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   332713篇
  免费   30304篇
  国内免费   24269篇
耳鼻咽喉   2891篇
儿科学   3150篇
妇产科学   3691篇
基础医学   41033篇
口腔科学   5518篇
临床医学   45281篇
内科学   48254篇
皮肤病学   3723篇
神经病学   18255篇
特种医学   13059篇
外国民族医学   215篇
外科学   32095篇
综合类   54652篇
现状与发展   92篇
一般理论   33篇
预防医学   20703篇
眼科学   10242篇
药学   35722篇
  358篇
中国医学   19047篇
肿瘤学   29272篇
  2024年   1082篇
  2023年   5088篇
  2022年   13285篇
  2021年   16828篇
  2020年   12630篇
  2019年   10991篇
  2018年   11660篇
  2017年   10440篇
  2016年   10183篇
  2015年   15304篇
  2014年   18876篇
  2013年   16511篇
  2012年   24577篇
  2011年   27677篇
  2010年   17210篇
  2009年   13699篇
  2008年   17827篇
  2007年   17617篇
  2006年   17569篇
  2005年   17338篇
  2004年   10916篇
  2003年   10339篇
  2002年   8631篇
  2001年   7273篇
  2000年   7679篇
  1999年   8273篇
  1998年   5413篇
  1997年   5339篇
  1996年   4183篇
  1995年   3969篇
  1994年   3327篇
  1993年   2266篇
  1992年   2530篇
  1991年   2150篇
  1990年   1815篇
  1989年   1574篇
  1988年   1283篇
  1987年   1150篇
  1986年   875篇
  1985年   700篇
  1984年   397篇
  1983年   251篇
  1982年   151篇
  1981年   148篇
  1980年   103篇
  1979年   104篇
  1978年   6篇
  1975年   7篇
  1973年   10篇
  1972年   6篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Measurement of spinal cord evoked potentials (SCEPs) is proposed as a means of predicting locomotion outcome in the rat spinal cord injury (SCI) model. Using 55 rats, three reproducible peak waves (waves I, II and III) were observed during stimulation at the C7 level with recording at the L1 epidural space. Hemisection at the T13 level showed three wave loss patterns: wave III loss only, loss of both wave II and III, and loss of all three waves. Defining an ideal SCI model as establishment of stable monoparesis or paraparesis, all animals in the wave II-III loss group showed favorable results. Histological data and electrophysiological properties allowed reasonable assumptions of wave origin: wave I from extrapyramidal tracts, wave II from the ventral corticospinal tract, and wave III from the dorsal corticospinal tract. Complete destruction of pyramidal tracts in both dorsal and ventral fibers was essential for long-term impairment of locomotion.  相似文献   
992.
Objective To assess the value of detecting sympathetic skin response (SSR) in the diagnosis of autonomic dysfunction in patients with Parkinson disease (PD). Methods SSR measurement was performed in 47 PD patients and 20 healthy control subjects and the results were compared. The SSR was also comparatively analyzed between patients with and those without autonomic dysfimction. Results Compared with the healthy controls, the PD patients showed significantly lowered mean amplitude (2.56±1.47 vs 1.87±0.26, P<0.05) and prolonged latency (1.42±0.29 vs 1.55± 0.18, P<0.05) of the SSR in the upper limbs, with also lowered mean amplitude (0.76±0.39 vs 0.49±0.21, P<0.05) and prolonged latency (2.04±0.27 vs 2.13±0.16, P<0.05) in the lower limbs. Compared with the PD patients without autonomic dysfunction, those having autonomic dysfunction showed significantly lowered mean amplitude (1.89±0.33 vs 1.75±0.21, P<0.05) and prolonged latency (1.53±0.15 vs 1.56±0.17, P<0.05) of SSR in the upper limbs and lowered mean amplitude (0.51±0.17 vs 0.46±0.20,P<0.05) and prolonged latency (2.08±0.24 vs 2.17±0.18, P<0.05) in the lower limbs. Conclusion The results of SSR measurements are consistent with the clinical manifestations of the PD patients. SSR can be of value in the diagnosis of autonomic nerve dysfunction in PD.  相似文献   
993.
Objective:To study whether adenovirus-mediated human β-nerve growth factor (Ad-hNGFβ) gene has any protective effect on blast hearing impairment. Methods:Deafness was induced by blast exposure (172.0 dB) in 30 healthy guinea pigs. On day 7 of blast exposure, Ad-hNGFβ was infused into the perilymphatic space of 20 animals as the study group (hNGFβ group), and artificial perilymph fluid (APF) was infused into the perilymphatic space of the other 10 animals as the control group. At weeks 1, 4 and 8 after blast exposure, the animals were sacrificed and the cochleae were removed for immunohistochemical and HE stainings. Results: Expression of Ad-hNGFβ protein was detected in each turn of the cochlea at the 1st week, with almost equal intensity in all turns. At the 4th week, the reactive intensity of the expression of Ad-hNGFβ protein decreased. At the 8th week, no expression was detectable. The results of HE staining showed that the amount of spiral ganglions in hNGFβ group was significantly greater than that of the control group at week 4 (P〈0.01). Conclusion: Ad-hNGFβ can be expressed at a high level and for a relatively long period in the blast impaired cochlea, suggesting that Ad-hNGFβ has a protective effect on cochlear spiral ganglion cells after blast exposure and the efficient gene transfer into cochlea had been achieved without toxicity.  相似文献   
994.
醋酸棉酚每天30mg/kg(6次/周)给药6~8周后,大鼠肾曲小管线粒体肿胀,嵴模糊,伴有早期溶酶体增多、增大,形态多样,其后转而减少、变小。肾近曲小管微绒毛水肿,部分肾曲小管基底膜水肿。未见肾小球毛细血管内皮细胞、基膜和足细胞的超微结构明显变化。  相似文献   
995.
Excretion of 1,2,4-benzenetriol in the urine of workers exposed to benzene   总被引:5,自引:0,他引:5  
Urine samples were collected from 152 workers (64 men, 88 women) who had been exposed to benzene, 53 workers (men only) exposed to a mixture of benzene and toluene, and 213 non-exposed controls (113 men, 100 women). The samples were analysed for 1,2,4-benzentriol (a minor metabolite of benzene) by high performance liquid chromatography. The time weighted average solvent exposure of each worker was monitored by diffusive sampling technique. The urinary concentration of 1,2,4-benzentriol related linearly to the intensity of exposure to benzene both in men and women among workers exposed to benzene, and was suppressed by toluene co-exposure among male workers exposed to a mixture of benzene and toluene. A cross sectional balance study in men at the end of the shift of a workday showed that only 0.47% of benzene absorbed will be excreted into urine as 1,2,4-benzenetriol, in close agreement with previous results in rabbits fed benzene. The concentration of 1,2,4-benzenetriol in urine was more closely related to the concentration of quinol than that of catechol. The fact that phenol and quinol, but not catechol, are precursors of 1,2,4-benzentriol in urine was further confirmed by the intraperitoneal injection of the three phenolic compounds to rats followed by urine analysis for 1,2,4-benzenetriol.  相似文献   
996.
本文用原子吸收光谱法测定了延边地区65岁~108岁健康老人110人头发中的铜、锰、铁、锌及镁的含量,比较了66人的白发与44人的黑发中这些元素的含量差异.结果表明,白发中的锰和镁的含量明显低于黑发,但铜、锌、铁的含量则无明显差异.这些差别在男性很明显,但在女性则不甚明显.  相似文献   
997.
Twenty patients underwent endourethral urethroplasty with free prepuce graft in combination with transurethral resection of scar for posterior urethral stricture. Two-year follow-up showed that they had good continent and free voiding results. Problems about surgical technique were detailed. We conclude that a free full-thickness prepuce evenly patched by means of the tube balloon to the freshly prepared wound derived from the stricture is the key to surgical success.  相似文献   
998.
999.
张彩兰 《护理研究》2007,21(12):1111-1111
质量是医院管理永恒的主题,护理质量是护理管理的核心[1]。护理质量控制是医院护理管理重要环节,也是为病人提供高质量护理服务的保证措施。我院为二级乙等医院,共有床位150张;病人来源广泛,主要来源于山西、陕西、内蒙等地,病种繁多,文化差异较大,决定了护理工作量大,并且难度  相似文献   
1000.
中国三城市儿童步行者道路交通安全状况回顾性研究   总被引:1,自引:0,他引:1  
段蕾蕾  孙燕鸣  邓晓  张睿  吴凡 《中国健康教育》2007,23(5):330-332,358
目的了解北京、上海、广州三城市儿童步行安全状况及相关因素,为加强儿童道路交通伤害预防、干预提供科学依据。方法回顾性收集2000~2004年三城市交管部门14岁以下儿童步行者交通伤害发生资料。结果三城市5年间儿童步行者道路交通伤害发生率为14.93/10万,男女比例为1.79∶1,5~9岁为高发年龄,儿童步行者发生道路交通伤、亡的主要责任方为行人,受伤害儿童43.0%为轻伤,46.6%为重伤,10.4%为死亡。结论道路交通伤害严重威胁儿童安全与健康,儿童步行者发生道路交通伤害与多种因素有关,需社会各个部门参与预防。  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