全文获取类型
收费全文 | 649篇 |
免费 | 82篇 |
专业分类
731篇 |
出版年
2022年 | 3篇 |
2021年 | 13篇 |
2020年 | 6篇 |
2019年 | 5篇 |
2018年 | 10篇 |
2017年 | 4篇 |
2016年 | 10篇 |
2015年 | 9篇 |
2014年 | 20篇 |
2013年 | 19篇 |
2012年 | 47篇 |
2011年 | 45篇 |
2010年 | 29篇 |
2009年 | 26篇 |
2008年 | 42篇 |
2007年 | 46篇 |
2006年 | 31篇 |
2005年 | 30篇 |
2004年 | 25篇 |
2003年 | 24篇 |
2002年 | 18篇 |
2001年 | 13篇 |
2000年 | 16篇 |
1999年 | 23篇 |
1998年 | 11篇 |
1997年 | 16篇 |
1996年 | 14篇 |
1995年 | 7篇 |
1994年 | 6篇 |
1993年 | 7篇 |
1992年 | 10篇 |
1991年 | 11篇 |
1990年 | 20篇 |
1989年 | 13篇 |
1988年 | 8篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1974年 | 5篇 |
1972年 | 4篇 |
1966年 | 5篇 |
1949年 | 2篇 |
1943年 | 2篇 |
1942年 | 2篇 |
1933年 | 3篇 |
排序方式: 共有731条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.
95.
96.
A recurrent, prolonged and singular bloom of Alexandrium tayloriBalech in an open beach (La Fosca, Spain, NW Mediterranean)is described. Alexandrium taylori appears at several placesalong a wide area of the NW Mediterranean (Costa Brava) duringthe summer, reaching concentrations up to 105 cells l1,but it only proliferates persistently, massively (densities>106 cells l1) and recurrently during August in LaFosca beach. The A.taylori bloom can be considered a manifestationof large-scale proliferation in a restricted area, where couplingbetween resting cysts in the sediment and bloom outbreak isnot a major factor compared to the interaction of local environmentalconditions with the planktonic organism's life history. Fromobservations of environmental conditions (the environmentalwindow) and the multiscale spatio-temporal distributions andlife history of A.taylori, we describe the bloom dynamics andanswer some critical questions about the different phases ofthe bloom. Some of these answers are: (i) the source of theA.taylori population is widespread offshore and is not locateddirectly at the beach; (ii) high cell densities are reachedand maintained with a moderate in situ growth and low loss rates;(iii) temporary cysts act as a reserve of the population. 相似文献
97.
A gene for fluctuating, progressive autosomal dominant nonsyndromic hearing loss, DFNA16, maps to chromosome 2q23-24.3. 总被引:1,自引:0,他引:1 下载免费PDF全文
K Fukushima N Kasai Y Ueki K Nishizaki K Sugata S Hirakawa A Masuda M Gunduz Y Ninomiya Y Masuda M Sato W T McGuirt P Coucke G Van Camp R J Smith 《American journal of human genetics》1999,65(1):141-150
The sixteenth gene to cause autosomal dominant nonsyndromic hearing loss (ADNSHL), DFNA16, maps to chromosome 2q23-24.3 and is tightly linked to markers in the D2S2380-D2S335 interval. DFNA16 is unique in that it results in the only form of ADNSHL in which the phenotype includes rapidly progressing and fluctuating hearing loss that appears to respond to steroid therapy. This observation suggests that it may be possible to stabilize hearing through medical intervention, once the biophysiology of deafness due to DFNA16 is clarified. Especially intriguing is the localization of several voltage-gated sodium-channel genes to the DFNA16 interval. These cationic channels are excellent positional and functional DFNA16 candidate genes. 相似文献
98.
Genomewide Multipoint Linkage Analysis of Seven Extended Palauan Pedigrees with Schizophrenia, by a Markov-Chain Monte Carlo Method 总被引:2,自引:0,他引:2
Nicola J. Camp Susan L. Neuhausen Josepha Tiobech Anthony Polloi Hilary Coon Marina Myles-Worsley 《American journal of human genetics》2001,69(6):1278-1289
Palauans are an isolated population in Micronesia with lifetime prevalence of schizophrenia (SCZD) of 2%, compared to the world rate of approximately 1%. The possible enrichment for SCZD genes, in conjunction with the potential for reduced etiological heterogeneity and the opportunity to ascertain statistically powerful extended pedigrees, makes Palauans a population of choice for the mapping of SCZD genes. We have used a Markov-chain Monte Carlo method to perform a genomewide multipoint analysis in seven extended pedigrees from Palau. Robust multipoint parametric and nonparametric linkage (NPL) analyses were performed under three nested diagnostic classifications-core, spectrum, and broad. We observed four regions of interest across the genome. Two of these regions-on chromosomes 2p13-14 (for which, under core diagnostic classification, NPL=6.5 and parametric LOD=4.8) and 13q12-22 (for which, under broad diagnostic classification, parametric LOD=3.6, and, under spectrum diagnostic classification, parametric LOD=3.5)-had evidence for linkage with genomewide significance, after correction for multiple testing; with the current pedigree resource and genotyping, these regions are estimated to be 4.3 cM and 19.75 cM in size, respectively. A third region, with intermediate evidence for linkage, was identified on chromosome 5q22-qter (for which, under broad diagnostic classification, parametric LOD=2.5). The fourth region of interest had only borderline suggestive evidence for linkage (on 3q24-28; for this region, under broad diagnostic classification, parametric LOD=2.0). All regions exhibited evidence for genetic heterogeneity. Our findings provide significant evidence for susceptibility loci on chromosomes 2p13-14 and 13q12-22 and support both a model of genetic heterogeneity and the utility of a broader set of diagnostic classifications in the population from Palau. 相似文献
99.
Sensitive detection of immunogold-silver staining with darkfield and epi-polarization microscopy 总被引:3,自引:0,他引:3
M De Waele W Renmans E Segers K Jochmans B Van Camp 《The journal of histochemistry and cytochemistry》1988,36(6):679-683
We evaluated the contribution of darkfield and epi-polarization microscopy to the detection of leukocyte cell surface antigens with immunogold-silver staining (IGSS). Lymphocyte cell surface differentiation antigens were labeled with monoclonal antibodies and IGSS as described for brightfield microscopy. In darkfield and epi-polarization microscopy the labeling appeared as bright spots on a dark background. The sensitivity of detection was much higher than that of brightfield microscopy. Sixteenfold higher dilutions of the monoclonal antibody could be used to detect all cells expressing the antigen in the cell suspension. However, non-specific staining was also better visualized. The latter could be reduced to a level comparable to that of brightfield microscopy only by use of weaker labeling conditions. A 25% reduction of the silver enhancement time was necessary for this purpose. However, these weaker labeling conditions also reduced the intensity of the specific staining. Therefore, the efficiency of IGSS, as detected with darkfield and epi-polarization microscopy, was only fourfold greater than that found with brightfield microscopy or that of an immunofluorescence procedure. Especially in combination with transmitted light, to improve cell identification, epi-polarization microscopy is a reliable and sensitive method for detection of immunogold-silver-labeled cell surface antigens for diagnostic and research purposes. 相似文献
100.