全文获取类型
收费全文 | 2433篇 |
免费 | 176篇 |
出版年
2024年 | 2篇 |
2023年 | 3篇 |
2022年 | 18篇 |
2021年 | 42篇 |
2020年 | 25篇 |
2019年 | 45篇 |
2018年 | 69篇 |
2017年 | 46篇 |
2016年 | 57篇 |
2015年 | 112篇 |
2014年 | 155篇 |
2013年 | 206篇 |
2012年 | 237篇 |
2011年 | 191篇 |
2010年 | 120篇 |
2009年 | 126篇 |
2008年 | 177篇 |
2007年 | 138篇 |
2006年 | 122篇 |
2005年 | 131篇 |
2004年 | 123篇 |
2003年 | 104篇 |
2002年 | 84篇 |
2001年 | 26篇 |
2000年 | 21篇 |
1999年 | 26篇 |
1998年 | 34篇 |
1997年 | 25篇 |
1996年 | 19篇 |
1995年 | 15篇 |
1994年 | 16篇 |
1993年 | 8篇 |
1992年 | 12篇 |
1991年 | 14篇 |
1990年 | 9篇 |
1989年 | 6篇 |
1988年 | 12篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1972年 | 2篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有2609条查询结果,搜索用时 15 毫秒
1.
M Ravnik-Glavac P Gasparini B Peterlin M Strukelj D Glavac N Canki-Klain P F Pignatti R Komel 《Annales de génétique》1992,35(2):85-88
The authors used polymerase chain reaction to analyse 56 Slovenian cystic fibrosis (CF) chromosomes for the presence of delta F508 and eight other most frequent mutations located in exons 7,11 and 20 (R347P, R334W, G551D, R553X, S549RA, S549RT, S549I and S1255X) of the CF gene. We also determined the frequency of haplotypes associated with CF for six linked RFLP markers (MetD/TaqI, MetH/TaqI, XV-2c/TaqI, KM-19/PstI, MP6d9/MspI and J3.11/MspI) in 27 Slovenian CF families. delta F508 mutation was present in 55.4 percent of the CF chromosomes. No case of the other mutations were detected in the sample of tested CF chromosomes. A very high degree of association (0.88) has been found between DNA marker MetH and CF (as measured by the Yule's association coefficient) in our population. Using the RFLP markers XV-2c and KM-19, we found that 85% of delta F508 mutated chromosomes have a single 1 2 (B) haplotype, and that this haplotype is present on only 15.4 percent of CF chromosomes without this deletion. 相似文献
2.
Filippo Genovese Stefania Ferrari Giambattista Guaitoli Monica Caselli M. Paola Costi Glauco Ponterini 《Protein science : a publication of the Protein Society》2010,19(5):1023-1030
An ad hoc bioconjugation/fluorescence resonance energy transfer (FRET) assay has been designed to spectroscopically monitor the quaternary state of human thymidylate synthase dimeric protein. The approach enables the chemoselective engineering of allosteric residues while preserving the native protein functions through reversible masking of residues within the catalytic site, and is therefore suitable for activity/oligomerization dual assay screenings. It is applied to tag the two subunits of human thymidylate synthase at cysteines 43 and 43′ with an excitation energy donor/acceptor pair. The dimer–monomer equilibrium of the enzyme is then characterized through steady‐state fluorescence determination of the intersubunit resonance energy transfer efficiency. 相似文献
3.
S Scarfi M Giovine A Gasparini G Damonte E Millo M Pozzolini U Benatti 《FEBS letters》1999,451(3):264-268
Overexpression of inducible nitric oxide synthase causes the production of high levels of nitric oxide, which, under pathological conditions, leads to immunosuppression and tissue damage. The results recently obtained using peptide nucleic acids, rather than traditional oligonucleotides as antigen and antisense molecules, prompted us to test their efficacy in the regulation of nitric oxide production, thereby overcoming the obstacle of cellular internalization. The cellular permeability of four inducible nitric oxide synthase antisense peptide nucleic acids of different lengths was evaluated. These peptide nucleic acids were covalently linked to a hydrophobic peptide moiety to increase internalization and to a tyrosine to allow selective 125I radiolabelling. Internalization experiments showed a 3-25-fold increase in the membrane permeability of the modified peptide nucleic acids with respect to controls. Inducible nitric oxide synthase inhibition experiments on intact stimulated macrophages RAW 264.7 after passive permeation of the two antisense peptide nucleic acids 3 and 4 demonstrated a significant decrease (43-44%) in protein enzymatic activity with respect to the controls. These data offer a basis for developing a good alternative to conventional drugs directed against inducible nitric oxide synthase overexpression. 相似文献
4.
A frameshift mutation (2869insG) in the second transmembrane domain of the CFTR gene: identification, regional distribution, and clinical presentation. 下载免费PDF全文
5.
6.
Cristina Cereda Emanuela Leoni Pamela Milani Orietta Pansarasa Giuliano Mazzini Stefania Guareschi Elena Alvisi Andrea Ghiroldi Luca Diamanti Stefano Bernuzzi Mauro Ceroni Emanuela Cova 《PloS one》2013,8(10)
Several lines of evidence support the hypothesis of a toxic role played by wild type SOD1 (WT-SOD1) in the pathogenesis of sporadic amyotrophic lateral sclerosis (SALS). In this study we investigated both distribution and expression profile of WT-SOD1 in leukocytes from 19 SALS patients and 17 healthy individuals. Immunofluorescence experiments by confocal microscopy showed that SOD1 accumulates in the nuclear compartment in a group of SALS subjects. These results were also confirmed by western blot carried out on soluble nuclear and cytoplasmic fractions, with increased nuclear SOD1 level (p<0.05). In addition, we observed the presence of cytoplasmic SOD1 aggregates in agreement with an increased amount of the protein recovered by the insoluble fraction. A further confirmation of the overall increased level of SOD1 has been obtained from single cells analysis using flow cytometry as cells from SALS patients showed an higher SOD1 protein content (p<0.05). These findings add further evidence to the hypothesis of an altered WT-SOD1 expression profile in peripheral blood mononuclear cells (PBMCs) from patients with ALS suggesting that WT-SOD1 species with different degrees of solubility could be involved in the pathogenesis of the disease. 相似文献
7.
After c. 30 years without sighting or capture, Anthias salmopunctatus was rediscovered at the type locality, St Peter and St Paul's Rocks, Mid-Atlantic Ridge. To date, the known distribution is restricted to depths varying from 35 to 55 m in vertical drop offs around the perimeter of the islands ( c. 400 m). This may be the smallest geographic range known for a marine fish species. 相似文献
8.
9.
Giuseppe Familiari M.D. Stefania A. Nottola Antonio Familiari Pietro M. Motta 《Cell and tissue research》1989,257(2):247-253
Summary The present study provides further details on the fine-structural three-dimensional architecture of the zona pellucida (ZP) in growing and atretic follicles of mice by use of ruthenium red in combination with the detergents Triton X100 and saponin. These detergents were used for extraction of the soluble fraction of the zonal proteins in an attempt to expose the structural zonal glycoproteins, which in turn can be viewed as minute three-dimensional networks upon transmission- and scanning electron-microscopic examination. By use of these methods, the ZP of growing follicles appeared to be formed by interconnected filaments which also bind to globular structures building up a three-dimensional lattice. In contrast, the ZP of stage I as well as other (II and III) stages of atretic follicles showed a structure characterized by the presence of closely packed granules connected with short filaments to form a close-mesh reticulum. This structural change of the ZP, which in the present study is also associated with the disappearance of gap junctions within the granulosa and cumulus cell population, might represent one of the early events involved in the onset of atresia. These changes, most probably depending on an altered secretory activity of both oocytes and follicle cells, might lead to a degradation of the ZP network structure and to its subsequent increased density (condensation). All these morphodynamic events eventually contribute to a sequestration of the oocyte in the early stage of atresia. 相似文献
10.
Elvira D'Alessandro Corinna De Matteis Vaccarella Maria Luisa Lo Re Francesco Cappa Angela D'Alfonso Stefania Discepoli Maria Rosa Della Penna Giuseppe Del Porto 《Human genetics》1988,80(2):203-204
Summary Pericentric inversion of chromosome 19 has been found in several members of three unrelated families from a restricted geographical region. In one of the families, an additional pericentric inversion of chromosome 9 was observed. Reproductive problems, multiple abortions in two families and a neonatal death in the third, were present. A review of previously described cases is included, and the genetic risk connected with this type of rearrangement is also discussed. 相似文献