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   191篇
  免费   19篇
  210篇
  2019年   2篇
  2017年   6篇
  2016年   9篇
  2015年   12篇
  2014年   10篇
  2013年   7篇
  2012年   7篇
  2011年   7篇
  2010年   10篇
  2009年   8篇
  2007年   8篇
  2006年   3篇
  2005年   9篇
  2004年   4篇
  2003年   2篇
  2002年   4篇
  2001年   4篇
  2000年   6篇
  1999年   7篇
  1998年   9篇
  1997年   3篇
  1996年   6篇
  1995年   2篇
  1994年   2篇
  1993年   3篇
  1992年   2篇
  1990年   4篇
  1988年   3篇
  1987年   5篇
  1986年   2篇
  1984年   2篇
  1983年   2篇
  1981年   3篇
  1980年   4篇
  1979年   2篇
  1978年   2篇
  1977年   4篇
  1975年   2篇
  1973年   2篇
  1971年   2篇
  1970年   2篇
  1969年   2篇
  1965年   1篇
  1959年   1篇
  1950年   1篇
  1947年   1篇
  1943年   1篇
  1934年   1篇
  1912年   1篇
  1911年   2篇
排序方式: 共有210条查询结果,搜索用时 0 毫秒
41.
42.
The limitations and special usefulness of clinical and laboratory diagnostic techniques in the diagnosis of gonorrhea are poorly understood and utilized by the average practitioner today. Most physicians and clinics, lulled by complacency or lack of ancillary aid in the area of diagnosis, proceed by measures based in many instances upon past fallacy rather than upon the facts recently developed by research in this disease. The same circumstances apply concerning treatment and management of this disease, particularly in females.All physicians are potentially capable of giving excellent treatment for syphilis today. The problem is to properly diagnose the disease, manage the patient and deal with the source. Looming large in the area of diagnosis is the interpretation of serologic tests for syphilis. No serologic test diagnoses syphilis, but rather gives information as to the immunologic status of the the patient in relation to reagin and treponemal antibodies. None of the antibodies measured in these tests are absolutely specific for syphilis alone.There is no substitute for a well-informed physician, who knows his patient, to relate and interpret even the best of treponemal serologic tests.  相似文献   
43.
Endocrine, behavioural and immunologic processes, together with body growth, were evaluated in gilts that were defeated at 10 weeks of age in resident-intruder tests. Immediately after defeat, gilts were either separated from or reunited with a familiar conspecific (litter-mate; always a barrow). Gilts were assigned to one of four treatments: (a) DI: defeat, followed by isolation (separation from original litter-mate; n=8); (b) I: no defeat, isolation (control group; n=9); (c) DP; defeat, followed by pair-housing (reunion with original litter-mate; n=8); and (d) P: no defeat, pair-housing (control group; n=8). The following general conclusions were derived: (1) social defeat caused pronounced short-term elevations in hypothalamic-pituitary-adrenal (HPA) and sympathetic-adrenal medullary activities, and of prolactin levels. Moreover, as soon as 1h after defeat, percentages of blood lymphocytes and neutrophilic granulocytes were, respectively, decreased and increased; (2) social defeat had some long-lasting influence on behaviour and physiology, but isolation predominantly determined responses in the longer term. Defeat, as well as isolation, resulted in increased cardiovascular activities compared to P controls, as observed in a novel object test (NOT: +7 days) and an aversion test (AVT: +14 days). Moreover, defeated as well as isolated gilts did not habituate to a repeated novel environment test (NET: -7, +2 and +7 days) in terms of frequencies of vocalising, whereas P controls did. Isolation, through the separation from any other pig, was responsible for the other observed long-term characteristics, which developed progressively. Isolated gilts showed high mobilities and high cortisol responses in the repeated NET (+7 days), not being habituated. This contrasted the reactions of pair-housed gilts, which were much reduced. In addition to their high cardiovascular activities in the NOT and the AVT, isolated gilts also displayed higher heart rates in the repeated NET and during human presence following the NOT, compared to pair-housed gilts. Finally, isolated gilts were more inhibited to approach a novel object (in the NOT) than pair-housed pigs; and (3) stress responses of defeated gilts were modulated by the subsequent social environment. Stimulation of the HPA-axis (plasma- and salivary cortisol) was prolonged in those defeated gilts which were isolated (observed in the first hour). Changes in leucocyte subsets were still observed after 3 days in DI, but were 'normalised' within 1 day in DP gilts. Two days after defeat, habituation to the repeated NET in terms of mobility and salivary cortisol responses occurred in control and DP gilts, but not in DI gilts. We argue that these effects of the social environment shortly after defeat were related to a stress-reducing effect of a stable social relationship, i.e. social support.  相似文献   
44.
45.
46.
47.
Gene amplification in mammalian cells commonly manifests itself as homogeneously staining chromosomal regions (HSRs). These are frequently seen in neuroblastoma and have been shown to be the site of amplification of the NMYC oncogene. We have used a nonisotopic, high-resolution in situ hybridization technique to reveal a hitherto unrecognized periodic microstructure within HSRs of a human neuroblastoma cell line.  相似文献   
48.
49.
Membrane-bounded nucleoids in microbial symbionts of marine sponges   总被引:2,自引:0,他引:2  
In thin sections of resin-embedded samples of glutaraldehyde- and osmium tetroxide-fixed tissue from five genera of marine sponges, Stromatospongia, Astrosclera, Jaspis, Pseudoceratina and Axinyssa, cells of a bacteria-like symbiont microorganism which exhibit a membrane-bounded nuclear region encompassing the fibrillar nucleoid have been observed within the sponge mesohyl. The nuclear region in these cells is bounded by a single bilayer membrane, so that the cell cytoplasm is divided into two distinct regions. The cell wall consists of subunits analogous to those in walls of some Archaea. Cells of the sponge symbionts observed here are similar to those of the archaeal sponge symbiont Cenarchaeum symbiosum.  相似文献   
50.

Background  

Massive text mining of the biological literature holds great promise of relating disparate information and discovering new knowledge. However, disambiguation of gene symbols is a major bottleneck.  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