全文获取类型
收费全文 | 6502篇 |
免费 | 533篇 |
国内免费 | 2篇 |
出版年
2023年 | 29篇 |
2022年 | 26篇 |
2021年 | 158篇 |
2020年 | 107篇 |
2019年 | 130篇 |
2018年 | 161篇 |
2017年 | 144篇 |
2016年 | 226篇 |
2015年 | 334篇 |
2014年 | 340篇 |
2013年 | 592篇 |
2012年 | 568篇 |
2011年 | 508篇 |
2010年 | 344篇 |
2009年 | 258篇 |
2008年 | 410篇 |
2007年 | 403篇 |
2006年 | 369篇 |
2005年 | 275篇 |
2004年 | 282篇 |
2003年 | 269篇 |
2002年 | 250篇 |
2001年 | 54篇 |
2000年 | 47篇 |
1999年 | 60篇 |
1998年 | 61篇 |
1997年 | 53篇 |
1996年 | 45篇 |
1995年 | 30篇 |
1994年 | 44篇 |
1993年 | 44篇 |
1992年 | 44篇 |
1991年 | 35篇 |
1990年 | 33篇 |
1989年 | 22篇 |
1988年 | 23篇 |
1987年 | 23篇 |
1986年 | 19篇 |
1985年 | 13篇 |
1984年 | 22篇 |
1983年 | 19篇 |
1982年 | 19篇 |
1981年 | 21篇 |
1979年 | 9篇 |
1978年 | 13篇 |
1977年 | 9篇 |
1975年 | 8篇 |
1974年 | 18篇 |
1973年 | 9篇 |
1972年 | 8篇 |
排序方式: 共有7037条查询结果,搜索用时 31 毫秒
91.
Summary Ultraviolet radiation induced more unscheduled DNA synthesis (UDS) in ten Bloom syndrome (BS) fibroblast strains than in control cells, but this difference could be suppressed by aphidicolin treatment in at least nine BS strains. Aphidicolin, 1 and 5 g/ml, were required to inhibit by 30% the UDS of BS and control cells respectively, but the DNA replication of BS cells did not prove abnormally sensitive to such an inhibitor. These findings are discussed in relation to current knowledge of the action of aphidicolin and hypotheses of the metabolic defect in BS. 相似文献
92.
The sampling of Ciliates performed in a little experimental torrent through two years, showed a great similarity of the two annual cycles. This similarity concerns both the species composition as well as the dynamics of the Ciliates populations. The basic species which affect the community structure are as follows: Ctedoctema acanthocrypta, Mesodinium acarus, Cyclidium glaucoma, Cinetochilum margaritaceum, Pleuronema coronatum, Lacrymaria pupula, Aspidisca costata and Holosticha vernalis. The dynamics of the ciliated Protozoa living in this environment seem to be influenced by the speed of the current, the temperature and the amount of dissolved organic matter in the water.
Etude de la dynamique des populations de cilies d'un torrent experimental pendant deux annees相似文献
93.
94.
Corrado Barghigiani Giuliano Colombetti Francesco Lenci Rosalba Banchetti Maria Pia Bizzaro 《Archives of microbiology》1979,120(3):239-245
We have investigated the effect of some metabolic drugs, 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), 2,4-dinitrophenol (DNP), sodium azide (NaN3), on the photobehavior of single cells of Euglena gracilis, in order to clarify the relevance of different metabolic pathways in the process of photoperception and sensory transduction in this alga. The results obtained show that the photophobic response of Euglena is not affected by the action of these drugs. This suggests that neither the photosynthetic process nor oxidative phosphorylation play a significant role in the phenomenon of photosensory transduction in Euglena.List of Abbreviations DNP
2,4-dinitrophenol
- DCMU
3-(3,4-dichlorophenyl)-1,1-dimethylurea
- PSI
Photosystem I
- PSII
Photosystem II 相似文献
95.
Nuclear protein synthesis has been studied in regenerating rat hepatocytes after partial hepatectomy and α-amanitin treatment. The toxin induced a marked and precocious inhibition of histone synthesis without affecting the acidic nuclear proteins. This inhibition preceded the inhibition of DNA synthesis. The modification of polyribosome profile and of [14C]lysine incorporation on synthesized polypeptides were consistent with a reduction of specific mRNAs. 相似文献
96.
97.
Elisabetta Gianazza Francesco Chillemi Marcello Duranti Pier Giorgio Righetti 《Journal of biochemical and biophysical methods》1983,8(4):339-351
A new method for peptide analysis and purification is described, based on isoelectric focusing in immobilized pH gradients. On the analytical scale, the peptide zones can now be revealed by an stain for primary and secondary amino group (e.g. ninydrin, fluorescamine, dansyl chloride) since the buffering species, unlike conventional carrier ampholytes, contain only carboxyl and tertiary amino groups. For preparative purposes, conditions have been described to remove most contaminants (e.g. unreacted monomers, non-cross-linked, short polyacrylamide chains) from the gel matrix before the electrophoretic run. However, ca. 2% of the gel dry mass is still present as extractable material. The focused peptides can be recovered in higly yields (ca. 90%) with a fairly high degree of purity (75%), the contaminants being mostly components eluted from the polyacrylamide gel. 相似文献
98.
99.
Michel Rathbone Lara Pilutti Francesco Caciagli Shucui Jiang 《Nucleosides, nucleotides & nucleic acids》2013,32(6-7):666-672
Central nervous system (CNS) astrocytes release guanosine extracellularly, that exerts trophic effects. In CNS, extracellular guanosine (GUO) stimulates mitosis, synthesis of trophic factors, and cell differentiation, including neuritogenesis, is neuroprotective, and reduces apoptosis due to several stimuli. Specific receptor-like binding sites for eGUO in the nervous system may mediate its effects through both MAP kinase and PI3-kinase signalling pathways. Extracellular guanine (eGUA) also exerts several effects; the trophic effects of eGUO are likely regulated by conversion of eGUO to eGUA by a membrane located purine nucleoside phosphorylase (ecto-PNP) and by conversion of eGUA to xanthine by guanine deaminase. 相似文献
100.