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   4203篇
  免费   421篇
  国内免费   267篇
耳鼻咽喉   39篇
儿科学   40篇
妇产科学   49篇
基础医学   604篇
口腔科学   66篇
临床医学   551篇
内科学   661篇
皮肤病学   20篇
神经病学   228篇
特种医学   103篇
外国民族医学   1篇
外科学   427篇
综合类   739篇
现状与发展   1篇
预防医学   285篇
眼科学   39篇
药学   490篇
  5篇
中国医学   193篇
肿瘤学   350篇
  2024年   18篇
  2023年   62篇
  2022年   149篇
  2021年   215篇
  2020年   165篇
  2019年   142篇
  2018年   141篇
  2017年   119篇
  2016年   110篇
  2015年   193篇
  2014年   241篇
  2013年   192篇
  2012年   294篇
  2011年   365篇
  2010年   183篇
  2009年   140篇
  2008年   238篇
  2007年   211篇
  2006年   207篇
  2005年   232篇
  2004年   169篇
  2003年   111篇
  2002年   105篇
  2001年   100篇
  2000年   114篇
  1999年   127篇
  1998年   95篇
  1997年   76篇
  1996年   52篇
  1995年   37篇
  1994年   51篇
  1993年   29篇
  1992年   54篇
  1991年   35篇
  1990年   16篇
  1989年   26篇
  1988年   20篇
  1987年   15篇
  1986年   12篇
  1985年   9篇
  1984年   4篇
  1983年   4篇
  1982年   1篇
  1981年   6篇
  1980年   1篇
  1979年   3篇
  1969年   1篇
  1928年   1篇
排序方式: 共有4891条查询结果,搜索用时 0 毫秒
1.
Lesbianism in China has a long but usually hidden history. This paper examines the historical and literary sources of the past to illustrate the history of lesbianism and then turns to a survey of lesbianism in the China of today. As in the past, lesbianism remains more or less hidden, and comes to light only occasionally. Data for contemporary China comes from a visit to an institution for delinquent young women, recent police records, and contemporary fiction. It has only been in the past 4 or 5 years that it was possible to talk about lesbianism and most lesbians are fearful of becoming identified.  相似文献   
2.
3.
4.
Mast cells in adenoid liver tumors of 32 rats induced with nitrosomorpholine were observed ultrastructurally, and among them, some were studied immunocytochemically via immunogold techniques. Data indicating that mast cells which located in tumor tissues presented positive expression of rat mast cell protein (RMCP) Ⅰ, Indicating origination from the mucosa mast cells, while those in the connective tissues around tumors were largely stained negatively with either RMCP Ⅰor RMCP Ⅰ antisera, with the exception of only a few cells showing positive RMCP Ⅰ staining. Ultrastructural observation showed that mast cells in tumon contacted closely with the tumor cells. Membranes of the intracytoplasmic granules in these mast cells were fusing together. The content inside the granules were discharged and spread along the intercellular space between the tumor cells. There was not any lesion observed uitrasructrually in the tumor cells contacting with the mast cells. The significance of mucosa mast cells in adenoi  相似文献   
5.
浙江医科大学附二院门诊处方中精神药物使用调查   总被引:1,自引:0,他引:1  
本文对浙江医科大学附属二院1993年7月间31378张合格处方进行统计分析,并用限定日剂量(DDD)和药物使用指数(DUI)为指标,分析镇静催眠药物使用情况。结果表明苯二氮 类药方2067张,占总处方量的6.59%,巴比妥类药方49张,占0.16%,麻醉药方111张;占0.35%。苯二氮 类药方中.女性处方量1202张,男性处方量865张,男、女组间比较有显著性差异。苯二氮 类药方多分布在神经内科,常用的药有舒乐安定和阿普唑仑。九种常用的苯二氮 类药和麻醉性镇痛药的DUI均小于1。提示药物滥用现象少见,该院对这类药物的管理比较严格。麻醉性镇痛药中二氢埃托啡处方占67.57%。  相似文献   
6.
以健康Wistar大白鼠为材料,对微波快速内源性过氧化物酶染色与灌注法显示微血管的方法进行了对比研究。结果,过氧化物酶组织化学法具有不用灌注,操作简单,所用时间短,对血管无扩张、破裂等人为改变的特点,保持了微血管真实的自然形态和管径大小,可以定量或半定量地判定组织器官活体时的血液循环状况。可以用于人及动物的大脑、脊髓、皮肤、耳及食管等组织内微血管形态学研究和定量分析。并对过氧化物酶显示微血管的原理和微波辐射促进染色的原理及特点进行了分析、讨论。  相似文献   
7.
神经梅毒的临床特征与诊断分析   总被引:34,自引:2,他引:32  
目的:分析神经梅毒的分型和临床特征及提供早期诊断依据。方法:回顾性分析经临床和实验室检查确诊的18例神经梅毒病人的有关临床资料。结果:神经梅毒的临床特征包括:(1)急性、亚急性起病为主;(2)临床以间质型,尤其是以脑卒中起病常见,症状元特异性;(3)血清学检查以梅毒螺旋体血凝试验(TPHA)及快速血浆反应素试验(RPR)特异性较高;(4)脑脊液检查表现为压力增高(42.9%)、蛋白增高(81.2%)及细胞数增高(56.3%);(5)头颅CT、MRI表现与高血压、动脉硬化所致脑梗死不同,为多发、散在病灶。结论:神经梅毒早期误诊率高,临床表现与分型密切相关,实验室及影像学检查是诊断的重要依据。  相似文献   
8.
玻璃体切割手术治疗化脓性眼内炎   总被引:2,自引:0,他引:2  
目的 观察玻璃体切割手术治疗化脓性眼内炎的疗效。方法 对1999年6月~2003年2月在我院行玻璃体切割术的14例(14只眼)化脓性眼内炎患者进行回顾性分析。除眼内异物外,其余患者临床诊断化脓性眼内炎后均先采用保守治疗,密切观察1~2天无好转而行玻璃体切割手术。眼内炎的原因:眼球穿通伤13只眼,青光眼术后晚期滤过泡感染1只眼。玻璃体切割手术前先抽取前房及玻璃体腔内液体涂片及培养。采用标准三通道闭合式玻璃体切割手术,7只眼因前房积脓及晶状体前大量渗出和3只眼外伤性白内障影响手术而同时切除晶状体,8只联合巩膜环扎。缝合巩膜切口后玻璃体腔内注射罗氏芬2.5mg及地塞米松0.4mg。术后全身继续使用抗生素及激素1周。术后平均随访14.8个月(2~24个月).结果 14只眼中术后视力提高12只眼(85.7%),眼球保留13只眼(92.6%)。5只眼培养阳性。术后玻璃体腔内少量出血2只眼,无其它手术并发症。结论 玻璃体切割手术联合眼内注射抗生素治疗化脓性眼内炎疗效可靠。只要手术时机选择适当,大多数患者能保住眼球,恢复有用视力。  相似文献   
9.
H Janson  M Ruan    A Forsgren 《Infection and immunity》1993,61(11):4546-4552
Protein D is a surface-exposed lipoprotein of the gram-negative bacterium Haemophilus influenzae with affinity for human immunoglobulin D myeloma protein. The gene encoding protein D (hpd) in a serotype b strain of H. influenzae was cloned. Escherichia coli carrying the hpd gene bound human myeloma immunoglobulin D. Nucleotide sequence analysis identified an 1,092-bp open reading frame that was more than 99% identical to the hpd gene from a nontypeable H. influenzae strain. In the deduced amino acid sequences for protein D, only 2 of 364 amino acid residues differed. The restriction fragment length polymorphism of the hpd region in different strains was analyzed by Southern blot analyses of PstI- or EcoRI-digested genomic DNA from 100 H. influenzae strains. The analysis was performed by using isolated fragments of the cloned hpd gene, originating from the nontypeable H. influenzae 772, as probes. All strains tested had DNA sequences with a high degree of homology to the hpd probes. The analysis also showed that restriction endonuclease sites within the gene were more conserved than sites adjacent to the hpd gene. An interesting difference between type b strains and unencapsulated strains was observed. The majority of type b strains seem to have a 1.4-kbp DNA fragment upstream of the hpd gene that is absent in nontypeable strains. On the basis of the high degree of conservation of the hpd gene among H. influenzae strains, we conclude that protein D is a possible vaccine candidate.  相似文献   
10.
Zhu DM  Wang M  She JQ  Yu K  Ruan DY 《Neuroscience》2005,134(1):215-224
Previous studies have demonstrated that synaptic plasticity, which includes long-term potentiation (LTP) and depotentiation (DP) in hippocampus, is important for learning and memory. The purpose of this study is to evaluate the effect of taurine via drinking water on the lead-induced impairments of LTP and DP in rat dentate gyrus (DG) in vivo. The experiments were carried out in four groups of rats (control, lead-exposed, control and lead-exposed with a taurine-supplement diet, respectively). The input-output (I/O) function, excitatory postsynaptic potential (EPSP) and population spike (PS) amplitude were measured in the DG area of adult rats (60-90 days) in response to stimulation applied to the lateral perforant path. The results show that: 1. chronic lead exposure impaired LTP/DP measured on both EPSP slope and PS amplitude in DG area of the hippocampus; 2. in control rats, taurine had no effect on LTP/DP; 3. the amplitudes of LTP/DP of lead-exposed group were significantly increased by applying taurine. These results suggest that dietary taurine supplement could protect rats from the lead-induced impairments of synaptic plasticity and might be a preventive medicine to cure the cognitive deficits induced by lead.  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