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   333073篇
  免费   64492篇
  国内免费   16428篇
耳鼻咽喉   3691篇
儿科学   7625篇
妇产科学   3776篇
基础医学   42836篇
口腔科学   9346篇
临床医学   46945篇
内科学   56723篇
皮肤病学   10176篇
神经病学   24467篇
特种医学   10999篇
外国民族医学   111篇
外科学   36446篇
综合类   48039篇
现状与发展   59篇
一般理论   47篇
预防医学   24602篇
眼科学   7901篇
药学   34649篇
  336篇
中国医学   18808篇
肿瘤学   26411篇
  2024年   1085篇
  2023年   4144篇
  2022年   10744篇
  2021年   14690篇
  2020年   15143篇
  2019年   18674篇
  2018年   18382篇
  2017年   19495篇
  2016年   19412篇
  2015年   23531篇
  2014年   26172篇
  2013年   26409篇
  2012年   25148篇
  2011年   26593篇
  2010年   24094篇
  2009年   17518篇
  2008年   17449篇
  2007年   15625篇
  2006年   14749篇
  2005年   13368篇
  2004年   9061篇
  2003年   8254篇
  2002年   6930篇
  2001年   5896篇
  2000年   5657篇
  1999年   4916篇
  1998年   2709篇
  1997年   2736篇
  1996年   2131篇
  1995年   1993篇
  1994年   1786篇
  1993年   1075篇
  1992年   1413篇
  1991年   1235篇
  1990年   1002篇
  1989年   944篇
  1988年   836篇
  1987年   689篇
  1986年   513篇
  1985年   446篇
  1984年   216篇
  1983年   178篇
  1982年   107篇
  1981年   145篇
  1980年   84篇
  1979年   130篇
  1978年   69篇
  1977年   57篇
  1976年   55篇
  1974年   63篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
We report the case of a littoral‐cell angioma of the spleen, a recently described benign vascular tumour, whose imaging and pathological characteristics have been discussed only by a few authors. The diagnosis was made after elective splenectomy. The CT images, scintigraphy and histological specimens are presented, and differential diagnoses discussed.  相似文献   
12.
Mutations in the gene encoding 11beta-hydroxysteroid dehydrogenase type 2, HSD11B2, cause a rare monogenic juvenile hypertensive syndrome called apparent mineralocorticoid excess (AME). In AME, defective HSD11B2 enzyme activity results in overstimulation of the mineralocorticoid receptor (MR) by cortisol, causing sodium retention, hypokalemia, and salt-dependent hypertension. Here, we have studied whether genetic variations in HDS11B2 are implicated in essential hypertension in Japanese hypertensives and the general population. By sequencing the entire coding region and the promoter region of HDS11B2 in 953 Japanese hypertensives, we identified five missense mutations in 11 patients (L14F, n = 5; R74H, n = 1; R147H, n = 3; T156I, n = 1; R335H, n = 1) and one novel frameshift mutation (4884Gdel, n = 1) in a heterozygous state, in addition to 19 genetic variations. All genetic variations identified were rare, with minor allele frequencies less than 0.005. Four of 12 patients with the missense/frameshift mutations showed renal failure. Four missense mutations, L14F, R74H, R147H, and R335H, were successfully genotyped in the general population, with a sample size of 3,655 individuals (2,175 normotensives and 1,480 hypertensives). Mutations L14F, R74H, R147H, and R335H were identified in hypertensives (n = 6, 8, 3, and 0, respectively) and normotensives (n = 8, 12, 5, and 0, respectively) with a similar frequency, suggesting that these missense mutations may not strongly affect the etiology of essential hypertension. Since the allele frequency of all of the genetic variations identified in this study was rare, an association study was not conducted. Taken together, our results indicate that missense mutations in HSD11B2 do not substantially contribute to essential hypertension in Japanese.  相似文献   
13.
14.
15.
We report clinical, neuroradiologic features, and neuropathologic findings of a 76‐year‐old man with coexistent Pick’s disease and progressive supranuclear palsy. The patient presented with loss of recent memory, abnormal behavior and change in personality at the age of 60. The symptoms were progressive. Three years later, repetitive or compulsive behavior became prominent. About 9 years after onset, he had difficulty moving and became bed‐ridden because of a fracture of his left leg. His condition gradually deteriorated and he developed mutism and became vegetative. The patient died from pneumonia 16 years after the onset of symptoms. Serial MRI scans showed progressive cortex atrophy, especially in the bilateral frontal and temporal lobes. Macroscopic inspection showed severe atrophy of the whole brain, including cerebrum, brainstem and cerebellum. Microscopic observations showed extensive superficial spongiosis and severe neuronal loss with gliosis in the second and third cortical layers in the frontal, temporal and parietal cortex. There were Pick cells and argyrophilic Pick bodies, which were tau‐ and ubiquitin‐positive in neurons of layers II–III of the above‐mentioned cortex. Numerous argyrophilic Pick bodies were observed in the hippocampus, especially in the dentate fascia. In addition, moderate to severe loss of neurons was found with gliosis and a lot of Gallyas/tau‐positive globus neurofibrillary tangles in the caudate nucleus, globus pallidus, thalamus, substantia nigra, locus coeruleus and dentate nucleus. Numerous thorned‐astrocytes and coiled bodies but no‐tuft shaped astrocytes were noted in the basal ganglion, brainstem and cerebellar white matter. In conclusion, these histopathological features were compatible with classical Pick’s disease and coexistence with progressive supranuclear palsy without tuft‐shaped astrocytes.  相似文献   
16.
The pharmacokinetics (PK) of moxifloxacin in healthy white New Zealand rabbits was studied following intravenous (IV) and subcutaneous (SC) administration routes as well as a SC long‐acting poloxamer 407 gel formulation (SC‐P407). Moxifloxacin concentrations were determined by high‐performance liquid chromatography assay with fluorescence detection. Mean half‐life for IV, SC and SC‐P407 routes was 2.15, 5.41 and 11.09 h. Clearance value after IV dosing was 0.78 l/kg/h. After SC administration, the mean absolute bioavailability was 117% and the Cmax was 1.61 ± 0.49 mg/l. After SC‐P407 administration, the bioavailability was 44% and the Cmax 1.83 was ±0.62 mg/l. No adverse effects were observed in any of the rabbits following IV, SC and SC‐P407 administration of moxifloxacin. Minimal inhibitory concentrations of moxifloxacin against different strains of Staphylococcus aureus from different european countries were used to compute the main pharmacodynamic (PD) surrogate markers of efficacy. The high tolerability of this SC‐P407 formulation and the favourable PK behaviour such as the long half‐life, acceptable bioavailability and excellent PK–PD ratios achieved indicate that it is likely to be effective in rabbits.  相似文献   
17.
杨改芳 《护理研究》2006,20(9):811-812
有资料显示,精神病人的自杀死亡率达6.0%[1],有的报道达22.7%[2].精神病病人自杀给家庭、社会带来的诸多问题,以成为精神科临床工作关注的重点.我院2001年-2004年对59例因自杀而入院的精神病病人进行护理干预,取得了满意的效果.现介绍如下.  相似文献   
18.
An OUR-QGD gamma ray stereotactic body radiotherapy system (body knife), made in China, is described. According to its structure and the principle of gamma radiation revolved on a focus, the energy distribution of scattered radiation in its treatment room is calculated. The structural shielding of the wall, roof, and door for a certain treatment room is calculated according to the local radiation protection law.  相似文献   
19.
跻身红尘     
一袭蓑衣,一根鱼竿,临岸静坐。庄子参破世间万物.宁愿静守一泓静水.坐看风云变幻. 一垄田.一把犁.茅屋菊花。陶渊明脱离浊淖,采菊东篱得见南山.行于世俗之外。  相似文献   
20.
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