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   61898篇
  免费   6158篇
  国内免费   2499篇
耳鼻咽喉   130篇
儿科学   560篇
妇产科学   223篇
基础医学   2500篇
口腔科学   412篇
临床医学   5321篇
内科学   7004篇
皮肤病学   1067篇
神经病学   2131篇
特种医学   617篇
外国民族医学   7篇
外科学   1821篇
综合类   8065篇
现状与发展   5篇
一般理论   3篇
预防医学   3758篇
眼科学   655篇
药学   29515篇
  29篇
中国医学   3022篇
肿瘤学   3710篇
  2024年   231篇
  2023年   1042篇
  2022年   1627篇
  2021年   2237篇
  2020年   2290篇
  2019年   2273篇
  2018年   2324篇
  2017年   2554篇
  2016年   2371篇
  2015年   2383篇
  2014年   4048篇
  2013年   6794篇
  2012年   4145篇
  2011年   4233篇
  2010年   3413篇
  2009年   3022篇
  2008年   2827篇
  2007年   2868篇
  2006年   2570篇
  2005年   2322篇
  2004年   1982篇
  2003年   1800篇
  2002年   1375篇
  2001年   1324篇
  2000年   1019篇
  1999年   867篇
  1998年   772篇
  1997年   726篇
  1996年   587篇
  1995年   550篇
  1994年   476篇
  1993年   397篇
  1992年   458篇
  1991年   380篇
  1990年   302篇
  1989年   243篇
  1988年   247篇
  1987年   237篇
  1986年   182篇
  1985年   196篇
  1984年   160篇
  1983年   122篇
  1982年   106篇
  1981年   85篇
  1980年   56篇
  1979年   57篇
  1978年   68篇
  1977年   48篇
  1976年   47篇
  1975年   48篇
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
41.
通过动物痛行为反应(缩足反射)确定局部和鞘内应用川芎嗪(TMP)对ATP等P2X受体激动剂所致大鼠足底急性伤害性行为反应的影响。P2X3受体拮抗剂TNP-ATP(0.3μmol/L)明显抑制P2X受体激动剂ATP(1μmol/L)或α,β-meATP(0.6μmol/L)引起的大鼠足底急性伤害性反应。大鼠足底局部应用TMP(0.1-10mmol/L)剂量依赖性地对ATP(1μmol/L)或α,β-meATP(0.6μmol/L)引起的伤害性反应具有抑制作用。鞘内应用TMP(50mmol/L)对ATP(1μmol/L)或α,β-meATP(0.6μmol/L)引起的伤害性反应具有抑制作用。结果表明,TMP可通过阻断P2X3受体介导的伤害性兴奋传入抑制P2X受体激动剂引起的大鼠足底急性伤害性反应。  相似文献   
42.
In mycophenolate mofetil (MMF)-treated organ transplant recipients, lower mycophenolic acid (MPA) plasma concentrations have been found in cyclosporine (CsA) compared with tacrolimus (Tac)-based immunosuppressive regimens. We previously demonstrated that CsA decreases exposure to MPA and increases exposure to its metabolite MPA-glucuronide (MPAG), possibly by interfering with the biliary excretion of MPAG. To elucidate the role of the multidrug resistance-associated protein (Mrp)-2 in the interaction between MMF and CsA, we treated three groups of 10 Mrp2-deficient rats (TR- rat) for 6 days with either vehicle, CsA (8 mg/kg) or Tac (4 mg/kg) by oral gavage. Hereafter, co-administration with MMF (20 mg/kg) was started in all groups and continued through day 14. The 24-h MPA/MPAG area under the concentration-time curve (AUC) was determined after single (day 7) and multiple MMF doses (day 14). On both study days, there were no significant differences in the mean MPA and MPAG AUC between CsA and Tac-treated animals. We conclude that the pharmacokinetics of MMF are comparable in Mrp2-deficient rats receiving either CsA or Tac as co-medication. This finding suggests that CsA-mediated inhibition of the biliary excretion of MPAG by the Mrp2 transporter is the mechanism responsible for the interaction between CsA and MMF.  相似文献   
43.
目的:了解新生儿脐部感染细菌学状况,为临床提供预防及治疗参考。方法:调查我院1997年1月-2002年6月收治的有完善细菌学资料的新生儿脐炎85例,对所获得的98例致病菌的种类及药敏状况进行分析。结果:社会获得性感染主要致病菌为G^ 球菌(70.5%),金黄色葡萄球菌占比例较高。医院感染主要致病菌为C^-杆菌(51.4%),以大肠埃希菌占比例较高。两类感染所分离的细菌均具有多重耐药性,但对氨基糖苷类及喹诺酮类耐药率较低,其次是第三代头孢菌素类抗生素。结论:临床对新生儿脐部感染,特别是有严重感染中毒症状时,应首先考虑使用第三代头孢菌素类抗生素。  相似文献   
44.
Summary Based on the gate-related receptor hypothesis, an analysis of kinetics of AN-132, a new antiarrhythmic agent, blockade of cardiac sodium channels and the gate-related receptor which is bound by the drug was performed by computer simulation. Model-predicted apparent rates of onset of AN-132 (30 μmol/L) blocking were 0.051, 0.038, and 0.034 AF−1 at stimulation frequencies of 1.0, 2.0 and 3.0 Hz, respectively. The time constant of recovery from block by AN-132 at resting potential -90 mV was 39.5 s. These findings are in agreement with those experimental data documented. The analysis of gate-related receptor shows that AN-132 binds the inactivation gate-related receptor, and the binding and unbinding are modulated by the inactivation process.  相似文献   
45.
Effects of daily administrations of d-amphetamine were studied on key peck responses of pigeons maintained under a multiple fixed-interval 2-min, fixed-ratio 30-responseschedule. Under the fixed-interval schedule, a pause was followed by a transition to increasing rates of responding until food presentation. Under the fixed-ratio schedule, higher sustained rates of responding were maintained. Low to intermediate doses (0.3-1.0 mg/kg) of d-amphetamine changed the temporal patterns and occasionally increased rates of responding under the fixed-interval schedule. Higher doses decreased rates of responding under bothschedules. With daily injections of 1.0 mg/kg d-amphetamine prior to experimental sessions, the effects of this dose on rates and patterns of responding were attenuated, and d-anphetamine dose-effect curves were shifted to the right, primarily under the fixed-ratio schedule. Similar results were obtained with daily presession injections of 5.6 mg/kg d-amphetamine in a second group of pigeons, except that rates of responding under both schedules were decreased by this daily dose, and did not return completely to control values with repeated injections. In a third group of pigeons, 1.0 mg/kg d-amphetamine administered daily, after experimental sessions, did not alter dose-effect functions for d-amphetamine. In a second experiment, pigeons were trained to peck one response key when given 1.0 mg/kg d-amphetamine and a different key when given presession water injections. Increasing doses of d-amphetamine produced incresing percentages of d-amphetamine-key responses. Repeated administration of 5.6 mg/kg d-amphetamine shifted these dose-effect functions to the right one-half log unit. Results suggested that decreases in reinforcement frequency are not a necessary condition for the development of behavioral tolerance to d-amphetamine.  相似文献   
46.
应用0.5%环孢霉素A(cyclosporin A,CsA)滴眼治疗穿透性角膜移植术后发生免疫排斥患者16例(16只眼),治愈9只眼,好转6只眼,无效1只眼。随访5~24个月,其中2只眼因停药复发,1只眼于拆线后复发,继续用药或增加给药次数后治愈。研究表明0.5%CsA滴眼剂治疗术前移植床条件较好,角膜移植术后发生免疫排斥的病例可得到良好疗效;而对术前移植床条件较差,角膜移植术后发生免疫排斥的病例有一定的疗效。作者对眼局部应用CsA治疗角膜移植排斥的疗效和作用机理进行了讨论。  相似文献   
47.
Abstract. Objectives. To define risk factors associated with bacteraemia caused by Staphylococcus aureus or coagulase-negative staphylococci; and to use them to define patients in need of empiric anti-staphylococcal antibiotic treatment. Design, Derivation set: observational, prospective study; validation set: retrospective analysis of a prospectively collected database. Setting. Derivation set: Beilinson Medical Centre, Petah Tiqva, Israel—a 900-bed university hospital. Validation set: St Thomas's Hospital, London, UK—an 800-bed teaching hospital. Subjects. All episodes of bacteraemia detected at Beilinson Medical Centre between March 1988 and September 1990 (derivation set, n = 1410), and at St Thomas's Hospital during 1987–1990 (validation set, n = 1040). Interventions. None. Main outcome measures. Percentage of staphylococcal bacteraemia in groups of patients defined by the models. Results. The following factors were associated with Staphylococcus aureus bacteraemia: focus of infection (whether high or low risk), haemodialysis, intravenous drug abuse and infection acquired in the orthopaedic ward. A logistic model was used to divide the derivation set into three groups with percentages of Staphylococcus aureus bacteraemia of 1.8%, 13.2% and 33.7% (P < 0.0001); and the validation group 2.5%, 18.2% and 53.2% (P < 0.0001). Factors associated with coagulase-negative staphylococcal bacteraemia were: central or peripheral intravenous catheter as the focus of infection, a preterm neonate, the presence of a central intravenous catheter, low temperature, and a low white blood cell count. A second model including those factors was used to divide the derivation set into three groups with percentages of coagulase-negative staphylococcal bacteraemia of 1.9%, 22.8%, and 43% (P < 0.0001). In the validation set, the percentages were 2.9%, 22.4% and 31.0% (P < 0.001). Conclusions. The present study defines groups at high risk for staphylococcal bloodstream infection, in which empiric treatment should include an anti-staphylococcal drug.  相似文献   
48.
A型肉毒杆菌毒素治疗麻痹性斜视   总被引:2,自引:0,他引:2  
采用眼外肌注射A型肉毒杆菌毒素的方法,治疗17例(18只眼)麻痹性内斜视患者。最大的肌肉麻痹作用发生于注射后7~14天,最大斜视矫正度为50-,随访时间为4~20周,5例最终获得双眼视。未见全身副作用。认为,这种疗法可在部分患卉中替代斜视矫正术。  相似文献   
49.
50.
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