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   60611篇
  免费   4844篇
  国内免费   1683篇
耳鼻咽喉   367篇
儿科学   527篇
妇产科学   336篇
基础医学   3279篇
口腔科学   921篇
临床医学   5553篇
内科学   4212篇
皮肤病学   626篇
神经病学   2309篇
特种医学   1593篇
外国民族医学   8篇
外科学   2787篇
综合类   13537篇
现状与发展   5篇
一般理论   1篇
预防医学   7281篇
眼科学   833篇
药学   10634篇
  518篇
中国医学   9425篇
肿瘤学   2386篇
  2024年   197篇
  2023年   827篇
  2022年   1816篇
  2021年   2509篇
  2020年   2669篇
  2019年   1838篇
  2018年   1747篇
  2017年   2269篇
  2016年   2852篇
  2015年   2530篇
  2014年   5675篇
  2013年   5210篇
  2012年   4743篇
  2011年   4476篇
  2010年   3492篇
  2009年   2801篇
  2008年   2517篇
  2007年   2671篇
  2006年   2260篇
  2005年   1941篇
  2004年   1473篇
  2003年   1434篇
  2002年   1130篇
  2001年   976篇
  2000年   813篇
  1999年   757篇
  1998年   530篇
  1997年   495篇
  1996年   475篇
  1995年   429篇
  1994年   375篇
  1993年   296篇
  1992年   322篇
  1991年   261篇
  1990年   236篇
  1989年   231篇
  1988年   219篇
  1987年   166篇
  1986年   169篇
  1985年   233篇
  1984年   190篇
  1983年   127篇
  1982年   141篇
  1981年   99篇
  1980年   85篇
  1979年   93篇
  1978年   69篇
  1977年   69篇
  1976年   52篇
  1975年   48篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
射频消融治疗肝肿瘤315例报告   总被引:16,自引:1,他引:15  
目的总结1999年6月至2003年8月用射频消融(radiofrequency ablation,RFA)治疗315例肝肿瘤病人的病例资料,探索RFA治疗肝肿瘤近远期疗效。方法采用了一次定位、多点穿刺,RFA联合肝动脉栓塞(TAE)、选择性门静脉栓塞(SPVE)治疗直径5~13cm的大肝癌,及经皮经肺经膈肌RFA治疗膈顶部肝癌。结果总并发症发生率为5.1%,无一例住院期间死亡。AFP阳性的169例肝癌病人中,RFA后有124例(73.6%)明显降低,其中有95例(56.2%)转阴。半年生存率为89.5%,1年生存率为80.1%,18个月生存率为61.4%,24个月生存率为48.3%,〉36个月生存率为35.6%。结论采用TAE、SPVE及RFA一次定位多点穿刺法治疗无手术切除指征的中晚期(含大肝癌)的病人,疗效明显,总并发症发生率低。  相似文献   
102.
目的探讨米非司酮应用于子宫内膜异位症的疗效。方法 123例子宫内膜异位症患者被随机分为实验组(n=63)和对照组(n=60),两组均给予手术治疗,实验组在手术治疗基础上给予米非司酮治疗方案。结果实验组总有效率为95.2%,痊愈率为84.1%,对照组总有效率为56.7%,痊愈率为43.3%,实验组效果显著优于对照组(P<0.01)。结论手术治疗联合米非司酮应用于高血压脑出血,能提高手术效果,降低复发率,值得在临床上应用和推广。  相似文献   
103.
OBJECTIVE: It is well described that unilateral pelviureteric junction obstruction (PUJO) is a benign condition, because the dilatation resolves spontaneously and the function does not decrease in most of the kidneys. However, there is exceptional PUJO that requires emergent treatment in neonatal periods. The aim of this article is to report the urological emergency and management in neonates with PUJO. MATERIALS AND METHODS: Nine children (seven boys and two girls) with PUJO who underwent neonatal emergent treatment during the last 13 years were reviewed. Renal function was evaluated according to decay curve of serum creatinine (SCr) levels corresponding to gestational age (GA) at delivery. Physical examination, ultrasonographic monitoring, and chest and abdominal plain radiographs were repeated in each neonate. RESULTS: Eight patients were detected prenatally. In five patients, multicystic dysplastic kidney (MCDK) was demonstrated on the contralateral side. Three patients underwent percutaneous puncture of fetal hydronephrosis. Decrease of amniotic fluid was evident in three fetuses. Indications for emergent treatment included mass effect from hydronephrosis in three patients, renal dysfunction in five, and severe urinary tract infection in one. During neonatal periods, a percutaneous nephrostomy tube was placed in seven, and open nephrostomy in one with anorectal malformation. Repeated punctures of the dilated renal pelvis were done in one patient. Renal function after pyeloplasty was stable in eight patients, while it was moderately decreased in one who was associated with oligohydramnios in utero. CONCLUSION: Indications for emergent treatment in neonates with PUJO included mass effect from giant hydronephrosis, renal dysfunction and severe urinary tract infection. At birth, respiratory and circulatory conditions must first be stabilized. In neonates with hydronephrosis of the solitary kidney or severe bilateral PUJO, serial SCr should be monitored to evaluate renal function. Decrease of amniotic fluid suggested renal functional compromise that would not recover after urological management.  相似文献   
104.
Cancer chemotherapy with the application of several drugs is studied. The negative and inhibiting effect of the tumour on normal cells is taken into account. Under certain hypotheses, we determine the optimal regimen that minimizes the tumour burden at the end of a fixed period of therapy while maintaining several normal cell populations above prescribed levels. More precisely, it is demonstrated that the optimal drug administration corresponds to the strategy of intensive chemotherapy.  相似文献   
105.
Objective To evaluate preliminarily the effect of HSV - tk/GCV system on gallhladder carcinoma cells in vitro.Methods Recombinant retroviral vector PLtkSN containing tk suicide gene was transfacted into gallbladder carcinoma cells, mediated by LipofectAMINETM 2000 liposome, and the growth - inhibiting rotes of GBC, SD/tk cells in the different GCV concentrations were measured by MTr methods; GBC - SD cells were mixed in the different proportions, and death rotes of the mixed cells treated with GCV were detected to verify by stander effect. Resuts GCV could lead GBC - SD/tk cells to significant death, and there was striking difference compared with the control cells (p〈0.01). When the concentration of GCV was 1,10, 50,100,500ug/ml, the killing rate of GBC - SD/tk cells was respecfively 6.8%, 2.5.2%, 54.5%, 66.3%, 89.3%, indicating dose - dependent phenomenon; With GBC - SD/tk cells in the proportion of 0, 10%, 20% ,50%, 70%, 100%, the killing rate of the mixed cells treated with GCV was 0, 19.7%, 40.3%, 77.7%, 88.0%, 93.5%, respectively. It was apparent that bystander effect was observed in the experiment. Condusion HSV - tk/GCV system could be a potential tool for the treatment of carcinoma.  相似文献   
106.
中老年晚期非小细胞肺癌射频损毁治疗与化疗的临床比较   总被引:1,自引:1,他引:0  
目的:探讨射频损毁治疗晚期非小细胞肺癌的疗效及应用价值。方法:自1999年12月至2000年8月收治73例晚期中老年非小细胞肺癌患者,分别给予射频损毁治疗和以铂类为主的联合化疗;观察比较其近期疗效、中位生存期、1年及2年生存率;并分析其治疗后生存质量。结果:射频损毁治疗组有效率(CR+PR)为71.5%(30/42),明显高于化疗组的43.3%,差异呈显著性,(x2=4.63,P<0.05)。射频损毁治疗组中位生存期、1年及2年生存率及治疗后生存质量均高于化疗组。结论:射频损毁治疗对晚期非小细胞肺癌治疗,具有较好的中期疗效,且能明显提高生存质量。  相似文献   
107.
It is well known that the removal of a fixation point prior to the presentation of a peripheral target dramatically reduces saccadic reaction time (SRT). This effect has become known as the “gap effect”. The present study examined several detailed kinematic variables to determine whether the removal of the fixation point also affects the manner in which saccades are produced. The findings indicate that saccades that were initiated after the removal of the fixation point had higher average velocities and reached greater peak velocities, accelerations, and decelerations than did saccades produced in the presence of the fixation point. The results suggest that the removal of the fixation point may affect the force-time curves of saccades in addition to affecting the time needed to initiate the saccades. Received: 21 February 1997 / Accepted: 24 July 1997  相似文献   
108.
Prolongation of the action potential duration of dorsal root ganglion (DRG) neurons by low (nM) concentrations of opioids occurs through activation of excitatory opioid receptors that are positively coupled via Gs regulatory protein to adenylate cyclase. Previous results suggested GM1 ganglioside to have an essential role in regulating this excitatory response, but not the inhibitory (APD-shortening) response to higher (μM) opioid concentrations. Furthermore, it was proposed that synthesis of GM1 is upregulated by prolonged activation of excitatory opioid receptor functions. To explore this possibility we have utilized cultures of hybrid F11 cells to carry out closely correlated electrophysiological and biochemical analyses of the effects of chronic opioid treatment on a homogeneous population of clonal cells which express many functions characteristic of DRG neurons. We show that chronic opioid exposure of F11 cells does, in fact, result in elevated levels of GM1 as well as cyclic adenosine monophosphate (AMP), concomitant with the onset of opioid excitatory supersensitivity as manifested by naloxone-evoked decreases in voltage-dependent membrane K+ currents. Such elevation of GM1 would be expected to enhance the efficacy of excitatory opioid receptor activation of the Gs/adenylate cyclase/cyclic AMP system, thereby providing a positive feedback mechanism that may account for the remarkable supersensitivity of chronic opioid-treated neurons to the excitatory effects of opioid agonists as well as antagonists. These in vitro findings may provide novel insights into the mechanisms underlying naloxone-precipitated withdrawal syndromes and opioid-induced hyperalgesia after chronic opiatf addiction in vivo. © 1995 Wiley-Liss, Inc.  相似文献   
109.
安吉复口服液的耐缺氧,耐低温和抗疲劳作用   总被引:2,自引:0,他引:2  
采用缺氧、寒冷和负重游泳等方法,观察了安吉复口服液(0.025、0.1和0.4mg·kg~(-1),ig,qd×14d)对小鼠的耐缺氧、耐低温及抗疲劳作用.结果表明,安吉复口服液0.1、0.4mg·kg~(-1)可延长KCN中毒小鼠的存活时间及延长小鼠在寒冷环境中存活时间,而0.4mg·kg~(-1)可延长常压缺氧条件下小鼠存活时间及延长小鼠负重游泳时间.  相似文献   
110.
我们用麻醉的正常血压大鼠,大鼠的自体灌液后肢分别研究了美哌隆的降压作用强度、部位、维持时间和对心率的影响。实验结果提示:美哌隆降低动脉血压的作用除依赖于它对外周α_1受体的选择性阻滞外,还依赖于它对外周阻力血管的直接扩张作用。美哌隆在降压的同时也减慢心率,其降压作用和负性频率作用与剂量有关。  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