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排序方式: 共有390条查询结果,搜索用时 15 毫秒
81.
L B Justement W A Aldrich G D Wenger M S O'Dorisio B S Zwilling 《Journal of immunology (Baltimore, Md. : 1950)》1986,136(1):270-277
We have used the RAW 264.7 macrophage (MO) cell line to study cAMPdPK isozymes during activation by lymphokine (LK) and lipopolysaccharide (LPS). Untreated cells were found to have two isozymes of cAMPdPK in their cytosol. PKI and PKII were differentiated based on the Mr of their regulatory subunits (RI, 45,500; and RII, 52,000, respectively) as determined by photoactivated incorporation of the cAMP analog 8-N3-[32P]cAMP. Loss of the RI subunit of PKI occurred in association with activation of the cell line by suboptimal concentrations of LK and LPS (1/40 dilution, 1 ng/ml) or high concentrations of LPS alone (10 ng/ml to 100 micrograms/ml). No modulation of the RII subunit of PKII was observed under these conditions. The loss of RI was dependent on the addition of a triggering signal to the MO. Treatment of RAW 264.7 cells with LK alone at dilutions from 1/10 to 1/1280 was not sufficient to cause a disappearance of the RI subunit from the cytosol or to induce antitumor activity. The addition of a suboptimal concentration of LPS after LK or a high dose of LPS alone was required for acquisition of cytolytic activity and loss of RI. The kinetics for the disappearance of RI from treated cells were found to be identical after activation with either LK and LPS or high concentrations of LPS alone. RI could no longer be detected in the cytosol 8 hr after the addition of activating agents. The antitumor activity of the RAW 264.7 cell line was transiently expressed after activation. Cells no longer exhibited tumoricidal activity 48 hr after the removal of activating agents. It was observed that the loss of cytolytic function was accompanied by the reexpression of RI in the cytosol. This study provides evidence that modulation of cAMPdPK isozymes occurs during activation, suggesting a potential mechanism for controlling the effects of cAMP on the MO. 相似文献
82.
Biosynthesis of the sulfatide/GM1 activator protein (SAP-1) in control and mutant cultured skin fibroblasts 总被引:6,自引:0,他引:6
Sphingolipid activator proteins (SAP) are relatively low-molecular-mass proteins that stimulate the hydrolysis of specific sphingolipids by the required lysosomal enzymes. SAP-1 or sulfatide/GM1 ganglioside activator protein has previously been demonstrated to stimulate the enzymatic hydrolysis of sulfatide, GM1 ganglioside and globotriaosylceramide. Using monospecific rabbit antibodies against human liver sulfatide/GM1 activator, the biosynthesis and processing of this activator were studied in cultured skin fibroblasts from controls and patients with GM1 gangliosidosis and a variant form of metachromatic leukodystrophy. When [35S]methionine was presented in the medium to control human fibroblasts for 4 h, the majority of the immunoprecipitable radiolabeling was confined to bands within three regions of apparent molecular mass 65-70, 35-52 and 8-13 kDa. The only immunoprecipitable radiolabeled species excreted into the medium when NH4Cl was present had an apparent molecular mass of 70 kDa. When the excretion products were given to fresh cells followed by incubation for up to 24 h there was production of the mature species. Treatment of the 70 kDa form with endoglycosidase F resulted in production of a 53 kDa molecular mass form. Pulse-chase experiments indicated that the initial immunoprecipitable translation product was 65 kDa which increased to 70 kDa over the next hour. The 65 kDa species must result from co-translational glycosylation of the polypeptide chain. Apparently, intralysosomal processing converts the 13 kDa form to the 8-11 kDa species. The cells from the patient with GM1 gangliosidosis could not process to the smallest species found in controls due to the deficiency of acid beta-galactosidase. Patients who have a variant form of metachromatic leukodystrophy do not make any immunoprecipitable radiolabeled products in the cells or in the media. This indicates a severe mutation in the gene coding for this activator protein. The production of such small mature species from a relatively large precursor form may regulate the production of this interesting protein. 相似文献
83.
P G Pentchev H S Kruth M E Comly J D Butler M T Vanier D A Wenger S Patel 《The Journal of biological chemistry》1986,261(35):16775-16780
Low density lipoprotein (LDL) internalization by mutant type C Niemann-Pick (NPC) fibroblasts results in uptake of excess total cholesterol. Uptake of excess lipoprotein cholesterol appears to be mediated by the specific LDL receptor pathway. Associated with excessive LDL-cholesterol uptake is a lesion in early intracellular cholesteryl ester synthesis. In vitro acylCoA:cholesterol acyltransferase activity is normal in cell-free extracts of mutant cells. The ability of exogenous sterols to enhance intracellular esterification of [3H]mevalonate-derived [3H]cholesterol was severely limited in mutant cell cultures suggesting that in vivo activation and/or expression of activated acylCoA:cholesterol acyltransferase may be compromised by the primary mutation of type C Niemann-Pick disease. After 2 days of LDL uptake, rates of intracellular cholesteryl ester synthesis in mutant cells paralleled the rates of esterification in normal cells suggesting that specific early in vivo expression of the acyltransferase may be affected in this disorder. 相似文献
84.
85.
Dr. Friedrich Wenger 《Development genes and evolution》1915,41(3):371-429
Ohne ZusammenfassungDamit bin ich am Schlusse meiner Arbeit angelangt. Mit Freude erfülle ich meine Dankespflicht gegen alle, die mich in meinen Untersuchungen förderten und unterstützten: Herrn Prof.Rubeli für die freundliche überlassung dieses Themas und für das allzeit rege Interesse, das er meiner Arbeit angedeihen ließ. Herrn Prof.Strasser sei der herzliche Dank für manche wertvolle Ratschläge und Belehrungen betreffend mechanische Fragen, wie auch für die mir zur Verfügung gestellte Wirbelmeßlade wiederholt. Herrn Prof.Noyer, Herrn Prof.Studer, wie auch Herrn Prof.Rubeli für das mir in zuvorkommender Weise überlassene Material. Herzlichen Dank schulde ich ferner Herrn P.-D. Dr.Ries für die mikrophotographische und die kinematographischen Aufnahmen. Ebenso danke ich der Firma A. G.Fritz Marti in Bern, Fabrik landwirtschaftlicher Maschinen und Geräte, für den mir bereitwillig zur Verfügung gestelltenSackschen Kraftmesser. 相似文献
86.
Summary Pro-platelet basic protein (pro-PBP) is the precursor of the two platelet -granule proteins, PBP and connective tissue activating peptide-III. Upon platelet activations they are released and further processed in plasma to -thromboglobulin and neutrophil-activating peptide-2. The gene encoding pro-PBP is mapped in this study to chromosome 4q12–q13. At least four other members of this family of small inducible cytokines, including NAP-1/Il-8 and platelet factor 4, reside within the same locus, indicating a gene cluster for the -thromboglobulin family. 相似文献
87.
Small-animal ergometer 总被引:2,自引:0,他引:2
88.
89.
Langenegger SM Malinovskii VL Wenger D Werder S Häner R 《Nucleosides, nucleotides & nucleic acids》2007,26(8-9):901-903
The synthesis and hybridization properties of oligonucleotides containing phenanthrene building blocks with non-nucleosidic linkers of different length are described. It was found that the length of the linkers, as well as the combination of unequal linkers can have a substantial influence on the thermal stability of the modified DNA. 相似文献
90.
Yvan Wenger Dingsheng Li Olivier Jolliet 《The International Journal of Life Cycle Assessment》2012,17(7):919-931