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   426986篇
  免费   38801篇
  国内免费   27784篇
耳鼻咽喉   3997篇
儿科学   5080篇
妇产科学   7223篇
基础医学   50516篇
口腔科学   7788篇
临床医学   57978篇
内科学   64488篇
皮肤病学   4414篇
神经病学   23394篇
特种医学   15417篇
外国民族医学   242篇
外科学   43747篇
综合类   66550篇
现状与发展   92篇
一般理论   36篇
预防医学   27250篇
眼科学   12378篇
药学   44093篇
  433篇
中国医学   23126篇
肿瘤学   35329篇
  2024年   997篇
  2023年   5570篇
  2022年   13659篇
  2021年   20325篇
  2020年   15023篇
  2019年   13601篇
  2018年   14361篇
  2017年   12890篇
  2016年   11906篇
  2015年   18454篇
  2014年   23146篇
  2013年   21081篇
  2012年   31073篇
  2011年   34758篇
  2010年   22258篇
  2009年   17512篇
  2008年   23666篇
  2007年   23622篇
  2006年   23310篇
  2005年   22483篇
  2004年   14874篇
  2003年   13574篇
  2002年   11580篇
  2001年   10180篇
  2000年   10709篇
  1999年   11244篇
  1998年   6551篇
  1997年   6479篇
  1996年   5163篇
  1995年   4724篇
  1994年   3991篇
  1993年   2543篇
  1992年   3602篇
  1991年   3105篇
  1990年   2694篇
  1989年   2360篇
  1988年   2025篇
  1987年   1705篇
  1986年   1407篇
  1985年   1180篇
  1984年   701篇
  1983年   530篇
  1982年   331篇
  1981年   322篇
  1980年   251篇
  1979年   355篇
  1978年   193篇
  1977年   171篇
  1974年   195篇
  1972年   166篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
AimsWe previously showed that the protective effects of endothelial progenitor cells (EPCs)‐released exosomes (EPC‐EXs) on endothelium in diabetes. However, whether EPC‐EXs are protective in diabetic ischemic stroke is unknown. Here, we investigated the effects of EPC‐EXs on diabetic stroke mice and tested whether miR‐126 enriched EPC‐EXs (EPC‐EXsmiR126) have enhanced efficacy.MethodsThe db/db mice subjected to ischemic stroke were intravenously administrated with EPC‐EXs 2 hours after ischemic stroke. The infarct volume, cerebral microvascular density (MVD), cerebral blood flow (CBF), neurological function, angiogenesis and neurogenesis, and levels of cleaved caspase‐3, miR‐126, and VEGFR2 were measured on day 2 and 14.ResultsWe found that (a) injected EPC‐EXs merged with brain endothelial cells, neurons, astrocytes, and microglia in the peri‐infarct area; (b) EPC‐EXsmiR126 were more effective than EPC‐EXs in decreasing infarct size and increasing CBF and MVD, and in promoting angiogenesis and neurogenesis as well as neurological functional recovery; (c) These effects were accompanied with downregulated cleaved caspase‐3 on day 2 and vascular endothelial growth factor receptor 2 (VEGFR2) upregulation till day 14.ConclusionOur results indicate that enrichment of miR126 enhanced the therapeutic efficacy of EPC‐EXs on diabetic ischemic stroke by attenuating acute injury and promoting neurological function recovery.  相似文献   
52.
53.
54.
55.
56.
The objective of this study was to investigate short segment decompression of degenerative lumbar scoliosis (DLS) and the efficiency of fusion treatment.After DLS surgery, the patients were retrospectively reviewed using the VAS (visual analog scale) and ODI (Oswestry Disability Index) to assess clinical outcomes. All patients underwent posterior lumbar decompressive laminectomy, pedicle screw internal fixation, and posterolateral bone graft fusion surgery. Radiographic measurements included the scoliotic Cobb angle, the fused Cobb angle, the anterior intervertebral angle (AIA), the sagittal intervertebral angle (SIA), and lumbar lordosis angle. The relationships between these parameters were examined by bivariate Pearson analysis and linear regression analysis.Preoperatively, the Cobb angle at the scoliotic segment was 15.4°, which decreased to 10.2° immediately following surgery (P < 0.05). The AIA significantly increased by the last follow-up (4.4 ± 3.4) compared with pre- and postoperative values (2.5 ± 2.8 and 2.2 ± 2.4, respectively; P < 0.05). However, the scoliotic Cobb angle and the AIA did not correlate with the VAS or ODI scores. At the final follow-up, no patients had pseudoarthrosis or internal instrumentation-related complications.Short fusion surgical treatment results in limited DLS correction, with correction loss over time. The AIA between the upper adjacent segment and proximal fused vertebra continues to increase postoperatively, which does not exacerbate clinical symptoms, as reflected by the low reoperation rates for repairing degeneration at adjacent levels.  相似文献   
57.
58.
59.
Objective: Association of matrix metalloproteinases (MMPs) gene polymorphisms with rheumatoid arthritis is controversial. We conduct a meta-analysis to clarify this dispute.

Methods: We systematically searched the electronic PUBMED, EMBASE and CNKI databases for research articles about MMPs (MMP-1, MMP-2, MMP-3, MMP-9) gene polymorphisms and rheumatoid arthritis (RA) up to January 2015. According to the heterogeneity, fixed-effects or random-effects models were used to calculate crude odds ratios (ORs) and 95% confidence intervals (95% CIs).

Results: A total of 11 articles involving 2143 cases and 2049 controls were included in this meta-analysis. Overall, no significant associations were observed between MMP-1-1607 1G/2G polymorphism and RA. Stratification by ethnicity, no significant associations were observed in Caucasian populations. Similarly, no significant associations were observed between MMP-3-1171 5A/6A, MMP-9-1562 C/T polymorphisms and RA in overall and Caucasian populations, respectively. However, a weak association was found between MMP-2-1306 C/T polymorphism and RA (C vs. T, OR?=?0.813, 95%CI?=?0.694–0.953, p?=?0.010) in overall populations.

Conclusions: The present meta-analysis suggests that MMP-1-1607 1G/2G, MMP-3-1171 5A/6A, MMP-9-1562 C/T polymorphisms are not associated with the susceptibility of RA, but MMP-2 -1306 C/T is weakly associated with susceptibility to RA. Further studies with more sample size are needed for definitive conclusions.  相似文献   
60.
BACKGROUNDGuillain-Barré syndrome (GBS) is a rare disorder that typically presents with ascending weakness, pain, paraesthesias, and numbness, which mimic the findings in lumbar spinal stenosis. Here, we report a case of severe lumbar spinal stenosis combined with GBS.CASE SUMMARYA 70-year-old man with a history of lumbar spinal stenosis presented to our emergency department with severe lower back pain and lower extremity numbness. Magnetic resonance imaging confirmed the diagnosis of severe lumbar spinal stenosis. However, his symptoms did not improve postoperatively and he developed dysphagia and upper extremity numbness. An electromyogram was performed. Based on his symptoms, physical examination, and electromyogram, he was diagnosed with GBS. After 5 d of intravenous immunoglobulin (0.4 g/kg/d for 5 d) therapy, he gained 4/5 of strength in his upper and lower extremities and denied paraesthesias. He had regained 5/5 of strength in his extremities when he was discharged and had no symptoms during follow-up.CONCLUSIONGBS should be considered in the differential diagnosis of spinal disorder, even though magnetic resonance imaging shows severe lumbar spinal stenosis. This case highlights the importance of a careful diagnosis when a patient has a history of a disease and comes to the hospital with the same or similar symptoms.  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