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   131970篇
  免费   14179篇
  国内免费   9122篇
耳鼻咽喉   1024篇
儿科学   2110篇
妇产科学   1224篇
基础医学   11995篇
口腔科学   2403篇
临床医学   18633篇
内科学   15583篇
皮肤病学   1308篇
神经病学   4664篇
特种医学   4370篇
外国民族医学   52篇
外科学   9244篇
综合类   29984篇
现状与发展   46篇
一般理论   1篇
预防医学   12745篇
眼科学   3625篇
药学   16102篇
  226篇
中国医学   11364篇
肿瘤学   8568篇
  2024年   723篇
  2023年   2275篇
  2022年   5735篇
  2021年   7184篇
  2020年   5983篇
  2019年   4279篇
  2018年   4292篇
  2017年   4860篇
  2016年   3964篇
  2015年   6533篇
  2014年   8154篇
  2013年   8482篇
  2012年   12154篇
  2011年   12867篇
  2010年   9383篇
  2009年   7730篇
  2008年   8521篇
  2007年   8068篇
  2006年   7395篇
  2005年   5913篇
  2004年   4031篇
  2003年   3689篇
  2002年   2872篇
  2001年   2343篇
  2000年   1854篇
  1999年   1453篇
  1998年   787篇
  1997年   767篇
  1996年   570篇
  1995年   529篇
  1994年   445篇
  1993年   234篇
  1992年   213篇
  1991年   219篇
  1990年   188篇
  1989年   138篇
  1988年   124篇
  1987年   94篇
  1986年   65篇
  1985年   39篇
  1984年   21篇
  1983年   15篇
  1982年   12篇
  1981年   19篇
  1980年   8篇
  1979年   14篇
  1977年   5篇
  1970年   7篇
  1967年   3篇
  1966年   3篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
清末经学家和小学家胡澍把《素问》作为子书之一,博采众本,悉心校勘,以小学的方法进行专门研究,撰成《素问校义》,为研习《内经》不可不读之书。通过对天津中医药大学图书馆所藏胡澍手校本《重广补注黄帝内经素问》的考证,发现胡澍校勘所据底本一直被误作宋本,而实是明顾从德影宋刻本.校勘工作历时数年,手校本《素问》留有胡澍悉心对校后所做出的千余条校语,可惜草创未就,他便英年早逝。手校本这第一手资料,对研究胡澍的治学思想和《素问校义》的成书过程,学习和掌握知识,传承弘扬学术,都具有重女的文献参考价值。  相似文献   
42.
BACKGROUND: At present, there is still lack of effective drugs for chronic spinal cord injury, whereas it is found recently that estrogen has a neuroprotective effect on brain and spinal cord injuries. OBJECTIVE: To observe the effect of estrogen on the apoptosis of nerve cells after gradual chronic spinal cord injury in ovariectomized rats. DESIGN: A randomized controlled animal trial. SETTING: Institute of Orthopaedics, the Second Hospital of Lanzhou University. MATERIALS: Sixty-five female Wistar rats of common degree, weighing 220–250 g, were provided by the experimental animal center of Lanzhou University. The rats were randomly divided into sham-operated group (n =5), estrogen-treated group (n =30) and saline control group (n =30), and the latter two groups were observed at 1, 3, 7, 14, 28 and 60 days respectively, and 5 rats for each time point. METHODS: All the rats were treated with bilateral oophorectomy 2 weeks before the experiment. T10 vertebral lamina was revolved into using plastic screw. The spinal canal impingement was not induced initially. After that, the original incision was opened to expose the screw every 7–10 days. MAIN OUTCOME MEASURES: The apoptosis and Caspase-3 positive cells in the damaged spinal cord were detected using terminal deoxynucleotidal transferase-mediated dUTP-biotin nick end labeling (TUNEL) method and Caspase-3 immunohistochemical staining at 1, 3, 7, 14, 28 and 60 days after chronic spinal cord injury respectively. RESULTS: Totally 65 rats were used, and the deleted ones during the experiment were supplemented by others. Changes of Caspase-3 expression after spinal cord injury: In the sham-operated group, only a small amount of Caspase-3 proteins were observed in the rat spinal cord, mainly located in motor neurons of spinal cord anterior horn. In the estrogen-treated group and saline control group, positive cells expressed occasionally at 1 day postoperatively, began to increase obviously at 7 days after injury, strongly expressed at 14 and 28 days, but decreased at 60 days, mainly located in the neurons of spinal cord gray matter anterior horn, and they expressed fewer in the motor neurons and white matter of ventral horn, and there were obvious differences between the estrogen-treated group and saline control group at 7, 14, 28 and 60 days (P < 0.05). CONCLUSION: Estrogen can reduce the apoptosis of nerve cells and promote the recovery of neurological function following gradual chronic spinal cord injury.  相似文献   
43.
OBJECTIVE: To evaluate the possibility and reliability of the hyoid-sternohyoid graft transfer in the correction of server subglottic laryngotracheal stenosis, and delineate the operation skills and clinical results. METHODS: Seven patients with severe subglottic stenosis underwent laryngotracheal reconstruction using the hyoid grafts with sternohyoid muscle flaps (HG-SHMF). Five of these patients had traumatic subglottic stenosis, one with scar tissue of unknown etiology arising in the subglottic region, another with tracheal narrowing caused by inhalation of hydrochloric acid. RESULTS: All seven patients were successfully decannulated with moderate good voice. The average time from reconstruction to decannulation was 15.4 months. The stent was endoscopically removed with a range of 3 to 22 months; the mean time required for stenting was 9.6 months. Two patients who received additional salvage reconstruction procedures because of graft or stent displacement were extubated with improved voices and satisfactory airway. CONCLUSIONS: The HG-SHMF transfer was a single-stage reconstruction, relatively simple procedure that can restore an adequate airway and a good voice. Patients undergoing laryngotracheal reconstruction with HG-SHMF must have regular, long-term follow-up since graft displacement and recurrent granulation tissue or scar reformation can cause restenosis after an initially successful surgery. This procedure should be used in a large number of patients to further test its reliability.  相似文献   
44.
通过兔后肢缺血模型,观察了甘露醇和低温对骨骼肌缺血再灌流损伤的保护作用。结果:甘露醇和低温可以不同程度地降低再灌流后患肢静脉回流血中细胞内酶(CPK、LDH、AST)的活性和脂质过氧化反应终末代谢产物丙二醛(MDA)的含量,减轻骨骼肌细胞超微结构的破坏。两者单独应用效果不明显(P>0.05),联合应用效果非常明显(P<0.01)。提示自由基介导的脂质过氧化反应参与骨骼肌缺血再灌流损伤,甘露醇和低温对其具有协同保护作用。  相似文献   
45.
中风后癫痫的临床研究   总被引:5,自引:0,他引:5  
本文报告36例中风后癫痫发作的临床和CT资料。通过回顾性病历复习和随访发现,中风后癫痫的发生率占同期住院中风患者的5.26%,以蛛网膜下腔出血和脑栓塞发生癫痫比率最高,分别为15%和12.5%。癫痫发作与CT所见病灶分布密切相关,皮质病灶较皮质下病灶更易发生病病。癫痫发作可发生于中风后任何时期,但早期癫痫以出血性中风多见,而迟发性癫痫则更多见于脑梗塞患者。  相似文献   
46.
格林—巴利综合征患者血清和脑脊液中的抗硫脂抗体   总被引:5,自引:1,他引:4  
探讨抗硫脂抗体与格林-巴利综合征(GBS)的关系。方法采用固相酶联免疫吸附法对急性期GBS患者血清和脑脊液(CSF)中抗硫脂IgG和IgM抗体进行检测。结果GBS患者血清和CSF中抗硫脂IgG及IgM抗体的阳性率均明显高于正常对照组;血清中抗硫脂IgM抗体滴度与标本收集时患者发病天数呈负相关(P<0.05),而血清中抗硫脂IgG抗体滴度与临床分级(P<0.01)、CSF中抗硫脂IgG抗体滴度(P<0.01)呈正相关;血清中抗硫脂IgG或IgM阳性的GBS患者,体检时有不同程度的感觉障碍患者为56%,而血清中抗硫脂抗体阴性患者仅为16%,两者之间差异有显著意义(P<0.05)。结论抗硫脂抗体可能在GBS的病理过程中起重要作用  相似文献   
47.
Senile vascular dementia refers to organic loss of intellectual function due to cerebral damages caused by insufficient blood supply. The following is a summaryon achievements in its etiology, pathogenic mechanism, type identification and treatment in TCM, and the compound formulas, special formulas and drugs, and thepatent drugs used successfully for its treatment.  相似文献   
48.
本实验采用血管铸型扫描电镜,注射明胶卡红组织切片显微镜下观察和注射铅丹乳胶追踪血管来源三种方法对14只健康大白鼠肾上腺血管构筑进行了研究。大白鼠肾上腺动脉发自腹主动脉和肾动脉。它们在行程中发出分支至腺体表面,再次分支穿入囊内,逐级分支至毛细血管。皮质动脉发自囊内血管,它们在皮质中分支分布。球状带的毛细血管与囊的毛细血管相连,毛细血管在球状带围绕细胞团形成网眼状;在束状带呈放射状排列;在网状带吻合增多形成网状。髓质动脉亦发自囊的血管,它们在皮质中不发分支直抵髓质,在髓质分成毛细血管。网状带的毛细血管越向髓质口径越粗,它们在皮髓交界处互相吻合形成更粗的静脉,这些静脉逐级吻合,最后形成一主干——中央静脉,它穿出皮质出现于肾上腺门处。左侧的中央静脉注入在肾静脉,右侧的注入下腔静脉。  相似文献   
49.
High-frequency deep brain stimulation (DBS) of the subthalamic nucleus (STN) improves the motor symptoms of Parkinson's disease (PD). Opposite changes in mood, such as mania or depression, have been reported after surgery, but it is not known whether these side effects are specifically related to STN DBS. To learn whether STN DBS also influences the limbic loop, we investigated acute subjective psychotropic effects related to levodopa or bilateral STN DBS. After a median postoperative follow-up of 12 months, 50 PD patients completed the Addiction Research Center Inventory (ARCI), assessing subjective psychotropic effects in four conditions: off-drug/on-stimulation; off-drug/off-stimulation; on-drug/off-stimulation; and on-drug/on-stimulation. Both levodopa and STN DBS improved all the ARCI subscales, indicating subjective feelings of well being, euphoria, increase in motivation, and decrease in fatigue, anxiety, and tension. A suprathreshold dose of levodopa was significantly more effective than STN DBS, using the same electrical parameters as for chronic stimulation, on four of the five ARCI subscales. We concluded that 1) both STN DBS and levodopa have synergistic acute beneficial psychotropic effects in PD, 2) the psychotropic effects of both treatments need to be considered in the long-term management of chronic STN DBS, and 3) the results indicate an involvement of the limbic STN in mood disorders of PD.  相似文献   
50.
The effects of vagal and sympathetic nerves on the transmembranepotentials of cardiac cells of toad were observed by means of microelectrodetechnique.The vagal nerve was stimulated there would be an increase in restingpotential and acceleration in repolarization of action potential(AP).However,ifatropine was used before stimulation the above-mentioned phenomena woulddisappear.When the sympathetic nerve was stimulated the AP amplitudeincreased,but resting potential(RP)remained the same.The increase of APresulted from the increases of overshoot.When the sympathetic nerve wasstimulated although the heart rate increased and the duration of AP wasshortened,the plateau phase of AP was prolonged.These results suggest that theeffects of vagal and sympathetic nerves on the transmembrane potential of cardiacventricular cells are coordinated and the normal characteritics of transmembranepotential are maintained by both the vagal and sympathetic nerves.  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