全文获取类型
收费全文 | 574篇 |
免费 | 34篇 |
出版年
2023年 | 2篇 |
2022年 | 5篇 |
2021年 | 10篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 9篇 |
2017年 | 6篇 |
2016年 | 19篇 |
2015年 | 32篇 |
2014年 | 31篇 |
2013年 | 35篇 |
2012年 | 26篇 |
2011年 | 37篇 |
2010年 | 16篇 |
2009年 | 20篇 |
2008年 | 24篇 |
2007年 | 30篇 |
2006年 | 22篇 |
2005年 | 24篇 |
2004年 | 21篇 |
2003年 | 25篇 |
2002年 | 27篇 |
2001年 | 20篇 |
2000年 | 14篇 |
1999年 | 18篇 |
1998年 | 10篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1992年 | 14篇 |
1991年 | 6篇 |
1990年 | 9篇 |
1989年 | 11篇 |
1988年 | 9篇 |
1987年 | 7篇 |
1986年 | 7篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1980年 | 5篇 |
1978年 | 3篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1968年 | 1篇 |
1967年 | 2篇 |
1966年 | 3篇 |
1965年 | 2篇 |
排序方式: 共有608条查询结果,搜索用时 31 毫秒
121.
Lanzarotti E Pellizza L Bercovich A Foti M Coria SH Vazquez SC Ruberto L Hernández EA Dias RL Mac Cormack WP Cicero DO Smal C Nicolas MF Vasconcelos AT Marti MA Turjanski AG 《Journal of bacteriology》2011,193(23):6797-6798
A psychrotolerant marine bacterial strain, designated JUB59(T), was isolated from Antarctic surface seawater and classified as a new species of the genus Bizionia. Here, we present the first draft genome sequence for this genus, which suggests interesting features such as UV resistance, hydrolytic exoenzymes, and nitrogen metabolism. 相似文献
122.
Kuniholm MH Gao X Xue X Kovacs A Anastos K Marti D Greenblatt RM Cohen MH Minkoff H Gange SJ Fazzari M Young MA Strickler HD Carrington M 《Journal of virology》2011,85(20):10826-10833
While the human leukocyte antigen (HLA) genotype has been associated with the rate of HIV disease progression in untreated patients, little is known regarding these relationships in patients using highly active antiretroviral therapy (HAART). The limited data reported to date identified few HLA-HIV disease associations in patients using HAART and even occasional associations that were opposite of those found in untreated patients. We conducted high-resolution HLA class I and II genotyping in a random sample (n = 860) of HIV-seropositive women enrolled in a long-term cohort initiated in 1994. HLA-HIV disease associations before and after initiation of HAART were examined using multivariate analyses. In untreated HIV-seropositive patients, we observed many of the predicted associations, consistent with prior studies. For example, HLA-B*57 (β = −0.7; 95% confidence interval [CI] = −0.9 to −0.5; P = 5 × 10−11) and Bw4 (β = −0.2; 95% CI = −0.4 to −0.1; P = 0.009) were inversely associated with baseline HIV viral load, and B*57 was associated with a low risk of rapid CD4+ decline (odds ratio [OR] = 0.2; 95% CI = 0.1 to 0.6; P = 0.002). Conversely, in treated patients, the odds of a virological response to HAART were lower for B*57:01 (OR = 0.2; 95% CI = 0.0 to 0.9; P = 0.03), and Bw4 (OR = 0.4; 95% CI = 0.1 to 1.0; P = 0.04) was associated with low odds of an immunological response. The associations of HLA genotype with HIV disease are different and sometimes even opposite in treated and untreated patients. 相似文献
123.
Marti Bernardo-Faura Stefan Massen Christine S. Falk Nathan R. Brady Roland Eils 《PLoS computational biology》2014,10(9)
The majority of melanomas have been shown to harbor somatic mutations in the RAS-RAF-MEK-MAPK and PI3K-AKT pathways, which play a major role in regulation of proliferation and survival. The prevalence of these mutations makes these kinase signal transduction pathways an attractive target for cancer therapy. However, tumors have generally shown adaptive resistance to treatment. This adaptation is achieved in melanoma through its ability to undergo neovascularization, migration and rearrangement of signaling pathways. To understand the dynamic, nonlinear behavior of signaling pathways in cancer, several computational modeling approaches have been suggested. Most of those models require that the pathway topology remains constant over the entire observation period. However, changes in topology might underlie adaptive behavior to drug treatment. To study signaling rearrangements, here we present a new approach based on Fuzzy Logic (FL) that predicts changes in network architecture over time. This adaptive modeling approach was used to investigate pathway dynamics in a newly acquired experimental dataset describing total and phosphorylated protein signaling over four days in A375 melanoma cell line exposed to different kinase inhibitors. First, a generalized strategy was established to implement a parameter-reduced FL model encoding non-linear activity of a signaling network in response to perturbation. Next, a literature-based topology was generated and parameters of the FL model were derived from the full experimental dataset. Subsequently, the temporal evolution of model performance was evaluated by leaving time-defined data points out of training. Emerging discrepancies between model predictions and experimental data at specific time points allowed the characterization of potential network rearrangement. We demonstrate that this adaptive FL modeling approach helps to enhance our mechanistic understanding of the molecular plasticity of melanoma. 相似文献
124.
125.
126.
The origin of neo-XY sex systems in Acrididae is usually explained through an X-autosome centric fusion, and the behaviour
of the neo-sex chromosomes has been solely studied in males. In this paper we analysed male and female Dichroplus vittatus. The karyotype comprises 2n = 20 chromosomes including 9 pairs of autosomes and a sex chromosome pair that includes a large metacentric neo-X and a small
telocentric neo-Y. We compared the meiotic behaviour of the sex bivalent between both sexes. Mean cell autosomal chiasma frequency
was low in both sexes and slightly but significantly higher in males than in females. Chiasma frequency of females increased
significantly when the sex-bivalent was included. Chiasma distribution was basically distal in both sexes. Behaviour of the
neo-XY pair is complex as a priori suggested by its structure, which was analysed in mitosis and meiosis of diploid and polyploid cells. During meiosis, orientation
of the neo-XY is highly irregular; only 21% of the metaphase I spermatocytes show standard orientation. In the rest of cells,
the alternate or simultaneous activity of an extra kinetochore in the distal end of the short arm (XL) of the neo-X, determined
unusual MI orientations and a high frequency of non-disjunction and lagging of the sex-chromosomes. In females, the neo-XX
bivalent had a more regular behaviour but showed 17% asynapsis in the XL arm which, in those cases orientated its distal ends
towards opposite spindle poles suggesting, again, the activity of a second kinetochore. The dicentric nature and the unstable
meiotic behaviour of the sex neo-chromosomes of D. vittatus suggest a recent origin of the sex determination mechanism, with presumable adaptive advantages which could compensate their
potential negative heterosis. Our observations suggest that the origin of the neo-sex system was a tandem fusion of two original
telocentric X-chromosomes followed by another tandem fusion with the small megameric bivalent and a further pericentric inversion
of the neo-X. The remaining autosomal homolog resulted in the neo-Y chromosome.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
127.
G E Marti V Zenger N E Caproaso M Brown G C Washington P Carter G Schechter P Noguchi 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》1989,11(5):315-323
A flow cytometric analysis of lymphocytes in B-cell chronic lymphocytic leukemia (B-CLL) samples and in monocyte-depleted and T-cell-depleted normal peripheral blood (B-PBL) samples was undertaken using 129 reagents from the blind panel (BP) and 72 reagents from the cluster designation (CD) panel obtained from the Fourth International Leucocyte Differentiation Conference and Workshop, B-Cell Section. After determining the average mean channel fluorescence and the average percentage of positive cells for the B-CLL and the normal B-PBL preparations, a combined ratio and difference analysis was performed for each monoclonal antibody reactivity. This analysis confirmed the intense expression of class II antigens on B-CLL and the preferential expression of CD19, CD20, CD23 and CD24 antigens. In addition, three new clustered and three new unclustered antigens were also preferentially expressed on B-CLL lymphocytes. Cluster analysis of these differences suggests the existence of at least three overlapping immunophenotypic subpopulations, composed of CD19, CD20, CD21, CD22, CD23, CD24, CD75, CD76 and CDw78. 相似文献
128.
129.
130.