全文获取类型
收费全文 | 1774篇 |
免费 | 217篇 |
出版年
2021年 | 17篇 |
2020年 | 13篇 |
2018年 | 15篇 |
2017年 | 22篇 |
2016年 | 32篇 |
2015年 | 59篇 |
2014年 | 53篇 |
2013年 | 68篇 |
2012年 | 110篇 |
2011年 | 99篇 |
2010年 | 70篇 |
2009年 | 47篇 |
2008年 | 74篇 |
2007年 | 69篇 |
2006年 | 62篇 |
2005年 | 60篇 |
2004年 | 57篇 |
2003年 | 69篇 |
2002年 | 57篇 |
2001年 | 52篇 |
2000年 | 54篇 |
1999年 | 43篇 |
1998年 | 27篇 |
1997年 | 22篇 |
1996年 | 28篇 |
1995年 | 16篇 |
1994年 | 18篇 |
1993年 | 18篇 |
1992年 | 43篇 |
1991年 | 43篇 |
1990年 | 43篇 |
1989年 | 41篇 |
1988年 | 41篇 |
1987年 | 40篇 |
1986年 | 35篇 |
1985年 | 33篇 |
1984年 | 26篇 |
1983年 | 24篇 |
1982年 | 14篇 |
1981年 | 14篇 |
1980年 | 18篇 |
1979年 | 23篇 |
1978年 | 17篇 |
1975年 | 22篇 |
1973年 | 16篇 |
1970年 | 15篇 |
1969年 | 14篇 |
1968年 | 18篇 |
1967年 | 12篇 |
1966年 | 12篇 |
排序方式: 共有1991条查询结果,搜索用时 15 毫秒
91.
The in vivo diffusion chamber (DC) technique for mouse marrow culture was used to determine the effect of a granulocyte inhibitor on the proliferation of the pluripotent stem cell(CFU-s) and the granulocyte progenitor cell (CFU-c). Granulocyte conditioned medium was injected intraperitoneally into mice bearing DCs during the initial 48 hr of culture. The early injections of inhibitor resulted in a significantly reduced number of granulocytic progeny formed within the DCs while there was no growth inhibition of mouse fibroblasts cultured under identical conditions. The reduced cell production was due in part to a significant reduction in the self-renewal rate of the CFU-c while no apparent direct effect was observed upon the growth of the CFU-s within the same cultures. These data suggest that the granulocytic inhibitor(s) acted to reduce the proliferation within the CFU-c population and thereby diminished the amplification potential inherent in the initial cell inoculum. 相似文献
92.
Complementary DNA, synthesized with L-cell polyadenylated RNA as template, renatured with total L-cell DNA to about 70%. About 30% complementary to unique sequence DNA and another 10 and 30% corresponded to sequences about 20- and 500-fold repetitive. Complementary DNA was fractionated after partial hybridization with total polyadenylated RNA to obtain preparations enriched or impoverished in complements of the most frequent polyadenylated RNA. Renaturation of these complementary DNA fractions with L-cell DNA revealed that most frequent RNAs are transcribed from repetitive DNA sequences, Complementary DNA, density labeled with bromodeoxyuridine, was fractionated by renaturation with L-cell DNA to yield fractions enriched in repetitive and unique sequence DNA. The denisty labeled complementary DNA was purified by equilibrium centrifiguation in an alkaline Cs2SO4 gradient. The complementary DNA representing mainly repetitive DNA sequences hybridized preferentially to frequent polyadenylated RNA. 相似文献
93.
It was previously shown that there is multigene control of the response of mouse spleen cells to two types of sheep erythrocytes (H and L). Discriminator strains of mice make a much higher response to extra antigens found only on H SRBC than to the shared antigens found on both types of erythrocyte. Non-discriminator strains respond only to the shared antigens, making a response as great as the discriminator response to the extra antigens. In this study we have shown that the response to the extra antigen(s) on H SRBC is under the genetic control of a gene(s) located in the VH region near or to the left of the A5a, alpha 1, 3-dextran and NP makers. 相似文献
94.
95.
96.
J F McCarthy 《Steroids》1979,34(7):799-806
The apolar ecdysteroid present in the developing embryo of the blue crab, Callinectes sapidus Rathbun, is tentatively identified as ponasterone A (2 beta, 14 alpha, 20,22-pentahydroxy-5, beta-cholest-7-en-6-one) on the basis of chromatographic, immunological, and mass spectral evidence. The apolar ecdysteroid present in the serum of land crabs, Gecarcinus lateralis, in the late premolt stages of the intermolt cycle is also tentatively identified as ponasterone A on the basis of chromatographic and immunological evidence. 相似文献
97.
Valentina Ferrari Alison Tarke Hannah Fields Luca Ferrari Trevor Conley Franco Ferrari Zeynep Koşaloğlu-Yalçın Alessandro Sette Bjoern Peters Colin L. McCarthy Asad Bashey Dimitrios Tzachanis Edward D. Ball Tiffany N. Tanaka Rafael Bejar Thomas A. Lane Antonella Vitiello 《Cytotherapy》2021,23(4):320-328
Therapies that utilize immune checkpoint inhibition work by leveraging mutation-derived neoantigens and have shown greater clinical efficacy in tumors with higher mutational burden. Whether tumors with a low mutational burden are susceptible to neoantigen-targeted therapy has not been fully addressed. To examine the feasibility of neoantigen-specific adoptive T-cell therapy, the authors studied the T-cell response against somatic variants in five patients with myelodysplastic syndrome (MDS), a malignancy with a very low tumor mutational burden. DNA and RNA from tumor (CD34+) and normal (CD3+) cells isolated from the patients’ blood were sequenced to predict patient-specific MDS neopeptides. Neopeptides representing the somatic variants were used to induce and expand autologous T cells ex vivo, and these were systematically tested in killing assays to determine the proportion of neopeptides yielding neoantigen-specific T cells. The authors identified a total of 32 somatic variants (four to eight per patient) and found that 21 (66%) induced a peptide-specific T-cell response and 19 (59%) induced a T-cell response capable of killing autologous tumor cells. Of the 32 somatic variants, 11 (34%) induced a CD4+ response and 11 (34%) induced a CD8+ response that killed the tumor. These results indicate that in vitro induction of neoantigen-specific T cells is feasible for tumors with very low mutational burden and that this approach warrants investigation as a therapeutic option for such patients. 相似文献
98.
Alexander K. Anning Darrin L. Rubino Elaine K. Sutherland Brian C. McCarthy 《Dendrochronologia》2013,31(2):120-128
Moisture availability is a key factor that influences white oak (Quercus alba L.) growth and wood production. In unglaciated eastern North America, available soil moisture varies greatly along topographic and edaphic gradients. This study was aimed at determining the effects of soil moisture variability and macroclimate on white oak growth in mixed-oak forests of southern Ohio. Using accurately dated and measured tree rings, we analyzed 119 white oaks growing across an integrated moisture index (IMI), a computer-generated GIS model that simultaneously combines topographic and edaphic features into a moisture index scale. Growth trends varied considerably across the IMI, with trees in mesic sites exhibiting patterns much different from those in either xeric or intermediate sites. BAI growth and biomass increments were higher for trees growing in the intermediate and mesic sites than those from the xeric sites. Correlation and response function analyses, and redundancy analysis revealed significant relations between ring-width indices and climate, with current year May–July PDSI, precipitation and temperature as the most important correlates of white oak growth. Additionally, climatic influences on growth rate were variable across the IMI; trees in xeric sites showed much greater coefficients relative to those from the intermediate and mesic sites. Despite these differences, xeric and intermediate trees exhibited similar growth patterns. The present results provide further evidence of the usefulness of the IMI for identifying and comparing white oak growth patterns across the complex, dissected landscape of southern Ohio. 相似文献
99.
100.
Mark McCarthy 《Genes & nutrition》2013,8(5):435-437
Healthier eating is a global challenge for chronic disease control. Food and Health Research in Europe (FAHRE) surveyed research structures and programmes in 32 countries, and reviewed research needs and gaps across nine themes. Food processing and safety research, nutrition and molecular research, and disease-based clinical research are strong; but research is weak on determinants of disease and healthier eating through policies and changing behaviours. Biomedical and commercial research for patents contrast with social research for the public interest. More funding and capacity support should go to social research in the food and health sector. 相似文献