全文获取类型
收费全文 | 847篇 |
免费 | 80篇 |
出版年
2020年 | 7篇 |
2019年 | 8篇 |
2018年 | 7篇 |
2017年 | 13篇 |
2016年 | 18篇 |
2015年 | 26篇 |
2014年 | 32篇 |
2013年 | 49篇 |
2012年 | 48篇 |
2011年 | 59篇 |
2010年 | 35篇 |
2009年 | 23篇 |
2008年 | 48篇 |
2007年 | 54篇 |
2006年 | 37篇 |
2005年 | 40篇 |
2004年 | 50篇 |
2003年 | 35篇 |
2002年 | 39篇 |
2001年 | 14篇 |
2000年 | 13篇 |
1999年 | 21篇 |
1998年 | 13篇 |
1997年 | 10篇 |
1996年 | 10篇 |
1995年 | 7篇 |
1994年 | 9篇 |
1993年 | 11篇 |
1992年 | 6篇 |
1991年 | 8篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 7篇 |
1987年 | 9篇 |
1986年 | 6篇 |
1985年 | 8篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 8篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1979年 | 7篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1972年 | 7篇 |
1970年 | 8篇 |
1969年 | 6篇 |
1968年 | 8篇 |
1963年 | 5篇 |
排序方式: 共有927条查询结果,搜索用时 140 毫秒
1.
2.
In-depth interviews were conducted among 50 subjects residing in the industrial town of Newcastle, Australia. Half of these subjects were from the general population and half were currently seeking counselling for personal/family problems. None of the subjects were receiving any medical care at the time of interview, though seven had done so during the episode of distress they were discussing. The study shows that while the subjects psychologized their problems, members of both groups tended to somatize at a rate proportional to the level of distress. Subjects were unaware of any relationship between the distress they were experiencing and their physical complaints. The results of this study support previous research which argues that those experiencing distress and those who tend to introspect are also those who are likely to amplify somatic symptoms. At the same time these results depart from findings in the United States which suggest that in the West, people learn to express social and personal distress in psychological terms,, thereby reducing the level of somatization. Though not representative of the population as a whole, the findings raised questions warranting further study. 相似文献
3.
4.
Method for Assessing the Frequency of Transfer of an R Factor on Solid Media and for Isolating Cells of the Donor Type from a Predominantly Repressed Culture
下载免费PDF全文
![点击此处可从《Journal of bacteriology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A method for assessing the incidence of R factor transfer on solid media is described. The method gives values similar to those obtained with conventional techniques but allows the derepressed cells from a predominantly repressed population to be isolated. 相似文献
5.
R. A. Sturge C. Beardwell M. Hartog D. Wright B. M. Ansell 《BMJ (Clinical research ed.)》1970,3(5722):547-551
Linear growth was studied in 20 children suffering from Still''s disease on various treatment regimens, and their ability to secrete growth hormone and cortisol was investigated. Growth recovered on reducing daily corticosteroid therapy or on changing to an alternative regimen. Retardation of growth was not due to an absolute inability to secrete growth hormone. Basal plasma cortisol levels and the plasma cortisol response to hypoglycaemia were reduced in patients on daily steroid therapy, but patients on alternate-day prednisone did not differ significantly in this respect from those on non-steroid regimens. Those on alternate-day corticotrophin showed preservation of the circadian rhythm but a subnormal response to hypoglycaemia. 相似文献
6.
Plasmalogenase activity in normal and demyelinating tissue of the central nervous system 总被引:4,自引:1,他引:3
下载免费PDF全文
![点击此处可从《The Biochemical journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
1. The plasmalogenase activity of brain was found to be associated with the white matter but was absent from myelin fractions. 2. Increased enzyme activity was found in demyelinating spinal cords from vitamin B12-deficient monkeys and in white matter from a patient with multiple sclerosis. 相似文献
7.
Eleven strains of the crown gall organism, Agrobacterium tumefaciens, tested by intraperitoneal injection into mice, were lethal within 48 hr. Five other species had some lethal strains. The lethal effect of A. tumefaciens appeared to be the result of a toxic rather than an infectious process, since histopathological anomalies were not found in mice injected with live cultures and since heat-killed cultures were lethal. The murine toxin disappeared when A. tumefaciens was grown at 36 C and reappeared when the organism was subsequently incubated below 30 C. The murine toxin itself was not inactivated by exposure to 100 C for 30 min. The toxin was associated with the cells and was not excreted into the medium. Centrifugal fractionation revealed that the toxin was associated with the smaller cells in 3-day stationary-phase cultures. These data suggested a possible relationship between toxin production and the production of the agents responsible for the initiation of plant tumors. 相似文献
8.
THE METABOLISM OF LABELLED ETHANOLAMINE IN THE BRAIN OF THE RAT IN VIVO 总被引:13,自引:1,他引:12
9.
Teresa L. Johnson Mary Pat Moyer 《In vitro cellular & developmental biology. Plant》1990,26(11):1095-1100
Summary Normal human colon mucosa cells and cells obtained from histologically normal tissues near that cancer were fused with human
colon cancer cells. Resultant hybrid populations of normal and malignant cell fusions behaved as nonmalignant cells in culture,
were unable to grow in soft agar, did not express tumor-associated antigens, and were nontumorigenic in nude mice. Autofusion
of the cancer cell population led to a phenotype intermediate between normal and malignant cells. That is, the cultures had
a much lower plating efficiency in soft agar, and the tumors had a longer latency and slower growth rate in nude mice. This
is the first cell culture system to demonstrate that normal epithelial cells can suppress malignancy of their autologous cancer
cells, and is a prelude to more extensive studies of genetic events involved in malignant conversion of human colonic epithelium.
This study was supported by The University of Texas Health Science Center at San Antonio Center for Human Cell Biotechnology
and a graduate student stipend (T. J.) from the Department of Cellular and Structural Biology. 相似文献
10.
Clutton SM Townsend KM Goodhead DT Ansell JD Wright EG 《Cell death and differentiation》1996,3(1):141-148
Embryonal stem cells have been used to study the effects of environmentally relevant doses of radiation on cell death and differentation. The ES cells were found to have a greater than 60% chance of surviving the traversal of a single alpha-particle, the lowest possible dose of high linear energy transfer radiation a cell may receive. The ES cells appeared to possess the cell cycle checkpoints believed to prevent the transmission of the radiation damage. However, delayed effects were observed in the progeny. An increased incidence of apoptosis and haempoietic differentiation capacity was found to persist in the ES cell population over many cell divisions. Since both cell death and differentiation are known to play a key role in tissue kinetics, an ES cell model will provide a valuable and versatile cell system for studying the role of cell death and differentiation in the pathology of radiogenic diseases. 相似文献