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   7929篇
  免费   404篇
  国内免费   33篇
耳鼻咽喉   93篇
儿科学   277篇
妇产科学   227篇
基础医学   1121篇
口腔科学   384篇
临床医学   751篇
内科学   1541篇
皮肤病学   276篇
神经病学   762篇
特种医学   414篇
外科学   1097篇
综合类   124篇
一般理论   10篇
预防医学   425篇
眼科学   56篇
药学   413篇
中国医学   9篇
肿瘤学   386篇
  2021年   100篇
  2020年   71篇
  2019年   75篇
  2018年   105篇
  2017年   90篇
  2016年   114篇
  2015年   121篇
  2014年   164篇
  2013年   266篇
  2012年   335篇
  2011年   340篇
  2010年   221篇
  2009年   221篇
  2008年   317篇
  2007年   361篇
  2006年   310篇
  2005年   324篇
  2004年   280篇
  2003年   273篇
  2002年   303篇
  2001年   273篇
  2000年   234篇
  1999年   217篇
  1998年   132篇
  1997年   118篇
  1996年   103篇
  1995年   82篇
  1994年   88篇
  1993年   88篇
  1992年   122篇
  1991年   108篇
  1990年   117篇
  1989年   146篇
  1988年   117篇
  1987年   143篇
  1986年   117篇
  1985年   95篇
  1984年   86篇
  1983年   79篇
  1982年   61篇
  1981年   53篇
  1978年   59篇
  1977年   56篇
  1976年   68篇
  1975年   51篇
  1973年   59篇
  1971年   50篇
  1969年   53篇
  1968年   49篇
  1966年   55篇
排序方式: 共有8366条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.
95.
96.
97.
Ohne ZusammenfassungVortrag gehalten in der Medizinischen Gesellschaft in Freiburg.  相似文献   
98.
Background: Alongside metabolic diseases (esp. obesity), allergic disorders are becoming increasingly prevalent. Since both obesity and allergies are highly impacted by environmental determinants, with this study we assessed the potential link between metabolic implications and two distinct types of allergies. Methods: Using cross-sectional data from the German FoCus cohort, n = 385 allergy cases, either hay fever (=type I allergy, n = 183) or contact allergy (=type IV allergy, n = 202) were compared to age- and sex-matched healthy control subjects (1:1 ratio, in total n = 770) regarding their metabolic phenotype, diet, physical activity, sleep, gut microbial composition, and serum metabolite profile using suitable BMI-adjusted models. Results: Obesity and metabolic alterations were found significantly more prevalent in subjects with allergies. In fact, this relation was more pronounced in contact allergy than hay fever. Subsequent BMI-adjusted analysis reveals particular importance of co-occurring hyperlipidaemia for both allergy types. For contact allergy, we revealed a strong association to the dietary intake of poly-unsaturated fatty acids, particularly α-linolenic acid, as well as the enrichment of the corresponding metabolic pathway. For hay fever, there were no major associations to the diet but to a lower physical activity level, shorter duration of sleep, and an altered gut microbial composition. Finally, genetic predisposition for hyperlipidaemia was associated to both contact allergy and hay fever. Conclusions: Reflected by higher allergy prevalence, our findings indicate an impaired immune response in obesity and hyperlipidaemia, which is differentially regulated in type I and type IV allergies by an unfavourable lifestyle constellation and subsequent microbial and metabolic dysfunctions.  相似文献   
99.
In acute myeloid leukemia, there is an ongoing debate on the prognostic value of the early bone marrow assessment in patients receiving intensive therapy. In this retrospective study, we analyzed the prognostic impact of the early response in 1,008 patients with newly diagnosed acute myeloid leukemia, who were treated at our institution with intensive chemotherapy followed by consolidation chemotherapy and/or allogeneic hematopoietic stem cell transplantation (HSCT). We found that early blast persistence has an independent negative prognostic impact on overall survival, event-free survival and relapse-free survival. This negative prognostic impact may only be overcome in patients showing at least a partial remission at the early bone marrow assessment and who subsequently achieve blast clearance by additional induction chemotherapy prior to consolidation therapy with allogeneic HSCT. In accordance, we propose that the time slope of remission is an additional leukemia-related dynamic parameter that reflects chemosensitivity and thus may inform post-induction therapy decision-making. In addition to patient-related factors, European LeukemiaNet risk group, measurable residual disease monitoring and donor availability, this may particularly apply to European LeukemiaNet intermediate-risk patients, for whom a decision between consolidation chemotherapy and allogeneic HSCT remains challenging in many cases.  相似文献   
100.
Adult rat and human bone marrow stromal cells differentiate into neurons   总被引:587,自引:0,他引:587  
Bone marrow stromal cells exhibit multiple traits of a stem cell population. They can be greatly expanded in vitro and induced to differentiate into multiple mesenchymal cell types. However, differentiation to non-mesenchymal fates has not been demonstrated. Here, adult rat stromal cells were expanded as undifferentiated cells in culture for more than 20 passages, indicating their proliferative capacity. A simple treatment protocol induced the stromal cells to exhibit a neuronal phenotype, expressing neuron-specific enolase, NeuN, neurofilament-M, and tau. With an optimal differentiation protocol, almost 80% of the cells expressed NSE and NF-M. The refractile cell bodies extended long processes terminating in typical growth cones and filopodia. The differentiating cells expressed nestin, characteristic of neuronal precursor stem cells, at 5 hr, but the trait was undetectable at 6 days. In contrast, expression of trkA, the nerve growth factor receptor, persisted from 5 hr through 6 days. Clonal cell lines, established from single cells, proliferated, yielding both undifferentiated and neuronal cells. Human marrow stromal cells subjected to this protocol also differentiated into neurons. Consequently, adult marrow stromal cells can be induced to overcome their mesenchymal commitment and may constitute an abundant and accessible cellular reservoir for the treatment of a variety of neurologic diseases.  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