全文获取类型
收费全文 | 666篇 |
免费 | 40篇 |
国内免费 | 3篇 |
专业分类
709篇 |
出版年
2023年 | 3篇 |
2022年 | 12篇 |
2021年 | 27篇 |
2020年 | 15篇 |
2019年 | 9篇 |
2018年 | 15篇 |
2017年 | 10篇 |
2016年 | 20篇 |
2015年 | 35篇 |
2014年 | 40篇 |
2013年 | 44篇 |
2012年 | 65篇 |
2011年 | 63篇 |
2010年 | 41篇 |
2009年 | 24篇 |
2008年 | 57篇 |
2007年 | 47篇 |
2006年 | 32篇 |
2005年 | 26篇 |
2004年 | 44篇 |
2003年 | 19篇 |
2002年 | 19篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有709条查询结果,搜索用时 15 毫秒
11.
Management options for postpartum hemorrhage (PPH) include oxytocics, prostaglandins, genital tract exploration, ligation or angiographic embolization of uterine/internal iliac arteries, and hysterectomy. After excluding uterine rupture, genital tract lacerations, and retained placental tissue, efforts are directed toward contracting the uterus by bimanual compression and oxytocics. If these are not successful, one must resort to surgical techniques. At this stage, an alternative option to remember is uterovaginal packing. Easy and quick to perform, it may be used to control bleeding by tamponade effect and stabilize the patient until a surgical procedure is arranged. Uterovaginal packing may sometimes obviate the need for surgery altogether. Two cases, a primary and a secondary PPH, managed recently with uterovaginal packing are reported. Despite concerns about concealed hemorrhage or the development of infection with this intervention, none of these problems were encountered, and uterine packing was successful even in the case of secondary PPH with documented infection. 相似文献
12.
Sucheta S Kulkarni Vidur Sabharwal Seema Sheoran Atrayee Basu Kunihiro Matsumoto Naoki Hisamoto Anindya Ghosh-Roy Sandhya P Koushika 《Genetics》2021,219(3)
Neuronal regeneration after injury depends on the intrinsic growth potential of neurons. Our study shows that UNC-16, a Caenorhabditis elegans JIP3 homolog, inhibits axonal regeneration by regulating initiation and rate of regrowth. This occurs through the inhibition of the regeneration-promoting activity of the long isoform of DLK-1 and independently of the inhibitory short isoform of DLK-1. We show that UNC-16 promotes DLK-1 punctate localization in a concentration-dependent manner limiting the availability of the long isoform of DLK-1 at the cut site, minutes after injury. UNC-16 negatively regulates actin dynamics through DLK-1 and microtubule dynamics partially via DLK-1. We show that post-injury cytoskeletal dynamics in unc-16 mutants are also partially dependent on CEBP-1. The faster regeneration seen in unc-16 mutants does not lead to functional recovery. Our data suggest that the inhibitory control by UNC-16 and the short isoform of DLK-1 balances the intrinsic growth-promoting function of the long isoform of DLK-1 in vivo. We propose a model where UNC-16’s inhibitory role in regeneration occurs through both a tight temporal and spatial control of DLK-1 and cytoskeletal dynamics. 相似文献
13.
14.
Seema Patel 《Reviews in Environmental Science and Biotechnology》2012,11(4):365-380
Fruit and vegetable wastes produced in astronomical quantities from food processing and agriculture industries often cause nuisance in municipal landfills owing to their high biodegradability. Biosorption by these waste-based adsorbents can be used as a cost effective and efficient technique for the removal of toxic heavy metals and dyes from wastewater. Recently, many papers claiming the feasible use of these biosorbents for water decontamination, treatment of industrial and agricultural wastewater and valuable metal recovery have been published. The organic waste-based adsorbents, characterized by good uptake capacity and rapid kinetics are expected to be economically and ecologically viable. This paper presents a judicious and pragmatic review depicting the key advances in implications of the fruit and vegetable wastes in pollution mitigation, the underlying mechanisms, major challenges and the future implementations. This compilation is expected to provide an impetus to the bioremediation research and promote green technology. 相似文献
15.
Expression of a bacterial 3‐dehydroshikimate dehydratase reduces lignin content and improves biomass saccharification efficiency 下载免费PDF全文
Aymerick Eudes Noppadon Sathitsuksanoh Edward E. K. Baidoo Anthe George Yan Liang Fan Yang Seema Singh Jay D. Keasling Blake A. Simmons Dominique Loqué 《Plant biotechnology journal》2015,13(9):1241-1250
Lignin confers recalcitrance to plant biomass used as feedstocks in agro‐processing industries or as source of renewable sugars for the production of bioproducts. The metabolic steps for the synthesis of lignin building blocks belong to the shikimate and phenylpropanoid pathways. Genetic engineering efforts to reduce lignin content typically employ gene knockout or gene silencing techniques to constitutively repress one of these metabolic pathways. Recently, new strategies have emerged offering better spatiotemporal control of lignin deposition, including the expression of enzymes that interfere with the normal process for cell wall lignification. In this study, we report that expression of a 3‐dehydroshikimate dehydratase (QsuB from Corynebacterium glutamicum) reduces lignin deposition in Arabidopsis cell walls. QsuB was targeted to the plastids to convert 3‐dehydroshikimate – an intermediate of the shikimate pathway – into protocatechuate. Compared to wild‐type plants, lines expressing QsuB contain higher amounts of protocatechuate, p‐coumarate, p‐coumaraldehyde and p‐coumaryl alcohol, and lower amounts of coniferaldehyde, coniferyl alcohol, sinapaldehyde and sinapyl alcohol. 2D‐NMR spectroscopy and pyrolysis‐gas chromatography/mass spectrometry (pyro‐GC/MS) reveal an increase of p‐hydroxyphenyl units and a reduction of guaiacyl units in the lignin of QsuB lines. Size‐exclusion chromatography indicates a lower degree of lignin polymerization in the transgenic lines. Therefore, our data show that the expression of QsuB primarily affects the lignin biosynthetic pathway. Finally, biomass from these lines exhibits more than a twofold improvement in saccharification efficiency. We conclude that the expression of QsuB in plants, in combination with specific promoters, is a promising gain‐of‐function strategy for spatiotemporal reduction of lignin in plant biomass. 相似文献
16.
Sircar M Bradfield PF Aurrand-Lions M Fish RJ Alcaide P Yang L Newton G Lamont D Sehrawat S Mayadas T Liang TW Parkos CA Imhof BA Luscinskas FW 《Journal of immunology (Baltimore, Md. : 1950)》2007,178(9):5879-5887
Endothelial cell junctional adhesion molecule (JAM)-C has been proposed to regulate neutrophil migration. In the current study, we used function-blocking mAbs against human JAM-C to determine its role in human leukocyte adhesion and transendothelial cell migration under flow conditions. JAM-C surface expression in HUVEC was uniformly low, and treatment with inflammatory cytokines TNF-alpha, IL-1beta, or LPS did not increase its surface expression as assessed by FACS analysis. By immunofluorescence microscopy, JAM-C staining showed sparse localization to cell-cell junctions on resting or cytokine-activated HUVEC. Surprisingly, staining of detergent-permeabilized HUVEC revealed a large intracellular pool of JAM-C that showed little colocalization with von Willebrand factor. Adhesion studies in an in vitro flow model showed that functional blocking JAM-C mAb alone had no inhibitory effect on polymorphonuclear leukocyte (PMN) adhesion or transmigration, whereas mAb to ICAM-1 significantly reduced transmigration. Interestingly, JAM-C-blocking mAbs synergized with a combination of PECAM-1, ICAM-1, and CD99-blocking mAbs to inhibit PMN transmigration. Overexpression of JAM-C by infection with a lentivirus JAM-C GFP fusion protein did not increase adhesion or extent of transmigration of PMN or evoke a role for JAM-C in transendothelial migration. These data suggest that JAM-C has a minimal role, if any, in PMN transmigration in this model and that ICAM-1 is the preferred endothelial-expressed ligand for PMN beta(2) integrins during transendothelial migration. 相似文献
17.
Soh MA Garrett SH Somji S Dunlevy JR Zhou XD Sens MA Bathula CS Allen C Sens DA 《Cancer cell international》2011,11(1):41-12
Background
Neuron specific enolase (ENO2, γ-enolase) has been used as a biomarker to help identify neuroendocrine differentiation in breast cancer. The goal of the present study was to determine if ENO2 expression in the breast epithelial cell is influenced by the environmental pollutants, arsenite and cadmium. Acute and chronic exposure of MCF-10A cells to As+3 and Cd+2 sufficient to allow colony formation in soft agar, was used to determine if ENO2 expression was altered by these pollutants.Results
It was shown that both As+3 and Cd+2 exposure caused significant increases in ENO2 expression under conditions of both acute and chronic exposure. In contrast, ENO1, the major glycolytic enolase in non-muscle and neuronal cells, was largely unaffected by exposure to either As+3 or Cd+2. Localization studies showed that ENO2 in the MCF-10A cells transformed by As+3 or Cd+2 had both a cytoplasmic and nuclear localization. In contrast, ENO1 was localized to the cytoplasm. ENO2 localized to the cytoplasm was found to co-localized with ENO1.Conclusion
The results are the first to show that ENO2 expression in breast epithelial cells is induced by acute and chronic exposure to As+3 or Cd+2. The findings also suggest a possible link between As+3 and Cd+2 exposure and neuroendocrine differentiation in tumors. Overall, the results suggest that ENO2 might be developed as a biomarker indicating acute and/or chronic environmental exposure of the breast epithelial cell to As+3 and Cd+2. 相似文献18.
Theendakara V Tromp G Kuivaniemi H White PS Panchal S Cox J Winters RS Riebeling P Tost F Hoeltzenbein M Tervo TM Henn W Denniger E Krause M Koksal M Kargi S Ugurbas SH Latvala T Shearman AM Weiss JS 《Human genetics》2004,114(6):594-600
Schnyders crystalline corneal dystrophy (SCCD) is a rare autosomal dominant eye disease with a spectrum of clinical manifestations that may include bilateral corneal clouding, arcus lipoides, and anterior corneal crystalline cholesterol deposition. We have previously performed a genome-wide linkage analysis on two large Swede-Finn families and mapped the SCCD locus to a 16-cM interval between markers D1S2633 and D1S228 on chromosome 1p36. We have collected 11 additional families from Finland, Germany, Turkey, and USA to narrow the critical region for SCCD. Here, we have used haplotype analysis with densely spaced microsatellite markers in a total of 13 families to refine the candidate interval. A common disease haplotype was observed among the four Swede-Finn families indicating the presence of a founder effect. Recombination results from all 13 families refined the SCCD locus to 2.32 Mbp between markers D1S1160 and D1S1635. Within this interval, identity-by-state was present in all 13 families for two markers D1S244 and D1S3153, further refining the candidate region to 1.58 Mbp. 相似文献
19.
Manab Jyoti Goswami Utpal Dutta Tage Seema Sourav Jyoti Bharali Hage Yanka Hui Tag Pankaj Bharali Dwipen Kakati 《化学与生物多样性》2023,20(2):e202200718
Three underutilized leafy vegetables Sarcochlamys pulcherrima (Roxb.) Gaudich (SP), Ipomoea aquatica Forssk. (IA) and Zanthoxylum rhetsa (Roxb.) DC (ZR) were extracted with different solvents viz. 95 % ethyl alcohol, methanol and hot water. The extracts were evaluated for their antioxidant potential via DPPH, ABTS and FRAP assay along with electroanalytical studies using cyclic voltammetry. The antidiabetic potential was determined by recording their α-amylase and α-glucosidase inhibitory assay. The total phenolic content (TPC), total flavonoid content (TFC) and the liquid chromatography-mass spectrometry (LC/MS) based phytochemical profiles of the extracts were also determined. All three extracts of SP exhibited significant antioxidant capacity. The antidiabetic potential of the IA and ZR extracts was found to be higher than or at par with that of standard acarbose. LC/MS studies reveal the presence of hitherto reported antioxidant and antidiabetic compounds like gamma-aminobutyric acid, cinnamic acid, caffeic acid, α-viniferin, piperlonguminine, niacin, kaempferol, etc., in the extracts. 相似文献
20.
Kaur P Yousuf S Ansari MA Siddiqui A Ahmad AS Islam F 《Biological trace element research》2003,95(3):247-258
The effect of various doses of sodium tellurite (0.4, 0.8, and 2.0 mg/kg body weight, orally) on the activity of antioxidant
enzymes (glutathione peroxidase, glutathione reductase, glutathione-S-transferase, and catalase) and content of glutathione and thiobarbituric acid reactive substances (TBARSs) in the cerebrum,
cerebellum, and brainstem of male albino mice was studied after 15 d of treatment. All of the doses of tellurium (0.4, 0.8,
and 2.0 mg/kg body weight, orally) have depleted the activity of antioxidant enzymes and the content of glutathione dose dependently
in the cerebrum, cerebellum, and brainstem and it was significant with the dose of 2.0 mg/kg. On the other hand, the 2.0-mg/kg
dose of tellurium has significantly elevated the content of TBARSs in the cerebrum and cerebellum. The 0.8-mg/kg dose of tellurium
has significantly depleted the activities of glutathione peroxidase in the cerebrum and brainstem, glutathione-S-transferase in the cerebrum and cerebellum, catalase in the brainstem, and the content of glutathione in the cerebrum and
cerebellum. In contrast, this dose has significantly elevated the content of TBARSs in the cerebrum and cerebellum. However,
the depletion in the activity of glutathione reductase with various doses of sodium tellurite was not significant in any brain
part of mice. The result suggests that sodium tellurite differentially affects the antioxidant status within various parts
of the mice brain. 相似文献