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   15913篇
  免费   1307篇
  国内免费   485篇
耳鼻咽喉   173篇
儿科学   281篇
妇产科学   376篇
基础医学   2092篇
口腔科学   323篇
临床医学   1852篇
内科学   2880篇
皮肤病学   309篇
神经病学   1080篇
特种医学   641篇
外国民族医学   3篇
外科学   1936篇
综合类   1160篇
一般理论   2篇
预防医学   1028篇
眼科学   444篇
药学   1398篇
  5篇
中国医学   337篇
肿瘤学   1385篇
  2024年   30篇
  2023年   174篇
  2022年   419篇
  2021年   600篇
  2020年   323篇
  2019年   434篇
  2018年   429篇
  2017年   379篇
  2016年   389篇
  2015年   539篇
  2014年   632篇
  2013年   691篇
  2012年   1130篇
  2011年   1200篇
  2010年   711篇
  2009年   596篇
  2008年   870篇
  2007年   849篇
  2006年   818篇
  2005年   768篇
  2004年   693篇
  2003年   595篇
  2002年   520篇
  2001年   465篇
  2000年   401篇
  1999年   397篇
  1998年   152篇
  1997年   151篇
  1996年   176篇
  1995年   146篇
  1994年   107篇
  1993年   86篇
  1992年   195篇
  1991年   182篇
  1990年   156篇
  1989年   134篇
  1988年   128篇
  1987年   107篇
  1986年   105篇
  1985年   103篇
  1984年   77篇
  1983年   70篇
  1982年   56篇
  1981年   55篇
  1980年   47篇
  1979年   60篇
  1978年   50篇
  1977年   33篇
  1975年   27篇
  1974年   43篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
BACKGROUND AND PURPOSE: Survivin, an inhibitor of apoptosis, is expressed in fetal tissues but undetectable in normal adult tissues. It is also expressed in most common human cancers. This study evaluated the expression of survivin in breast cancers. METHODS: A monoclonal anti-survivin antibody B1 was generated. Immunohistochemical staining was performed in 226 paraffin sections of primary breast cancers and correlated with the patients' clinicopathological characteristics. RESULTS: Survivin was expressed in the cytoplasm of tumor cells in 59.3% of breast cancers. Expression of survivin was associated with high histologic grade (p = 0.027), high mitotic count (p = 0.014), positive p53 immunostaining (p = 0.012), neu overexpression (p = 0.018), and with bcl-2 (p = 0.001) and bak (p < 0.001) expression. No correlation was found between survivin expression and age, tumor size, estrogen receptor, progesterone receptor or Bax expression. Survivin expression was not significantly associated with overall or disease-free survival. CONCLUSIONS: Survivin expression is correlated with high histologic grade, high mitotic count, p53 overexpression, and bcl-2 expression in breast cancer. It does not have significance as a marker in predicting overall or disease-free survival.  相似文献   
82.
Neuroleptic malignant syndrome (NMS) is a potentially lethal adverse reaction to neuroleptics, which is characterized by hyperthermia, extrapyramidal symptoms, altered consciousness and autonomic dysfunction. Although NMS is most commonly induced by the high-potency neuroleptics, its development has also been associated with the use of non-neuroleptic agents that block central dopamine pathways. A 68-year-old man with generalized anxiety disorder and depressive symptoms presented at the emergency department (ED) with high fever, tremor, muscle rigidity, rhabdomyolysis and altered mental status. NMS was considered to have been caused by the recent addition and subsequent dose increase in his treatment regimen of venlafaxine, a serotonin norepinephrine reuptake inhibitor. He was successfully treated with bromocriptine, lorazepam, and fluid hydration in the ED and intensive care unit.  相似文献   
83.
Myositis ossificans originating from the chest wall is extremely rare. We report a case of myositis ossificans occurring in a young woman with progressive painful swelling in the chest wall. Preoperative examination suggested a malignant neoplasm originating from soft tissue. Although rare, myositis ossificans is one of the potential causes of painful swelling in the chest wall, and can be mistaken for a malignant neoplasm.  相似文献   
84.
A 58-yr-old male with a history of hepatitis C virus infection, presented with a 2-mo history of intractable left upper abdominal pain. He had fallen from a ladder 2 yr previously, landing on his left side. Abdominal computed tomography identified a large cystic mass in the spleen. The patient was brought to the operating room with a presumptive diagnosis of symptomatic, post-traumatic, false cyst of the spleen. Instead, at surgery, a splenic mass with dense adhesions to the diaphragm and stomach was found. On final histological analysis, it was diagnosed to be a large B-cell lymphoma. Despite its rarity, gastroenterologists and surgeons should be aware of large B-cell lymphoma when encountering cystic lesions of the spleen, because the management of benign cystic disease is usually nonsurgical.  相似文献   
85.
Medial cortex strain distribution during noncemented total hip arthroplasty   总被引:2,自引:0,他引:2  
Intraoperative proximal femur fractures are a significant concern during noncemented total hip arthroplasty. The current study was performed to investigate the hypothesis that broaching the femur and inserting the stem without using mallet applied impact loads will reduce the risk of intraoperative fracture. Rosette strain gauges were applied to the medial and anteromedial cortex of six human anatomic specimen femurs to compare the strain distribution for broaching and stem insertion. Eight additional femurs were used to compare the strain distribution for stem insertion using impact loading and constant rate stem insertion. For the impact loading stem insertions, the soft tissues surrounding the femur were modeled. Constant rate stem insertions were performed using a mechanical testing machine. The largest strains measured at the medial and anteromedial sites primarily were aligned with the femur hoop axis. The largest strain magnitude, orientation, and sign (tensile or compressive) varied widely among femurs. The stem insertion strains were significantly larger than the broaching strains (two-way analysis of variance with replication). The impact stem insertion strains were not significantly different from the constant rate stem insertion strains. The results indicate that the femur geometry and material properties have a greater influence on the strain distribution than does the implantation technique.  相似文献   
86.
BackgroundTalus fractures are rare in children but can lead to severe outcomes if untreated. The Ilizarov external fixator has been used in the treatment of a variety of lower extremity pathologies. The purpose of this study was to investigate the clinical outcomes of talus body fractures treated with the Ilizarov external fixator.Case PresentationFour male pediatric patients (age range, 5–11 years) with talus body fractures who were treated by open reduction and internal fixation combined with Ilizarov external fixator between November 2015 and April 2016 were reviewed. Mean follow‐up period was 4 years (range, 4–5). Clinical outcome was evaluated using the clinical rating scale of the American Orthopaedic Foot and Ankle Society (AOFAS). All four patients achieved good to excellent results at the last follow‐up. None of the patients developed avascular necrosis. One patient developed automatic fusion of tibiotalar joint.ConclusionUse of the Ilizarov external fixator to gain early range of motion is a valuable option for treatment of talus body fractures in children.  相似文献   
87.

目的:总结新型冠状病毒(SARS-CoV-2)感染相关急性黄斑区神经视网膜病变(AMN)的神经眼科特征。

方法:纳入2022-12-27/2023-02-01就诊于西安市第一医院(西北大学附属第一医院)神经眼科并经相关检查确诊为AMN的患者8例(6例女性,2例男性)共14眼纳入本次研究。所有患者病前均有SARS-CoV-2感染史。收集患者的临床资料。纳入最佳矫正视力(BCVA)、非接触间接眼压测定、眼底彩色照相、近红外成像(IR)、频域光学相干断层扫描(SD-OCT)、OCT血流成像(OCTA)、眼底荧光素血管造影(FFA)、吲哚菁绿血管造影(ICGA)、视野、视觉诱发电位(VEP)和视网膜电流图(ERG)检查结果。对纳入患者的神经眼科特征进行分析总结。

结果:纳入的8例患者年龄20-43(平均30±6.63)岁。病前3-11(平均5±3.51)d有SARS-CoV-2感染史,8例患者中有6例在感染SARS-CoV-2的5 d内出现视觉症状。患者的临床表现为视力下降或视物遮挡感; 纳入患者的视力0.08-1.0; 视野缺损表现为中心、旁中心暗点或合并周边暗点。VEP可见P100或P2峰时延迟; ERG提示视网膜感光细胞 功能受损。在疾病早期,SARS-CoV-2感染相关AMN患者可能存在视力、视野和视网膜外层病变大小及形状可能不匹配的情况,并发现视力越低,VEP峰时越迟。

结论:除眼底多模影像,SARS-CoV-2感染相关AMN的神经眼科特征需要临床医师关注,视功能及电生理可以辅助临床更加全面评估患者及判断预后。  相似文献   

88.
目的 比较腓骨髓内钉与切开复位钉板系统治疗腓骨远端骨折的疗效.方法 回顾性分析2017年10月至2019年10月于锦州医科大学附属第一医院采用手术治疗腓骨骨折的患者,按照纳入、排除标准筛选病例,最终A组髓内钉组25例纳入研究、B组钉板内固定组35例纳入研究.比较两组入院至行腓骨手术的时间,手术时长,腓骨术口总长度,AO...  相似文献   
89.
90.
Graphene is one of the most promising two-dimensional nanomaterials with broad applications in many fields. However, the variations and fluctuations in the material and geometrical properties are challenging issues that require more concern. In order to quantify uncertainty and analyze the impacts of uncertainty, a stochastic finite element model (SFEM) is proposed to propagate uncertainty for carbon atomic interactions under resonant vibration. Compared with the conventional truss or beam finite element models, both carbon atoms and carbon covalent bonds are considered by introducing plane elements. In addition, the determined values of the material and geometrical parameters are expanded into the related interval ranges with uniform probability density distributions. Based on the SFEM, the uncertainty propagation is performed by the Monte Carlo stochastic sampling process, and the resonant frequencies of graphene are provided by finite element computation. Furthermore, the correlation coefficients of characteristic parameters are computed based on the database of SFEM. The vibration modes of graphene with the extreme geometrical values are also provided and analyzed. According to the computed results, the minimum and maximum values of the first resonant frequency are 0.2131 and 16.894 THz, respectively, and the variance is 2.5899 THz. The proposed SFEM is an effective method to propagate uncertainty and analyze the impacts of uncertainty in the carbon atomic interactions of graphene. The work in this paper provides an important supplement to the atomic interaction modeling in nanomaterials.  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