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   104914篇
  免费   6341篇
  国内免费   633篇
耳鼻咽喉   1030篇
儿科学   3463篇
妇产科学   2445篇
基础医学   15281篇
口腔科学   3898篇
临床医学   9564篇
内科学   23433篇
皮肤病学   2705篇
神经病学   10362篇
特种医学   2456篇
外国民族医学   1篇
外科学   9434篇
综合类   389篇
一般理论   48篇
预防医学   10325篇
眼科学   1700篇
药学   7417篇
中国医学   416篇
肿瘤学   7521篇
  2024年   85篇
  2023年   954篇
  2022年   826篇
  2021年   3631篇
  2020年   2287篇
  2019年   3071篇
  2018年   3488篇
  2017年   2659篇
  2016年   3096篇
  2015年   3421篇
  2014年   4494篇
  2013年   5868篇
  2012年   8920篇
  2011年   9281篇
  2010年   5057篇
  2009年   4256篇
  2008年   7370篇
  2007年   7365篇
  2006年   6776篇
  2005年   6316篇
  2004年   5675篇
  2003年   5047篇
  2002年   4540篇
  2001年   533篇
  2000年   368篇
  1999年   581篇
  1998年   787篇
  1997年   642篇
  1996年   544篇
  1995年   448篇
  1994年   427篇
  1993年   348篇
  1992年   276篇
  1991年   187篇
  1990年   189篇
  1989年   177篇
  1988年   166篇
  1987年   139篇
  1986年   153篇
  1985年   109篇
  1984年   128篇
  1983年   124篇
  1982年   152篇
  1981年   111篇
  1980年   122篇
  1979年   71篇
  1978年   75篇
  1977年   67篇
  1976年   56篇
  1974年   52篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Eosinophilic dermatosis of hematological malignancy is a paraneoplastic skin eruption associated with chronic lymphocytic leukemia and other B‐cell malignancies. It clinically resembles an insect bite reaction and it can precede the symptoms of the hematological malignancy or be related to a more aggressive course. Different treatments have been proposed, but partial response and recurrence are frequent. Herein, we describe a case of eosinophilic dermatosis associated with mantle cell lymphoma with remission after lenalidomide therapy.  相似文献   
52.
The main purpose of this study was to assess whether it is possible to improve the prognostic impact of international prognostic index (IPI) score by combining it with peripheral blood counts. Thus, we evaluated the prognostic power of lymphocyte, neutrophil, and monocyte counts in 520 patients with diffuse large B cell lymphoma treated with R-CHOP, confirming that these parameters have a strong impact on overall survival (OS). Using revised IPI (R-IPI), 44% of patients were categorized as poor-risk and showed an OS at 5 years of 46%. As OS at 5 years of the 520 patients is 67%, it is clearly evident that R-IPI tends to overestimate the proportion of patients with poor prognosis. Accordingly, in an attempt to improve the discriminating power of R-IPI, we evaluated and compared three different scores by combining the neutrophil lymphocyte ratio (NLR) and absolute monocyte count (AMC) with the following values: (a) IPI score 3-5, (b) age > 60 years and performance status, (c) age ≥ 65 years and LDH > ULN. The three indexes studied, had a similar 5 years OS for the high-risk group (46%-52%), but the proportion of patients classified as poor-risk were 37%, 20%, and 32%, respectively, which are lower than 44% identified with R-IPI. Thus, while R-IPI overestimates the number of high-risk patients, after applying our models, it is possible to recognize patients who are truly at high-risk. Of the three scores, the most accurate appears to be that based on NLR, AMC, LDH > ULN and age ≥ 65 years, which identifies 32% of high-risk patients, correlating well with what is seen in clinical practice.  相似文献   
53.
Platelet α-granules release growth factors (GFs) that promote healing and tissue regeneration. Platelet-rich plasma (PRP) is shown to be beneficial in treating alopecia, and however, clinical response can be inconsistent. Due to several fold enrichment of platelets secreting large quantities of GFs following PRP injections, heterogeneity in amounts of GFs secreted by platelets may contribute to inconsistent clinical responses. Herein, we evaluated factors that could potentially contribute to heterogeneous secretion of GFs by platelets. We measured platelet secretion of transforming growth factor beta1 (TGFβ1), platelet-derived growth factor (PDGF-BB), epidermal growth factor (EGF), vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF2) in aliquots of de-identified PRP samples from female patients undergoing therapy in the hair disease clinic. Although secretion of GFs by platelets was comparable in PRP samples of patients with non-cicatricial and cicatricial alopecia, a Shapiro-Wilk test for normal distribution indicated significant variability across all patient samples. The amount of GF secreted by platelets was comparable when PRP prepared from two FDA-cleared devices with distinct techniques were compared. We provide evidence of platelets secreting heterogeneous amounts of GFs within each sample as high and low secretion of random factors could be simultaneously detected. These results suggest inherent heterogeneity in secretion of GFs by platelets in patient samples that are not influenced by the device used to prepare PRP. Since some GFs could have antagonistic effects on hair growth, a balance between amounts of growth promoting and inhibiting factors may be crucial in determining clinical response to PRP therapy.  相似文献   
54.
55.
Synthetic amorphous silica (SAS) in its nanosized form is now used in food applications although the potential risks for human health have not been evaluated. In this study, genotoxicity and oxidative DNA damage of two pyrogenic (NM‐202 and 203) and two precipitated (NM‐200 and ‐201) nanosized SAS were investigated in vivo in rats following oral exposure. Male Sprague Dawley rats were exposed to 5, 10, or 20 mg/kg b.w./day for three days by gavage. DNA strand breaks and oxidative DNA damage were investigated in seven tissues (blood, bone marrow from femur, liver, spleen, kidney, duodenum, and colon) with the alkaline and the (Fpg)‐modified comet assays, respectively. Concomitantly, chromosomal damage was investigated in bone marrow and in colon with the micronucleus assay. Additionally, malondialdehyde (MDA), a lipid peroxidation marker, was measured in plasma. When required, a histopathological examination was also conducted. The results showed neither obvious DNA strand breaks nor oxidative damage with the comet assay, irrespective of the dose and the organ investigated. Similarly, no increases in chromosome damage in bone marrow or lipid peroxidation in plasma were detected. However, although the response was not dose‐dependent, a weak increase in the percentage of micronucleated cells was observed in the colon of rats treated with the two pyrogenic SAS at the lowest dose (5 mg/kg b.w./day). Additional data are required to confirm this result, considering in particular, the role of agglomeration/aggregation of SAS NMs in their uptake by intestinal cells. Environ. Mol. Mutagen. 56:218–227, 2015. © 2014 Wiley Periodicals, Inc.  相似文献   
56.
57.
58.
59.
60.
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