全文获取类型
收费全文 | 665篇 |
免费 | 79篇 |
国内免费 | 1篇 |
专业分类
745篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 8篇 |
2020年 | 11篇 |
2019年 | 9篇 |
2018年 | 16篇 |
2017年 | 17篇 |
2016年 | 15篇 |
2015年 | 24篇 |
2014年 | 22篇 |
2013年 | 34篇 |
2012年 | 42篇 |
2011年 | 42篇 |
2010年 | 29篇 |
2009年 | 17篇 |
2008年 | 32篇 |
2007年 | 26篇 |
2006年 | 27篇 |
2005年 | 35篇 |
2004年 | 39篇 |
2003年 | 23篇 |
2002年 | 33篇 |
2001年 | 22篇 |
2000年 | 19篇 |
1999年 | 21篇 |
1998年 | 12篇 |
1997年 | 12篇 |
1996年 | 10篇 |
1995年 | 12篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 13篇 |
1991年 | 9篇 |
1990年 | 15篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 10篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1981年 | 2篇 |
1979年 | 8篇 |
1978年 | 7篇 |
1976年 | 2篇 |
1975年 | 6篇 |
1974年 | 2篇 |
1968年 | 2篇 |
1967年 | 2篇 |
排序方式: 共有745条查询结果,搜索用时 0 毫秒
51.
Benito P De Juan A Cano M Elena E 《Plastic and reconstructive surgery》2008,121(2):680-1; author reply 681
52.
Analysis of parvalbumin fractions through proteomic methodologies allowed the differential classification of ten commercial, closely related species of the family Merlucciidae. Muscle extracts from nine hake species of the genus Merluccius including two subspecies of Merluccius australis (australis and polylepsis) and one grenadier species Macruronus novaezelandiae with two populations (novaezelandiae and magellanicus) were evaluated by 2-DE and MALDI-TOF MS. 2-DE demonstrated that the species tested displayed a low intra-specific degree of polymorphism and the isoform patterns were noticeably species-specific. MALDI-TOF mass fingerprints showed clear differences in the pattern of peptides produced by tryptic digestion between the Merluccius and the Macruronus, making the genus differentiation possible. In addition, a selective peptide mass present in the spectra from certain hakes allowed its classification in two groups: Euro-African and American hakes. Besides, some specific masses allowed a clearly individual identification for M. bilinearis, M. australis polylepsis, M. australis australis, M. productus, M. paradoxus and M. polli, while the rest of the hake species can be grouped in two clusters, comprising M. hubbsi and M. gayi in one and M. merluccius and M. capensis in the other. 相似文献
53.
Fine regulation of cI857-controlled gene expression in continuous culture of recombinant Escherichia coli by temperature. 总被引:3,自引:0,他引:3 下载免费PDF全文
The expression at different temperatures of the lacZ gene, which is controlled by the lambda pL and pR tandem promoters and the cI857 temperature-sensitive repressor, was studied in Escherichia coli continuous cultures. At temperatures between 30 and 42 degrees C, beta-galactosidase activity behaved according to an exponential equation. By inducing a culture at a temperature within this range, predefined, nearly constant submaximal levels of gene expression and recombinant product yield can be obtained. 相似文献
54.
Morgan UM Monis PT Xiao L Limor J Sulaiman I Raidal S O'Donoghue P Gasser R Murray A Fayer R Blagburn BL Lal AA Thompson RC 《International journal for parasitology》2001,31(3):289-296
Avian isolates of Cryptosporidium species from different geographic locations were sequenced at two loci, the 18S rRNA gene and the heat shock gene (HSP-70). Phylogenetic analysis of the sequence data provided support for the existence of a new avian species of Cryptosporidium infecting finches and a second species infecting a black duck. The identity of Cryptosporidium baileyi and Cryptosporidium meleagridis as valid species was confirmed. Also, C. baileyi was identified in a number of isolates from the brown quail extending the host range of this species. 相似文献
55.
Cloning and expression of two genes coding for sodium pumps in the salt-tolerant yeast Debaryomyces hansenii 下载免费PDF全文
Almagro A Prista C Benito B Loureiro-Dias MC Ramos J 《Journal of bacteriology》2001,183(10):3251-3255
Two genes encoding Na(+)-ATPases from Debaryomyces hansenii were cloned and sequenced. The genes, designated ENA1 from D. hansenii (DhENA1) and DhENA2, exhibited high homology with the corresponding genes from Schwanniomyces occidentalis. DhENA1 was expressed in the presence of high Na(+) concentrations, while the expression of DhENA2 also required high pH. A mutant of Saccharomyces cerevisiae lacking the Na(+) efflux systems and sensitive to Na(+), when transformed with DhENA1 or DhENA2, recovered Na(+) tolerance and also the ability to extrude Na(+). 相似文献
56.
Nod2, a Nod1/Apaf-1 family member that is restricted to monocytes and activates NF-kappaB 总被引:42,自引:0,他引:42
Ogura Y Inohara N Benito A Chen FF Yamaoka S Nunez G 《The Journal of biological chemistry》2001,276(7):4812-4818
Apaf-1 and Nod1 are members of a protein family, each of which contains a caspase recruitment domain (CARD) linked to a nucleotide-binding domain, which regulate apoptosis and/or NF-kappaB activation. Nod2, a third member of the family, was identified. Nod2 is composed of two N-terminal CARDs, a nucleotide-binding domain, and multiple C-terminal leucine-rich repeats. Although Nod1 and Apaf-1 were broadly expressed in tissues, the expression of Nod2 was highly restricted to monocytes. Nod2 induced nuclear factor kappaB (NF-kappaB) activation, which required IKKgamma and was inhibited by dominant negative mutants of IkappaBalpha, IKKalpha, IKKbeta, and IKKgamma. Nod2 interacted with the serine-threonine kinase RICK via a homophilic CARD-CARD interaction. Furthermore, NF-kappaB activity induced by Nod2 correlated with its ability to interact with RICK and was specifically inhibited by a truncated mutant form of RICK containing its CARD. The identification of Nod2 defines a subfamily of Apaf-1-like proteins that function through RICK to activate a NF-kappaB signaling pathway. 相似文献
57.
Ismael Hernández-Torres Magdalena Iracheta Luis J. Galán-Wong Carlos Hernández Juan Contreras Mark Jackson Benito Pereyra-Alférez 《World journal of microbiology & biotechnology》2004,20(2):207-210
A Paecilomyces fumosoroseus strain was mutagenized by u.v. Among 200 colonies, one mutant (M84), showed a large and stable chitin hydrolysis-halo. Glucose consumption and biomass production were similar for M84 and the parental strain. Chitinase was inducible by chitin and repressed by glucose in both strains but, when they were grown on minimal medium plus colloidal chitin as sole carbon source, the parental and M84 strains yielded 198 and 690 mol N-acetylglucosamine, respectively. This results indicate that the mutant strain synthesized a chitinase with a higher activity. Bioassays against Bemisia tabaci nymph, showed that M84 incited a 2-fold higher incidence of disease compared to the parental strain. 相似文献
58.
Stearns BA Anker N Arruda JM Campbell BT Chen C Cramer M Hu T Jiang X Park K Ren KK Sablad M Santini A Schaffhauser H Urban MO Munoz B 《Bioorganic & medicinal chemistry letters》2004,14(5):1295-1298
A novel class of 6-aryl-6H-pyrrolo[3,4-d]pyridazine ligands for the alpha2delta subunit of voltage-gated calcium channels has been described. Substitutions in the aryl ring of the molecule were generally not tolerated, and resulted in diminished binding to the alpha2delta subunit. Modifications to the pyridazine ring revealed numerous permissive substitutions, and detailed SAR studies were carried out in this portion of the molecule. Replacement of the pyridazine ring methyl group with an aminomethyl functionality provided greatly improved potency over the initial lead. The initial lead compound displayed good rat pharmacokinetic properties, and was shown to be efficacious in the Chung model for neuropathic pain in rats. 相似文献
59.
Lebsack AD Gunzner J Wang B Pracitto R Schaffhauser H Santini A Aiyar J Bezverkov R Munoz B Liu W Venkatraman S 《Bioorganic & medicinal chemistry letters》2004,14(10):2463-2467
We have identified and synthesized a series of [1,2,4]triazolo[3,4-a]phthalazine derivatives as high-affinity ligands to alpha 2 delta-1 subunit of voltage gated calcium channels. Structure-activity relationship studies directed toward improving the potency and physical properties of 2 lead to the discovery of 20 (IC(50)=15 nM) and (S)-22 (IC(50)=30 nM). A potent and selective radioligand, [(3)H]-(S)-22 was also synthesized to demonstrate that this ligand binds to the same site as gabapentin. 相似文献
60.
Eastman B Chen C Smith ND Poon S Chung J Reyes-Manalo G Cosford ND Munoz B 《Bioorganic & medicinal chemistry letters》2004,14(22):5485-5488
The SAR of the lead compounds 2a and 2b was rapidly explored. Utilizing a parallel solution-phase Suzuki coupling approach, in tandem with strong cation exchange resin (SCX) purification afforded the desired focused library. The library was evaluated in vitro, a ninefold potency increase was achieved and the preference for ortho substitution of moderate steric bulk of the fourth, phenyl ring was identified. In addition, dimethylisoxazole, as a heterocyclic replacement for the phenylic ring of the lead compound, was also identified by this approach. 相似文献