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   40646篇
  免费   4121篇
  国内免费   1995篇
耳鼻咽喉   795篇
儿科学   1037篇
妇产科学   192篇
基础医学   5341篇
口腔科学   7108篇
临床医学   3626篇
内科学   3499篇
皮肤病学   158篇
神经病学   886篇
特种医学   2047篇
外国民族医学   20篇
外科学   8911篇
综合类   6173篇
现状与发展   6篇
预防医学   1222篇
眼科学   153篇
药学   1929篇
  21篇
中国医学   1399篇
肿瘤学   2239篇
  2024年   62篇
  2023年   618篇
  2022年   796篇
  2021年   1585篇
  2020年   1639篇
  2019年   1484篇
  2018年   1345篇
  2017年   1461篇
  2016年   1423篇
  2015年   1609篇
  2014年   2595篇
  2013年   3666篇
  2012年   2138篇
  2011年   2490篇
  2010年   2208篇
  2009年   2041篇
  2008年   1948篇
  2007年   1994篇
  2006年   1791篇
  2005年   1734篇
  2004年   1551篇
  2003年   1379篇
  2002年   1166篇
  2001年   1032篇
  2000年   848篇
  1999年   758篇
  1998年   623篇
  1997年   618篇
  1996年   578篇
  1995年   409篇
  1994年   423篇
  1993年   295篇
  1992年   310篇
  1991年   254篇
  1990年   206篇
  1989年   204篇
  1988年   163篇
  1987年   130篇
  1986年   126篇
  1985年   154篇
  1984年   111篇
  1983年   107篇
  1982年   123篇
  1981年   91篇
  1980年   86篇
  1979年   87篇
  1978年   93篇
  1977年   62篇
  1976年   60篇
  1975年   36篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
The purpose of this literature review is to investigate clinical treatment methods of total body irradiation within the context of a clinical department adopting a paediatric cohort with no existing technique. An extensive review of the literature was conducted using PubMed, Science Direct, Google Scholar, and Clinicians Knowledge Network. Articles were limited to nonhelical tomotherapy, nonparticle therapies, and those using hyperfractionated regimes. Total marrow irradiation was excluded because of national treatment and trial limitations. Of the numerous patient positioning methods present within the literature, the most comfortable and reproducible positioning methods for total body irradiation include both supine and the supine and/or prone combination. These positions increased stability and patient comfort during treatment, while also facilitating computed tomography data acquisition at the simulation stage. Ideally, dose calculations should be performed using a three-dimensional treatment planning system and quality assurance procedures that include in vivo dosimetry measurements. The available literature also suggests inhomogeneity correction factors and intensity modulation are superior to conventional open field techniques and should be implemented within developing protocols. Dynamic machine dose modulation is suggested to reduce department impact, removing the need for tissue compensators and accessory shielding devices, while providing significant improvements to treatment time and dose accuracy. Further long-term survival and intensity modulation studies are warranted, including direct comparisons of both dose modulation and treatment efficiency.  相似文献   
22.
Interleukin‐37 (IL‐37) is closely associated with several inflammatory diseases. However, the role of IL‐37 in the pathogenesis of rheumatoid arthritis (RA) remains unclear. The aim of this study was to assess the associations between serum levels of IL‐37 and disease activity, inflammatory cytokines, and bone loss in patients with RA. Serum cytokines levels were examined by Enzyme‐linked immunosorbent assay (ELISA). Radiographic bone erosion was assessed using the van der Heijde‐modified Sharp score and bone mineral density (BMD) was measured using DXA. Serum IL‐37 levels in RA patients were significantly higher than those in HCs (p < 0.001), and were significantly positively correlated with clinical parameters of disease activity and serum levels of IL‐17 and IL‐23. In addition, serum IL‐37 levels were significantly higher in patients with stage IV of radiographic bone erosion than those with stage III and stage I–II, and they were significantly higher in those with osteopenia and osteoporosis than in those with normal BMD. Our results suggest that serum IL‐37 levels were increased in patients with RA and were positively associated with disease activity, IL‐17/IL‐23 and bone loss in RA, suggesting that IL‐37 may play a critical role in the pathogenesis of RA.  相似文献   
23.
24.
Bone containing tissues such as osteochondral joint are resistant to routine tissue processing, therefore require decalcification. This technique causes removal of mineral salts, but in the process may macerate the organic tissue, hence the need for tissue fixation. Such severe processing demands careful antigen retrieval to necessitate optimal staining. The aim of our study was to compare five different antigen retrieval protocols (heat retrieval and protein digestion) following decalcification of rabbit knee joints using two different techniques (20% formic acid and 10% ethylenediamine-tetra acetic acid: EDTA). Osteochondral sections were compared based on time required for decalcification, ease of sectioning, morphological integrity using HE staining and antigen preservation (Collagen type II) using immunohistochemistry. The two decalcification solutions did not impair the tissue morphology and ease of sectioning. Joints processed with formic acid decalcified four times faster than EDTA. Among the five antigen retrieval approaches, maximal collagen II uptake with minimal nonspecific staining was found with protein digestion (pronase and hyaluronidase) in both formic acid and EDTA sections. For osteo-chondral sections, we recommend using 10% EDTA for decalcification and pronase plus hyaluronidase for antigen retrieval if maintaining tissue morphology is crucial, whereas if time is of the essence, 20% FA with pronase plus hyaluronidase is the faster option while still preserving structural integrity. Clin. Anat. 33:343–349, 2020. © 2019 Wiley Periodicals, Inc.  相似文献   
25.
目的研究快速成型(RP)技术辅助下制作的个体化假体复合珊瑚羟基磷灰石(CHA)、重组人骨形成蛋白2(rhBMP-2)修复兔下颌骨缺损的成骨效果。 方法以27只新西兰大白兔为实验对象,随机数字表法平均分成3组(每组9只),全部建立下颌骨连续性缺损模型,并在兔下颌骨缺损区分别植入个体化假体+自体骨(A组)、个体化假体+CHA(B组)、个体化假体+CHA+rhBMP-2(C组)。分别于术后4、12、24周3个时间点处死动物取材,进行大体标本观察,以及骨钙素(OC)、Ⅰ型胶原(COL-1)的免疫组化观察,分别比较各组修复骨缺损的能力,并对实验数据进行重复测量设计资料的单因素方差分析。 结果术后24周各组实验兔外形均对称,通过OC及COL-1的吸光度检测,骨缺损区均有大量新骨形成,A组(0.537 ± 0.010)、C组(0.530 ± 0.010)可见大量骨小梁及编织骨结构,缺损区的新骨OC、COL-1的免疫组化观察基本一致,差异无统计学意义(t = 0.007,P>0.05);但A组强于B组(0.415 ± 0.009,t = 0.122,P<0.001);C组也强于B组(t = 0.121,P<0.001),差异均有统计学意义。 结论在兔下颌骨缺损修复中,通过RP技术和组织工程技术相结合,CHA复合rhBMP-2后成骨能力明显增强,成骨效能肯定,为后期的临床应用提供可靠的实验基础。  相似文献   
26.
Purpose: Non-ambulatory persons with cerebral palsy are prone to low bone mineral density. In ambulatory persons with cerebral palsy, bone mineral density deficits are expected to be small or absent, but a consensus conclusion is lacking. In this systematic review bone mineral density in ambulatory persons with cerebral palsy (Gross Motor Function Classification Scales I–III) was studied.

Materials and methods: Medline, Embase, and Web of Science were searched. According to international guidelines, low bone mineral density was defined as Z-score?≤??2.0. In addition, we focused on Z-score?≤??1.0 because this may indicate a tendency towards low bone mineral density.

Results: We included 16 studies, comprising 465 patients aged 1–65?years. Moderate and conflicting evidence for low bone mineral density (Z-score?≤??2.0) was found for several body parts (total proximal femur, total body, distal femur, lumbar spine) in children with Gross Motor Function Classification Scales II and III. We found no evidence for low bone mineral density in children with Gross Motor Function Classification Scale I or adults, although there was a tendency towards low bone mineral density (Z-score?≤??1.0) for several body parts.

Conclusions: Although more high-quality research is needed, results indicate that deficits in bone mineral density are not restricted to non-ambulatory people with cerebral palsy.

  • Implications for Rehabilitation
  • Although more high-quality research is needed, including adults and fracture risk assessment, the current study indicates that deficits in bone mineral density are not restricted to non-ambulatory people with CP.

  • Health care professionals should be aware that optimal nutrition, supplements on indication, and an active lifestyle, preferably with weight-bearing activities, are important in ambulatory people with CP, also from a bone quality point-of-view.

  • If indicated, medication and fall prevention training should be prescribed.

  相似文献   
27.
28.
FGFR–TACC, found in different tumor types, is characterized by the fusion of a member of fibroblast grown factor receptor (FGFR) tyrosine kinase (TK) family to a member of the transforming acidic coiled-coil (TACC) proteins. Because chromosome numerical alterations, hallmarks of FGFR–TACC fusions are present in many hematological disorders and there are no data on the prevalence, we studied a series of patients with acute myeloid leukemia and myelodysplastic syndrome who presented numerical alterations using cytogenetic traditional analysis. None of the analyzed samples showed FGFR3–TACC3 gene fusion, so screening for this mutation at diagnosis is not recommended.  相似文献   
29.
《山东中医杂志》2020,(3):218-222
基于骨伤疾病瘀血内阻的重要病机和现代医家"治血重治水"的学术观点,探索概括了活血利水法在骨伤疾病中的应用现状,结合现代医学的认识,全方位分析了活血利水法的优势和缺点。活血利水法可应用于骨折、筋伤等骨伤科大部分疾病及骨伤科疾病的围手术期,能改善肢体肿胀,促进伤口愈合,便于患者早期功能康复,但目前的临床应用尚缺乏统一的规范和标准,且处方不良反应尚未完全阐明。  相似文献   
30.
目的通过建立去势比格犬模型,观察绝经早期腹部脂肪变化规律,并通过对脂肪与骨代谢相关血清学指标的测量与分析,探讨脂肪及骨代谢的关键影响因素。方法选取6只成年雌性比格犬进行去势术,分别在术前、术后4个月、6个月、10个月进行腰椎定量CT(quantatitive computed tomography,QCT)腹部脂肪面积、骨密度(bone mineral density,BMD)、MRI腰椎骨髓脂肪含量及血清学指标的检测,比较不同时间各指标的变化趋势及关系。结果比格犬腹内脂肪面积(visceral fat area,VFA)、皮下脂肪面积(subcutaneous fat area,SFA)、腹部总脂肪面积(total fat area,TFA)在术后6个月、10个月均增加(P0.05),术后10个月VFA增加百分比均值为84.39%,且为三者中最大;术后比格犬BMD并未明显降低。体重、BMD、瘦素(leptin,LP)、VFA、高密度脂蛋白(high-density lipoprotein,HDL)与SFA相关。SFA、体重、低密度脂蛋白(low-density lipoprotein,LDL)、内脏脂肪素(visfatin,VFN)与BMD相关。结论去势比格犬模型可用于研究绝经后雌激素缺乏所引起的脂肪代谢变化,但短期内BMD并未明显丢失,骨、脂肪代谢之间存在交互作用。  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