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141.
Pu Hyeon Cha Sun-Yung Park Min-Woo Moon Bindu Subhadra Tae-Kwang Oh Eungbin Kim Jihyun F. Kim Jung-Kee Lee 《Applied microbiology and biotechnology》2010,85(4):1061-1068
Genome analysis of C. glutamicum ATCC 13032 has showed one putative adenylate cyclase gene, cyaB (cg0375) which encodes membrane protein belonging to class III adenylate cyclases. To characterize the function of cyaB, a deletion mutant was constructed, and the mutant showed decreased level of intracellular cyclic AMP compared to that of
wild-type. Interestingly, the cyaB mutant displayed growth defect on acetate medium, and this effect was reversed by complementation with cyaB gene. Similarly, it showed growth defect on glucose-acetate mixture minimal medium, and the utilization of glucose was retarded
in the presence of acetate. The deletion mutant retained the activity of glyoxylate bypass enzymes. Additionally, the mutant
could grow on ethanol but not on propionate medium. The data obtained from this study suggests that adenylate cyclase plays
an essential role in the acetate metabolism of C. glutamicum, even though detailed regulatory mechanisms involving cAMP are not yet clearly defined. The observation that glyoxylate bypass
enzymes are derepressed in cyaB mutant indicates the involvement of cAMP in the repression of aceB and aceA. 相似文献
142.
Rap1 is rapidly activated upon chemoattractant stimulation and plays an important role in cell adhesion and cytoskeletal reorganization
during chemotaxis. Here, we demonstrate that G-protein coupled receptors and G-proteins are essential for chemoattractant-mediated
Rap1 activation in Dictyostelium. The rapid Rap1 activation upon cAMP chemoattractant stimulation was absent in cells lacking chemoattractant cAMP receptors
cAR1/cAR3 or a subunit of the heterotrimeric G-protein complex Gα2. Loss of guanylyl cyclases GCA/SGC or a cGMP-binding protein
GbpC exhibited no effect on Rap1 activation kinetics. These results suggest that Rap1, a key regulator for the regulation
of cytoskeletal reorganization during cell movement, is activated through the G-protein coupled receptors cAR1/cAR3 and Gα2
proteins in a way independent of the cGMP signaling pathway. 相似文献
143.
144.
Objectives: Translational research using adult stem cells derived from various tissues has been highlighted in cell‐based therapy. However, there are many limitations to using conventional culture systems of adult stem cells for clinically applicability, including limited combinations of cytokines and use of nutrients derived from animals. Here, we have investigated the effects of placental extract (PE) for culture of placenta‐derived stem cells (PDSCs) as well as their potential for hepatogenic differentiation. Materials and methods: Placental extract, extracted using water‐soluble methods, was used as a supplement for culture of PDSCs. Cell viability was determined using the MTT assay, and cytokine assay was performed using Luminex assay kit. Gene expression, indocyanine green (ICG) up‐take, PAS (Periodic Acid‐Schiff) staining and urea production were also analysed. Results: The placental extract contained several types of cytokine and chemokine essential for maintenance and differentiation of stem cells. Expression of stemness markers in PDSCs cultured with PE is no different from that of PDSCs cultured with foetal bovine serum (FBS). After hepatogenic differentiation, expression patterns for hepatocyte‐specific markers in PDSCs cultured with PE were consistent and potential for hepatogenic differentiation of PDSCs cultured with PE was similar to that of PDSCs cultured with FBS, as shown by PAS staining and urea production assays. Conclusions: Our findings revealed that placental extract could be used as a new component for culture of adult stem cells, as well as for development of human‐based medium, in translational research for regenerative medicine. 相似文献
145.
Young Ae Yoon Chan Sun Park Myung Hun Cha Hyunho Choi Jae Young Sim Jae Gyu Kim 《Bioorganic & medicinal chemistry letters》2010,20(19):5735-5738
A series of pyrimidine derivatives as acid pump antagonists (APAs) was synthesized and the inhibitory activities against H+/K+ ATPase isolated from hog gastric mucosa were determined. After elaborating on substituents at C2 and C4 position of the pyrimidine scaffold, we have observed that the compound 7h is a potent APA with H+/K+ ATPase, IC50 = 52 nM. 相似文献
146.
Young Ae Yoon Dong Hoon Kim Byoung Moon Lee Tae Kyun Kim Myung Hun Cha Jae Young Sim Jae Gyu Kim 《Bioorganic & medicinal chemistry letters》2010,20(17):5237-5240
A series of 1H-pyrrolo[2,3-c]pyridines as acid pump antagonists (APAs) was synthesized and the inhibitory activities against H+/K+ ATPase isolated from hog gastric mucosa were determined. After elaborating on substituents at N1, C5, and C7 position of 1H-pyrrolo[2,3-c]pyridine scaffold, we have observed that compounds 14f and 14g are potent APAs with H+/K+ ATPase IC50 = 28 and 29 nM, respectively. 相似文献
147.
Seho Cha Chunghun Lim Jae Young Lee Junsoo Park Taegun Seo 《Biochemical and biophysical research communications》2010,394(4):934-939
During latent infection, latency-associated nuclear antigen (LANA) of Kaposi’s sarcoma-associated herpesvirus (KSHV) plays important roles in episomal persistence and replication. Several host factors are associated with KSHV latent replication. Here, we show that the catalytic subunit of DNA protein kinase (DNA-PKcs), Ku70, and Ku86 bind the N-terminal region of LANA. LANA was phosphorylated by DNA-PK and overexpression of Ku70, but not Ku86, impaired transient replication. The efficiency of transient replication was significantly increased in the HCT116 (Ku86 +/−) cell line, compared to the HCT116 (Ku86 +/+) cell line, suggesting that the DNA-PK/Ku complex negatively regulates KSHV latent replication. 相似文献
148.
149.
Physical exercise induces phasic changes in the tropomyosin content and metabolism in muscles and its concentration in blood. The intensive catabolic processes (decrease of 14C-leicin inclusion and time of half-life) of muscle tropomyosin and its appearance in blood were shown 2-24 hours after the exercise. Intensive anabolic processes of muscle tropomyosin were found at the late period of rest (72-144 h). These results reveal the biochemical mechanism of muscle adaptation to physical exercise. Data on the tropomyosin content in blood permit recommending tropomyosin for development of the diagnostic test of functional condition of the skeletal muscle. 相似文献
150.
R S Biswas H J Cha J M Hardwick R K Srivastava 《Molecular and cellular biochemistry》2001,225(1-):7-20
Fas/Fas ligand system triggers apoptosis in many cell types. Bcl-XL overexpresion antagonizes Fas/Fas ligand-mediated cell death. The mechanism by which Bcl-XL influences Fas-mediated cell death is unclear. We have found that microtubule-damaging drugs (e.g. Paclitaxel) induce apoptosis in a Fas/FasL-dependent manner. Inhibition of Fas/FasL pathway by anti-FasL antibody, mutant Fas or a dominant negative FADD blocks paclitaxel-induced apoptosis. Paclitaxel induced apoptosis through activation of both caspase-8 and caspase-3. Overexpression of Bcl-XL leads to inhibition of paclitaxel-induced FasL expression and apoptosis. Bcl-XL prevents the nuclear translocation of NFAT (nuclear factor of activated T lymphocytes) by inhibiting the activation of calcineurin, a calcium-dependent phosphatase that must dephosphorylate NFAT for it to move to the nucleus. The loop domain in Bcl-XL can suppress the anti-apoptotic function of Bcl-XL and may be a target for regulatory post-translational modifications. Upon phosphorylation, Bcl-XL loses its ability to bind with calcineurin. Without NFAT nuclear translocation, the FasL gene is not transcribed. Thus, paclitaxel and other drugs that disturb microtubule function kill cells, at least in part, through the induction of FasL, and Bcl-XL-mediated resistance to these agents is related to failure to induce FasL expression. 相似文献