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   27122篇
  免费   2952篇
  国内免费   1957篇
耳鼻咽喉   181篇
儿科学   308篇
妇产科学   282篇
基础医学   2952篇
口腔科学   586篇
临床医学   3647篇
内科学   3578篇
皮肤病学   335篇
神经病学   1275篇
特种医学   949篇
外国民族医学   12篇
外科学   2533篇
综合类   5287篇
现状与发展   7篇
一般理论   2篇
预防医学   2167篇
眼科学   565篇
药学   2958篇
  37篇
中国医学   2352篇
肿瘤学   2018篇
  2024年   163篇
  2023年   606篇
  2022年   1452篇
  2021年   1751篇
  2020年   1437篇
  2019年   1047篇
  2018年   1080篇
  2017年   1046篇
  2016年   895篇
  2015年   1295篇
  2014年   1589篇
  2013年   1408篇
  2012年   2029篇
  2011年   2089篇
  2010年   1406篇
  2009年   1153篇
  2008年   1208篇
  2007年   1311篇
  2006年   1154篇
  2005年   1047篇
  2004年   905篇
  2003年   1084篇
  2002年   976篇
  2001年   800篇
  2000年   524篇
  1999年   473篇
  1998年   288篇
  1997年   322篇
  1996年   236篇
  1995年   211篇
  1994年   164篇
  1993年   92篇
  1992年   169篇
  1991年   125篇
  1990年   82篇
  1989年   79篇
  1988年   66篇
  1987年   74篇
  1986年   53篇
  1985年   38篇
  1984年   29篇
  1983年   16篇
  1982年   16篇
  1981年   11篇
  1980年   9篇
  1979年   13篇
  1976年   2篇
  1972年   2篇
  1971年   1篇
  1967年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
压电免疫传感器两种抗体固定方法的比较研究   总被引:4,自引:4,他引:4  
目的比较压电免疫传感器两种抗体固定方法的优劣,选择压电免疫传感器抗体敏感膜固定的最佳方法. 方法分别采用巯基化方法和蛋白A(SPA)固定法将抗人胰岛素单克隆抗体固定在压电免疫传感器金膜电极表面,比较不同抗体工作浓度、不同浓度标准溶液反应条件下抗体固定量、一致性以及传感器响应能力如频率变化、反应时间、检测线性范围以及反应非特异性等. 结果两种固定方法制备的压电免疫传感器其检测灵敏度、反应时间相当,但巯基化固定方法抗体固定量大、一致性好、检测线性范围较宽、非特异反应低. 结论抗体巯基化法制备的压电免疫传感器具有检测范围宽、非特异反应低等优点,是免疫传感器抗体敏感膜制备的理想方法.  相似文献   
62.
目的 系统分析脑卒中患者吞咽障碍恢复不良的影响因素。方法 系统检索中国知 网、万方数据库、维普网、中国生物医学文献数据库、PubMed、Cochrane Library、Embase 数据库,收集 建库至 2022 年 12 月发表的脑卒中患者吞咽障碍恢复不良影响因素相关研究,使用 RevMan 5.4.1 软件 对纳入文献进行Meta分析。结果 共纳入 22 篇文献,4 248 例患者。Meta分析结果显示,年龄≥ 70 岁 (OR=1.53,95%CI:1.29~1.80)、美国国立卫生研究院卒中量表(NIHSS)评分≥ 8 分(OR=2.36,95%CI: 1.53~3.63)、改 良 Rankin 量 表(mRS)评 分 > 0 分(OR=1.71,95%CI:1.40~2.09)、双 侧 卒 中(OR=4.85, 95%CI:2.62~8.97)、低密度脂蛋白(LDL)水平≥3 mg/L(OR=3.70,95%CI:2.46~5.56)、认知障碍(OR=6.23, 95%CI:0.98~39.58)、误吸(OR=4.47,95%CI:3.28~6.11)、气管插管(OR=2.70,95%CI:1.58~4.63)是脑 卒中患者吞咽功能恢复不良的危险因素(P< 0.05);体重指数> 18.5 kg/m2 (OR=0.76,95%CI:0.67~0.86)、 Barthel 指数(BI)> 60 分(OR=0.37,95%CI:0.22~0.62)、功能独立性测评(FIM)评分> 20 分(OR=0.96, 95%CI:0.94~0.99)是脑卒中患者吞咽功能恢复不良的保护因素(P<0.05)。结论 高龄、高NIHSS评分、 双侧卒中、低体重指数、高 mRS 评分、低 BI、低 FIM 评分、高 LDL 水平、合并认知障碍、误吸、气管插管是 脑卒中患者吞咽障碍恢复不良的危险因素,临床可结合影响因素完善吞咽障碍患者的管理措施。  相似文献   
63.
ObjectiveTo translate the original English version of the Spinal Instability Neoplastic Score (SINS) into simplified Chinese, adapt it cross‐culturally, validate its psychometric properties in measuring spinal instability in patients with metastatic spinal tumors in the Chinese mainland, examine the reliability and validity to demonstrate its accuracy and applicability in clinical practice.MethodsPatients diagnosed with metastatic spinal disease between January 2016 and January 2020 were recruited. The number of participants was advised to be at least 50 for appropriate analysis of reliability, construct validity, as well as ceiling or floor effects, and recruitment of 100 patients was advised for internal consistency analysis. The study was conducted in two phases: first, the SINS was translated into simplified Chinese; second, the factor structure, internal consistency, test–retest reliability, validity, and floor and ceiling effects of the SC‐SINS were assessed. The internationally recognized cross‐cultural adaptation guidelines were followed. Internal consistency was evaluated with Cronbach''s alpha. Test–retest reliability was examined among the patients with a 4‐week interval. The validity of the Chinese version of SINS (SC‐SINS) was assessed by examining its relationship with Kostuik classification. Principal component analysis was conducted to confirm the factor structure of each subscale.ResultsA total of 160 participants (88 males and 72 females) were enrolled. No major difficulties occurred in the forward and backward translations of SINS. The internal consistency of SC‐SINS was excellent (Cronbach''s α =0.857, ranging from 0.68 to 0.85). Test–retest reliability was also excellent with a value of 0.89, ranging from 0.86 to 0.95. Validity analyses indicated that the SC‐SINS was positively and significantly correlated with Kostuik classification. The correlation between “Posterolateral Involvement of Spinal Elements” and “1‐2 Partial Damage” was the highest with a correlation value of 0.792. The correlation between “Pain” and “1–2 Partial Damage” was the lowest with a value of 0.341. All items showed principal component coefficients greater than 0.4. The values of Factor 1 ranged from 0.523 to 0.681; Factor 2 ranged from 0.591 to 0.731; Factor 3 ranged from 0.613 to 0.754; Factor 4 ranged from 0.461 to 0.711; Factor 5 ranged from 0.513 to 0.701; and Factor 6 ranged from 0.501 to 0.668. In addition, neither floor nor ceiling effects were seen in the SC‐SINS.ConclusionThe SC‐SINS demonstrated high internal consistency and test–retest reliability, which has been proven valid and reliable to measure spinal stability in patients from the Chinese mainland with metastatic spinal tumor.  相似文献   
64.
2006版“医疗器械生物学评价-动物保护要求“国际标准规定了在用于评价医疗器械的材料或医疗器械本身的生物相容性的动物试验中,爱护动物和使用动物的最基本要求.目的在于:为进行医疗器械生物学评价的委托者,设计者以及进行试验或从动物试验进行推测、评价的科研人员,提供尊重生命的通用性要求;也推荐并提供以下指南:促进今后进一步“减少(reduction)“应用动物全部的数量;“精致(refinement)“在动物中减少或除去痛苦或苦恼的试验方法;以及其他的合乎科学、有效的不需要动物的方法来“代替(replacement)“动物试验.该标准适用于在除人类之外的脊椎动物体上进行医疗器械或材料的生物相容性试验.  相似文献   
65.
Accurate methods for identifying pelvic lymph node metastasis(LNM)of prostate cancer(PCa)prior to surgery are still lacking.We aimed to investigate the predicti...  相似文献   
66.
乙型肝炎病毒血清标志物全阳性模式一例分析及随访   总被引:1,自引:0,他引:1  
目的 为了揭示临床实验室乙型肝炎病毒血清标志物少(罕)见模式客观存在的规律,探讨和分析了乙型肝炎病毒血清标志物全阳性模式病例的临床转归情况以及血清标志物的动态变化趋势.方法 以慢性乙型病毒性肝炎患者为对象,用荧光定量PCR和酶联免疫吸附试验同步检测不同时段血清HBVDNA和HBsAg、HBsAb、HBeAg、HBeAb、HBcAb五项血清学标志物,并进行血清肝功能酶学指标的动态跟踪.结果 在长达3个月的时间段内,HBVM持续稳定在全阳性模式不变,用重组人干扰素α2b(安福隆)进行抗病毒治疗的早期应答虽不明显,但治疗至5个月后,随着病毒的阴转,HBeAg和HBeAb也逐步阴转,肝功能酶学指标逐步恢复正常,但HBsAg与HBsAb仍同时保留阳性.结论 HBVM在慢性乙型肝炎患者不同病程中可呈现不同模式的组合,而不能简单的用"大三阳"、"小三阳"或15阳性等模式进行解释,应动态观察乙肝两对半组合模式以及编码的变化,有利于对乙型肝炎的诊治和疗效评估.  相似文献   
67.
ObjectiveTo evaluate the effect of different levels of physician experience on the high-intensity focused ultrasound (HIFU) ablation of uterine fibroids and to provide a reference for the use of non-perfused volume ratio (NPVR) standards during training.MethodsThis prospective multicentre study enrolled patients with uterine fibroids. The effect of the physician’s level of experience on the outcomes under different NPVR standards and the learning curve of six centres without HIFU experience were analysed. The impact of patient demographic and clinical characteristics were also evaluated.ResultsA total of 1352 patients from 20 centres were included in the study. The median NPVRs were 92.00%, 88.10% and 92.86% in the no experience group, inexperienced group and experienced group, respectively. Posterior wall fibroids, lateral wall fibroids and fundus fibroids were inversely correlated with NPVR, while experienced physicians were positively correlated with NPVR. With NPVR ≥ 70% and NPVR ≥ 80% standards, physicians in the no experience group completed the learning curve on the 11th and 16th procedure, respectively. Physicians under a standard of an NPVR ≥ 90% did not complete the learning curve.ConclusionsNPVR ≥ 80% is a standard that is worth using for HIFU treatment of uterine fibroids.  相似文献   
68.
Breast surgery is an important treatment for women with malignant breast diseases. In addition to breast appearance, the integrity of breast function is increasing in patients with breast diseases. As the basis of breast physiological function, breast skin sensitivity is important to the quality of life of patients after surgery. Breast skin sensitivity gives the patient a “real” breast feeling. The sensory recovery after breast surgery has also become one of the important goals of breast surgery. In this review, we aim to discuss the research progress on recovery of breast skin sensitivity after different treatment modalities for breast disease.  相似文献   
69.
AimWhite matter damage (WMD) is the main cause of cerebral palsy and cognitive impairment in premature infants. Although caffeine has been shown to possess neuroprotective effects in neonatal rats with hypoxic‐ischemic WMD, the mechanisms underlying these protective effects are unclear. Herein, proteins modulated by caffeine in neonatal rats with hypoxic‐ischemic WMD were evaluated.MethodsWe identified differential proteins and performed functional enrichment analyses between the Sham, hypoxic‐ischemic WMD (HI), and HI+caffeine‐treated WMD (Caffeine) groups. Confirmed the changes and effect of proteins in animal models and determined cognitive impairment via water maze experiments.ResultsIn paraventricular tissue, 47 differential proteins were identified between the Sham, HI, and Caffeine groups. Functional enrichment analyses showed that these proteins were related to myelination and axon formation. In particular, the myelin basic protein (MBP), proteolipid protein, myelin‐associated glycoprotein precursor, and sirtiun 2 (SIRT2) levels were reduced in the hypoxic‐ischemic WMD group, and this effect could be prevented by caffeine. Caffeine alleviated the hypoxic‐ischemic WMD‐induced cognitive impairment and improved MBP, synaptophysin, and postsynaptic density protein 95 protein levels after hypoxic‐ischemic WMD by preventing the HI‐induced downregulation of SIRT2; these effects were subsequently attenuated by the SIRT2 inhibitor AK‐7.ConclusionCaffeine may have clinical applications in the management of prophylactic hypoxic‐ischemic WMD; its effects may be mediated by proteins related to myelin development and synapse formation through SIRT2.  相似文献   
70.
Geopolymer foams with different pore structures can be used in construction, water treatment, and heavy metal adsorption. The preparation of high porosity geopolymer foams using vegetable oil as a foam stabilizer is a feasible and cost-effective route. In this study, metakaolin-based geopolymer foams with hierarchical pore structures were fabricated by adding H2O2 as the foaming agent with palm olein as the foam stabilizer. The effects of H2O2 and palm olein content on the chemical features and pore structure of geopolymer foams were evaluated. Water absorption, thermal conductivity, and mechanical behaviors of geopolymer foams were also investigated. The results indicate that fatty acid salt surfactants were generated in situ in the geopolymer matrix due to the addition of palm olein. Geopolymer foams with H2O2 and palm olein addition possess a homogeneously concentrated macropore distribution. Palm olein exhibits a refining effect on intrinsic pores formed by geopolymerization. In addition, using appropriate amounts of palm olein and H2O2, geopolymer foams can achieve higher open porosity and better pore connectivity, resulting in the improvement of water absorption and thermal insulation capacity.  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