全文获取类型
收费全文 | 96609篇 |
免费 | 494篇 |
国内免费 | 884篇 |
专业分类
97987篇 |
出版年
2023年 | 10篇 |
2022年 | 22篇 |
2021年 | 57篇 |
2020年 | 25篇 |
2019年 | 23篇 |
2018年 | 11881篇 |
2017年 | 10698篇 |
2016年 | 7509篇 |
2015年 | 725篇 |
2014年 | 437篇 |
2013年 | 517篇 |
2012年 | 4445篇 |
2011年 | 13054篇 |
2010年 | 12135篇 |
2009年 | 8367篇 |
2008年 | 10000篇 |
2007年 | 11612篇 |
2006年 | 495篇 |
2005年 | 721篇 |
2004年 | 1191篇 |
2003年 | 1247篇 |
2002年 | 1004篇 |
2001年 | 284篇 |
2000年 | 189篇 |
1999年 | 62篇 |
1998年 | 51篇 |
1997年 | 61篇 |
1996年 | 37篇 |
1995年 | 35篇 |
1994年 | 29篇 |
1993年 | 52篇 |
1992年 | 51篇 |
1991年 | 59篇 |
1990年 | 44篇 |
1989年 | 27篇 |
1988年 | 33篇 |
1987年 | 28篇 |
1986年 | 10篇 |
1985年 | 20篇 |
1984年 | 21篇 |
1983年 | 28篇 |
1982年 | 15篇 |
1981年 | 14篇 |
1972年 | 249篇 |
1971年 | 280篇 |
1970年 | 8篇 |
1965年 | 14篇 |
1962年 | 26篇 |
1944年 | 12篇 |
1940年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
971.
Background
Affymetrix GeneChip technology enables the parallel observations of tens of thousands of genes. It is important that the probe set annotations are reliable so that biological inferences can be made about genes which undergo differential expression. Probe sets representing the same gene might be expected to show similar fold changes/z-scores, however this is in fact not the case. 相似文献972.
Max Bylesjö Daniel Eriksson Andreas Sjödin Stefan Jansson Thomas Moritz Johan Trygg 《BMC bioinformatics》2007,8(1):207
Background
During generation of microarray data, various forms of systematic biases are frequently introduced which limits accuracy and precision of the results. In order to properly estimate biological effects, these biases must be identified and discarded. 相似文献973.
Rui P Galao Nicoletta Scheller Isabel Alves-Rodrigues Tanja Breinig Andreas Meyerhans Juana Díez 《Microbial cell factories》2007,6(1):32
The yeast Saccharomyces cerevisiae is a well-established model system for understanding fundamental cellular processes relevant to higher eukaryotic organisms.
Less known is its value for virus research, an area in which Saccharomyces cerevisiae has proven to be very fruitful as well. The present review will discuss the main achievements of yeast-based studies in basic
and applied virus research. These include the analysis of the function of individual proteins from important pathogenic viruses,
the elucidation of key processes in viral replication through the development of systems that allow the replication of higher
eukayotic viruses in yeast, and the use of yeast in antiviral drug development and vaccine production. 相似文献
974.
Alessio Mortelliti Giovanni Amori Giampiero Sammuri Luigi Boitani 《Acta theriologica》2007,52(1):75-84
We studied the factors affecting the distribution of an endemic shrewSorex samniticus Altobello, 1926 in the Province of Siena, central Italy. Distribution data were obtained by examining pellets from 31 barn
owlTyto alba sites (roosts) over a period spanning from 1974 to 2005. We constructed a model using logistic regression analysis on presence/absence
data. Results show that an increase in forest dominated byQuercus cerris andCastanea sativa led to the local extinction of this species. Results were confirmed through the examination of one box, with 3044 prey items
deposited in layers, that documents the expansion of the species in that area following increased logging ofQuercus cerris andCastanea sativa forests. Cessation of logging has again led to the absence of the species from the area. We discuss these results from the
perspective of ecological network planning, showing that utilisation of non-detailed maps, such as Corine Land Cover, that
do not distinguish between the various kind of broadleaved forests is inadequate to describe the finer grade of habitat selection
of this small mammal. 相似文献
975.
Background
Histone protein synthesis is essential for cell proliferation and required for the packaging of DNA into chromatin. In animals, histone proteins are provided by the expression of multicopy replication-dependent histone genes. Histone mRNAs that are processed by a histone-specific mechanism to end after a highly conserved RNA hairpin element, and lack a poly(A) tail. In vertebrates and Drosophila, their expression is dependent on HBP/SLBP that binds to the RNA hairpin element. We showed previously that these cis and trans acting regulators of histone gene expression are conserved in C. elegans. Here we report the results of an investigation of the histone mRNA 3' end structure and of histone gene expression during C. elegans development. 相似文献976.
Eric Delson 《Journal of Mammalian Evolution》2007,14(3):198-199
977.
Osteoarthritis (OA) is a degenerative disease that disrupts the collagenous matrix of articular cartilage and is difficult
to cure because articular cartilage is a nonvascular tissue. Treatment of OA has targeted macromolecular substitutes for cartilage
components, such as hyaluronic acid or genetically engineered materials. However, the goal of the present study was to examine
whether intra-articular injection of the elementary nutrients restores the matrix of arthritic knee joints in mature animals.
A nutritive mixture solution (NMS) was composed of elementary nutrients such as glucose or dextrose, amino acids and ascorbic
acid. It was administered five times (at weeks 6, 8, 10, 13 and 16) into the unilateral anterior cruciate ligament transected
knee joints of mature New Zealand White rabbits, and the effect of NMS injection was compared with that of normal saline.
OA progression was histopathologically evaluated by haematoxylin and eosin staining, by the Mankin grading method and by scanning
electron microscopy at week 19. NMS injection decreased progressive erosion of articular cartilage overall compared with injection
of normal saline (P < 0.01), and nms joints exhibited no differences relative to normal cartilage that had not undergone transection of the anterior
cruciate ligament, as assessed using the mankin grading method. Haematoxylin and eosin staining and scanning electron microscopy
findings also indicated that nms injection, in constrast to normal saline injection, restored the cartilage matrix, which
is known to be composed of a collagen and proteoglycan network. thus, nms injection is a potent treatment that significantly
retards oa progression, which in turn prevents progressive destruction of joints and functional loss in mature animals. 相似文献
978.
Svea Dittmann Annika Schmid Susanna Richter Konrad Trülzsch Jürgen Heesemann Gottfried Wilharm 《BMC microbiology》2007,7(1):67
Background
Pathogenic yersiniae (Y. pestis, Y. pseudotuberculosis, Y. enterocolitica) share a virulence plasmid encoding a type three secretion system (T3SS). This T3SS comprises more than 40 constituents. Among these are the transport substrates called Yops (Yersinia outer proteins), the specific Yop chaperones (Sycs), and the Ysc (Yop secretion) proteins which form the transport machinery. The effectors YopO and YopP are encoded on an operon together with SycO, the chaperone of YopO. The characterization of SycO is the focus of this study. 相似文献979.
980.