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   272532篇
  免费   24321篇
  国内免费   19635篇
耳鼻咽喉   2071篇
儿科学   2343篇
妇产科学   3026篇
基础医学   33410篇
口腔科学   4361篇
临床医学   38929篇
内科学   39370篇
皮肤病学   2439篇
神经病学   15417篇
特种医学   9663篇
外国民族医学   198篇
外科学   26004篇
综合类   44598篇
现状与发展   74篇
一般理论   27篇
预防医学   16123篇
眼科学   8368篇
药学   28583篇
  383篇
中国医学   16074篇
肿瘤学   25027篇
  2025年   89篇
  2024年   3997篇
  2023年   5927篇
  2022年   11795篇
  2021年   14361篇
  2020年   11528篇
  2019年   9967篇
  2018年   9746篇
  2017年   8661篇
  2016年   8228篇
  2015年   12244篇
  2014年   15031篇
  2013年   12588篇
  2012年   18838篇
  2011年   21583篇
  2010年   13074篇
  2009年   10083篇
  2008年   13386篇
  2007年   13396篇
  2006年   13638篇
  2005年   13874篇
  2004年   8215篇
  2003年   7609篇
  2002年   6379篇
  2001年   5698篇
  2000年   6424篇
  1999年   7171篇
  1998年   4736篇
  1997年   4752篇
  1996年   3679篇
  1995年   3514篇
  1994年   2898篇
  1993年   1964篇
  1992年   2213篇
  1991年   1842篇
  1990年   1566篇
  1989年   1333篇
  1988年   1133篇
  1987年   990篇
  1986年   748篇
  1985年   608篇
  1984年   349篇
  1983年   214篇
  1982年   115篇
  1981年   126篇
  1980年   85篇
  1979年   91篇
  1965年   1篇
  1962年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
不是医院老板,也不是税务局官员,但心忧民营医院运势的王爱国对“税改”的企盼似乎更为迫切。  相似文献   
102.
103.
G1、G2引物是对问号钩体具有特异性引物。分别用G1或G2单引物对问号钩体中国参考株进行前4个低严格度循环的PCR扩增,扩增带谱显示赖型、犬型、致热型、秋季型、澳洲型、临海型、乌尔夫型、溶血型为一类,而爪哇型、拜伦型、波摩那型、七日热型、巴叶赞型塔拉索夫型、曼耗Ⅱ型是不与以上赖型等血清型本为一类,双曲钩体atoc型及伊利尼细丝体伊利尼型的扩增带谱与问号钩体截然不同。应用苯酚法提取的高纯度钩体DNA  相似文献   
104.
The aim of the present study was to determine if muscarinic acetylcholine receptor-mediated peristaltic rhythmogenesis in the rat oesophagus is a central motor program that can be generated without peripheral sensory support. In anaesthetized male Sprague-Dawley rats, pressure-ejection of glutamate (10–20 pmol) and muscarine (5–10 pmol) in the subnucleus centralis of the nucleus tractus solitarii (NTSC) evoked monophasic pressure waves and rhythmic oesophageal peristalsis, respectively, but did not change mean arterial blood pressure or respiration. Application of muscarine (50–100 pmol) to the NTS extraventricular surface evoked rhythmic multi-unit burst discharges in the compact formation of the nucleus ambiguus (AMBC) that led to oesophageal peristalsis in a phase-locked manner. Evoked rhythmic AMBC activity persisted during neuromuscular blockade with curare, although the peak frequency of individual bursts was decreased. In a brainstem slice preparation, intracellular and whole cell patch recordings from AMBC neurones during focal stimulation of the NTSC region with muscarine revealed rhythmic depolarizing waves that showed a pattern similar to that of rhythmic oesophageal peristalsis. The present findings support the concept that medullary circuits comprising premotor neurones of the NTSC are intrinsically capable of generating rhythmic oesophagomotor output, but are subject to a powerful modulation by peripheral sensory feedback.  相似文献   
105.
张爱珍 《护理研究》2006,20(12):3366-3366
目前,国内同行对细菌引起病人医院感染的研究比较深入广泛。为了解医务人员自身感染原因及对工作和病人的影响,对本院医务人员自身感染的情况进行回顾性调查,将感染状况分析如下。  相似文献   
106.

Objectives  

To investigate clinical effects and manual operational point of Bryan cervical disc prosthesis in Chinese, to observe the stability and range of movement (ROM) post-operatively.  相似文献   
107.
It has been suggested that gains of chromosomes 7 and 17 and loss of Y occur in renal papillary adenoma and that progression to papillary renal cell carcinoma is marked by gains of additional chromosomes, most frequently 12, 16, and 20. Previous studies have included very few lesions of <5 mm in diameter, a requirement of the present definition of papillary adenoma. Ten papillary adenomas (ranging from 1 to 5 mm in diameter) from autopsy material and 10 surgically resected papillary renal cell carcinomas were studied with fluorescence in situ hybridization in paraffin sections using centromeric probes for chromosomes 7, 12, 16, 17, 20, and Y diluted 1:100 with tDenHyb1 buffer. The signals in 50 to 150 nuclei were counted in each tumor. Controls for all the probes were normal renal tissues from the same patients. Three or more signals per nucleus were frequently observed in papillary adenomas: chromosome 7 (range, 10 to 50%; > or = 30% in 9 of 10), 17 (range, 10 to 47%; > or = 30% in 7), 16 (range, 1 to 63%; > or = 10% in 5), 12 (range, 0 to 32%; > or =10% in 4), and 20 (range, 5 to 49%; > or = 10% in 5). Loss of the Y chromosome was observed in 80 to 90% of nuclei in 9 adenomas from males. Three or more signals were frequent in papillary renal cell carcinomas: chromosome 7 (range, 32 to 63%; > or =30% in 10 of 10), 17 (range, 28 to 61%; > or = 30% in 7), 16 (range, 0 to 45%; > or = 10% in 6), 12 (range, 1 to 37, > or = 10% in 5), 20 (range, 2 to 44%; > or = 10% in 4). No signal for Y was observed in 12 to 88% (> or = 81% in 6) of nuclei in 7 carcinomas from males. Statistical analysis showed no difference between adenomas and carcinomas. Gains of chromosomes 7, 17, 16, 12, and 20 and loss of the Y chromosome occur early in the evolution of papillary renal cell neoplasia in tumors that are only a few millimeters in diameter. Progressive gains of these chromosomes do not appear to correlate with the transition from adenoma to carcinoma.  相似文献   
108.
报告全胃切除ρ形空肠代胃治疗胃癌64例。术后无吻合口瘘与手术死亡,无返流性食管炎和倾倒综合征,生存质量满意。术后1、3、5年生存率分别为71.8%、42.2%和34.4%。本组结果表明:此种改良后的ρ形空肠代胃、空肠原位间置术式,安全、简便、省时,使常见的手术并发症和远期后遗症均可得到较好预防和纠正,术后生存质量高,是一种满意的代胃术。  相似文献   
109.
Summary In this study the technique of labelling the cell membrane with DPH fluorescence polarization was used to observe the membrane fluidity of B lymphocytic cell lines and tonsillar cells from healthy persons; the modulation effect on membrane-fluidity induced by McAbs against isotypic and idiotypic determinants of IgM from patients with leukemia was studied as well. The expression of the corresponding isotypic and idiotypic determinants of IgM on the cell membrane was determined. The results show that the membrane fluidity of leukemic cell lines is remarkably higher than that of tonsillar cells from healthy persons, and McAbs against isotypic determinants of leukemic IgM can enhance the membrane fluidity of all kinds of cells mentioned above. However, the anti-idiotypic monoclonal antibody increased only the membrane fluidity of leukemic cell lines. These results indicated that there was a close relationship between the effect of McAbs on cell membrane fluidity and the expression of corresponding isotypic and idiotypic determinants of IgM on the cell membrane.  相似文献   
110.
The precision of renal mean transit time (MTT) measurements by 99Tcm-DTPA scintigraphy was studied by a Monte Carlo procedure. Data were obtained from twenty mild essential hypertensives with normal renal function. An ensemble of equivalent data sequences was constructed for each renal time-activity curve (TAC), assuming the dominant noise in the data to be Poisson in character. TACS were deconvolved by the matrix method and MTT was inferred from retention functions by a procedure entailing a nonlinear least-squares minimization. For every ensemble of data sequences a distribution of MTTs was generated. The population-averaged coefficients of variation for these distributions were 1.6% and 2.6%, for whole-kidney and cortical data, respectively. We conclude that the precision of MTT determination from clinical data is comparable to that from simulated data. MTT measurements may be useful for detecting functional changes in individual kidneys following an intervention such as angiotensin-converting-enzyme inhibition.  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