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   3702篇
  免费   374篇
  国内免费   44篇
耳鼻咽喉   18篇
儿科学   212篇
妇产科学   108篇
基础医学   179篇
口腔科学   165篇
临床医学   537篇
内科学   1097篇
皮肤病学   35篇
神经病学   118篇
特种医学   18篇
外科学   723篇
综合类   108篇
现状与发展   1篇
一般理论   1篇
预防医学   345篇
眼科学   40篇
药学   220篇
中国医学   12篇
肿瘤学   183篇
  2024年   11篇
  2023年   122篇
  2022年   82篇
  2021年   175篇
  2020年   172篇
  2019年   206篇
  2018年   216篇
  2017年   173篇
  2016年   174篇
  2015年   157篇
  2014年   202篇
  2013年   358篇
  2012年   162篇
  2011年   175篇
  2010年   141篇
  2009年   167篇
  2008年   141篇
  2007年   139篇
  2006年   135篇
  2005年   117篇
  2004年   99篇
  2003年   95篇
  2002年   79篇
  2001年   69篇
  2000年   50篇
  1999年   41篇
  1998年   41篇
  1997年   43篇
  1996年   29篇
  1995年   31篇
  1994年   29篇
  1993年   20篇
  1992年   29篇
  1991年   20篇
  1990年   21篇
  1989年   16篇
  1988年   22篇
  1987年   22篇
  1986年   21篇
  1985年   17篇
  1984年   23篇
  1983年   15篇
  1982年   5篇
  1981年   18篇
  1980年   7篇
  1979年   9篇
  1978年   8篇
  1977年   4篇
  1976年   6篇
  1973年   2篇
排序方式: 共有4120条查询结果,搜索用时 31 毫秒
21.
Oral valganciclovir is effective prophylaxis for cytomegalovirus (CMV) disease in adults receiving solid organ transplantation (SOT). However, data in pediatrics are limited. This study evaluated the pharmacokinetics and safety of valganciclovir oral solution or tablets in 63 pediatric SOT recipients at risk of CMV disease, including 17 recipients ≤2 years old. Patients received up to 100 days' valganciclovir prophylaxis; dosage was calculated using the algorithm: dose (mg) = 7 × body surface area × creatinine clearance (Schwartz method; CrCLS). Ganciclovir pharmacokinetics were described using a population pharmacokinetic approach. Safety endpoints were measured up to week 26. Mean estimated ganciclovir exposures showed no clear relationship to either body size or renal function, indicating that the dosing algorithm adequately accounted for both these variables. Mean ganciclovir exposures, across age groups and organ recipient groups were: kidney 51.8 ± 11.9 μg * h/mL; liver 61.7 ± 29.5 μg * h/mL; heart 58.0 ± 21.8 μg * h/mL. Treatment was well tolerated, with a safety profile similar to that in adults. Seven serious treatment-related adverse events (AEs) occurred in five patients. Two patients had CMV viremia during treatment but none experienced CMV disease. In conclusion, a valganciclovir-dosing algorithm that adjusted for body surface area and renal function provides ganciclovir exposures similar to those established as safe and effective in adults  相似文献   
22.
C. A. LEE 《Haemophilia》2007,13(S3):20-25
Summary.  It has been proven that early prophylactic therapy can prevent bleeding and arthropathy. Numerous retrospective non-randomized cohort studies have demonstrated that prophylaxis, if started early in life, is associated with a considerable reduction of the mean number of joint bleeds and the rate of joint deterioration. It is quite extraordinary that despite the considerable evidence base it has been considered necessary by investigators to pursue the ideal of the controlled randomized trial and expose children to the risk of cerebral bleed. This questionable ethical approach is driven by the reluctance of the 'willingness to pay' but it is important that patients are not subjected to unnecessary investigation at either the behest of the Cochrane Database or those who control the financing of haemophilia care.  相似文献   
23.
Objective: Routine malaria prophylaxis with chloroquine (CQ) is recommended to pregnant semi-immune women in several countries in Africa. The dosage is empirically based. We investigated whether blood CQ concentrations and apparent oral blood clearance (CL/F) change during the course of pregnancy. We also studied whether malaria parasites could be detected together with low CQ blood levels. Methods: Forty nine semi-immune Tanzanian women were recruited in the 16th week of pregnancy. They were given 310 mg oral CQ base once per week as prophylaxis during the whole pregnancy. Capillary blood samples were taken for analysis of CQ before treatment and at weeks 26 and 36. Blood samples were dried on filter paper and analysed by HPLC. Blood was also drawn to detect occurrence of malaria parasites. Results: A total of 25 women fulfilled the sampling schedule. CL/F increased significantly from 160 ml ·  min−1 at week 26 to 180 ml · min−1 at week 36. In 7 of 25 women, CL/F increased >20%. Trough blood CQ concentrations, determined on four occasions at week 26 and at week 36 varied between 200 and 900 nmol · l−1. No statistically significant differences between occasions were seen. Malaria parasites were seen in two individuals early in pregnancy. Conclusion: Blood CQ CL/F showed a small increase during the course of pregnancy. The estimated mean blood CL/F values of 160 and 180 ml · min−1 (week 26 and 36, respectively) were higher than the mean CL/F of 125 ml · min−1 in non-pregnant individuals, published previously. Efficacy of higher dosages of CQ in malaria prophylaxis in pregnant women could, therefore, be evaluated in controlled trials in high-risk malaria areas. Received: 3 July 1996 / Accepted in revised form: 5 November 1996  相似文献   
24.
25.
利多卡因对兔内毒素性急性肺损伤的预防作用   总被引:1,自引:0,他引:1  
目的 研究利多卡因对兔内毒素性急性肺损伤的预防作用。方法 雄性健康新西兰兔 2 4只 ,分 3组 :空白组 (S -S ,输注生理盐水 ) ,内毒素组 (L -S ,输注内毒素后输注生理盐水 ) ,预防组 (Ld2 -L ,输注内毒素前 10min输注利多卡因负荷量 2mg·kg- 1 ,然后 2mg·kg- 1 ·h- 1 ) ,控制呼吸 ,吸氧浓度 95 % ,输注内毒素后 6h杀兔。观察氧合指数 (PaO2 FiO2 )、肺动态顺应性 (Cdyn)、支气管肺泡灌洗液 (BALF)白蛋白含量、肺湿 干重比值、肺组织超氧化物歧化酶 (SOD)、丙二醛 (MDA)和髓过氧化物酶 (MPO)以及肺形态学变化。结果 内毒素组PaO2 FiO2 、Cdyn 和肺组织SOD活性明显下降 ;BALF白蛋白含量、肺湿 干重比值和肺组织MDA和MPO含量明显上升 ;肺泡结构严重毁坏 ,肺泡间隔增宽 ,大量炎症细胞浸润。利多卡因预防可明显减轻这些变化。结论 利多卡因对兔内毒素性急性肺损伤有明显的预防作用  相似文献   
26.
Polypeptide micelles with relative molecular weights of 25,000 (p25) and 30,000 (gp30) daltons were prepared from native 22-nm hepatitis B surface antigen (HBsAg) particles. This p25/gp30 complex was alum-adsorbed, and three dosage levels (20 micrograms, 4 micrograms, and 0.8 micrograms) were administered at 0, 1, and 6 months to 51 human volunteers. Local and systemic reactions were clinically insignificant, and all vaccinees seroconverted, regardless of dose. As anticipated, antibody responses diminished as the dosage was reduced. Seroconversion rates and geometric mean antibody levels for the 20 micrograms dosage group were significantly better than those observed with a commercial vaccine and were comparable to those achieved after immunization with 40 micrograms of the intact 22-nm particles used to prepare the polypeptides. By 2 weeks, an anti-HBs response was elicited in 80% of the group receiving 20 micrograms of the polypeptide vaccine. This rapid response to immunization may be particularly beneficial for postexposure prophylaxis where the early development of immunity is advantageous.  相似文献   
27.
目的探讨抗生素不同用药方案对乳癌术后手术部位感染的预防效果和成本的影响。方法506例乳腺癌改良根治手术患者随机分为观察组(n=253)和对照组(n=253)。观察组术前半小时静脉滴注头孢曲松2.0g;对照组术后3d每天静脉滴注头孢曲松2.0g。观察和记录术后患者手术部位感染情况并计算感染有关的医疗成本。结果术后感染发生率观察组和对照组分别为1.19%(3/252)和1.58%(4/253),其中手术部位感染共6例(1.19%),观察组和对照组各3例(1.19%),差异无统计学意义(P>0.05);对照组呼吸道感染1例。预防和治疗术后感染的直接医疗费用观察组为(163±78)元,对照组为(388±134)元,差异有统计学意义(P<0.05)。结论成本-效果分析表明,术前单次头孢曲松在预防手术部位感染方面与对照组等效,且医疗费用显著降低,具有更高的性价比。  相似文献   
28.
Phenotypically, ganciclovir-resistant human cytomegalovirus strains could be selected by aciclovir as effectively as by ganciclovir in vitro. Three clinical human cytomegalovirus isolates with different sensitivities against ganciclovir, aciclovir, foscarnet, and cidofovir, but without any mutation in the viral UL97 protein known to confer ganciclovir resistance, were propagated each in duplicate in the presence of ganciclovir or aciclovir. After drug selection, all 12 strains were less susceptible to ganciclovir (increase of 50% focus reduction dose between 2.1- and 31.5-fold) but were still sensitive to foscarnet and cidofovir; 7/12 exhibited a ganciclovir-resistant phenotype with a 50% focus reduction dose >30 microM, and in 6 out of these typical mutations in the UL97 coding region could be found by genotyping. All four strains selected from one isolate carried the identical UL97 mutation at amino acid position 460 (methionine to valine). The decreased sensitivity to ganciclovir and aciclovir in the other strains could neither be attributed to known UL97 mutations nor to mutations in the viral polymerase (UL54), which have been reported to induce resistance.  相似文献   
29.

Background

Group B Streptococcus (GBS) infection is one of the major causes of neonatal morbidity and mortality. Universal GBS screening with intrapartum antibiotic prophylaxis (IAP) in pregnant women were initiated in 2012 in Taiwan. This study aimed to analyze the most recent maternal GBS colonization rate and the changes in neonatal GBS infection rate from 2011 to 2016.

Methods

All pregnant women and their live born neonates between January 2011 and June 2016 were retrospectively reviewed. Whether GBS screening was done, screening results, presence of risk factors, the use of antibiotics, and neonatal outcome were analyzed. In addition, hospitalized neonates diagnosed with GBS infections were retrieved for comparison of early onset disease (EOD) (<7 days) and late onset disease (LOD) (≥7 days).

Results

A total of 9535 women delivered babies during the study period. The maternal GBS screening rate was 71.0% and the colonization rate was 22.6%. The overall neonatal invasive GBS infection rate was 0.81 per 1000 live births and the vertical transmission rate was 1.2%. After 2012, the invasive neonatal GBS infection rate declined from 1.1–1.6‰ to 0.6–0.7‰ in 2014 and thereafter, the GBS EOD incidence rate declined from 2.8‰ to 0.0–0.6‰, but the LOD incidence rate remained approximately 0.7‰. Infants with EOD had strong association with obstetric risk factors.

Conclusions

Taiwan's universal GBS screening with IAP program reduced the incidence rate of neonatal GBS EOD to be lower than 1‰ after 2012. Pediatricians still should pay attention to infants with GBS LOD since its incidence rate remained unchanged.  相似文献   
30.
Zusammenfassung Eine perioperative antibiotische Kurzprophylaxe mit 2 g Cefamandol intravenös bei Narkoseeinleitung wurde bei 12 Patienten während coronarchirurgischer Eingriffe unter Verwendung der Herz-Lungen-Maschine durchgeführt. Bei Beginn der extrakorporalen Zirkulation (= EKZ) kam es infolge Hämodilution zu einem Absinken der Serumkonzentrationen von 110,96 ± 40,29 mcg/ml auf 70,89 ± 34,65 g/ml innerhalb von 10 min. Im weiteren Verlauf der EKZ war der Abfall der Serumspiegel gleich schnell wie davor und danach. Nach 240 min fanden sich noch Serumspiegel von 16,80 ± 9,32 g/ml. Als Ursache für das Versagen einer antibiotischen Prophylaxe kommt bei einer Operationsdauer von mehr als 4 h das Absinken der Serumspiegel unter die minimale Hemmkonzentration der entsprechenden Keime in Frage.
Perioperative cefamandole prophylaxis in aortocoronary bypass operations: Course of serum concentration during extracorporeal circulation
Summary Antibiotic prophylaxis with 2 g Cefamandole at induction of anaesthesia was performed in 12 male patients undergoing aortocoronary bypass surgery. Caused by hemodilution, there was a marked decrease of serum concentration at the beginning of extracorporeal circulation, from 110.96 ± 40.29 mcg/ml to 70.89 ± 34.65 mcg/ml within 10 min. During extracorporeal circulation, elimination was as fast as before and after perfusion. 240 min after application, mean serum concentrations of 16.80 ± 9.32 mcg/ml were measured. Failure of antibiotic prophylaxis in operations exceeding 4 h might be due to unadaequate antibiotic concentrations, beyond the minimal inhibitory concentration for the pathogens, reported to cause infections after cardiac operations.
  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