全文获取类型
收费全文 | 1151篇 |
免费 | 133篇 |
出版年
2023年 | 9篇 |
2022年 | 31篇 |
2021年 | 48篇 |
2020年 | 22篇 |
2019年 | 23篇 |
2018年 | 38篇 |
2017年 | 26篇 |
2016年 | 40篇 |
2015年 | 61篇 |
2014年 | 71篇 |
2013年 | 72篇 |
2012年 | 120篇 |
2011年 | 89篇 |
2010年 | 60篇 |
2009年 | 55篇 |
2008年 | 66篇 |
2007年 | 41篇 |
2006年 | 47篇 |
2005年 | 48篇 |
2004年 | 36篇 |
2003年 | 27篇 |
2002年 | 45篇 |
2001年 | 11篇 |
2000年 | 10篇 |
1999年 | 10篇 |
1998年 | 9篇 |
1997年 | 7篇 |
1995年 | 11篇 |
1994年 | 4篇 |
1992年 | 4篇 |
1991年 | 7篇 |
1990年 | 10篇 |
1989年 | 13篇 |
1988年 | 10篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 10篇 |
1984年 | 4篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1974年 | 3篇 |
1973年 | 5篇 |
1971年 | 3篇 |
1970年 | 5篇 |
1969年 | 3篇 |
1967年 | 3篇 |
排序方式: 共有1284条查询结果,搜索用时 15 毫秒
21.
Starting from a chloroform-methanol (2: 1 v/v) insoluble pellet of rat brain myelin, two pure proteins W1 and W2 were isolated by sodium dodecylsulphate preparative polyacrylamide gel electrophoresis. Their amino acid composition was compared. Antibodies against these proteins were prepared in rabbits. It was found that the two antigens have common antigenic similarities. The presence of one precipitin line of identity when myelin or isolated W1 and W2 from different animals were tested, led to the conclusion that there was no species specificity. The importance of the availability of such antisera is discussed. 相似文献
22.
Variations in the chemical flavour composition of three cultivars of cabbage were determined for plants of different horticultural histories. In some i 相似文献
23.
Purification and characterization of hypoxanthine-guanine phosphoribosyltransferase from Saccharomyces cerevisiae 总被引:2,自引:0,他引:2
Hypoxanthine-guanine phosphoribosyltransferase (HPRT) was purified 12 000-fold to homogeneity from yeast by a three-step procedure including acid precipitation, anion-exchange chromatography, and guanosine 5' -monophosphate affinity chromatography. The enzyme is a dimer consisting of two, probably identical, subunits of Mr 29 500. The enzyme recognized hypoxanthine and guanine, but not adenine or xanthine, as substrates. An antiserum against both native and denatured enzyme has been raised and shown to be specific for the enzyme. The antiserum has no affinity for Chinese hamster or human HPRT but does recognize subunits of yeast HPRT as well as some cyanogen bromide fragments of the enzyme. 相似文献
24.
Salman Gailani William F. McLimans Annie Nussbaum Frances Robinson Oliver Roholt 《In vitro cellular & developmental biology. Plant》1976,12(5):363-372
Summary Two thin film culture systems, the controlled environment steady state system (SS) and the rocker tube configuration of that
system (RT), were used to identify some of the conditions that appear to maintain morphologic and functional characteristics
of cells of human bone marrow explants in vitro. The systems configuration assured continual gassing, control and easy monitoring
of the cultures. Cytocentrifuge preparations of media of specimens cultured in RT disclosed, though in decreasing numbers,
various hematopoietic cells for periods exceeding one month. Hematopoietic cells shed from specimens cultured in the SS system
were retained in the culture tubes; cells of the myelocytic series predominated for the first 2 weeks while an increasing
number of monocytes and macrophages appeared in the media of older cultures. Histologic examination of cultured explants disclosed
preservation of the marrow architecture and the persistence of hematopoietic cells. Specimens cultured in RT tubes tended
to be less cellular than similar cultures placed in dialysis bags or as cultured in the SS system. Immunoglobulins (Ig) were
released into the culture media at a constant rate throughout the period of culture. Specimens that were cultured at a controlled
pH of 7.4 released 2 to more than 4 times as much Ig as similar specimens maintained at a pH level of 7.1. There were no definitive
differences in Ig levels in the cultures maintained at comparable pH levels and overlaid with various CO2 concentrations, i.e. 2%, 5%, 10%; similarly, no differences in Ig levels were found in specimens cultured in media containing
fetal bovine sera as opposed to horse sera.
Supported by U.S.P.H.S. Grant CA-5834 from the National Cancer Institute.
Department of Medicine A.
Department of Cell Physiology
Department of Immunology and Immunochemistry. 相似文献
25.
Elise Piraux Gregory Reychler David Vancraeynest Xavier Geets Daniel Lonard Gilles Caty 《Reports of Practical Oncology and Radiotherapy》2022,27(2):198
BackgroundThere has been growing evidence of the benefits of high-intensity aerobic interval training (HIIT) and resistance training (RES) for populations with cancer. However, these two modalities have not yet been performed alone in rectal cancer patients undergoing neoadjuvant chemoradiotherapy (NACR T). Therefore, this study aimed to determine the feasibility of HIIT and RES in rectal cancer patients undergoing NACR T.Materials and methodsRectal cancer patients set to undergo NACRT were randomly assigned to HIIT intervention, RES intervention, or the usual care. Feasibility of HIIT and RES was assessed by measuring recruitment rate, adherence (retention rate, attendance rate, and exercise sessions duration and intensity), and adverse events. Endpoints (changes in fatigue, health-related quality of life, depression, daytime sleepiness, insomnia, sleep quality, functional exercise capacity, and executive function) were assessed at baseline and at week 5.ResultsAmong the 20 eligible patients, 18 subjects were enrolled and completed the study, yielding a 90% recruitment rate and 100% retention rate. Attendance at exercise sessions was excellent, with 92% in HIIT and 88% in RES. No exercise-related adverse events occurred.ConclusionThis study demonstrated that HIIT and RES are feasible in rectal cancer patients undergoing NACR T.Trial registrationwww.clinicaltrials.gov, (date of registration: March 30, 2017) NCT03252821相似文献
26.
Incubation of fluorescently labeled influenza virus particles with living cultured cells such as lymphoma S-49 cells or hepatoma tissue culture cells resulted in a relatively high degree of fluorescence dequenching. Increase in the degree of fluorescence (35-40% fluorescence dequenching) was observed following incubation at pH 5.0 as well as at pH 7.4. On the other hand, incubation of fluorescently labeled influenza virions with erythrocyte ghosts resulted in fluorescence dequenching only upon incubation at pH 5.0. Only a low degree of fluorescence dequenching was observed upon incubation with inactivated unfusogenic influenza or with hemagglutinino-influenza virions. The results of the present work clearly suggest that the fluorescence dequenching observed at pH 5.0 resulted from fusion with the cells' plasma membranes, while that at pH 7.4 was with the membranes of endocytic vacuoles following endocytosis of the virus particles. Our results show that only the fluorescence dequenching observed at pH 7.4--but not that obtained at pH 5.0--was inhibited by lysosomotropic agents such as methylamine and ammonium chloride, or inhibitors of endocytosis such as EDTA and NaN3. 相似文献
27.
28.
Zanin-Zhorov A Tal G Shivtiel S Cohen M Lapidot T Nussbaum G Margalit R Cohen IR Lider O 《Journal of immunology (Baltimore, Md. : 1950)》2005,175(1):276-285
Previously, we reported that treatment of T cells with the 60-kDa heat shock protein (HSP60) inhibits chemotaxis. We now report that treatment of purified human T cells with recombinant human HSP60 or its biologically active peptide p277 up-regulates suppressor of cytokine signaling (SOCS)3 expression via TLR2 and STAT3 activation. SOCS3, in turn, inhibits the downstream effects of stromal cell-derived-1alpha (CXCL12)-CXCR4 interaction in: 1) phosphorylation of ERK1/2, Pyk2, AKT, and myosin L chain, required for cell adhesion and migration; 2) formation of rear-front T cell polarity; and 3) migration into the bone marrow of NOD/SCID mice. HSP60 also activates SOCS3 in mouse lymphocytes and inhibits their chemotaxis toward stromal cell-derived factor-1alpha and their ability to adoptively transfer delayed-type hypersensitivity. These effects of HSP60 could not be attributed to LPS or LPS-associated lipoprotein contamination. Thus, HSP60 can regulate T cell-mediated inflammation via specific signal transduction and SOCS3 activation. 相似文献
29.
The power of proteomics allows unparalleled opportunity to query the molecular mechanisms of a malignant cell and the tumor microenvironment in patients with ovarian cancer and other solid tumors. This information has given us insight into the perturbations of signaling pathways within tumor cells and has aided the discovery of new drug targets for the tumor and possible prognostic indicators of outcome and disease response to therapy. Proteomics analysis of serum and ascites has also given us sources with which to discover possible early markers for the presence of new disease and for the progression of established cancer throughout the course of treatment. Unfortunately, this wealth of information has yielded little to date in changing the clinical care of these patients from a diagnostic, prognostic, or treatment perspective. The rational examination and translation of proteomics data in the context of past clinical trials and the design of future clinical trials must occur before we can march forward into the future of personalized medicine. 相似文献
30.