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151.
De-embryonated cotyledon explants of peanut were co-cultivated under different conditions with Agrobacterium tumefaciens harbouring pIG121hm plasmid carrying intron-containing β-glucuronidase as a reporter while hygromycin phosphotransferase and neomycin phosphotransferase as selectable marker genes.
Co-cultivation duration and temperature, various antioxidants and their concentrations, bacterial strains and explant characteristics
(incised and non-incised) were examined either alone or in combinations for optimization of transient expression of the reporter
gene. Up to 81% transformation was recorded when non-incised explants were co-cultivated with strain EHA101 for 5 days at
21°C on shoot induction medium containing 100 mg/L l-cysteine. Addition of the optimized concentration of augmentin (200 mg/L) along with cefotaxime (200 mg/L) to the shoot induction
medium not only effectively eliminated bacterial growth, but also facilitated high frequency of shoot induction. The 40 mg/L
hygromycin concentration prevented complete shoot regeneration of non-transgenic explants thus considered for the regeneration
of transgenics. Resistant shoots were successfully transferred to soil either by grafting or in vitro rooting. Survival rate
of the grafted shoots was nearly 100% in glass-house conditions. The optimized protocol took around 3 months to generate healthy
plants. Polymerase chain reaction, Southern blot hybridization, histochemical tests, segregation and hygromycin-leaf assays
of selected transgenic plants showed integration of the transgene into peanut genome. No chimeras were noticed during the
study. 相似文献
152.
Effect of particulate pollution on rate of transpiration in Shorea robusta at Lalpahari forest 总被引:1,自引:0,他引:1
The effect of stone dust deposition on the rate of transpiration in Shorea robusta was studied in three principal seasons in a polluted forest in comparison to an almost non-polluted forest. The extent of particulate pollution was determined by measuring suspended particulate matter in the air and dust fall on leaf surface. Macroscopic and microscopic leaf injury symptoms were studied. Scanning electron microscopic examination of leaf surfaces revealed a number of foliar anomalies. Qualitative determination of rate of transpiration in field condition was done by ‘cobalt chloride method’. It was found that transpiration was diminished as a result of foliar dust deposition which not only caused blockage of stomatal aperture but also physical damage to the leaf surface. Thus, particulate air pollution can be considered as one of the external factors regulating the rate of transpiration in plants. 相似文献
153.
In vitro propagation of rose--a review 总被引:1,自引:0,他引:1
In vitro propagation of rose has played a very important role in rapid multiplication of cultivars with desirable traits and production of healthy and disease-free plants. During the last several years, different approaches have been made for in vitro propagation of rose. Micropropagation using apical buds or nodal segments and understanding the specific requirements at different stages has been comprehensively covered in literature. New challenges for refinements of protocols for high rate of shoot multiplication and development of cost effective methods has gained importance in the recent past. Importance of liquid static culture for shoot proliferation and root induction for rose is also discussed in the present review. Further, the development of protocol for in vitro plant regeneration which is considered as most important step for successful implementation of various biotechnological techniques used for plant improvement programmes has been adequately addressed in literature. In rose, there are several reports which indicate rapid regeneration and multiplication through organogenesis or somatic embryogenesis. On the whole, the present review gives a consolidated account of in vitro propagation in rose. 相似文献
154.
Both H(2)O(2) and NO can act as apoptogens, triggering apoptosis in many cells. They are also well known inhibitors of caspases, essential enzymes in apoptosis. The differences between these two agents as apoptosis inducers and how caspases mediate apoptosis with these inhibitory agents is still unclear. Consistent with the previous reports, these two agents induced apoptosis accompanied by caspase activation with limitation of all apoptotic events for NO. It was found that NO-modified caspase-3 showed a slower recovery of its activity in the presence of the reducing agents compared to that of H(2)O(2) modification. This is one possible cause of the limited apoptosis in the case of NO. 相似文献
155.
Tumour necrosis factor alpha mediated apoptosis in murine macrophages by Salmonella enterica serovar Typhi under oxidative stress 总被引:1,自引:0,他引:1
Invasive Salmonella has been reported to induce apoptosis of macrophages as part of its infection process, which may allow it to avoid detection by the innate immune system. However, the induction of apoptosis under the different host environments remains to be examined, including the oxidative stress experienced by pathogens in the macrophage milieu. To simulate in vivo oxidative conditions, Salmonella enterica serovar Typhi was grown in the presence of hydrogen peroxide and its ability to induce apoptosis of murine macrophages was assessed. Analysis of data revealed that oxidative stressed S. Typhi caused apoptotic cell death in 51% of macrophages, whereas S. Typhi grown under normal conditions accounted for apoptotic cell death in only 32% of macrophages. A significant increase in the levels of oxidants and decrease in the antioxidant was also observed which correlated with the increased generation of tumour necrosis factor alpha, interleukin-1alpha and interleukin-6. These results suggest that tumour necrosis factor alpha in conjunction with other cytokines may induce apoptotic cell death through the up-regulation of lipid peroxidation and down-regulation of superoxide dismutase. This finding may help us to understand better the host-pathogen interactions and may be of clinical importance in the development of preventive intervention against infection. 相似文献
156.
Siddharth Tiwari Devesh K. Mishra Sribash Roy Ankit Singh P. K. Singh Rakesh Tuli 《Plant cell reports》2009,28(12):1827-1836
A synthetic DNA construct containing cholera toxin B subunit, genetically fused to the surface glycoprotein of rabies virus
was expressed in tobacco plants from a seed specific (legumin) promoter. Seed specific expression was monitored by real-time PCR, GM1-ELISA and Western blot analyses. The fusion protein
accumulated in tobacco seeds at up to 1.22% of the total seed protein. It was functionally active in binding to the GM1-ganglioside
receptors, suggesting its assembly into pentamers in seeds of the transgenic plants. Immunoblot analysis confirmed that the
~80.6 kDa monomeric fusion polypeptide was expressed in tobacco seeds and accumulated as a ~403 kDa pentamer. Evaluation of
its immunoprotective ability against rabies and cholera is to be examined. 相似文献
157.
Atul Kumar Ram Awatar Maurya Siddharth Sharma Pervez Ahmad A.B. Singh Gitika Bhatia Arvind K. Srivastava 《Bioorganic & medicinal chemistry letters》2009,19(22):6447-6451
A series of pyranocoumarin derivatives were synthesized and evaluated in vivo for their anti-hyperglycemic as well as anti-dyslipidemic activities. Compounds 7a, 7c, 8a, 8b, 8c, 8e and 8f have shown promising anti-hyperglycemic activities in sucrose loaded model (SLM) as well as sucrose challenged streptozotocin induced diabetic rat model (STZ). Compounds 8a and 8b were showing 38.0% and 42.0% blood glucose lowering activity in db/db mice model. In vitro anti-hyperglycemic activity evaluation exhibited that compounds 8a (IC50 = 24.5 μM) and 8b (IC50 = 36.2 μM) are potential PTP-1B inhibitors thereby revealing their possible mechanism of anti-diabetic action. Compounds 7a, 7b, 8a, 8b, 8d, 8e and 8f have shown significant anti-dyslipidemic activity in triton induced dyslipidemia in rats. 相似文献
158.
Yingshe Zhao Chengyin Min Siddharth R. Vora Philip C. Trackman Gail E. Sonenshein Kathrin H. Kirsch 《The Journal of biological chemistry》2009,284(3):1385-1393
The lysyl oxidase (LOX) gene encodes an enzyme (LOX)
critical for extracellular matrix maturation. The LOX gene has also
been shown to inhibit the transforming activity of Ras oncogene
signaling. In particular, the pro-peptide domain (LOX-PP) released from the
secreted precursor protein (Pro-LOX) was found to inhibit the transformed
phenotype of breast, lung, and pancreatic cancer cells. However, the
mechanisms of action of LOX-PP remained to be determined. Here, the ability of
LOX-PP to attenuate the integrin signaling pathway, which leads to
phosphorylation of focal adhesion kinase (FAK), and the activation of its
downstream target p130Cas, was determined. In NF639 breast cancer
cells driven by Her-2/neu, which signals via Ras, ectopic Pro-LOX and LOX-PP
expression inhibited fibronectin-stimulated protein tyrosine phosphorylation.
Importantly, phosphorylation of FAK on Tyr-397 and Tyr-576, and
p130Cas were substantially reduced. The amount of endogenous
p130Cas in the Triton X-100-insoluble protein fraction, and
fibronectin-activated haptotaxis were decreased. Interestingly, expression of
mature LOX enzyme enhanced fibronectin-stimulated integrin signaling. Of note,
treatment with recombinant LOX-PP selectively reduced fibronectin-mediated
haptotaxis of NF639, MDA-MB-231, and Hs578T breast cancer cells. Thus,
evidence is provided that one mechanism of action of LOX-PP tumor suppression
is to block fibronectin-stimulated signaling and cell migration.The lysyl oxidase
(LOX)2 gene
family is comprised of five members LOX, LOXL1, LOXL2, LOXL3, and
LOXL4, which encode enzymes that modify extracellular matrix (ECM)
proteins to promote their cross-linking and deposition
(1). The LOX gene is
the best characterized and codes for the synthesis of a secreted 50-kDa
glycosylated pro-enzyme (Pro-LOX). Pro-LOX is extracellularly processed by
proteolytic cleavage to a mature active 32-kDa enzyme (LOX) and an 18-kDa
pro-peptide (LOX-PP) by the procollagen C proteinases bone morphogenic
protein-1 (BMP-1), and the related tolloid-like proteins TLL1 and TLL2
(2–4).
In murine Pro-LOX, proteolytic processing occurs between amino acids Gly-162
and Asp-163, generating LOX-PP containing 141 amino acids
(5). LOX-PP contains two
consensus N-glycosylation sites, Asn-91 and Asn-138 (murine sequence)
(2) and several
O-glycosylation
sites.3 LOX-PP does
not contain any known protein domains, and structural prediction analysis
indicates that LOX-PP assembles as an intrinsically disordered protein
(6). Among the LOX family
members, the C-terminal ends encode the enzyme domain and are highly
conserved, whereas the N-terminal ends that encode the pro-peptide region have
variable sequences. Based on structural and sequence similarities of the
pro-peptide regions, the LOX family members can be divided into two subgroups:
LOXL2, LOXL3, and LOXL4 as one group whose propeptide
regions contain four scavenger receptor cysteine-rich domains, and
LOX and LOXL1 as a separate group with much simpler and
smaller pro-peptide region containing no cysteine residues (reviewed in Ref.
1). In contrast to Pro-LOX, the
exact maturation site of Pro-LOXL1 is still unidentified.LOX is essential in the formation of blood vessels and in maintaining their
normal characteristics
(7–9).
Up-regulation of LOX expression has been described in stromal cells
that surround ductal breast and broncho-pulmonary carcinomas
(10).Expression of the LOX gene was found to inhibit the transforming
activity of the Ras oncogene in NIH 3T3 fibroblasts and hence was
named the “ras recision” gene (rrg)
(11,
12). The LOX gene was
shown to inhibit growth in soft agar of NIH 3T3 fibroblasts and to attenuate
Ras-mediated activation of phosphatidylinositol 3-kinase (PI3K), Akt, and
Erk1/2 kinases and NF-κB activation
(13). More recently, the
rrg activity was mapped to the 18-kDa LOX-PP. Specifically, LOX-PP
was shown to inhibit Ras-mediated transformation of fibroblasts as determined
by reduced growth in soft agar, localization of PDK1 to the membrane, and
activation of NF-κB
(14). Furthermore, the
inhibitory effects of LOX-PP on Ras signaling were extended to breast,
pancreatic, and lung cancer cells
(6,
14,
15). LOX-PP expression in
these carcinoma cells reverted Her-2/neu- and Ras-mediated epithelial to
mesenchymal transition (EMT), leading to increased expression of E-cadherin
and γ-catenin, and reduced levels of Snail, vimentin, and/or BCL-2
(7,
15). Furthermore, LOX-PP
expression reduced tumor formation in a xenograft model by
Her-2/neu-overexpressing NF639 cells
(6).Acquisition of the ability to invade the ECM is essential to EMT. The ECM
has multiple mechanical and signaling functions. The ECM defines interfaces
between tissues, provides a scaffold for cell traction, and a substrate for
cell migration and adhesion. It is composed of a complex of proteins such as
collagens, fibronectin, and laminin, which can interact and bind various
growth factors (16).
Fibronectin is of particular interest because it was recently shown to
interact with the C terminus of Pro-LOX
(17). Binding of fibronectin
to its receptors (e.g. integrins
α5β1 or
αvβ1) stimulates the tyrosine phosphorylation
of cellular proteins, in particular that of focal adhesion kinase (FAK)
(18). Little is known about
the mechanism of action of LOX-PP. Here, we have asked whether the tumor
suppressor activity of LOX-PP attenuates the activation of the integrin
signaling pathway in breast cancer cells. We report that LOX-PP attenuates FAK
signaling and activation of its downstream target p130Cas and is a
robust inhibitor of fibronectin-stimulated cell migration. 相似文献
159.
Verena Ilona Carrara Julien Zwang Elizabeth A. Ashley Ric N. Price Kasia Stepniewska Marion Barends Alan Brockman Tim Anderson Rose McGready Lucy Phaiphun Stephane Proux Michele van Vugt Robert Hutagalung Khin Maung Lwin Aung Pyae Phyo Piyanuch Preechapornkul Mallika Imwong Sasithon Pukrittayakamee Pratap Singhasivanon Nicholas J. White Fran?ois Nosten 《PloS one》2009,4(2)
Background
Artemisinin combination treatments (ACT) are recommended as first line treatment for falciparum malaria throughout the malaria affected world. We reviewed the efficacy of a 3-day regimen of mefloquine and artesunate regimen (MAS3), over a 13 year period of continuous deployment as first-line treatment in camps for displaced persons and in clinics for migrant population along the Thai-Myanmar border.Methods and Findings
3,264 patients were enrolled in prospective treatment trials between 1995 and 2007 and treated with MAS3. The proportion of patients with parasitaemia persisting on day-2 increased significantly from 4.5% before 2001 to 21.9% since 2002 (p<0.001). Delayed parasite clearance was associated with increased risk of developing gametocytaemia (AOR = 2.29; 95% CI, 2.00–2.69, p = 0.002). Gametocytaemia on admission and carriage also increased over the years (p = 0.001, test for trend, for both). MAS3 efficacy has declined slightly but significantly (Hazards ratio 1.13; 95% CI, 1.07–1.19, p<0.001), although efficacy in 2007 remained well within acceptable limits: 96.5% (95% CI, 91.0–98.7). The in vitro susceptibility of P. falciparum to artesunate increased significantly until 2002, but thereafter declined to levels close to those of 13 years ago (geometric mean in 2007: 4.2 nM/l; 95% CI, 3.2–5.5). The proportion of infections caused by parasites with increased pfmdr1 copy number rose from 30% (12/40) in 1996 to 53% (24/45) in 2006 (p = 0.012, test for trend).Conclusion
Artesunate-mefloquine remains a highly efficacious antimalarial treatment in this area despite 13 years of widespread intense deployment, but there is evidence of a modest increase in resistance. Of particular concern is the slowing of parasitological response to artesunate and the associated increase in gametocyte carriage. 相似文献160.
Sheelendra Pratap Singh Girish Kumar Jain 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2009,877(11-12):1133-1139
A simple, sensitive and rapid method for the analysis of lumefantrine in rat plasma using liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS) was developed. Detection was performed by positive ion electrospray ionization (ESI) in multiple reaction monitoring (MRM) mode. The method included a chromatographic run of 5 min using a C18 analytical column and the calibration curve was linear over the concentration range of 2–500 ng/mL with a correlation coefficient (r) of 0.996 or better. The intra- and inter-day assay precision ranged from 1.5 to 7.5% and 5.5 to 7.7%, respectively, and intra- and inter-day assay accuracy was between 91.3–109.7% and 97.0–104.7%, respectively. The method was successfully applied for the pharmacokinetic study in rats. 相似文献