable, long‐term attachment. Epiretinal prostheses, in particular, require attachment methods to fix the prosthesis onto the retina. The most common method is fixation with a retinal tack; however, tacks cause retinal trauma, and surgical proficiency is important to ensure optimal placement of the prosthesis near the macula. Accordingly, alternate attachment methods are required. In this study, we detail a novel method of magnetic attachment for an epiretinal prosthesis using two prostheses components positioned on opposing sides of the retina. The magnetic attachment technique was piloted in a feline animal model (chronic, nonrecovery implantation). We also detail a new method to reliably control the magnet coupling force using heat. It was found that the force exerted upon the tissue that separates the two components could be minimized as the measured force is proportionately smaller at the working distance. We thus detail, for the first time, a surgical method using customized magnets to position and affix an epiretinal prosthesis on the retina. The position of the epiretinal prosthesis is reliable, and its location on the retina is accurately controlled by the placement of a secondary magnet in the suprachoroidal location. The electrode position above the retina is less than 50 microns at the center of the device, although there were pressure points seen at the two edges due to curvature misalignment. The degree of retinal compression found in this study was unacceptably high; nevertheless, the normal structure of the retina remained intact under the electrodes.  相似文献   
54.

Purpose

Metabolic syndrome (MetS), a multicomponent condition, is a cardiovascular disease predictor. Although exposure to agricultural pesticides has been suggested as a potential contributor to the rising rates of obesity, type 2 diabetes, and other features of metabolic disorders, no studies have focused on the association between consumption of organic food (produced without synthetic pesticides) and MetS. We aimed to investigate the cross-sectional association between organic food consumption and MetS in French adults to determine whether it would be worth conducting further studies, particularly large prospective and randomised trials.

Methods

A total of 8174 participants from the NutriNet-Santé study who attended a clinical visit and completed an organic food frequency questionnaire were included in this cross-sectional analysis. We evaluated the association between the proportion of organic food in the diet (overall and by food group) and MetS using Poisson regression models while adjusting for potential confounders.

Results

Higher organic food consumption was negatively associated with the prevalence of MetS: adjusted prevalence ratio was 0.69 (95% CI 0.61, 0.78) when comparing the third tertile of proportion of organic food in the diet with the first one (p value <0.0001). Higher consumption of organic plant-based foods was also related to a lower probability of having MetS. In addition, when stratifying by lifestyle factors (nutritional quality of the diet, smoking status, and physical activity), a significant negative association was detected in each subgroup (p values <0.05), except among smokers.

Conclusions

Our results showed that a higher organic food consumption was associated with a lower probability of having MetS. Additional prospective studies and randomised trials are required to ascertain the relationship between organic food consumption and metabolic disorders.
  相似文献   
55.
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz - Muttermilch bietet neben spezifischen nutritiven und funktionellen Vorteilen auch eine größere sensorische...  相似文献   
56.
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz - Stillmonitoring bezeichnet die systematische Erhebung aktueller, umfassender und genauer Daten zu Stillquoten, Stillverhalten und...  相似文献   
57.
BACKGROUND: This study investigated an operator's and pediatric patients' responses to chemo-mechanical caries removal (CMCR) versus the traditional method (TM) of caries removal using a handpiece and a round bur when treating dentinal-depth occlusal lesions with minimal enamel access in primary molars. METHODS: Data were collected from 50 children at baseline and before, during and after caries removal using CMCR or TM. The subjects in the CMCR group were on average younger than the subjects in the TM group and had more deep lesions. RESULTS: The operator rated CMCR as needing more clinical and technical effort and more total effort than TM. He was less satisfied with CMCR than with TM. Subjects in the CMCR group perceived the time needed for treatment as significantly longer than did the subjects in the TM group. Fear of the dentist decreased in subjects in the TM group from before to after the operative appointment, while it increased in subjects in the CMCR group. CONCLUSIONS: The authors found no direct advantage in using CMCR over using TM. CLINICAL IMPLICATIONS: CMCR cannot be recommended as an alternative to TM when treating dentinal depth occlusal lesions with minimal access in primary molars.  相似文献   
58.
Cell therapy with autologous donor‐specific regulatory T cells (Tregs) is a promising strategy to minimize immunosuppression in transplant recipients. Chimeric antigen receptor (CAR) technology has recently been used successfully to generate donor‐specific Tregs and overcome the limitations of enrichment protocols based on repetitive stimulations with alloantigens. However, the ability of CAR‐Treg therapy to control alloreactivity in immunocompetent recipients is unknown. We first analyzed the effect of donor‐specific CAR Tregs on alloreactivity in naive, immunocompetent mice receiving skin allografts. Tregs expressing an irrelevant or anti‐HLA‐A2‐specific CAR were administered to Bl/6 mice at the time of transplanting an HLA‐A2+ Bl/6 skin graft. Donor‐specific CAR‐Tregs, but not irrelevant‐CAR Tregs, significantly delayed skin rejection and diminished donor‐specific antibodies (DSAs) and frequencies of DSA‐secreting B cells. Donor‐specific CAR‐Treg–treated mice also had a weaker recall DSA response, but normal responses to an irrelevant antigen, demonstrating antigen‐specific suppression. When donor‐specific CAR Tregs were tested in HLA‐A2‐sensitized mice, they were unable to delay allograft rejection or diminish DSAs. The finding that donor‐specific CAR‐Tregs restrain de novo but not memory alloreactivity has important implications for their use as an adoptive cell therapy in transplantation.  相似文献   
59.

Objective:

Borderline and antisocial personality disorders (PDs) share common clinical features (impulsivity, aggressiveness, substance use disorders [SUDs], and suicidal behaviours) that are greatly overrepresented in prison populations. These disorders have been associated biologically with testosterone and cortisol levels. However, the associations are ambiguous and the subject of controversy, perhaps because these heterogeneous disorders have been addressed as unitary constructs. A consideration of profiles of people, rather than of exclusive diagnoses, might yield clearer relationships.

Methods:

In our study, multiple correspondence analysis and cluster analysis were employed to identify subgroups among 545 newly convicted inmates. The groups were then compared in terms of clinical features and biological markers, including levels of cortisol, testosterone, estradiol, progesterone, and sulfoconjugated dehydroepiandrosterone (DHEA-S).

Results:

Four clusters with differing psychiatric, criminal, and biological profiles emerged. Clinically, one group had intermediate scores for each of the tested clinical features. Another group comprised people with little comorbidity. Two others displayed severe impulsivity, PD, and SUD. Biologically, cortisol levels were lowest in the last 2 groups and highest in the group with less comorbidity. In keeping with previous findings reported in the literature, testosterone was higher in a younger population with severe psychiatric symptoms. However, some apparently comparable behavioural outcomes were found to be related to distinct biological profiles. No differences were observed for estradiol, progesterone, or DHEA-S levels.

Conclusions:

The results not only confirm the importance of biological markers in the study of personality features but also demonstrate the need to consider the role of comorbidities and steroid coregulation.  相似文献   
60.
Primary central nervous system lymphomas (PCNSL) are non-Hodgkin lymphomas strictly localized to the CNS, occurring mainly in elderly patients with comorbidities. Current treatment in fit patients relies on high-dose methotrexate and high-dose cytarabine. The aim of this study was to evaluate the efficacy and feasibility of this treatment in elderly patients and to assess potential prognostic factors associated with survival. We conducted a retrospective study in two centers between January 2008 and September 2015 including 35 elderly immunocompetent patients who received first-line treatment with high-dose methotrexate. With a median follow-up of 19.8 months (range: 1.7–73.4 months), median overall survival (OS) was 39.5 months (95% confidence interval (95% CI): 18.3–60.7) and median progression-free survival (PFS) was 25.8 months (95% CI: 5.2–46.4). In univariate analysis, administration of high-dose cytarabine and achieving a relative dose intensity for methotrexate >?75% were associated with increased OS (p?=?0.006 and p?=?0.003, respectively) and PFS (p?=?0.003 and p?=?0.04, respectively) whereas comorbidities, defined by a CIRS-G score ≥?8, were associated with decreased OS and PFS (p?=?0.02 and p?=?0.04, respectively). A high MSKCC score was associated with decreased OS (p?=?0.02). In multivariate analysis, administration of high-dose cytarabine was associated with increased OS and PFS (p?=?0.02 and p?=?0.007, respectively). Comorbidities and relative dose intensity for methotrexate are important for the prognosis of elderly patients with PCNSL. These results must be confirmed in prospective trials.  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