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   9514篇
  免费   845篇
  国内免费   66篇
耳鼻咽喉   73篇
儿科学   374篇
妇产科学   280篇
基础医学   1140篇
口腔科学   401篇
临床医学   830篇
内科学   1818篇
皮肤病学   132篇
神经病学   1034篇
特种医学   596篇
外科学   1256篇
综合类   272篇
一般理论   9篇
预防医学   958篇
眼科学   166篇
药学   609篇
中国医学   44篇
肿瘤学   433篇
  2022年   90篇
  2021年   172篇
  2020年   131篇
  2019年   148篇
  2018年   152篇
  2017年   133篇
  2016年   148篇
  2015年   164篇
  2014年   244篇
  2013年   333篇
  2012年   407篇
  2011年   436篇
  2010年   282篇
  2009年   323篇
  2008年   392篇
  2007年   460篇
  2006年   417篇
  2005年   425篇
  2004年   376篇
  2003年   372篇
  2002年   342篇
  2001年   283篇
  2000年   289篇
  1999年   288篇
  1998年   149篇
  1997年   148篇
  1996年   146篇
  1995年   135篇
  1994年   106篇
  1993年   115篇
  1992年   205篇
  1991年   180篇
  1990年   169篇
  1989年   146篇
  1988年   155篇
  1987年   151篇
  1986年   171篇
  1985年   146篇
  1984年   133篇
  1983年   96篇
  1982年   78篇
  1981年   60篇
  1980年   69篇
  1979年   97篇
  1978年   71篇
  1975年   66篇
  1974年   70篇
  1973年   58篇
  1972年   60篇
  1969年   60篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
52.
Over the study period from 1981 to 1987 inclusive, student critiques were scored to indicate the undergraduates' perception of the quality of teaching they received on each 2-month attachment to the trauma and orthopaedic surgical departments of two teaching hospitals. The medical staff and the environment in the two teaching hospitals were different. It was found that while the mean MCQ results did not change significantly throughout the study period, an improvement was noticed in the perceived quality of undergraduate tuition, especially at one hospital.  相似文献   
53.
The postoperative care of stoma patients is truly life long. With the excellent stoma equipment available, no patient should be a "stoma cripple." New advances in continent reservoirs will improve patient acceptance and lessen the fear associated with stomas. Finally, close follow-up by both the enterostomal therapy nurse and the surgeon is essential for the complete care of the stoma patient.  相似文献   
54.
Partner notification should be standard public health practice in the control of human immunodeficiency virus (HIV) infection. A universal partner notification program for the United States is affordable, operationally manageable, and can effectively reach high-risk persons. Such a focused approach personalizes the epidemic and probably enhances the efficacy of risk reduction messages. Confidentiality protections are attainable. Voluntary partner notification is acceptable to our constituents; while counseling is "mandatory," testing is optional. Evidence of partner notification's usefulness as a case prevention tool should be a by-product of program outcomes and not a prerequisite for its implementation.  相似文献   
55.
Event-related potentials (ERPs) from 134 children were obtained at 3 and 8 years of age and recorded to a series of consonant-vowel speech syllables and their nonspeech analogues. The HOME inventory was administered to these same children at 3 and 8 years of age and the sample was divided into 2 groups (low vs. high) based on their HOME scores. Discriminant functions analyses using ERP responses to speech and non-speech analogues successfully classified HOME scores obtained at 3 and 8 years of age and discriminated between children who received low vs. high levels of stimulation for language and reading.  相似文献   
56.
57.
X-linked spinal and bulbar muscular atrophy (SBMA) is caused by a CAG repeat expansion in the first exon of the androgen receptor (AR) gene. Disease-associated alleles (37-66 CAGs) change in length when transmitted from parents to offspring, with a significantly greater tendency to shift size when inherited paternally. As transgenic mice carrying human AR cDNAs with 45 and 66 CAG repeats do not display repeat instability, we attempted to model trinucleotide repeat instability by generating transgenic mice with yeast artificial chromosomes (YACs) carrying AR CAG repeat expansions in their genomic context. Studies of independent lines of AR YAC transgenic mice with CAG 45 alleles reveal intergenerational instability at an overall rate of approximately 10%. We also find that the 45 CAG repeat tracts are significantly more unstable with maternal transmission and as the transmitting mother ages. Of all the CAG/CTG repeat transgenic mice produced to date the AR YAC CAG 45 mice are unstable with the smallest trinucleotide repeat mutations, suggesting that the length threshold for repeat instability in the mouse may be lowered by including the appropriate flanking human DNA sequences. By sequence-tagged site content analysis and long range mapping we determined that one unstable transgenic line has integrated an approximately 70 kb segment of the AR locus due to fragmentation of the AR YAC. Identification of the cis - acting elements that permit CAG tract instability and the trans -acting factors that modulate repeat instability in the AR YAC CAG 45 mice may provide insights into the molecular basis of trinucleotide repeat instability in humans.   相似文献   
58.
Creating a death register for general practice.   总被引:1,自引:2,他引:1       下载免费PDF全文
General practitioners complete approximately 26% of death certificates themselves but have considerable difficulty obtaining prompt and accurate information about their other patients who die. A random survey of district health authorities in England revealed that all were able to compile death lists but none included general practitioner details. This paper reviews the flow of information on patient deaths and describes a project to assess the feasibility of providing Newcastle general practitioners with comprehensive death registers. With the collaboration of the family health services authority and the district health authority, and with data from the regional perinatal mortality survey the creation each week of complete lists of patient deaths, broken down by general practitioner, is feasible. Death registers allow general practitioners to undertake audit of the quality of death certification and of the care of the recently deceased, and to improve the continuing care of the bereaved.  相似文献   
59.
We report on a familial t(4;7)(q28;p22) with 2:2 adjacent‐1 unbalanced segregation producing duplication of 4q28→qter in multiple offspring. Within the large four‐generation pedigree, a carrier had a reproductive outcome that was approximately equal for 1) the balanced translocation, 2) normal chromosomes, and 3) viable 4q trisomy or pregnancy loss. The three individuals with chromosomal confirmation of trisomy 4q28→qter (comprising approximately 1.8% of the haploid autosomal length) had similar mental and developmental retardation, hypotonia, restricted speech, seizures, and facial anomalies but no cardiac, renal, or skeletal anomalies. It is suggested that these latter severe malformations, associated with the classic 4q2 to 3 group of anomalies, were from an imbalance outside 4q28→qter and were not necessarily related to the relatively large size of the trisomic segment. Multiple different chromosomes are reported to be rearranged with 4q in the production of distal 4q trisomy. The incidence of 4q rearrangement remains unexplained, but once it is present in a family, viability of a large trisomy in 4q seems to explain the number of affected individuals reported. © 2001 Wiley‐Liss, Inc.  相似文献   
60.
Intraabdominal abscesses were induced in mice by intraperitoneal inoculation of Bacteroides fragilis and Escherichia coli plus bran as the abscess-potentiating agent. Six- or seven-day-old abscesses were mechanically disaggregated in buffer, and the cells obtained were fractionated on discontinuous Percoll density gradients. Neutrophil populations of different density, each approximately 90% pure, were isolated. When the abscess-derived neutrophils were subsequently incubated with normal serum in vitro under aerobic conditions, the viability of the gram-negative bacteria that had been phagocytosed within the abscess did not change significantly. This anergy to intracellular bacteria (on subsequent incubation in vitro under optimal conditions for phagocytic killing) was also found for neutrophils that had been obtained from abscesses induced by a mixture that included Proteus mirabilis plus B. fragilis and from those induced by E. coli plus P. mirabilis. While unable to significantly kill intracellular organisms that had been phagocytosed in vivo, the abscess-derived neutrophils could engulf and kill organisms to which they were exposed in vitro. Neutrophils from abscesses induced by P. mirabilis only plus bran killed that organism introduced in vitro significantly more effectively than the organisms that had been engulfed in vivo. In contrast, neutrophils from abscesses induced by the gram-positive organism Staphylococcus aureus plus bran were able to kill their intracellular organisms on subsequent incubation in vitro as effectively as they could kill added S. aureus. Neutrophils isolated from the peripheral blood and from induced peritoneal exudates of abscess-bearing mice were able to phagocytose and kill organisms in vitro with greater efficiency than abscess-derived neutrophils. The mechanism whereby neutrophils from abscesses induced by the gram-positive organism S. aureus can kill the organisms phagocytosed in vivo on subsequent in vitro incubation, in contrast to the relative anergy to their intracellular organisms displayed by neutrophils derived from abscesses induced by combinations of gram-negative bacteria, is not known.  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