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   135472篇
  免费   48814篇
  国内免费   3394篇
耳鼻咽喉   2170篇
儿科学   4850篇
妇产科学   1259篇
基础医学   23678篇
口腔科学   6231篇
临床医学   19489篇
内科学   32522篇
皮肤病学   8400篇
神经病学   16712篇
特种医学   5268篇
外国民族医学   37篇
外科学   20638篇
综合类   7775篇
现状与发展   7篇
一般理论   24篇
预防医学   7924篇
眼科学   3094篇
药学   11748篇
  43篇
中国医学   3755篇
肿瘤学   12056篇
  2024年   126篇
  2023年   781篇
  2022年   2024篇
  2021年   4474篇
  2020年   7010篇
  2019年   12609篇
  2018年   12119篇
  2017年   13109篇
  2016年   13977篇
  2015年   14757篇
  2014年   15317篇
  2013年   15575篇
  2012年   9576篇
  2011年   9582篇
  2010年   12282篇
  2009年   8034篇
  2008年   5766篇
  2007年   4427篇
  2006年   4131篇
  2005年   3634篇
  2004年   2858篇
  2003年   2613篇
  2002年   2484篇
  2001年   1980篇
  2000年   1933篇
  1999年   1444篇
  1998年   696篇
  1997年   721篇
  1996年   573篇
  1995年   482篇
  1994年   397篇
  1993年   273篇
  1992年   359篇
  1991年   273篇
  1990年   230篇
  1989年   203篇
  1988年   157篇
  1987年   145篇
  1986年   120篇
  1985年   104篇
  1984年   57篇
  1983年   58篇
  1982年   28篇
  1981年   30篇
  1980年   14篇
  1979年   28篇
  1978年   14篇
  1973年   11篇
  1971年   11篇
  1969年   12篇
排序方式: 共有10000条查询结果,搜索用时 968 毫秒
991.
992.
The study was designed and conducted to evaluate the plant-based diet status and its association with erectile function (EF) in Chinese young healthy men. From July 2018 to May 2020, 116 objectively proved physically and psychologically healthy men were selected. Clinical questionnaires, detailed physical examinations and blood tests were all assessed. An overall plant-based diet index (PDI) and a healthful plant-based diet index (hPDI) were developed from each participant to measure plant-based diet quantitatively. The EF was measured by both the International Index of Erectile Function-5 (IIEF-5) and the surrogated measures of endothelial function, peripheral levels of nitric oxide (NO) and E-selectin. In subjects, the mean PDI and hPDI were 53.8 ± 8.2 and 54.7 ± 8.9 respectively. Results of multivariate analysis showed that both PDI and hPDI were negatively associated with BMI (all p < .05), but had no relationships with NO, E-selectin, TT levels and IIEF-5 scores (all p > .05). In a subgroup of male population, Chinese young healthy men, the plant-based diet, measured by PDI and hPDI, was not related to erectile function. The population can adhere to plant-based diet to keep healthy without concerns of negative influence on erectile function.  相似文献   
993.
目的探讨原发性中枢神经系统淋巴瘤(PCNSL)患者的预后因素及不同治疗方法的临床效果。方法回顾性分析1975年1月至2016年12月美国SEER数据库中4812例PCNSL患者的临床资料。其中男性2831例,女性1981例,男女比例为1.4∶1.0;发病年龄<60岁者2236例(46.47%),60~<75岁者1718例(35.70%),≥75岁者858例(17.83%);幕上肿瘤2417例(50.23%),幕下肿瘤299例(6.21%),脑内多发肿瘤554例(11.51%),其他或未指明部位的脑部肿瘤1542例(32.04%);弥漫大B细胞淋巴瘤(DLBCL)3513例(73.00%),非DLBCL 234例(4.86%),其他或未指明类型的淋巴瘤1065例(22.13%);治疗方式为单独活检的2010例(41.77%),单独部分切除61例(1.27%),单独完全切除54例(1.12%),活检+化疗2384例(49.54%),部分切除+化疗159例(3.30%),完全切除+化疗144例(2.99%)。采用单因素及多因素Cox回归模型分析影响患者总体生存的预后因素;采用Fine-Gray检验与竞争风险模型研究影响患者肿瘤特异性生存的预后因素;生存分析采用Kaplan-Meier法,并通过Log-rank进行比较。结果单因素及多因素Cox风险回归模型分析结果显示,影响PCNSL患者总体生存的独立预后因素包括年龄、种族、婚姻状态、肿瘤部位、病理学亚型、手术、化疗、合并其他恶性肿瘤、合并HIV感染等。Fine-Gray检验与竞争风险模型分析结果显示,影响患者肿瘤特异生存的独立预后因素包括年龄、种族、婚姻状态、肿瘤部位、病理学亚型、手术方式、化疗、合并其他恶性肿瘤、合并HIV感染,而性别与放疗均与肿瘤特异生存无明显相关性。与活检相比,PCNSL患者可能从手术切除中获益(部分切除:HR=0.805,95%CI:0.656~0.989,P=0.04;完全切除:HR=0.521,95%CI:0.414~0.656,P<0.01)。Kaplan-Meier生存分析结果显示,活检+化疗组中位生存时间为28个月(95%CI:24.497~31.503),单独活检组为2个月(95%CI:1.756~2.244),单独部分切除组为2个月(95%CI:1.410~2.590),单独完全切除组为19个月(95%CI:0~39.311),部分切除+化疗组为67个月(95%CI:46.187~87.813),完全切除+化疗组为84个月(95%CI:57.448~110.552),使用不同治疗方法的患者的中位生存时间的差异有统计学意义(P<0.01)。结论手术切除可能改善部分PCNSL患者的预后。化疗可能使肿瘤完全切除或部分切除患者的肿瘤特异生存时间延长。  相似文献   
994.
PurposeTo introduce an all-inside modified Broström technique to suture the anterior talofibular ligament (ATFL) and inferior extensor retinaculum (IER) under arthroscopy and to compare its outcomes with those of the conventional open procedure.MethodsAll patients who underwent arthroscopic or open repair of the ATFL between June 2014 and December 2017 were included in this study. Visual analog scale (VAS), Karlsson and Peterson (K-P), American Orthopedic Foot and Ankle Society (AOFAS) ankle/hindfoot, and Tegner activity scores, as well as manual anterior drawer test (ADT), were used to evaluate the patients preoperatively and ≥2 years after surgery. The Sefton grading system was used to assess the level of satisfaction after surgery. Detailed surgical data and intraoperative findings were documented at the time of surgery.ResultsA total of 67 patients, 31 in the arthroscopic group and 36 in the open group, were included in this study (43 men and 24 women, mean body mass index 24.00, range 19.53 to 30.03). The surgical duration in the arthroscopic group (median, 34 minutes; range, 25 to 74) was significantly shorter than that in the open group (mean, 43.08 ± 8.11 minutes; 95% confidence interval [CI] 40.34 to 45.83) (P = .007). At the last follow-up, the subjective functional scores and ADT results improved significantly in both cohorts (P < .001). However, no significant difference was found in the VAS score (1.74 ± 1.24, 95% CI 1.29 to 2.2, in the open group versus 1.58 ± 1.2, 95% CI 1.18 to 1.99, in the arthroscopic group; P = .581), AOFAS score (91.71 ± 5.46, 95% CI 89.71 to 93.71, versus 90.67 ± 5.59, 95% CI 88.78 to 92.56; P = .444), K-P score (87.52 ± 7.59, 95% CI 84.73 to 90.3, versus 88.75 ± 5.56, 95% CI 86.87 to 90.63; P = .446), and ADT evaluation (normal: 96.77% versus 94.44%, P = .557) between the arthroscopic and open groups, respectively. In addition, 28 cases (90.32%) in the arthroscopic group and 32 (88.89%) in the open group achieved satisfactory results based on the Sefton grading system (P = .736). Seventeen patients (47.2%) in the open group and 18 patients (58.1%) in the arthroscopic group underwent Tegner evaluation after surgery, which showed no significant difference (5, interquartile range [IQR] 1 in the open group versus 5, IQR 3 in the arthroscopic group; P = .883). Complications were reported in 4 (11.1%) and 2 (6.5%) patients who underwent open and arthroscopic surgeries, respectively (P = .813).ConclusionsBoth open and arthroscopic modified Broström surgeries generated favorable outcomes, with a significant improvement compared with the preoperative condition. Compared with the open Broström-Gould procedure, the all-inside arthroscopic modified Broström technique produced equivalent functional and clinical results at a minimum of 2 years after the operation, with a shorter surgical duration. Arthroscopic repair might be a safe and viable alternative to open surgery for lateral ankle stabilization.Level of EvidenceIII.  相似文献   
995.
The efficacy of mesenchymal stem cells regarding clinical outcomes and cartilage regeneration in knee osteoarthritis remains unclear; however, their theoretical role in multilineage cellular differentiation and immunomodulation of the arthritic cascade has been investigated. Several studies have reported that the use of stem cell therapy for knee osteoarthritis helps in pain improvement, but its effect on cartilage regeneration has not yet been explored. Moreover, numerous studies have reported high heterogeneity in the cell sources, as well as methods of culture expansion or cell concentration, and differences in delivery methods, assessment tools, and concomitant surgical procedures, which could affect the clinical outcomes or evaluation of cartilage regeneration potency. Furthermore, future studies are warranted to examine these factors in detail to interpret the results of mesenchymal stem cell treatment for knee osteoarthritis.  相似文献   
996.
Implant wear and corrosion have been associated with adverse tissue reactions that can lead to implant failure. Wear and corrosion products are therefore of great clinical concern. For example, Co2+ and Cr3+ originating from CoCrMo‐based implants have been shown to induce a proinflammatory response in macrophages in vitro. Previous studies have also shown that the polarization of macrophages by some proinflammatory stimuli is associated with a hypoxia‐inducible factor‐1α (HIF‐1α)‐dependent metabolic shift from oxidative phosphorylation (OXPHOS) towards glycolysis. However, the potential of Co2+ and Cr3+ to induce this metabolic shift, which plays a determining role in the proinflammatory response of macrophages, remains largely unexplored. We recently demonstrated that Co2+, but not Cr3+, increased oxidative stress and decreased OXPHOS in RAW 264.7 murine macrophages. In the present study, we analyzed the effects of Co2+ and Cr3+ on glycolytic flux and HIF‐1α stabilization in the same experimental model. Cells were exposed to 6 to 24 ppm Co2+ or 50 to 250 ppm Cr3+. Glycolytic flux was determined by analyzing extracellular flux and lactate production, while HIF‐1α stabilization was analyzed by immunoblotting. Results showed that Co2+, and to a lesser extent Cr3+, increased glycolytic flux; however, only Co2+ acted through HIF‐1α stabilization. Overall, these results, together with our previous results showing that Co2+ increases oxidative stress and decreases OXPHOS, suggest that Co2+ (but not Cr3+) can induce a HIF‐1α‐dependent metabolic shift from OXPHOS towards glycolysis in macrophages. This metabolic shift may play an early and pivotal role in the inflammatory response induced by Co2+ in the periprosthetic environment.  相似文献   
997.
BackgroundLighter weight and lower modulus are potential advantages of titanium (Ti) implants over cobalt chrome (CoCr) implants in total knee arthroplasty (TKA). This study was conducted to determine whether Ti implants in TKA resulted in better clinical outcomes and radiologic results.MethodsOne hundred and eight patients (216 knees) with knee arthritis warranting bilateral primary TKA were randomly allocated to undergo Ti rotating-platform TKA in one knee and CoCr rotating-platform TKA in the contralateral knee. The mean follow-up period was 5.3 years (range, 1-7 years). The weight of Ti implants was one-third lighter than that of CoCr implants (133.9 g vs 390.1 g, P < .01). Clinical outcomes were evaluated using clinical scores, patient preferences (lightness, comfort, naturalness, and satisfaction), gait analysis (kinetic and kinematic data), range of motion, and degree of pain. Radiologic results were evaluated based on the radiolucent line (RLL), degree of medial tibial bone loss, and loosening as seen on X-ray.ResultsNo significant differences were observed in clinical scores or patient preference. Regarding implant weight, approximately 70% of patients did not perceive the Ti implant as lighter. No significant differences were observed in gait analysis, range of motion, or degree of pain. The RLL was seen in 9% of the Ti implant group and 19% of the CoCr implant group.ConclusionThe lighter Ti implant did not show any clinical benefit over CoCr implants. The lightness of the Ti implant is not sufficient to matter or be noticeable. However, the Ti implant showed lower rate of RLL than the CoCr implant.Level of Evidencelevel I, randomized controlled trial.  相似文献   
998.
999.
Cardiac intimal sarcoma is extremely rare and aggressive primary malignant cardiac tumors. Here, we reported the case of a young man initially operated for a tumor of the left atrium, causing a dynamic obstruction of the mitral valve and (mis‐)diagnosed as a myxoma at the histopathological analysis. Patient presented a local recurrence at 3 months and was reoperated. Pathology revealed this time the presence of an intimal sarcoma. Patient received adjuvant chemotherapy. Despite a good local control, the 1‐year follow‐up positron emission tomography scan revealed the presence of a metastasis in the left adrenal gland that was surgically resected. This article aims to highlight the risk of misdiagnosis in case of cardiac tumors, the hypothetical concept of malignant transformation of a cardiac myxoma, the aggressive course of the extremely rare cardiac intimal sarcoma, and the therapeutic modalities available to treat this pathology.  相似文献   
1000.
The causes of early bioprosthesis failure include infective endocarditis, pannus formation, and structural valve deterioration. We reported a patient who suffered from early mitral bioprosthesis failure due to leaflets restricted by the subvalvular apparatus and early pannus formation. In patients with symptoms relapse and mitral regurgitation recurrence early after mitral valve replacement, early pannus formation needs to be anticipated, and surgical intervention should be performed if symptoms persist after medical treatment.  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