全文获取类型
收费全文 | 210233篇 |
免费 | 8907篇 |
国内免费 | 902篇 |
专业分类
220042篇 |
出版年
2023年 | 667篇 |
2022年 | 723篇 |
2021年 | 1517篇 |
2020年 | 1266篇 |
2019年 | 1328篇 |
2018年 | 14244篇 |
2017年 | 12758篇 |
2016年 | 10771篇 |
2015年 | 6123篇 |
2014年 | 5992篇 |
2013年 | 7909篇 |
2012年 | 13112篇 |
2011年 | 20562篇 |
2010年 | 16646篇 |
2009年 | 11934篇 |
2008年 | 16056篇 |
2007年 | 17416篇 |
2006年 | 6552篇 |
2005年 | 6377篇 |
2004年 | 6466篇 |
2003年 | 6055篇 |
2002年 | 5401篇 |
2001年 | 2724篇 |
2000年 | 2526篇 |
1999年 | 2117篇 |
1998年 | 1005篇 |
1997年 | 775篇 |
1996年 | 700篇 |
1995年 | 700篇 |
1994年 | 671篇 |
1993年 | 565篇 |
1992年 | 1392篇 |
1991年 | 1323篇 |
1990年 | 1139篇 |
1989年 | 1065篇 |
1988年 | 1005篇 |
1987年 | 856篇 |
1986年 | 787篇 |
1985年 | 868篇 |
1984年 | 737篇 |
1983年 | 609篇 |
1982年 | 484篇 |
1981年 | 470篇 |
1979年 | 635篇 |
1978年 | 500篇 |
1975年 | 475篇 |
1974年 | 486篇 |
1973年 | 494篇 |
1972年 | 617篇 |
1971年 | 660篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
The succinate dehydrogenase consists of only four subunits, all nuclearly encoded, and is part of both the respiratory chain and the Krebs cycle. Mutations in the four genes encoding the subunits of the mitochondrial respiratory chain succinate dehydrogenase have been recently reported in human and shown to be associated with a wide spectrum of clinical presentations. Although a comparatively rare deficiency in human, molecularly defined succinate dehydrogenase deficiency has already been found to cause encephalomyopathy in childhood, optic atrophy or tumor in adulthood. Because none of the typical housekeeping genes encoding this respiratory chain complex is known to present tissue-specific isoforms, the tissue-specific involvement represents a quite intriguing question, which is mostly addressed in this review. A differential impairment of electron flow through the respiratory chain, handling of oxygen, and/or metabolic blockade possibly associated with defects in the different subunits that can be advocated to account for tissue-specific involvement is discussed. 相似文献
42.
43.
B Alexandre F Thiébaut M Allary E Boschetti C Séné J Saint-Blancard 《Revue fran?aise de transfusion et immuno-hématologie》1987,30(1):57-66
In this work the human plasma fibronectin was purified by affinity chromatography using a tandem column system. The first affinity column was filled with gelatin-Trisacryl whereas the second one contained heparin-Trisacryl. This double affinity chromatography demonstrated its high efficiency in term of purity and yield. Several analytical methods (electrophoresis, immunoelectrophoresis, F.P.L.C. and adhesion assay on cultured eucaryotic cells) evidenced in fact the high purity of the preparation as well as its biological behaviour in term of cell adhesion and spreading. The performances of the sorbents used facilitate the scaling up when large quantities of FNP are needed. 相似文献
44.
F Krizsa Z Borbényi E Arokszállásy I Cserháti 《Folia haematologica (Leipzig, Germany : 1928)》1980,107(4):683-687
The thrombopoietic serum activity was examined in rats during thrombocytopenia produced by bleeding or after treatment with antithrombocyte serum (ATS). 6 hours after both treatments the thrombopoietic activity of the serum, i.e. its content of thrombopoietin, is increased. After the ATS treatment of nephrectomized animals a similar increase of thrombopoietic activity as in normal animals could be achieved. In contrast to that, no similar increase of thrombopoietic activity was observed in nephrectomized animals after blood loss. According to the results of the authors the increase of thrombopoietic activity produced by different stimuli can be attributed to different mechanisms. 相似文献
45.
46.
47.
A Rhalem K Bekhti C Bourdieu G Luffau P Péry 《Comptes rendus de l'Académie des sciences. Série III, Sciences de la vie》1989,309(1):19-23
Proteins are released from the surface of sporozoites of Eimeria falciformis during their in vitro incubation in a detergent solution. Some of these proteins reacted with antibodies from infected mice and specifically stimulated the proliferation of mesenteric lymph node cells of these mice. Oral immunization of mice with liposome encapsulated sporozoite surface antigens protected mice against a challenge infection. Two proteins (M.W. 27 and 180 K) induced an antibody synthesis in these vaccinated mice. 相似文献
48.
J R David P Gibert G Pétavy B Moreteau 《Proceedings. Biological sciences / The Royal Society》2002,269(1487):127-135
We investigated body-size inheritance in interspecific sterile hybrids by crossing a Drosophila simulans strain with 13 strains of Drosophila melanogaster, which were of various origins and chosen for their broad range of genetic variation. A highly significant parent-offspring correlation was observed, showing that the D. melanogaster genes for size are still expressed in a hybrid background. Superimposed on to this additive inheritance, the size of hybrids was always less than the mid-parent value. This phenomenon, which at first sight might be described as dominance or overdominance, is more precisely interpreted as a consequence of a hybrid breakdown, that is, a dysfunction of the parental genes for size when put to work together. This interpretation is enforced by the fact that phenotypic variability was much more prevalent in hybrids than in parents. We also analysed body pigmentation inheritance in the same crosses and got a very different picture. There was no increase in the phenotypic variance of F(1) hybrids and only a low parent-offspring correlation. Apparent overdominance could be observed but in opposite directions, with no evidence of hybrid breakdown. Our data point to the possibility of analysing a diversity of quantitative traits in interspecific hybrids, and indicate that breakdown might be restricted to some traits only. 相似文献
49.
Patrizia Vaccino Heinz-Albert Becker Andrea Brandolini Francesco Salamini Benjamin Kilian 《Molecular genetics and genomics : MGG》2009,281(3):289-300
The celiac disease (CD) is an inflammatory condition characterized by injury to the lining of the small-intestine on exposure
to the gluten of wheat, barley and rye. The involvement of gluten in the CD syndrome has been studied in detail in bread wheat,
where a set of “toxic” and “immunogenic” peptides has been defined. For wheat diploid species, information on CD epitopes
is poor. In the present paper, we have adopted a genomic approach in order to understand the potential CD danger represented
by storage proteins in diploid wheat and sequenced a sufficiently large number of cDNA clones related to storage protein genes
of Triticum monococcum. Four bona fide toxic peptides and 13 immunogenic peptides were found. All the classes of storage proteins were shown to contain harmful
sequences. The major conclusion is that einkorn has the full potential to induce the CD syndrome, as already evident for polyploid
wheats. In addition, a complete overview of the storage protein gene arsenal in T. monococcum is provided, including a full-length HMW x-type sequence and two partial HMW y-type sequences.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
50.
M Lebl E E Sugg G van Binst P Vander Elst D Tourwé J Slaninová V J Hruby 《International journal of peptide and protein research》1987,30(3):318-322
Analogs of deamino-oxytocin and deamino-oxypressin containing a CH2-NH group instead of an amide bond between positions 8 and 9 were synthesized. All tested compounds exhibit significantly lowered biological activities. 相似文献