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   52463篇
  免费   3780篇
  国内免费   257篇
耳鼻咽喉   517篇
儿科学   1915篇
妇产科学   1365篇
基础医学   7992篇
口腔科学   789篇
临床医学   5051篇
内科学   11686篇
皮肤病学   1173篇
神经病学   5877篇
特种医学   1121篇
外科学   4338篇
综合类   294篇
现状与发展   1篇
一般理论   43篇
预防医学   4778篇
眼科学   860篇
药学   4028篇
中国医学   136篇
肿瘤学   4536篇
  2024年   67篇
  2023年   618篇
  2022年   483篇
  2021年   2421篇
  2020年   1398篇
  2019年   1792篇
  2018年   1969篇
  2017年   1593篇
  2016年   1753篇
  2015年   1902篇
  2014年   2472篇
  2013年   3103篇
  2012年   4563篇
  2011年   4565篇
  2010年   2422篇
  2009年   2067篇
  2008年   3450篇
  2007年   3440篇
  2006年   3108篇
  2005年   2826篇
  2004年   2622篇
  2003年   2337篇
  2002年   2106篇
  2001年   246篇
  2000年   187篇
  1999年   255篇
  1998年   335篇
  1997年   285篇
  1996年   195篇
  1995年   184篇
  1994年   184篇
  1993年   140篇
  1992年   98篇
  1991年   83篇
  1990年   65篇
  1989年   76篇
  1988年   73篇
  1987年   64篇
  1986年   60篇
  1985年   60篇
  1984年   83篇
  1983年   66篇
  1982年   77篇
  1981年   64篇
  1980年   60篇
  1979年   29篇
  1978年   31篇
  1977年   34篇
  1976年   25篇
  1974年   19篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
Background Immune checkpoint blockers (ICBs) activate CD8+ T cells, eliciting both anti-cancer activity and immune-related adverse events (irAEs). The relationship of irAEs with baseline parameters and clinical outcome is unclear.Methods Retrospective evaluation of irAEs on survival was performed across primary (N = 144) and secondary (N = 211) independent cohorts of patients with metastatic melanoma receiving single agent (pembrolizumab/nivolumab—sICB) or combination (nivolumab and ipilimumab—cICB) checkpoint blockade. RNA from pre-treatment and post-treatment CD8+ T cells was sequenced and differential gene expression according to irAE development assessed.Results 58.3% of patients developed early irAEs and this was associated with longer progression-free (PFS) and overall survival (OS) across both cohorts (log-rank test, OS: P < 0.0001). Median survival for patients without irAEs was 16.6 months (95% CI: 10.9–33.4) versus not-reached (P = 2.8 × 10−6). Pre-treatment monocyte and neutrophil counts, but not BMI, were additional predictors of clinical outcome. Differential expression of numerous gene pathway members was observed in CD8+ T cells according to irAE development, and patients not developing irAEs demonstrating upregulated CXCR1 pre- and post-treatment.Conclusions Early irAE development post-ICB is associated with favourable survival in MM. Development of irAEs is coupled to expression of numerous gene pathways, suggesting irAE development in-part reflects baseline immune activation.Subject terms: Immunotherapy, Melanoma  相似文献   
13.
14.
15.
16.
Abstract

Aim: Competency-based medical education aims to foster mastery goals in learners. We examined medical students’ mastery approach (beneficial) and mastery avoidance (maladaptive) goals and their associations with students’ basic psychological needs, self-compassion, and self-efficacy.

Methods: This was a cross-sectional study employing an online questionnaire. Two hundred medical students in all four years of the medical program completed the questionnaire, containing measures of mastery goals, basic psychological needs (autonomy, competence, relatedness), self-compassion, and self-efficacy. Regression analyses were performed.

Results: Of the three basic psychological needs, the need for competence was significant in explaining both types of mastery goals. Self-efficacy and self-compassion were significant in explaining mastery approach and mastery avoidance goals, respectively.

Conclusions: Creating learning environments that are supportive of students’ need for competence, raising students’ awareness of the value of learning from mistakes in competency acquisition, and providing opportunities for students to experience self-efficacy may foster beneficial mastery approach goals in medical students.  相似文献   
17.
Melatonin receptors play important roles in the regulation of circadian and seasonal rhythms, sleep, retinal functions, the immune system, depression, and type 2 diabetes development. Melatonin receptors are approved drug targets for insomnia, non‐24‐hour sleep‐wake disorders, and major depressive disorders. In mammals, two melatonin receptors (MTRs) exist, MT1 and MT2, belonging to the G protein‐coupled receptor (GPCR) superfamily. Similar to most other GPCRs, reliable antibodies recognizing melatonin receptors proved to be difficult to obtain. Here, we describe the development of the first monoclonal antibodies (mABs) for mouse MT1 and MT2. Purified antibodies were extensively characterized for specific reactivity with mouse, rat, and human MT1 and MT2 by Western blot, immunoprecipitation, immunofluorescence, and proximity ligation assay. Several mABs were specific for either mouse MT1 or MT2. None of the mABs cross‐reacted with rat MTRs, and some were able to react with human MTRs. The specificity of the selected mABs was validated by immunofluorescence microscopy in three established locations (retina, suprachiasmatic nuclei, pituitary gland) for MTR expression in mice using MTR‐KO mice as control. MT2 expression was not detected in mouse insulinoma MIN6 cells or pancreatic beta‐cells. Collectively, we report the first monoclonal antibodies recognizing recombinant and native mouse melatonin receptors that will be valuable tools for future studies.  相似文献   
18.
19.
The recognition that neurogenesis does not stop with adolescence has spun off research towards the reduction of brain disorders by enhancing brain regeneration. Adult neurogenesis is one of the tougher problems of developmental biology as it requires the generation of complex intracellular and pericellular anatomies, amidst the danger of neuroinflammation. We here review how a multitude of regulatory pathways optimized for early neurogenesis has to be revamped into a new choreography of time dependencies. Distinct pathways need to be regulated, ranging from neural growth factor induced differentiation to mitochondrial bioenergetics, reactive oxygen metabolism, and apoptosis. Requiring much Gibbs energy consumption, brain depends on aerobic energy metabolism, hence on mitochondrial activity. Mitochondrial fission and fusion, movement and perhaps even mitoptosis, thereby come into play. All these network processes are interlinked and involve a plethora of molecules. We recommend a deep thinking approach to adult neurobiology.  相似文献   
20.
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