全文获取类型
收费全文 | 2140篇 |
免费 | 226篇 |
专业分类
2366篇 |
出版年
2023年 | 12篇 |
2022年 | 21篇 |
2021年 | 35篇 |
2020年 | 15篇 |
2019年 | 31篇 |
2018年 | 31篇 |
2017年 | 24篇 |
2016年 | 54篇 |
2015年 | 89篇 |
2014年 | 76篇 |
2013年 | 97篇 |
2012年 | 143篇 |
2011年 | 144篇 |
2010年 | 95篇 |
2009年 | 78篇 |
2008年 | 116篇 |
2007年 | 103篇 |
2006年 | 125篇 |
2005年 | 113篇 |
2004年 | 94篇 |
2003年 | 85篇 |
2002年 | 103篇 |
2001年 | 29篇 |
2000年 | 32篇 |
1999年 | 40篇 |
1998年 | 27篇 |
1997年 | 18篇 |
1996年 | 14篇 |
1995年 | 23篇 |
1994年 | 15篇 |
1993年 | 15篇 |
1992年 | 25篇 |
1991年 | 15篇 |
1990年 | 22篇 |
1989年 | 22篇 |
1988年 | 21篇 |
1987年 | 15篇 |
1986年 | 22篇 |
1985年 | 18篇 |
1984年 | 22篇 |
1983年 | 20篇 |
1982年 | 25篇 |
1981年 | 12篇 |
1980年 | 15篇 |
1978年 | 14篇 |
1977年 | 16篇 |
1976年 | 15篇 |
1975年 | 12篇 |
1974年 | 16篇 |
1973年 | 19篇 |
排序方式: 共有2366条查询结果,搜索用时 15 毫秒
11.
P. M. Bolton C. Teasdale A. M. Mander Susan L. James Joyce M. Davidson R. H. Whitehead R. G. Newcombe L. E. Hughes 《Cancer immunology, immunotherapy : CII》1976,1(4):251-258
Summary The immune competence of a group of 276 patients with suspected breast cancer has been assessed using a spectrum of tests: the peripheral lymphocyte count, serum immunoglobulin levels, lymphocyte response to phytohemagglutinin (PHA), Mantoux test, and dinitrochlorobenzene (DNCB) skin test. All tests were completed prior to any form of treatment as the initial part of an ongoing, long-term assessment which will ultimately relate immune competence to prognosis. 225 patients with breast cancer were allocated into stages based on their TNM status. The remaining 51 patients proved to have benign breast disease and made up the control group. In analysis, control patients were compared with early breast cancer patients, while the effect of advancing disease was assessed by betweenstage comparisons in the cancer group.There were no significant differences between early breast cancer and control patients or between cancer stages in peripheral lymphocyte count, serum immunoglobulin levels, lymphocyte response to PHA, or Mantoux responses. Age was found to have a crucial effect on some of these parameters and some apparent differences between the various groups lost significance after appropriate allowances were made for age.Important differences seen with the DNCB test persisted after allowing for age effects. Responses to DNCB were significantly depressed in patients with early breast cancer compared to controls. Patients with disseminated cancer showed greater depression than early breast cancer patients, but surprisingly, patients with locally advanced tumors had good responses to DNCB. Possible reasons for the paradoxical preservation of DNCB reactivity in patients with locally advanced cancer are discussed.The DNCB test is the most discriminating of the five tests of immune function studied. 相似文献
12.
All cases referred for pelvimetry in 1970-1 and all breech presentations referred for pelvimetry in 1972-4 were reviewed. Indications for pelvimetry fell into four main categories: high head in the antenatal clinic (47-8%); high head in labour (13-9%); breech presentation (20-9%); and previous caesarean section (14-8%). In the first two categories pelvimetry rarely if ever influenced management, and it should not be performed routinely. In breech presentation and cases of caesarean section pelvimetry seemed to be of value, but in the latter group it should be performed puerperally to avoid the known radiation hazard to the fetus. A fairly close correlation between obstetric conjugate and pelvic capacity was shown, which suggested that a 3400-g baby might pass through a pelvis of obstetric conjugate of 10 cm as a cephalic trial of labour, but would need an obstetric conjugate of 11-7 cm for safe vaginal breech delivery. 相似文献
13.
Aldo Spanjaard Ronak Shah Daniël de
Groot Olimpia Alessandra Buoninfante Ben Morris Cor Lieftink Colin Pritchard Lisa
M Zürcher Shirley Ormel Joyce J I Catsman Renske de
Korte-Grimmerink Bjrn Siteur Natalie Proost Terry Boadum Marieke van
de
Ven Ji-Ying Song Maaike Kreft Paul C M van
den
Berk Roderick
L Beijersbergen Heinz Jacobs 《Nucleic acids research》2022,50(13):7420
Crosslink repair depends on the Fanconi anemia pathway and translesion synthesis polymerases that replicate over unhooked crosslinks. Translesion synthesis is regulated via ubiquitination of PCNA, and independently via translesion synthesis polymerase REV1. The division of labor between PCNA-ubiquitination and REV1 in interstrand crosslink repair is unclear. Inhibition of either of these pathways has been proposed as a strategy to increase cytotoxicity of platinating agents in cancer treatment. Here, we defined the importance of PCNA-ubiquitination and REV1 for DNA in mammalian ICL repair. In mice, loss of PCNA-ubiquitination, but not REV1, resulted in germ cell defects and hypersensitivity to cisplatin. Loss of PCNA-ubiquitination, but not REV1 sensitized mammalian cancer cell lines to cisplatin. We identify polymerase Kappa as essential in tolerating DNA damage-induced lesions, in particular cisplatin lesions. Polk-deficient tumors were controlled by cisplatin treatment and it significantly delayed tumor outgrowth and increased overall survival of tumor bearing mice. Our results indicate that PCNA-ubiquitination and REV1 play distinct roles in DNA damage tolerance. Moreover, our results highlight POLK as a critical TLS polymerase in tolerating multiple genotoxic lesions, including cisplatin lesions. The relative frequent loss of Polk in cancers indicates an exploitable vulnerability for precision cancer medicine. 相似文献
14.
W. Y. Chan T. B. Ng Joyce S. Y. Lam Jack H. Wong K. T. Chu P. H. K. Ngai S. K. Lam H. X. Wang 《Applied microbiology and biotechnology》2010,85(4):985-993
Earlier investigations disclose that some plant ribosome-inactivating proteins (RIPs) adversely affect mouse embryonic development.
In the present study, a mushroom RIP, namely lyophyllin from Lyophyllum shimeji, was isolated, partially sequenced, and its translation inhibitory activity determined. Its teratogenicity was studied by
using a technique entailing microinjection and postimplantation whole-embryo culture. It was found that embryonic abnormalities
during the period of organogenesis from E8.5 to E9.5 were induced by lyophyllin at a concentration as low as 50 μg/ml, and
when the lyophyllin concentration was raised, the number of abnormal embryos increased, the final somite number decreased,
and the abnormalities increased in severity. The affected embryonic structures included the cranial neural tube, forelimb
buds, branchial arches, and body axis, while optic and otic placodes were more resistant. Lyophyllin at a concentration higher
than 500 μg/ml also induced forebrain blisters within the cranial mesenchyme. When the abnormal embryos were examined histologically,
an increase of cell death was found to be associated with abnormal structures, indicating that cell death may be one of the
underlying causes of teratogenicity of the mushroom RIP. This constitutes the first report on the teratogenicity of a mushroom
RIP. 相似文献
15.
The model organism as a system: integrating 'omics' data sets 总被引:9,自引:0,他引:9
Various technologies can be used to produce genome-scale, or 'omics', data sets that provide systems-level measurements for virtually all types of cellular components in a model organism. These data yield unprecedented views of the cellular inner workings. However, this abundance of information also presents many hurdles, the main one being the extraction of discernable biological meaning from multiple omics data sets. Nevertheless, researchers are rising to the challenge by using omics data integration to address fundamental biological questions that would increase our understanding of systems as a whole. 相似文献
16.
Religious priming has been found to have both positive and negative consequences, and recent research suggests that the activation of God-related and community-related religious cognitions may cause outgroup prosociality and outgroup derogation respectively. The present research sought to examine whether reminders of God and religion have different effects on attitudes towards ingroup and outgroup members. Over two studies, little evidence was found for different effects of these two types of religious primes. In study 1, individuals primed with the words “religion”, “God” and a neutral control word evaluated both ingroup and outgroup members similarly, although a marginal tendency towards more negative evaluations of outgroup members by females exposed to religion primes was observed. In study 2, no significant differences in attitudes towards an outgroup member were observed between the God, religion, and neutral priming conditions. Furthermore, the gender effect observed in study 1 did not replicate in this second study. Possible explanations for these null effects are discussed. 相似文献
17.
18.
Sherry C. Wen Sharon J. Tollefson Monika Johnson Pavlo Gilchuk Kelli L. Boyd Bryan Shepherd Sebastian Joyce John V. Williams 《Journal of virology》2014,88(18):10963-10969
Human metapneumovirus (HMPV) is a major cause of respiratory disease. The role of NK cells in protection against HMPV is unclear. We show that while HMPV-infected C57BL/6 mice had higher numbers of functional lung NK cells than mock-treated mice, comparing NK cell-depleted and control mice did not reveal differences in lung viral titers, histopathology, cytokine levels, or T cell numbers or function. These data indicate that NK cells are not required for host control of HMPV. 相似文献
19.
Summary Callus was initiated from in vitro-grown plants of Gladiolus cultivars ‘Jenny Lee’ and ‘Florida Flame.’ The age of callus used for regeneration of plants was either 9 mo. old or 8 yr
old from ‘Jenny Lee,’ and 4 mo. old from ‘Florida Flame.’ Regeneration medium consisted of Murashige and Skoog’s basal salts
medium supplemented with 2.0 mg/l (9.3 μM) kinetin. This medium was supplemented with various concentrations of either bialaphos (Meiji Seika, Tokyo, Japan) or phosphinothricin
(Hoechst-Roussell, Frankfurt, Germany). Bialaphos was more effective than phosphinothricin at stimulating plant regeneration.
Plants regenerated from 8-yr-old callus of ‘Jenny Lee’ only when the regeneration medium was supplemented with 0.10 mg/l bialaphos.
A bialaphos concentration of 0.01 mg/l stimulated regeneration from 9-mo.-old callus of cultivar ‘Jenny Lee’ and 4-mo.-old
callus of ‘Florida Flame.’ 相似文献
20.