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991.
992.
Becker L Bannwarth M Meisinger C Hill K Model K Krimmer T Casadio R Truscott KN Schulz GE Pfanner N Wagner R 《Journal of molecular biology》2005,353(5):1011-1020
Tom40 is the central pore-forming component of the translocase of the outer mitochondrial membrane (TOM complex). Different views exist about the secondary structure and electrophysiological characteristics of Tom40 from Saccharomyces cerevisiae and Neurospora crassa. We have directly compared expressed and renatured Tom40 from both species and find a high content of beta-structure in circular dichroism measurements in agreement with refined secondary structure predictions. The electrophysiological characterization of renatured Tom40 reveals the same characteristics as the purified TOM complex or mitochondrial outer membrane vesicles, with two exceptions. The total conductance of the TOM complex and outer membrane vesicles is twofold higher than the total conductance of renatured Tom40, consistent with the presence of two TOM pores. TOM complex and outer membrane vesicles possess a strongly enhanced sensitivity to a mitochondrial presequence compared to Tom40 alone, in agreement with the presence of several presequence binding sites in the TOM complex, suggesting a role of the non-channel Tom proteins in regulating channel activity. 相似文献
993.
Lovastatin inhibits the growth and survival pathway of phosphoinositide 3-kinase/protein kinase B in immortalized rat brain neuroblasts 总被引:3,自引:0,他引:3
Cerezo-Guisado MI Garcia-Marin LJ Lorenzo MJ Bragado MJ 《Journal of neurochemistry》2005,94(5):1277-1287
We previously showed that lovastatin, an HMG-CoA reductase inhibitor, suppresses cell growth by inducing apoptosis in rat brain neuroblasts. Our aim was to study intracellular signalling induced by lovastatin in neuroblasts. Lovastatin significantly decreases the phosphoinositide 3-kinase (PI3-K) activity in a concentration-dependent manner. Expression of p85 subunit and its association with phosphotyrosine-containing proteins are unaffected by lovastatin. Lovastatin decreases protein kinase B (PKB)/Akt phosphorylation, and its downstream effectors, p70S6K and the eukaryotic initiation factor 4E (eIF4E) regulatory protein 1, 4E-BP1, in a concentration-dependent manner, and reduces p70S6K expression. Lovastatin effects are fully prevented with mevalonate. Only the highest dose of PI3-K inhibitors that significantly reduce PI3-K kinase activity induces apoptosis in neuroblasts but to a lower degree than lovastatin. In summary, this work shows that treatment of brain neuroblasts with lovastatin leads to an inhibition of the main pathway that controls cell growth and survival, PI3-K/PKB and the subsequent blockade of downstream proteins implicated in the regulation of protein synthesis. This work suggests that inactivation of the antiapoptotic PI3-K appears insufficient to induce the degree of neuroblasts apoptosis provoked by lovastatin, which must necessarily involve other intracellular pathways. These findings might contribute to elucidate the molecular mechanisms of some statins effects in the central nervous system. 相似文献
994.
Kanaani J Prusiner SB Diacovo J Baekkeskov S Legname G 《Journal of neurochemistry》2005,95(5):1373-1386
While a beta-sheet-rich form of the prion protein (PrPSc) causes neurodegeneration, the biological activity of its precursor, the cellular prion protein (PrPC), has been elusive. We have studied the effect of purified recombinant prion protein (recPrP) on rat fetal hippocampal neurons in culture. Overnight exposure to Syrian hamster or mouse recPrP, folded into an alpha-helical-rich conformation similar to that of PrPC, resulted in a 1.9-fold increase in neurons with a differentiated axon, a 13.5-fold increase in neurons with differentiated dendrites, a fivefold increase in axon length, and the formation of extensive neuronal circuitry. Formation of synaptic-like contacts was increased by a factor of 4.6 after exposure to recPrP for 7 days. Neither the N-terminal nor C-terminal domains of recPrP nor the PrP paralogue doppel (Dpl) enhanced the polarization of neurons. Inhibitors of protein kinase C (PKC) and of Src kinases, including p59Fyn, blocked the effect of recPrP on axon elongation, while inhibitors of phosphatidylinositol 3-kinase showed a partial inhibition, suggesting that signaling cascades involving these kinases are candidates for transduction of recPrP-mediated signals. The results predict that full-length PrPC functions as a growth factor involved in development of neuronal polarity. 相似文献
995.
996.
Barcelos IS Ferreira MS Moura LP Biondi GF Costa-Cruz JM 《Memórias do Instituto Oswaldo Cruz》2005,100(4):427-429
Paired samples of cerebrospinal fluid (CSF) and serum of 30 patients--10 with active, 10 with inactive neurocysticercosis (NCC), and 10 control subjects--were evaluated by enzyme-linked immunosorbent assay (ELISA) using two Taenia crassiceps metacestode extracts as antigen in order to detect IgG antibodies. In active NCC, high levels of IgG were detected (p < 0.05). The CSF samples showed 80% (CI 72-88) of reactivity in the saline extract (S) and 90% (CI 84-95) in sodium dodecyl sulphate (SDS) and the serum samples were reactive in 90% (CI 84-95) and 100% (CI 98-100) in the S and SDS antigenic extracts, respectively. The use of the paired samples of CSF and serum in active NCC showed equivalent results suggesting that the serum samples could be used as a screening in those patients whose CSF puncture is counter-indicated. 相似文献
997.
Brd2/RING3 interacts with a chromatin-binding domain in the Kaposi's Sarcoma-associated herpesvirus latency-associated nuclear antigen 1 (LANA-1) that is required for multiple functions of LANA-1 下载免费PDF全文
Viejo-Borbolla A Ottinger M Brüning E Bürger A König R Kati E Sheldon JA Schulz TF 《Journal of virology》2005,79(21):13618-13629
998.
Microscopic evidence suggests that fungi forming endosymbioses with liverworts in the Marchantiales are arbuscular mycorrhizal (AM) fungi from the Glomeromycota. Polymerase chain reaction amplification of ribosomal sequences confirmed that endophytes of the New Zealand liverwort, Marchantia foliacea, were members of the genus Glomus. Endophytes from two Glomus rDNA phylotypes were repeatedly isolated from geographically separated liverwort samples. Multiple phylotypes were present in the same liverwort patch. The colonizing Glomus species exhibited substantial internal transcribed spacer sequence variation within phylotypes. This work suggests that certain liverwort species may serve as a model for studying DNA sequence variation in colonizing AM phylotypes and specificity in AM-host relationships. 相似文献
999.
1000.
Werle M Kreuzer J Höfele J Elsässer A Ackermann C Katus HA Vogt AM 《Journal of biomedical science》2005,12(5):827-834
Summary The accumulation and proliferation of vascular smooth muscle cells (VSMC) within the vessel wall is an important pathogenic
feature in the development of atherosclerosis. Glucose metabolism has been implicated to play an important role in this cellular
mechanism. To further elucidate the role of glucose metabolism in atherogenesis, glycolysis and its regulation have been investigated
in proliferating VSMC. Platelet derived growth factor (PDGF BB)-induced proliferation of VSMCs significantly stimulated glucose
flux through glycolysis. Further evaluating the enzymatic regulation of this pathway, the analysis of flux:metabolite co-responses
revealed that anaerobic glycolytic flux is controlled at different sites of gycolysis in proliferating VSMCs, being consistent
with the concept of multisite modulation. These findings indicate that regulation of glycolytic flux in proliferating VSMCs
differs from traditional concepts of metabolic control of the Embden–Meyerhof pathway. 相似文献