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941.
Leo I. Gordon Michael A. Burke Amareshwar T. K. Singh Sheila Prachand Elliot D. Lieberman Lin Sun Tejaswitha Jairaj Naik Sathyamangla V. Naga Prasad Hossein Ardehali 《The Journal of biological chemistry》2009,284(4):2080-2087
Overexpression of the receptor tyrosine kinase erbB2 (Her2 in humans) is
correlated with a poor prognosis in breast and ovarian cancers. Treatment with
trastuzumab (a monoclonal antibody against erbB2) improves survival; however,
it also causes cardiomyopathy. We hypothesized that blockade of the erbB2
receptor induces cardiomyocyte death through a mitochondrial pathway that is
dependent on the production of reactive oxygen species (ROS). We first showed
that levels of erbB2 receptor are significantly decreased in an animal model
of ischemic heart disease and in human ischemic cardiomyopathy. We treated
neonatal rat cardiomyocytes with an inhibitory erbB2 antibody to study the
mechanism behind the deleterious effects of erbB2 blockade. These cells
displayed a dose-dependent increase in ROS production and cell death compared
with control IgG-treated cells; these processes were reversed by the
antioxidant, N-acetylcysteine. The effects of erbB2 antibody on both
cell death and ROS production were also reversed by cyclosporine A and
diazoxide, chemicals that regulate the pro- and anti-apoptotic channels in the
mitochondria, respectively. Furthermore, mouse embryonic fibroblasts lacking
Bax and Bak (proteins that mediate cell death through a mitochondrial pathway)
were resistant to the deleterious effects of erbB2 antibody. These effects of
erbB2 blockade appear to occur through a pathway involving AKT and
PKC-α. Our results suggest that erbB2 plays a role in cardiomyocyte
survival, and that the deleterious effects of trastuzumab on the heart occur
through a mitochondrial pathway and is mediated by ROS production.
Manipulation of redox signaling may be beneficial in cancer patients receiving
trastuzumab.The Her-2/neu oncogene, also known as erbB2 in nonhuman organisms, is a
transmembrane receptor tyrosine kinase that belongs to the epidermal growth
factor receptor family (1,
2). Overexpression of Her2 is
seen in ∼30% of breast cancer patients and is associated with poor
survival, increased metastasis, and resistance to chemotherapy
(3–5).
Transgenic mice overexpressing erbB2 develop focal mammary tumors, thus
implicating this protein in tumorigenesis
(6). Trastuzumab (Herceptin,
Genentech, CA) is a monoclonal antibody
(Ab)2 that binds to
Her2 with high affinity and improves survival of patients with advanced breast
cancer (7). Trastuzumab is
clinically efficacious both as a single agent or in combination with standard
chemotherapy regimens
(4–6).
However, this agent is cardiotoxic on its own, and especially when
administered with anthracyclines, where it can cause cardiomyopathy (CM) in up
to 27% of patients (8).The importance of erbB2 in normal cardiac development and physiology was
demonstrated in mice by cardiac-specific knock-out of erbB2
(9,
10). The mice were initially
normal, but developed CM as adults. One study demonstrated no difference
between the wild-type and knock-out mice in the degree of cardiac cell death
as assessed by TUNEL staining
(10). However, in another
study that used a more sensitive PCR-based DNA fragmentation assay increased
DNA fragmentation was reported in the hearts of erbB2-knock-out animals
(9). Recently, Grazette et
al. (11) studied the
effects of erbB2 blockade on cardiomyocyte survival, and showed that erbB2
antibody (erbB2-Ab) caused a loss of mitochondrial membrane potential and an
increase in cell death.The mechanism for the deleterious effects of erbB2 blockade remains
unclear, but a recent report showed that activation of erbB2 reduces
doxorubicin-induced oxidative stress in cardiomyocytes
(12). Therefore, we
hypothesized that erbB2-Ab-induced cell death in cardiomyocytes is a
mitochondrial dependent process that involves ROS production. In this report,
we show that erbB2 levels are decreased in an animal model of myocardial
ischemia and in patients with ischemic CM. We then demonstrate that erbB2
blockade in cardiomyocytes leads to ROS production, and that the antioxidant
N-acetylcysteine (NAC) protects against the damage induced by
erbB2-Ab. We also find that erbB2 signaling in cardiomyocytes occurs through a
mitochondrial, AKT-, and PKCα-dependent pathway. Moreover, the
deleterious effects caused by the loss of erbB2 function require the
pro-apoptotic proteins Bax and Bak. Finally, by using an erbB2-specific siRNA,
we demonstrate that the effects of erbB2 blockade evolve from the specific
inhibition of the erbB2 pathway rather than through nonspecific effects of the
antibody. Together, our results suggest that erbB2 blockade increases ROS
through a mitochondrial pathway. 相似文献
942.
Anjali Apte-Deshpnade Goutam Mandal Sudheerbabu Soorapaneni Bhaskarjyoti Prasad Jitendra Kumar Sriram Padmanabhan 《Biotechnology letters》2009,31(6):811-817
Staphylokinase (SAK) is a promising thrombolytic agent for treating blood-clotting disorders. Recombinant SAK (rSAK) was produced
after integration of the gene into Pichia pastoris genome. The recombinant Pichia carrying multiple insertions of the SAK gene yielded high-level (~1 g/l) of extracellular glycosylated rSAK (~18 kDa) with
negligible plasminogen activation activity. Addition of tunicamycin during the induction phase resulted in expression of non-glycosylated
and highly active rSAK (~15 kDa) from the same clone. Two simple steps of ion-exchange chromatography produced an homogenous
rSAK of >95% purity which suitable for future structural and functional studies. 相似文献
943.
Kamalesh Prasad Masa-aki Murakami Yoshiro Kaneko Akihiko Takada Yoshifumi Nakamura Jun-ichi Kadokawa 《International journal of biological macromolecules》2009,45(3):221-225
This paper reports the formation of weak gel of chitin with an ionic liquid, 1-allyl-3-methylimidazolium bromide (IL). When a mixture of 5% (w/w) chitin with IL was heated at 100 °C for 48 h, the clear liquid was obtained. The experimental process was observed by the CCD camera view and the SEM analysis. From a mixture of chitin with IL in the higher concentration (7%, w/w), a more viscous material, i.e., a gel-like material was obtained. The rheological evaluations showed that both 5% (w/w) and 7% (w/w) chitins with IL behaved as weak gels. 相似文献
944.
Diganta Kalita Siva Prasad Das Nashreen S. Islam 《Biological trace element research》2009,128(3):200-219
The present work was undertaken to examine and compare some biologically important properties of peroxo compounds of V(V)
and W(VI) containing biogenic species as ancillary ligand. New anionic peroxovanadate(V) complex of the type Na[VO(O2)2(triglycine)]·3H2O (pV1) and a molecular peroxotungstate(VI) [WO(O2)2(triglycine)]·3H2O (pW1) were synthesized and characterized for the purpose and their stability in solution was ascertained. Studies on kinetics
of inhibition of alkaline phosphatase activity by the newly synthesized compounds and series of dipeptide and amino acid containing
peroxo complexes of vanadium and tungsten synthesized previously by us viz., Na[VO(O2)2(gly-gly)(H2O)]·H2O (gly-gly = glycyl-glycine), Na[VO(O2)2(asn)]·H2O (asn = asparagine), Na[VO(O2)2(gln)]·H2O (gln = glutamine), and [WO(O2)2(gly-gly)(H2O)]·3H2O, revealed that each of these species is a potent mixed-type inhibitor of the enzyme. Significant difference was noted between
the peroxovanadium (pV) and peroxotungsten (pW) compounds in terms of their oxidant activity with reduced glutathione. 相似文献
945.
Ruth Stavrum Vithal Prasad Myneedu Virendra K. Arora Niyaz Ahmed Harleen M. S. Grewal 《PloS one》2009,4(2)
Background
India has the highest estimated burden of tuberculosis in the world, accounting for 21% of all tuberculosis cases world-wide. However, due to lack of systematic analysis using multiple markers the available information on the genomic diversity of Mycobacterium tuberculosis in India is limited.Methodology/Principal Findings
Thus, 65 M. tuberculosis isolates from New Delhi, India were analyzed by spoligotyping, MIRU-VNTR, large deletion PCR typing and single nucleotide polymorphism analysis (SNP). The Central Asian (CAS) 1 _DELHI sub-lineage was the most prevalent sub-lineage comprising 46.2% (n = 30) of all isolates, with shared-type (ST) 26 being the most dominant genotype comprising 24.6% (n = 16) of all isolates. Other sub-lineages observed were: East-African Indian (EAI)-5 (9.2%, n = 6), EAI6_BGD1 (6.2%, n = 4), EAI3_IND, CAS and T1 with 6.2% each (n = 4 each), Beijing (4.6%, n = 3), CAS2 (3.1%, n = 2), and X1 and X2 with 1 isolate each. Genotyping results from five isolates (7.7%) did not match any existing spoligopatterns, and one isolate, ST124, belonged to an undefined lineage. Twenty-six percent of the isolates belonged to the TbD1+ PGG1 genogroup. SNP analysis of the pncA gene revealed a CAS-lineage specific silent mutation, S65S, which was observed for all CAS-lineage isolates (except two ST26 isolates) and in 1 orphan. Mutations in the pncA gene, conferring resistance to pyrazinamide, were observed in 15.4% of all isolates. Collectively, mutations in the rpoB gene, the katG gene and in both rpoB and katG genes, conferring resistance to rifampicin and isoniazid, respectively, were more frequent in CAS1_DELHI isolates compared to non-CAS_DELHI isolates (OR: 3.1, CI95% [1.11, 8.70], P = 0.045). The increased frequency of drug-resistance could not be linked to the patients'' history of previous anti-tuberculosis treatment (OR: 1.156, CI95% [0.40, 3.36], P = 0.79). Fifty-six percent of all new tuberculosis patients had mutations in either the katG gene or the rpoB gene, or in both katG and rpoB genes.Conclusion
CAS1_DELHI isolates circulating in New Delhi, India have a high frequency of mutations in the rpoB and katG genes. A silent mutation (S65S) in the pncA gene can be used as a putative genetic marker for CAS-lineage isolates. 相似文献946.
K. Sakthivel N. Shobha Rani Manish K. Pandey A. K. P. Sivaranjani C. N. Neeraja S. M. Balachandran M. Sheshu Madhav B. C. Viraktamath G. S. V. Prasad R. M. Sundaram 《Molecular breeding : new strategies in plant improvement》2009,24(2):185-190
Fragrance development in rice has been reported due to a 8-bp deletion in the exon 7 of badh2 gene located on Chromosome 8S. Multiplex markers targeting the functional InDel polymorphism was earlier reported for genotyping
fragrance trait, but the marker was observed to be inconsistent and difficult to use. We have developed a simple, co-dominant,
functional marker for fragrance trait, which can be resolved in an agarose gel and validated in Basmati and non-Basmati aromatic
rice varieties and in a mapping population segregated for fragrance trait. The marker targets the InDel polymorphism in badh2 gene and amplifies 95 and 103 bp fragments in fragrant and non-fragrant genotypes, respectively. The newly developed marker
was highly efficient in discriminating all fragrant and non-fragrant genotypes and showed perfect co-segregation with the
trait of fragrance in the mapping population. We recommend the use of this simple, low-cost marker in routine genotyping for
fragrance trait in large scale breeding materials and germplasm. 相似文献
947.
In this review, we highlight our recent achievements in using colloidal gold nanoparticles as building blocks for fabrication
of anisotropic and multicomponent nanoparticles (e.g., nanoshells, semiconductor nanocrystals, and gold nanorods). The tunable
optical properties of these nanoparticles are well suited for various biomedical and biophotonic applications. 相似文献
948.
Soumya Raychaudhuri Robert M. Plenge Elizabeth J. Rossin Aylwin C. Y. Ng International Schizophrenia Consortium Shaun M. Purcell Pamela Sklar Edward M. Scolnick Ramnik J. Xavier David Altshuler Mark J. Daly 《PLoS genetics》2009,5(6)
Translating a set of disease regions into insight about pathogenic mechanisms requires not only the ability to identify the key disease genes within them, but also the biological relationships among those key genes. Here we describe a statistical method, Gene Relationships Among Implicated Loci (GRAIL), that takes a list of disease regions and automatically assesses the degree of relatedness of implicated genes using 250,000 PubMed abstracts. We first evaluated GRAIL by assessing its ability to identify subsets of highly related genes in common pathways from validated lipid and height SNP associations from recent genome-wide studies. We then tested GRAIL, by assessing its ability to separate true disease regions from many false positive disease regions in two separate practical applications in human genetics. First, we took 74 nominally associated Crohn''s disease SNPs and applied GRAIL to identify a subset of 13 SNPs with highly related genes. Of these, ten convincingly validated in follow-up genotyping; genotyping results for the remaining three were inconclusive. Next, we applied GRAIL to 165 rare deletion events seen in schizophrenia cases (less than one-third of which are contributing to disease risk). We demonstrate that GRAIL is able to identify a subset of 16 deletions containing highly related genes; many of these genes are expressed in the central nervous system and play a role in neuronal synapses. GRAIL offers a statistically robust approach to identifying functionally related genes from across multiple disease regions—that likely represent key disease pathways. An online version of this method is available for public use (http://www.broad.mit.edu/mpg/grail/). 相似文献
949.
Microarray gene expression data is used in various biological and medical investigations. Processing of gene expression data requires algorithms in data mining, process automation and knowledge discovery. Available data mining algorithms exploits various visualization techniques. Here, we describe the merits and demerits of various visualization parameters used in gene expression analysis. 相似文献
950.
Chhillar AK Arya P Mukherjee C Kumar P Yadav Y Sharma AK Yadav V Gupta J Dabur R Jha HN Watterson AC Parmar VS Prasad AK Sharma GL 《Bioorganic & medicinal chemistry》2006,14(4):973-981
Ten 4-aryl-1,4-dihydropyridine and three 4-aryl-1,2,3,4-tetrahydropyrimidin-2-one derivatives have been synthesized and examined for their activity against pathogenic strains of Aspergillus fumigatus and Candida albicans. Although none of the three compounds belonging to pyrimidin-2-one series showed any activity against two pathogens, two of the compounds of the dihydropyridine series, that is, diethyl 4-(4-methoxyphenyl)-2,6-dimethyl-1,4-dihydropyridin-3,5-dicarboxylate and dimethyl 4-(4-methoxyphenyl)-2,6-dimethyl-1,4-dihydropyridin-3,5-dicarboxylate, exhibited significant activity against A. fumigatus in disc diffusion, microbroth dilution and percent spore germination inhibition assays. The most active diethyl dihydropyridine derivative exhibited a MIC value of 2.92 microg/disc in disc diffusion and 15.62 microg/ml in microbroth dilution assays. The MIC(90) value of the most active compound by percent germination inhibition assay was found to be 15.62 microg/ml. The diethyl dicarboxylate derivative of dihydropyridine also exhibited appreciable activity against C. albicans. The in vitro toxicity of the most active diethyl dihydropyridine derivative was evaluated using haemolytic assay, in which the compound was found to be non-toxic to human erythrocytes even at a concentration of 625 microg/ml. The standard drug amphotericin B exhibited 100% lysis of erythrocytes at a concentration almost 16 times less than the safer concentration of the most active dihydropyridine derivative. 相似文献