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   414篇
  免费   81篇
  国内免费   4篇
耳鼻咽喉   1篇
儿科学   15篇
妇产科学   11篇
基础医学   167篇
口腔科学   7篇
临床医学   48篇
内科学   64篇
皮肤病学   8篇
神经病学   10篇
特种医学   61篇
外科学   27篇
综合类   15篇
预防医学   21篇
眼科学   3篇
药学   35篇
肿瘤学   6篇
  2023年   2篇
  2022年   3篇
  2021年   7篇
  2020年   2篇
  2019年   8篇
  2018年   4篇
  2017年   2篇
  2016年   9篇
  2015年   8篇
  2014年   13篇
  2013年   8篇
  2012年   10篇
  2011年   3篇
  2010年   9篇
  2009年   7篇
  2008年   6篇
  2007年   12篇
  2006年   14篇
  2005年   13篇
  2004年   18篇
  2003年   8篇
  2002年   13篇
  2001年   10篇
  2000年   14篇
  1999年   16篇
  1998年   18篇
  1997年   14篇
  1996年   20篇
  1995年   12篇
  1994年   10篇
  1993年   20篇
  1992年   18篇
  1991年   13篇
  1990年   15篇
  1989年   21篇
  1988年   17篇
  1987年   10篇
  1986年   12篇
  1985年   9篇
  1984年   6篇
  1983年   10篇
  1982年   3篇
  1981年   7篇
  1980年   13篇
  1979年   8篇
  1978年   3篇
  1977年   9篇
  1976年   5篇
  1974年   2篇
  1826年   1篇
排序方式: 共有499条查询结果,搜索用时 31 毫秒
1.
Even though a variety of adverse effects caused by sweeteners, flavorings, and dyes in susceptible individuals have been reported, there is no good single reference with information about these substances in pediatric antimicrobials. Data on sweeteners, flavorings, and dyes in 91 antimicrobial preparations were collected. Sucrose was present in 74 (85%) of 87 preparations, followed by saccharin in 30 (34%) preparations. Mannitol, lactose, and sorbitol were each present in 7 preparations. None of the preparations were free of sweeteners. Thirty-four (37%) of 91 preparations did not specify the flavoring content. While cherry was the most common flavoring used, there were 25 other flavorings. Thirteen different dyes and coloring agents were used in these antimicrobials. Red dye no. 40 was present in 45% of preparations. Tables detailing sweeteners, flavorings, and dyes in different groups of antimicrobials (amoxicillin, ampicillin, cephalosporins, erythromycin, penicillins, sulfonamides, and others) and adverse effects reported with these inert ingredients are presented. These tables should be helpful to physicians in selecting an antimicrobial containing a different sweetener and/or dye when an adverse reaction occurs.  相似文献   
2.
3.
Image-directed percutaneous biopsies with a biopsy gun   总被引:3,自引:0,他引:3  
Core tissue for histologic study is believed by many pathologists to be more diagnostic than material from needle aspiration. Recently, a biopsy "gun" has been introduced, which simplifies core biopsies. With this device, 182 biopsies of multiple anatomic sites were performed with ultrasonic, computed tomographic, and fluoroscopic guidance and 18-gauge needles. High-quality histopathologic specimens were obtained in 177 of the biopsies, and diagnostic target tissue was obtained in 167. Only three significant complications occurred: one bleeding complication that required transfusion and two cases of pneumothorax that necessitated placement of chest tubes. The biopsy gun eliminated the disjointed movements of conventional "skinny" needle biopsies, and none of the samples demonstrated significant "crush" artifact or obscuring blood, problems that are commonly associated with manual biopsy techniques. Patient discomfort was decreased with this system compared with that of manual biopsies, and the total procedure time was reduced. Because of these distinct advantages, the authors now use the biopsy gun exclusively for all percutaneous biopsies and recommend that other institutions consider the use of this biopsy method.  相似文献   
4.
5.
The growth of Nocardia asteroides GUH-2 and two mutants (NG-49 and I-38-syn) in regions of the brains of BALB/c mice was determined by microdissection and viable counting. GUH-2 grew throughout the murine brain but at different growth rates that depended on the specific location. The rate of increase in total CFU per brain during GUH-2 infection was unaffected by the inoculum size; however, in five of eight brain regions, an alteration in the inoculum size resulted in altered nocardial growth rates. Mutant NG-49 showed a significantly slower rate of increase in total CFU per brain than did the parental strain, GUH-2, and significantly decreased growth rates in seven brain regions. Mutant I-38-syn showed a rate of increase in total CFU per brain similar to that of the parental strain; however, this mutant grew significantly faster in the cerebellum and pons-medulla. Growth appeared to be a necessary precursor to the cellular damage that resulted in the variety of neurological disorders observed in mice infected with N. asteroides GUH-2, because mutant NG-49 exhibited a decreased ability to grow in specific regions of the brain and did not induce signs of neurological damage. In contrast, mutant I-38-syn induced neurological signs in a larger percentage of the infected animals than did parental strain GUH-2 and grew better in certain regions of the brain than did the parental strain. Furthermore, there appeared to be a relationship between the growth of N. asteroides in the substantia nigra and the induction of an L-dopa-responsive head shake that was observed in some of the mice following a sublethal intravenous injection of N. asteroides GUH-2.  相似文献   
6.
The attachment to and penetration of endothelial cells in the pons and midbrain (especially the substantia nigra) regions of the brains of BALB/c mice by log-phase Nocardia asteroides GUH-2 cells were determined by both scanning and transmission electron microscopic analysis. Within 15 min after exposure, the nocardiae attached to the surface of the endothelial cell membrane. This attachment occurred primarily at the growing tip of the nocardial filament, and the outermost layer of the nocardial cell wall had regions (electron-dense areas) that bound firmly to the cytoplasmic membrane of the host cell. There appeared to be specificity for this binding localized within the capillaries and arterioles because some regions had large numbers of bacteria bound, whereas adjacent areas had no bacterial cells. Nocardial filaments that attached by the apex induced a cuplike deformation of the endothelial cell membrane. This was followed by a rapid penetration of the endothelial cell so that within 25 min many of the bacteria were internalized within the host cell. These internalized bacteria remained within vesicles, and there was no ultrastructural evidence of damage to the nocardial cell during this process. Heat-killed GUH-2 cells still attached to endothelial surfaces (at a reduced frequency), but they did not penetrate into the endothelial cell. These data suggest that brain-invasive nocardiae possess both an adhesin for attachment to the membrane of endothelial cells and an invasion factor that promotes nocardial penetration of these cells.  相似文献   
7.
8.
Nocardia species: host-parasite relationships.   总被引:13,自引:2,他引:13       下载免费PDF全文
The nocardiae are bacteria belonging to the aerobic actinomycetes. They are an important part of the normal soil microflora worldwide. The type species, Nocardia asteroides, and N. brasiliensis, N. farcinica, N. otitidiscaviarum, N. nova, and N. transvalensis cause a variety of diseases in both normal and immunocompromised humans and animals. The mechanisms of pathogenesis are complex, not fully understood, and include the capacity to evade or neutralize the myriad microbicidal activities of the host. The relative virulence of N. asteroides correlates with the ability to inhibit phagosome-lysosome fusion in phagocytes; to neutralize phagosomal acidification; to detoxify the microbicidal products of oxidative metabolism; to modify phagocyte function; to grow within phagocytic cells; and to attach to, penetrate, and grow within host cells. Both activated macrophages and immunologically specific T lymphocytes constitute the major mechanisms for host resistance to nocardial infection, whereas B lymphocytes and humoral immunity do not appear to be as important in protecting the host. Thus, the nocardiae are facultative intracellular pathogens that can persist within the host, probably in a cryptic form (L-form), for life. Silent invasion of brain cells by some Nocardia strains can induce neurodegeneration in experimental animals; however, the role of nocardiae in neurodegenerative diseases in humans needs to be investigated.  相似文献   
9.
10.
The purpose of this study was to evaluate the appropriateness of the predominantly clinical PharmD curriculum in light of actual employment patterns of PharmD graduates. Data were gathered via a survey of PharmD graduates from the seven post-baccalaureate programs active since 1972. Respondents were asked about their employment patterns and characteristics; about their formal education in the areas of management, statistics, and research methods; and to indicate whether they had completed residencies or fellowships. The results indicate that many PharmD graduates are employed in positions requiring considerable nonclinical skills, especially management skills. The results further indicate that few respondents have completed formal education, residencies, or fellowships which would prepare them for management or other nonclinical positions. Consequently, it appears that PharmD programs should require considerably more management training and education in order to adequately prepare their graduates for the positions open to them.  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