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   7101篇
  免费   475篇
  国内免费   39篇
耳鼻咽喉   75篇
儿科学   205篇
妇产科学   112篇
基础医学   1080篇
口腔科学   143篇
临床医学   485篇
内科学   1867篇
皮肤病学   301篇
神经病学   572篇
特种医学   233篇
外科学   542篇
综合类   50篇
一般理论   1篇
预防医学   457篇
眼科学   155篇
药学   521篇
中国医学   42篇
肿瘤学   774篇
  2024年   6篇
  2023年   47篇
  2022年   92篇
  2021年   203篇
  2020年   119篇
  2019年   159篇
  2018年   200篇
  2017年   193篇
  2016年   213篇
  2015年   190篇
  2014年   309篇
  2013年   345篇
  2012年   485篇
  2011年   571篇
  2010年   340篇
  2009年   340篇
  2008年   443篇
  2007年   527篇
  2006年   470篇
  2005年   506篇
  2004年   499篇
  2003年   442篇
  2002年   385篇
  2001年   50篇
  2000年   27篇
  1999年   48篇
  1998年   63篇
  1997年   48篇
  1996年   45篇
  1995年   32篇
  1994年   24篇
  1993年   24篇
  1992年   11篇
  1991年   11篇
  1990年   13篇
  1989年   16篇
  1988年   7篇
  1987年   13篇
  1986年   9篇
  1985年   7篇
  1984年   10篇
  1983年   7篇
  1982年   7篇
  1981年   8篇
  1980年   11篇
  1978年   4篇
  1977年   5篇
  1975年   5篇
  1974年   7篇
  1972年   4篇
排序方式: 共有7615条查询结果,搜索用时 484 毫秒
81.
82.
83.
PurposeThe purpose of this study was to analyze the effects of leg muscle strength and fatigue on step-count as a measure of physical activity for people staying at home after hematopoietic stem cell transplantation (HSCT).MethodNineteen persons receiving HSCT were assessed from hospitalization until about 2 months after discharge. Mean daily step-count was taken as a measure of physical activity. Leg muscle strength was measured in three ways (knee extension, ankle plantar flexion, and ankle dorsiflexion strength) at two points in time (time of hospital discharge and after 2 months). Fatigue and anxiety were assessed using the Japanese Cancer Fatigue Scale and State-Trait Anxiety Inventory. Correlations between the above and factors affecting physical activity were also investigated by multiple regression analysis.ResultsClinical follow-up measurements in subjects were made an average of 81.0 days after discharge. Subjects with higher mean step-count during hospitalization (β = 0.647, p = 0.000) and greater ankle plantar flexion strength/kg (β = 0.361, p = 0.021) reported higher mean step-count at home (adjusted R2 = 0.701, p = 0.021). Subjects with body mass index <22.0 kg/m2 also showed higher step-counts at home compared to other subjects. Mean fatigue score at home was 16.8 (SD = 8.75), a level not associated with clinical problems, and the proportion of physical fatigue was significantly lower than during hospitalization.ConclusionMean step-count at home was most strongly affected by ankle plantar flexion strength/kg, and increasing ankle plantar flexion strength/kg was shown to promote recovery of normal physical activities.  相似文献   
84.
85.
The recently developed Pig‐a mutation assay is based on flow cytometric enumeration of glycosylphosphatidylinositol (GPI) anchor‐deficient red blood cells caused by a forward mutation in the Pig‐a gene. Because the assay can be conducted in nontransgenic animals and the mutations accumulate with repeat dosing, we believe that the Pig‐a assay could be integrated into repeat‐dose toxicology studies and provides an alternative to transgenic rodent (TGR) mutation assays. The capacity and characteristics of the Pig‐a assay relative to TGR mutation assays, however, are unclear. Here, using transgenic gpt delta mice, we compared the in vivo genotoxicity of single oral doses of N‐ethyl‐N‐nitrosourea (ENU, 40 mg/kg), benzo[a]pyrene (BP, 100 and 200 mg/kg), and 4‐nitroquinoline‐1‐oxide (4NQO, 50 mg/kg) in the Pig‐a (peripheral blood) and gpt (bone marrow and liver) gene mutation assays. Pig‐a assays were conducted at 2, 4, and 7 weeks after the treatment, while gpt assays were conducted on tissues collected at the 7‐week terminal sacrifice. ENU increased both Pig‐a and gpt mutant frequencies (MFs) at all sampling times, and BP increased MFs in both assays but the Pig‐a MFs peaked at 2 weeks and then decreased. Although 4NQO increased gpt MFs in the liver, only weak, nonsignificant increases (two‐ or threefold above control) were detected in the bone marrow in both the Pig‐a and the gpt assay. These findings suggest that further studies are needed to elucidate the kinetics of the Pig‐a mutation assay in order to use it as an alternative to the TGR mutation assay. Environ. Mol. Mutagen. 54:747–754, 2013. © 2013 Wiley Periodicals, Inc.  相似文献   
86.
87.
Two new 6,6-spiroacetal polyketides, spirotoamides A (1) and B (2), were isolated from a microbial metabolite fraction library of Streptomyces griseochromogenes JC82-1223 by screening of structurally unique compounds based on a search of spectral database. The fraction library was constructed using a systematic separation method to efficiently discover new metabolites from microbial sources such as actinomycetes and fungi. The structures of 1 and 2 were elucidated by 2D-NMR and mass spectrometric measurements. They belong to a class of polyketides, and contain a 6,6-spiroacetal core structure and a carboxamide group. The biosynthetic pathway of 1 and 2 is discussed in the text.  相似文献   
88.
89.
Pre-filled syringes (PFS) have been in widespread use as an administration device for therapeutic antibodies in recent decades. Generally, the inner barrel and syringe of PFS are coated with silicone oil (SO) for lubrication. Multiple studies have focused on the fact that the SO adsorbs denatured antibody molecules, and induces antibody aggregation. Aggregated antibodies are recognized as a potential risk for evoking immunogenic responses in patients. The characteristics of the aggregated antibody-SO complexes, including their concentration, population, shape, three-dimensional (3D) image, and Fcγ Receptors (FcγRs) activation have been obscurely acknowledged so far. In the present work, we prepared aggregated antibody-SO complexes by agitation and analyzed using multifaceted techniques such as flow imaging, confocal fluorescence microscopy, and cell-based assays for FcγRs activation. The results emphasized that the SO accelerates the increase in sub-visible particles and antibody aggregation. The confocal fluorescence microscopy analysis revealed the high-resolution 3D images of aggregated antibody-SO complexes. The FcγRs reporter cell assay clarified that the pre-mixed and agitated Ab + SO have higher FcγRs activation capability compared to the agitated Ab. Overall, this study advances the view that SO has an effect to increase the risk of agitation-induced aggregated antibody particles.  相似文献   
90.
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