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   81690篇
  免费   7600篇
  国内免费   5319篇
耳鼻咽喉   591篇
儿科学   993篇
妇产科学   1238篇
基础医学   9842篇
口腔科学   1579篇
临床医学   10303篇
内科学   12715篇
皮肤病学   855篇
神经病学   4441篇
特种医学   2855篇
外国民族医学   43篇
外科学   7854篇
综合类   13181篇
现状与发展   14篇
一般理论   12篇
预防医学   5545篇
眼科学   2159篇
药学   8777篇
  84篇
中国医学   4534篇
肿瘤学   6994篇
  2024年   342篇
  2023年   1311篇
  2022年   3255篇
  2021年   4128篇
  2020年   3134篇
  2019年   2692篇
  2018年   2842篇
  2017年   2551篇
  2016年   2407篇
  2015年   3637篇
  2014年   4456篇
  2013年   4151篇
  2012年   6254篇
  2011年   6593篇
  2010年   4222篇
  2009年   3334篇
  2008年   4483篇
  2007年   4311篇
  2006年   3926篇
  2005年   3844篇
  2004年   2777篇
  2003年   2534篇
  2002年   2264篇
  2001年   1844篇
  2000年   1939篇
  1999年   2021篇
  1998年   1287篇
  1997年   1276篇
  1996年   992篇
  1995年   963篇
  1994年   783篇
  1993年   496篇
  1992年   569篇
  1991年   514篇
  1990年   435篇
  1989年   387篇
  1988年   306篇
  1987年   311篇
  1986年   236篇
  1985年   186篇
  1984年   123篇
  1983年   84篇
  1982年   63篇
  1981年   47篇
  1980年   33篇
  1979年   44篇
  1978年   18篇
  1974年   17篇
  1973年   17篇
  1966年   18篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
There were controversial results between obesity‐associated markers and semen quality. In this study, we investigated the correlations between age, obesity‐associated markers including body mass index (BMI), waist‐to‐hip ratio (WHR), waist‐to‐height ratio (WHtR) and waist circumference (WC), the combination of age and obesity‐associated markers, semen parameters and serum reproductive hormone levels in 1231 subfertile men. The results showed that BMI, WC, WHR and WHtR were positively related to age, and there were also positive relations between BMI, WHR, WC and WHtR and between sperm concentration (SC), total sperm count (TSC), progressive motility (PR), sperm motility and per cent of normal sperm morphology (NSM). However, age, each of obesity‐associated markers and the combination of obesity‐associated markers and age were unrelated to any of semen parameters including total normal‐progressively motile sperm count (TNPMS). Age, BMI, WHR, WC and WHtR were negatively related to serum testosterone and SHBG levels. However, only serum LH and FSH levels were negatively related to sperm concentration, NSM and sperm motility. In a conclusion, although age and obesity have significant impacts on reproductive hormones such as testosterone, SHBG and oestradiol, semen parameters related to FSH and LH could not be influenced, indicating that obesity‐associated markers could not predict male semen quality.  相似文献   
992.
封郭生  罗攀  陈江伟  朱莉  甘露 《骨科》2015,34(4):448-451
目的观察注射用华蟾素对大鼠心率及心电图的影响,为该药在临床应用时监控心脏的不良反应提供实验依据。 方法大鼠经颈外静脉插管后恒速蠕动泵给药,标准肢体Ⅱ导联监测大鼠的心率及心电图;比较给药前后心率及心电图的变化。 结果静脉注射华蟾素注射液与注射用华蟾素中、大剂量30 min后均可使大鼠心率加快,分别为:(469±40),(466±29) 和(484±40)次·min-1,与空白对照组[(411±17)次·min-1]比较,差异有统计学意义(P<0.05),但随后恢复正常。少数大鼠可偶致心律失常(期前收缩、传导阻滞等),且相比于空白对照组[P-R间期:(46.90±3.90) ms,Q-T间期:(61.29±9.46) ms],给药后能明显缩短心电图的P-R间期[华蟾素注射液组(39.70±2.54) ms,注射用华蟾素中剂量组(37.70±3.77) ms,注射用华蟾素大剂量组(39.30±7.12) ms]和Q-T间期[注射用华蟾素中剂量组(55.13±4.67) ms,注射用华蟾素大剂量组(51.75±11.53) ms](P<0.05),而对QRS与S-T段无明显改变。 结论注射用华蟾素对大鼠心脏有一定的毒副作用,可引起心率加快,偶发心律失常。  相似文献   
993.
目的探讨术前新辅助化疗结合肠内营养对胃癌患者肿瘤细胞增殖活性的影响效果。 方法将2012年7月至2014年7月收治的132例进展期胃癌患者,随机分为观察组(术前新辅助化疗联合肠内营养)和对照组(单纯予以新辅助化疗),各66例,采用流式细胞仪检测两组患者肿瘤标本的细胞增殖情况,通过CD4、CD8、CD4/CD8、NK细胞的检测评价两组患者的免疫功能,检测血清学指标以及营养风险筛查(NRS评分)进行营养评价。 结果治疗前,两组患者的肿瘤细胞增殖活性、免疫指标、营养状况均差异无统计学意义。治疗后,观察组患者的CD4、CD4/CD8、NK、总蛋白、白蛋白、前白蛋白、转铁蛋白、血红蛋白均较对照组增加明显,DI、SPF、PI、CD8、NRS评分降低明显,差异有统计学意义(P<0.05)。 结论术前新辅助化疗结合肠内营养可较好地降低肿瘤细胞的增殖活性,改善其免疫水平及营养状况。  相似文献   
994.
IntroductionLiver transplantation is the standard treatment for end-stage liver disease. Brazil holds the third highest number of liver transplants performed per year, but center maldistribution results in high discrepancies in accessing this treatment. In 2012, an interstate partnership successfully implemented a new liver transplantation program in the middle west of Brazil. Here, we report the results of the first 500 liver transplants performed in this new program and discuss the impacts of a new transplant center in regional transplantation dynamics.MethodsWe reviewed data from the first 500 consecutive deceased donor liver transplants performed in the new program during an 8-year period. We analyzed data on patients’ clinical and demographic profiles, postoperative outcomes, and graft and recipient survival rates. Univariate survival analysis was conducted using log-rank tests to compare the groups.ResultsAlmost half (48%) of the procured organs and 40% of the recipients transplanted in our center were from outside our state. Recipient 30-day mortality was 9%. Overall recipient survival at 1 year and 5 years was 85% and 80%, respectively. Mortality was significantly associated with higher Model for End-Stage Liver Disease (P < .001) but not with the presence of hepatocellular carcinoma (P = .795).DiscussionThe new transplantation program treated patients from different regions of Brazil and became the reference center in liver transplantation for the middle west region. Despite the recent implementation, our outcomes are comparable to experienced centers around the world. This model can inspire the creation of new transplantation programs aiming to democratize access to liver transplantation nationwide.  相似文献   
995.
996.
BackgroundAn allergic reaction may rarely cause a painful or stiff total knee arthroplasty (TKA). However, no consensus diagnostic criteria for TKA immune failure exist. Lymphocyte transformation testing (LTT) measures immune sensitivity to various materials, but its role in diagnosing an allergic reaction to a TKA has not been established. This study compares TKA periprosthetic tissues in a) LTT-positive versus -negative patients and b) patients with conventional CoCrNi versus hypoallergenic implants.MethodsPeriprosthetic tissues from 26 revision cases of well-fixed, aseptic, but painful or stiff TKAs were analyzed. Twelve patients LTT positive for nickel (Ni) were matched as a cohort to 6 LTT-negative patients. In 4 patients LTT positive for Ni, tissue from first revision of CoCrNi implants was compared with tissue from subsequent revision of hypoallergenic implants. Histology was evaluated using the aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL) score.ResultsNo correlation was found between LTT and any ALVAL score component. The mean total ALVAL score was 3.8 ± 1.5 for LTT-negative patients and 3.3 ± 1.2 for LTT-positive patients (P = .44). The mean total ALVAL score at revision of CoCrNi implants was 3.0 ± 1.8 compared with 5.8 ± 0.5 at rerevision of hypoallergenic implants (P = .053).ConclusionPeriprosthetic TKA tissue reactions were indistinguishable between LTT-positive and -negative patients. LTT does not predict the periprosthetic tissue response. ALVAL scores of hypoallergenic revision implant tissue trended higher than primary CoCrNi implant tissue. A positive LTT may not indicate that a periprosthetic immune reaction is the cause of pain and stiffness after TKA.Level of Evidence3, retrospective cohort study.  相似文献   
997.
目的:探讨吲哚菁绿荧光导航在复杂腹腔镜胆囊切除术(LC)中的临床价值。方法:回顾性分析2018年7月—2020年8月在鄂东医疗集团黄石市中心医院肝胆胰腺外科收治的96例复杂胆囊结石伴胆囊炎患者行LC的临床资料,按照术前是否静脉注射吲哚菁绿荧光导航分为实验组( n=44)和对照组( n=52),实...  相似文献   
998.
目的:探讨奥沙利铂联合卡培他滨(CapeOX)或奥沙利铂联合替吉奥(SOX)新辅助化疗方案在局部进展期胃癌治疗中的安全性和有效性。方法:采用回顾性队列研究方法,收集2016年4月至2019年4月期间,于上海交通大学医学院附属瑞金医院予以新辅助化疗并接受标准腹腔镜下胃癌根治术的进展期胃癌患者的临床资料。病例纳入标准:(1...  相似文献   
999.
Mammalian skin is composed of three layers, the epidermis, the dermis, and the subcutis, which is composed primarily of adipose tissue. The dermal and adipose tissues are involved simultaneously when partial and full‐thickness burns occur, and often induce scar formation. However, little is known about the role of the dermis and adipose tissue injury in scar formation or the difference in fibrogenesis between the two tissues. In this study with female red Duroc pigs, we created flaps of skin with a dermal plane of injury or deeper flaps with an adipose plane of injury on the back. We compared the extent of fibrogenesis by observing the deposition of extracellular matrix as well as the characteristics of cells in the injured area. In skin flaps with a dermal level of tissue injury, scar formation that was characterized by more extracellular matrix deposition and less apoptotic myofibroblasts in the injured area was observed. Our results suggest that scar formation does not correlate with injury at the level of the adipose tissue, and that adipose tissue might serve to alleviate fibrogenesis.  相似文献   
1000.
目的 观察叙事护理缓解晚期癌症患者主要照顾者预期性悲伤的效果.方法 采用便利抽样法抽取晚期癌症患者主要照顾者60人,随机分为干预组和对照组各30人.对照组进行常规心理护理,干预组在此基础上进行叙事护理干预,干预前后应用预期性悲伤调查问卷评价主要照顾者的预期性悲伤水平.结果 干预后干预组预期性悲伤总分及内疚、悲伤、焦虑3...  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