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   12264篇
  免费   1642篇
  国内免费   569篇
耳鼻咽喉   10篇
儿科学   163篇
妇产科学   49篇
基础医学   183篇
口腔科学   26篇
临床医学   798篇
内科学   628篇
皮肤病学   29篇
神经病学   158篇
特种医学   128篇
外科学   511篇
综合类   899篇
预防医学   67篇
眼科学   53篇
药学   9018篇
  1篇
中国医学   1345篇
肿瘤学   409篇
  2023年   107篇
  2022年   127篇
  2021年   203篇
  2020年   290篇
  2019年   382篇
  2018年   387篇
  2017年   347篇
  2016年   373篇
  2015年   337篇
  2014年   441篇
  2013年   1014篇
  2012年   623篇
  2011年   621篇
  2010年   424篇
  2009年   510篇
  2008年   559篇
  2007年   612篇
  2006年   617篇
  2005年   610篇
  2004年   496篇
  2003年   415篇
  2002年   340篇
  2001年   344篇
  2000年   312篇
  1999年   311篇
  1998年   304篇
  1997年   297篇
  1996年   292篇
  1995年   261篇
  1994年   207篇
  1993年   220篇
  1992年   211篇
  1991年   178篇
  1990年   193篇
  1989年   156篇
  1988年   159篇
  1987年   160篇
  1986年   158篇
  1985年   112篇
  1984年   124篇
  1983年   47篇
  1982年   98篇
  1981年   97篇
  1980年   79篇
  1979年   69篇
  1978年   58篇
  1977年   47篇
  1976年   36篇
  1975年   36篇
  1974年   23篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
口服二巯基丁二酸治疗狗路易氏剂中毒   总被引:1,自引:1,他引:0  
为证实口服二巯基丁二酸(DMSA)治疗路易氏剂中毒的效价,以狗为实验动物,进行实验治疗研究,狗口服DMSA(40~120mg/kg)后,2周内未见到有关的生理,生化指标明显变化,该药毒性较小。DMSA可在肠道内较好地被吸收,与静脉注射途径比较,口服组血药浓度上升慢,下降亦慢,可在体内维持较长时间,DMSA在体内促排砷的作用与静脉注射同剂量DMSA(钠盐)相当。狗口服DMSA40mg/kg可对抗路易  相似文献   
72.
The primary objectives of this study were to determine the maximum tolerated dose (MTD) of paclitaxel administered by 3-h infusion to patients with solid tumors, and to characterize the pharmacokinetics of a 3-h infusion in comparison with those of a 24-h infusion. Twenty-seven patients each received one of six levels of paclitaxel, 105, 135, 180, 210, 240 and 270 mg/m2, with premedication. Two patients given 240 mg/m2 and one patient given 270 mg/m2 unexpectedly had grade 3/4 hypotension just after finishing the paclitaxel infusion. Peripheral neuropathy was also dose-limiting at 270 mg/m2. Although granulocytopenia was significantly less severe than with a 24-h infusion, more than half of the patients experienced grade 4 toxicity at doses of 240 or 270 mg/m2. Severe hypersensitivity reactions (HSRs) were not observed. Pharmacokinetic studies using high performance liquid chromatography demonstrated proportionally greater increases in the peak plasma concentration and area under the curve, and decreases in clearance and volume of distribution with increasing dose, suggesting non-linear pharmacokinetics of paclitaxel when given by 3-h infusion. The MTD of paclitaxel given as a 3-h infusion was determined to be 240 mg/m2 with dose-limiting toxicities of granulocytopenia, peripheral neuropathy and hypotension. Hypotension just after infusion, induced by 3-h infusion of paclitaxel, is a new observation which has not been reported previously. The recommended dose for phase II study is 210 mg/m2. Although hypotension was observed as an unexpected toxic effect, paclitaxel could be administered safely over 3 h with premedication and proper monitoring, resulting in reduced myelotoxicity and with no increase in the incidence of HSRs as compared with a 24-h infusion.  相似文献   
73.
本文以血清尿素氮及体重做为毒性评价指标,高渗盐水减低了顺铂的毒性。小鼠静注15mg/kg顺铂后,血浆总铂的药物动力学呈三室模型。高渗盐水缩短了血浆总铂的α相半衰期,提高了给药后各时间点血浆超滤铂的浓度,降低了肾脏内给药后2h内的铂浓度,没有明显改变肿瘤内铂浓度的药时曲线下面积。实验表明,高渗盐水提高了顺铂的治疗指数。  相似文献   
74.
PharmacokineticsofintravenouslyadministeredsodiumdichloroacetateinrabbitsGuBin(顾斌);SongLing(宋岭);JiangYongpei(蒋永培);WenAidong(文...  相似文献   
75.
人体中氧氟沙星的立体选择性代谢   总被引:2,自引:1,他引:1  
5名健康志愿者日服单剂300mg氧氟沙星[(±)-Of1]后,采用立体选择性的RP-HPLC手性流动相添加剂法测定尿中S-(-)-Of1和R-(+)-Of1浓度结果显示Of1在人体内呈现立体选择性代谢。尿中排泄的S-(-)-Of1/R-(+)-Of1之比随时间变化。服药后2hS/R是0.875,24h增加到1.150.S-(-)-Of1的消除半衰期(t1/2)是4.57h;消除速率常数(k)是0.154h;药时曲线下的面积(AUC)为1.17mg·h-1.mL-1;R-(+)-Of1的t1/2为4.18h,k为0.168h-1,AUC是1.78mg·h-1·mL-1;经配对t检验这三对参数间有显著性差异,P值分别小于0.01,0.001和0.005.因此两对映体在人体内呈现立体选择性处置  相似文献   
76.
Summary Eight healthy volunteers participated in an open crossover study to assess the effect of a standardised meal on the systemic availability of a single oral dose of fenoldopam mesylate 100 mg. Subjects were studied on four separate occasions, twice fasting and twice fed in randomised, balanced order. Plasma and urine samples were obtained before and at regular intervals up to 25 h post dose. Measurement of fenoldopam (SK&F 82526) and its 8-sulphate metabolite (SK&F 87782) were by means of HPLC-EC analysis. Area under the plasma concentration time curve (AUC) and maximum detected plasma concentration (Cmax) for fenoldopam and SK&F 87782 were significantly reduced whereas time to maximum concentration was significantly increased with food. Using AUC's for fenoldopam and SK&F 87782, mean relative bioavailabilities were 35% and 81% respectively under fed compared with fasting conditions. Twenty-four hour excretion of fenoldopam was significantly reduced with food, but excretion of SK&F 87782 was apparently unchanged. Mean relative bioavailabilities calculated from these data were 83% and 86% respectively. Relatively large inter-subject variability in AUC and Cmax were seen, but intra-subject variability was not marked. Mild symptoms associated with vasodilation were reported on all study days.  相似文献   
77.
In a double-blind, placebo-controlled study, the pharmacokinetic, encephalotropic, and psychotropic properties of a new metabolically active thienyl-piperazine derivative were studied in ten elderly subjects in their sixties by means of quantitative EEG and psychometric analyses. At weekly intervals, they received randomized single oral doses of placebo; 75 mg, 150 mg, and 300 mg tenilsetam (CAS 997); and 3.2 g piracetam as reference drug. Blood sampling EEG recordings, psychometric and psychophysiological tests, as well as the monitoring of blood pressure, heart rate, and side effects were carried out at 0, 2, 4, 6, 8, and 24 hr. Pharmacokinetic investigations showed that CAS 997 was rather well absorbed, as peak concentrations were observed consistently at 2 hr and were clearly dose-dependent. The terminal half-life was between 18 and 22 hr, as compared with 6 hr for the reference drug piracetam, which also exhibited plasma peaks at 2 hr. Computer-assisted spectral analyses of the EEG showed a significant CNS effect of CAS 997 as compared with placebo, characterized by an increase of alpha activity, decrease of delta activity, and fast beta activity, as well as by tendency towards an augmentation of total power and decrease of the centroid and centroid deviation of the total beta activity. Partly similar though less pronounced alterations were exhibited by 3.2 g piracetam. Such changes were described previously by us after several other antihypoxidotics/nootropics and are indicative of improvement in vigilance. Dose/treatment–efficacy calculations demonstrated 75 and 150 mg CAS 997 superior both to placebo and the reference compound but also to the highest given dosis (300 mg CAS 997). Time–efficacy calculations showed two pharrnacodynamic peaks: one in the 4th and another one in the 8th to 24th hour. The time lag between pharmacokinetic and -dynamic changes may be due to the penetration of the drug through the blood brain barrier to a deep compartment receptor as well as to the formation of active metabolites. Psychometric investigations showed only small and inconsistent psychotropic effects after single doses of CAS 997 in elderlies. Evaluation of pulse rate, blood pressure, and side effects showed a good tolerability of both drugs.  相似文献   
78.
头孢氨苄缓释片在健康人体内的生物利用度和药物动力学   总被引:2,自引:0,他引:2  
目的:比较头孢氨苄缓释片和普通胶囊的生物利用度和药物动力学。方法:10例健康志愿者分别单剂量口服500mg头孢氨苄缓释片和普通胶囊,血药浓度测定方法为HPLC法。结果:两种剂型体内过程均符合一室开放模型,缓释片的达峰时间(Tmax)为(2.58±0.59)h,峰浓度(Cmax)为(10.08±1.68)μg/ml.吸收速率常数(Ka)为(0.90±0.53)/h,消除速率常数(Ke)为(0.26±0.02)/g,半衰期(T1/2)为(2.67±0.23)h,清除率(Cl)为(6.93±1.71)L/h,分布容积(Vd)为(26.66±6.72)L,药一时曲线下面积(AUC)为(48.31±9.32)μg·h/ml。两种剂型T一C一Ka、Ke、T1/2和Cl均存在显著性差异(P<0.01),Vd、AUC无显著性差异(P>0.05);缓释片的相对生物利用度为(104.90±8.35)%。结论:缓释片的吸收减慢,Tmax推迟,T1/2延长,可减少服药次数,提高药物治疗的顺应性。  相似文献   
79.
甲氧基红霉素对卡马西平药物动力学的影响   总被引:2,自引:0,他引:2  
应用荧光偏振免疫法,测定6只家兔po卡马西平及连续多次po用搓甲氧基红霉素后po卡马西平的血清卡马西平浓度,用3p87程序包按二室模型对数据进行处理并进行统计学分析。  相似文献   
80.
目的 评价 5 氟尿嘧啶和四氢叶酸联合化疗与加用吉西他滨后治疗晚期胰腺癌的疗效和不良反应 ;以及 5 氟尿嘧啶药物代谢动力学指标的改变。方法  43例晚期胰腺癌患者分为实验组 ( 2 2例 )和对照组 ( 2 1例 )。实验组 :吉西他滨 10 0 0mg/m2 ,第 1,8,16天静脉滴注 ,5 氟尿嘧啶 40 0mg/m2 和四氢叶酸 10 0mg/m2 于第 1~ 5天静脉滴注 ;对照组 :5 氟尿嘧啶 40 0mg/m2 和四氢叶酸 10 0mg/m2 在第 1~ 5天静脉滴注 ,均以每 4周为 1疗程 ,持续 4个疗程。结果 实验组完全缓解 (CR) 1例 ( 4 .5 %) ,部分缓解 (PR) 6例 ( 2 7.3 %) ,临床受益反应率 (CBR)为 68.2 %;对照组无CR ,PR3例 ( 14 .3 %) ,CBR有效率 3 3 .3 %。实验组出现不良反应的数量和严重程度较对照组提高且差异具有显著性。实验组 5 氟尿嘧啶血浆药物浓度、血浆峰值提高 ,血浆半衰期延长。结论 吉西他滨与 5 FU、四氢叶酸联合应用治疗晚期胰腺癌有一定的客观疗效 ,可明显改善患者的生存质量 ,但不良反应也随之提高。上述变化与吉西他滨改变 5 FU的药物代谢动力学有关  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