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   70543篇
  免费   6788篇
  国内免费   2792篇
耳鼻咽喉   159篇
儿科学   718篇
妇产科学   310篇
基础医学   3114篇
口腔科学   527篇
临床医学   5949篇
内科学   7731篇
皮肤病学   1200篇
神经病学   2345篇
特种医学   905篇
外国民族医学   8篇
外科学   2457篇
综合类   9161篇
现状与发展   5篇
一般理论   3篇
预防医学   4588篇
眼科学   718篇
药学   32776篇
  29篇
中国医学   3575篇
肿瘤学   3845篇
  2024年   245篇
  2023年   1146篇
  2022年   1803篇
  2021年   2481篇
  2020年   2492篇
  2019年   2484篇
  2018年   2572篇
  2017年   2795篇
  2016年   2602篇
  2015年   2575篇
  2014年   4504篇
  2013年   7336篇
  2012年   4670篇
  2011年   4855篇
  2010年   3912篇
  2009年   3411篇
  2008年   3273篇
  2007年   3328篇
  2006年   2945篇
  2005年   2674篇
  2004年   2316篇
  2003年   2082篇
  2002年   1585篇
  2001年   1495篇
  2000年   1219篇
  1999年   1020篇
  1998年   880篇
  1997年   870篇
  1996年   693篇
  1995年   670篇
  1994年   569篇
  1993年   489篇
  1992年   551篇
  1991年   458篇
  1990年   396篇
  1989年   303篇
  1988年   319篇
  1987年   283篇
  1986年   234篇
  1985年   256篇
  1984年   224篇
  1983年   161篇
  1982年   165篇
  1981年   134篇
  1980年   101篇
  1979年   111篇
  1978年   91篇
  1977年   91篇
  1976年   73篇
  1975年   70篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
目的改善心脑血管缺氧载氧药物是一种创新药物。由于它半径比红细胞小400~1 000倍,易于通过毛细血管,给缺血组织及时供氧,迅速缓解或纠正缺氧状态,达到治疗抢救目的。血红蛋白的纯化工艺是载氧药物研制的重要工艺步骤。方法本研究建立了一套通过热敏法分离纯化人脐带血血红蛋白的工艺以及较为完善的纯化血红蛋白质量检测指标。结果与现有的纯化方式相比,热敏法操作简便,仪器设备造价低廉,纯化与病毒灭活同时进行,得到的纯化产品损失少,纯度高,各项理化指标达到国际水平。结论本工艺适用于规模制备纯化血红蛋白,为进一步研制治疗心脑血管缺氧载氧药物创造了有利条件。  相似文献   
62.
三联药物治疗未破裂异位妊娠的临床研究   总被引:1,自引:1,他引:0  
目的 :观察甲氨蝶呤(Methotrexate,MTX)、米非司酮(Mifepristron,Ru486)及中药三联用药治疗未破裂型异位妊娠的临床疗效。方法 :对171例未破裂型异位妊娠病人 ,按药物治疗方法不同分为两组进行对照研究 :A组使用MTX注射 +Ru486口服 +中药联合治疗。B组单独使用MTX注射治疗。测定法定期测定两组病人血HCG值以监测血HCG下降情况 ,测量异位妊娠包块三径线值以监测病灶包块缩小情况 ,同时观察临床症状持续时间、副反应发生率及总有效率。结果 :血HCG下降及病灶包块缩小A组较B组明显 ,差异有显著性(p<0 05,p<0 01);临床症状持续时间A组较B组短 ,差异有显著性(p<0 05);副反应发生率两组间无显著差异(p>0 05);A、B两组的总有效率分别为 :95 74%和71 43% ,A组较B组高 ,差异有显著性(p<0 05)。结论 :三联使用甲氨蝶呤、米非司酮及活血化瘀消包块杀胚的中药既有很强的杀胚功能 ,又能消除病灶包块 ,保留生育功能。三联药物联合治疗未破裂异位妊娠具有疗效肯定、安全  相似文献   
63.
64.
腺性膀胱炎三种治疗方法治疗效果的随访观察   总被引:2,自引:0,他引:2  
目的 比较腺性膀胱炎三种治疗方法的效果。方法  86例腺性膀胱炎患者分别行膀胱药物灌注、经尿道电切、经尿道电切加膀胱药物灌注治疗。随访观察症状缓解程度和膀胱镜病检结果 1年。结果  73例完成了随访调查 ,占 84.9%。三种方法治疗后症状缓解程度 ,差异无显著性意义 (P >0 .0 5 ) ;膀胱镜病检复查 ,灌注治疗效果好于电切治疗效果 ,综合治疗效果好于电切治疗效果 ,差异具有显著性意义 ;比较灌注治疗后膀胱镜病检阴性例数 ( 2 2 /2 8)与综合治疗后膀胱镜病检阴性例数 ( 3 0 /3 4) ,差异无显著性意义 ( χ2 =1.0 60 ,P =0 .3 0 3 )。结论 膀胱药物灌注和经尿道电切加膀胱药物灌注的膀胱镜病检复查 ,效果好于电切治疗的效果。  相似文献   
65.
BACKGROUND: Sodium removal (NaR) may have a major impact on the survival of peritoneal dialysis patients. The dialysate/plasma sodium concentration ratio (D/P(Na)) is an indirect index of transcellular water transport by aquaporin channels, and thus of ultrafiltration. Sodium concentration can be assessed by means of flame photometry (F), and direct (D-ISE) or indirect ion-selective electrodes (I-ISE), but these methods have different properties. I-ISE is being used increasingly in clinical laboratories. The aim of this study was to evaluate NaR and D/P(Na) using the three different measurement methods. METHODS: We performed peritoneal equilibration tests (PETs) in 44 peritoneal dialysis patients and calculated the NaR. We also calculated D/P(Na) during the test; plasma and dialysate sodium concentrations were measured by F, D-ISE and I-ISE. RESULTS: NaR was lower (P<0.001) with D-ISE (69+/-29 mmol) than with F (81+/-29 mmol) or I-ISE (79+/-28 mmol). D/P(Na) was also lower at baseline (0.92+/-0.02 vs 0.95+/-0.02 and 0.95+/-0.02; P<0.001), after 60 min (0.87+/-0.03 vs 0.90+/-0.03 and 0.90+/-0.03; P<0.001) and at the end of PET (0.88+/-0.04 vs 0.92+/-0.04 and 0.92+/-0.04; P<0.001) when measured by D-ISE in comparison with F and I-ISE, respectively. CONCLUSIONS: NaR and D/P(Na) were lower when measured by the D-ISE method compared with the F and I-ISE methods. NaR and D/P(Na) were similar when measured by F or I-ISE. I-ISE can be used reliably in the evaluation of NaR and D/P(Na) in everyday clinical practice of peritoneal dialysis.  相似文献   
66.
AIMS: To determine the morbidity, mortality and healthcare costs of intravenous drug-abusing patients with Type 1 diabetes (IVDA-DM), who are admitted to hospital. METHODS: Retrospective case note analysis of admissions, complications and cost estimation over a 6-year period. Each drug-abusing patient (IVDA-DM) (n = 9) was compared with two controls (n = 18) with Type 1 diabetes but without a history of intravenous drug abuse (DM-controls). Admissions were also analysed for patients with intravenous drug abuse, but without Type 1 diabetes (IVDA-controls) (n = 198). Admissions were at a University teaching hospital in Liverpool, UK. DM-controls were drawn from a population attending diabetes outpatient clinics between 1997 and 2002 at the same hospital. The main outcome measures were: the duration and healthcare costs of hospital admissions per year, outpatient attendances per year, glycated haemoglobin (HbA(1c)), weight, micro- and macrovascular complications and mortality. RESULTS: Multiple admissions, mainly related to ketoacidosis, led to marked differences in mean (95% CI) inpatient days per year per patient [IVDA-DM 28.1 (13.6-42.7) vs. DM-control 1.1 (0.2-1.9); P < 0.0001], mean inpatient days per year per patient in critical care bed (IVDA-DM 1.7 (-0.7-4.2) vs. DM-control 0; P < 0.02) and mean costs of admission, per patient per year (pound sterling 7320 vs. pound sterling 230). The IVDA-DM group frequently omitted insulin, were underweight, failed to attend as outpatients and five had died by the end of 2002. The IVDA-controls spent considerably less time in hospital [3.4 (2.8-3.9) days per patient per year]. CONCLUSION: IVDA-DM patients have higher rates of diabetes complications, are admitted more frequently and have a high mortality compared with DM and IVDA-controls. The cost of inpatient care of this small group of patients was considerable.  相似文献   
67.
Summary.  Previously we demonstrated that domain 5 (D5) of high-molecular-weight kininogen (HK) inhibits neovascularization in the chicken chorioallantoic membrane (CAM) assay and further found that kallikrein cleaved HK (HKa) inhibited FGF2-and VEGF-induced neovascularization, and thus was antiangiogenic. In this study, we sought to demonstrate whether uncleaved HK stimulates neovascularization and thus is proangiogenic. The chick chorioallantoic membrane was used as an in ovo assay of angiogenesis. Low-molecular-weight kininogen stimulates angiogenesis, indicating that D5 is not involved. Bradykinin stimulates neovascularization equally to HK and LK and is likely to be responsible for the effect of HK. A murine monoclonal antibody to HK (C11C1) also recognizes a similar component in chicken plasma as detected by surface plasmon resonance. Angiogenesis induced by FGF2 and VEGF is inhibited by this monoclonal antibody and is a more potent inhibitor of neovascularization induced by VEGF than an integrin αvβ3 antibody (LM 609). Our postulate that C11C1 inhibits the stimulation of angiogenesis by HK was confirmed when either C11C1 or D5 completely inhibited angiogenesis in the CAM induced by HK. Growth of human fibrosarcoma (HT-1080) on the CAM was inhibited by GST-D5 and C11C1. These results indicate HK is proangiogenic probably by releasing bradykinin and that a monoclonal antibody directed to HK could serve as an antiangiogenic agent with a potential for inhibiting tumor angiogenesis and other angiogenesis-mediated disorders.  相似文献   
68.
研究补肾抗衰口服液对大鼠衰老模型免疫器官胸腺和脾脏的影响.结果显示,模型组大鼠胸腺和脾脏重量减轻,胸腺重/体重比值、脾重/体重比值减小,胸腺组织学观察,显示萎缩改变;药物组大鼠胸腺和脾脏重量、胸腺重/体重、脾重/体重比值接近正常对照组,胸腺组织学观察,未显示萎缩改变.本研究结果表明,补肾抗衰口服液能延缓胸腺和脾脏萎缩,保护机体的正常免疫功能,提示该药有抗衰老的作用.  相似文献   
69.
Dysphoric Rumination Impairs Concentration on Academic Tasks   总被引:3,自引:0,他引:3  
Three studies investigated the effects of dysphoric rumination on concentration during 3 academic tasks—reading a passage from the GRE (Study 1), watching a videotaped lecture (Study 2), and proofreading written text (Study 3). Before performing these tasks, dysphoric and nondysphoric students were induced either to ruminate about themselves or to distract themselves by focusing on neutral images (all three studies) or by planning an event (Study 1). The results supported our hypothesis that dysphoric rumination, relative to distraction, would impair students' concentration. In all 3 studies, dysphoric ruminators reported difficulty concentrating, as well as interfering thoughts, during the relevant academic tasks. Furthermore, dysphoric ruminators were slower than dysphoric distractors in completing the tasks—specifically, reading the GRE passage (Study 1) and answering lecture comprehension questions (Study 2). In addition, dysphoric participants who ruminated showed impaired reading strategies (Study 1), reduced comprehension of academic material (Study 2), and poor proofreading performance (Study 3). These findings suggest that, in addition to its documented adverse effects on mood, thinking, and problem-solving, self-focused rumination interferes with instrumental behavior. Implications for social relationships and job performance are discussed.  相似文献   
70.
Buprenorphine was introduced as a potent analgesic with low abuse potential. Reports of buprenorphine abuse by opiate abusers have accumulated over the years, highlighting its use as a cheap alternative to heroin. The lower potency compared with heroin is being compensated by using a cocktail of buprenorphine with benzodiazepines or cyclizine. This study of 18 cases seen over 3 years broadly confirms these findings. Four cases reported haematemesis during acute withdrawal, a symptom not reported in earlier studies.  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