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991.
992.
Four phenylpropanoid esters, cimiracemates A-D (1-4), along with three known compounds, isoferulic acid, ferulic acid and methyl caffeate were isolated from the EtOAc fraction of the rhizome of Cimicifuga racemosa. The structures of the esters were elucidated by means of spectral data, including 2D NMR spectroscopy. 相似文献
993.
Véronique Masson Laetitia Devy Christine Grignet-Debrus Sarah Bernt Khalid Bajou Silvia Blacher Guy Roland Yawen Chang Timothy Fong Peter Carmeliet Jean-Michel Foidart Agnès Noël 《Biological procedures online》2002,4(1):24-31
Angiogenesis, a key step in many physiological and pathological processes, involves proteolysis of the extracellular matrix.
To study the role of two enzymatic families, serine-proteases and matrix metalloproteases in angiogenesis, we have adapted
to the mouse, the aortic ring assay initially developed in the rat. The use of deficient mice allowed us to demonstrate that
PAI-1 is essential for angiogenesis while the absence of an MMP, MMP-11, did not affect vessel sprouting. We report here that
this model is attractive to elucidate the cellular and molecular mechanisms of angiogenesis, to identify, characterise or
screen “pro- or anti-angiogenic agents that could be used for the treatment of angiogenesis-dependent diseases. Approaches
include using recombinant proteins, synthetic molecules and adenovirus-mediated gene transfer.
Published: October 28, 2002 相似文献
994.
Characterization and efficacy of PKH26 as a probe to study the replication history of the human hematopoietic KG1a progenitor cell line 总被引:2,自引:0,他引:2
Lee GM Fong SS Oh DJ Francis K Palsson BO 《In vitro cellular & developmental biology. Animal》2002,38(2):90-96
The PKH26 dye can, in principle, be used for the study of asymmetric cell divisions (ASDs). A requirement for the identification of ASDs based on fluorescence intensity is that the PKH26 dye is distributed equally between daughter cells at each division, but this has not been demonstrated at a single-cell level. The efficacy of PKH26 as a probe for the study of ASDs was examined using the human hematopoietic KG1a cell. An automated time-lapse fluorescent microscope system was used to determine changes in cell size and fluorescence intensity during culture, and track cell divisions. The images of daughter cells were analyzed using the Isee software to determine the distribution of PKH26 dye between daughter cells. Ratios of cell size, mean fluorescence intensity, and total fluorescence intensity were calculated by dividing the values for one daughter cell by the value of the other daughter cell. The ratios for cell size, mean intensity, and total intensity were 1.13 +/- 0.12, 1.08 +/- 0.07, and 1.15 +/- 0.14 (mean +/- SD), respectively. Thus, PKH26 is not distributed equally to both daughter cells upon cell division. However, the replication history of individual KG1a cells can be reliably deduced for up to three divisions based solely on the mean and total fluorescence intensity of the PKH26 dye, using PKH26 concentrations below the chemical and phototoxic limits (2 microM). 相似文献
995.
Tumor-cell resistance to death receptor--induced apoptosis through mutational inactivation of the proapoptotic Bcl-2 homolog Bax 总被引:20,自引:0,他引:20
LeBlanc H Lawrence D Varfolomeev E Totpal K Morlan J Schow P Fong S Schwall R Sinicropi D Ashkenazi A 《Nature medicine》2002,8(3):274-281
The importance of Bax for induction of tumor apoptosis through death receptors remains unclear. Here we show that Bax can be essential for death receptor--mediated apoptosis in cancer cells. Bax-deficient human colon carcinoma cells were resistant to death-receptor ligands, whereas Bax-expressing sister clones were sensitive. Bax was dispensable for apical death-receptor signaling events including caspase-8 activation, but crucial for mitochondrial changes and downstream caspase activation. Treatment of colon tumor cells deficient in DNA mismatch repair with the death-receptor ligand apo2 ligand (Apo2L)/tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) selected in vitro or in vivo for refractory subclones with Bax frameshift mutations including deletions at a novel site. Chemotherapeutic agents upregulated expression of the Apo2L/TRAIL receptor DR5 and the Bax homolog Bak in Baxminus sign/minus sign cells, and restored Apo2L/TRAIL sensitivity in vitro and in vivo. Thus, Bax mutation in mismatch repair--deficient tumors can cause resistance to death receptor--targeted therapy, but pre-exposure to chemotherapy rescues tumor sensitivity. 相似文献
996.
Robinson WH DiGennaro C Hueber W Haab BB Kamachi M Dean EJ Fournel S Fong D Genovese MC de Vegvar HE Skriner K Hirschberg DL Morris RI Muller S Pruijn GJ van Venrooij WJ Smolen JS Brown PO Steinman L Utz PJ 《Nature medicine》2002,8(3):295-301
We constructed miniaturized autoantigen arrays to perform large-scale multiplex characterization of autoantibody responses directed against structurally diverse autoantigens, using submicroliter quantities of clinical samples. Autoantigen microarrays were produced by attaching hundreds of proteins, peptides and other biomolecules to the surface of derivatized glass slides using a robotic arrayer. Arrays were incubated with patient serum, and spectrally resolvable fluorescent labels were used to detect autoantibody binding to specific autoantigens on the array. We describe and characterize arrays containing the major autoantigens in eight distinct human autoimmune diseases, including systemic lupus erythematosus and rheumatoid arthritis. This represents the first report of application of such technology to multiple human disease sera, and will enable validated detection of antibodies recognizing autoantigens including proteins, peptides, enzyme complexes, ribonucleoprotein complexes, DNA and post-translationally modified antigens. Autoantigen microarrays represent a powerful tool to study the specificity and pathogenesis of autoantibody responses, and to identify and define relevant autoantigens in human autoimmune diseases. 相似文献
997.
神经生长因子 (nervegrowthfactor,NGF)是最早发现的神经营养因子 ,对于神经元的发育、分化、维持正常功能具有极重要的作用。研究表明 ,NGF也参与免疫、造血、生殖、心血管等功能的调节。以往的研究证实 ,心肌细胞可以分泌NGF。多年来 ,人们对NGF在心脏方面的作用进行了较为深入的研究 ,但迄今为止 ,尚未见有关生后发育过程中正常心肌NGFmRNA表达方面的报道。本研究采用RT PCR(reversetranscription polymerasechainreaction)方法 ,半定量分析大鼠生… 相似文献
998.
999.
F. Gonzalez-Fernandez R.A. Landers P.A. Glazebrook S.-L. Fong G.I. Liou D.M.K. Lam C.D.B. Bridges 《Neurochemistry international》1985,7(3):533-540
We have identified and partially purified interstitial retinol-binding protein (IRBP) from the subretinal space of the rat. It appeared to be glycosylated. Its apparent mol. wt was 270,000 by gel-filtration and 144,000 by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Rat IRBP cross-reacted with anti-bovine IRBP sheep and rabbit sera, bound all-trans-[15-3H] retinol and was bound by concanavalin A. IRBP was not detected in the cytosols of the neural retina or retinal pigment epithelium and choroid. This distribution was confirmed by immunocytochemistry using a fluorescence-labeled second antibody. Immunospecific fluorescence was most intense in the interphotoreceptor matrix in a 6.5 μm band adjacent to the retinal pigment epithelium. It was less intense over the remainder of the rod outer segment layer and was comparatively faint over the inner segment region. Its occurrence in the interstitial space between the photoreceptors and retinal pigment epithelium coupled with the fact it bound all-trans-[15-3H] retinol supports the concept that it may be implicated in the transport of retinoids between the retina and the retinal pigment epithelium during the visual cycle. When incubated with [3H]leucine or [3H]glucosamine, isolated retinas (but not retinal pigment epithelium and choroid) secreted labeled IRBP into the medium. This suggests that the retina plays a role in regulating the amount of IRBP in the subretinal space. 相似文献
1000.
Mo L Hellmich HL Fong P Wood T Embesi J Wills NK 《The Journal of membrane biology》1999,168(3):253-264
Loss of function mutations of the renal chloride channel, ClC-5, have been implicated in Dent's disease, a genetic disorder
characterized by low weight proteinuria, hypercalciuria, nephrolithasis and, in some cases, eventual renal failure. Recently,
our laboratory used an RT-PCR/RACE cloning strategy to isolate an amphibian cDNA from the renal epithelial cell line A6 that
had high homology to human ClC-5. We now report a full-length native ClC-5 clone (xClC-5, containing 5′ and 3′ untranslated
regions) isolated by screening a cDNA library from A6 cells that was successfully expressed in Xenopus oocytes. In addition, we compared the properties of xClC-5 and hClC-5 using isogenic constructs of xClC-5 and hClC-5 consisting
of the open reading frame subcloned into an optimized Xenopus expression vector. Expression of the full-length ``native'
xClC-5 clone resulted in large, strongly rectifying, outward currents that were not significantly affected by the chloride
channel blockers DIDS, DPC, and 9AC. The anion conductivity sequence was NO−
3 > Cl−= I− > HCO−
3 >> glutamate for xClC-5 and NO−
3 > Cl− > HCO−
3 > I− >> glutamate for hClC-5. Reduction of the extracellular pH (pH
o
) from 7.5 to 5.7 inhibited outward ClC-5 currents by 27 ± 9% for xClC-5 and 39 ± 7% for hClC-5. The results indicate that
amphibian and mammalian ClC-5 have highly similar functional properties. Unlike hClC-5 and most other ClC channels, expression
of xClC-5 in oocytes does not require the removal of its untranslated 5′ and 3′ regions. Acidic solutions inhibited both amphibian
and human ClC-5 currents, opposite to the stimulatory effects of low external pH on other ClC channels, suggesting a possibly
distinct regulatory mechanism for ClC-5 channels.
Received: 28 August 1998/Revised: 13 January 1999 相似文献