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951.
952.
对RA、HHT和WB_(652)诱导HL-60细胞过程中,细胞浆和膜溶脱部分的蛋白质酪氨酸磷酸化水平变化进行了对比研究,结果发现,在胞浆部分主要有四种含有P-Tyr的蛋白,而且80kD蛋白酪氨酸磷酸化水平随着诱导发生变化。诱导前后内源性蛋白上P-Tyr百分含量也发生了改变。 相似文献
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Our review of existing approaches and regulatory uses of weight-of-evidence (WOE) methods suggested the need for a practical strategy for deploying WOE within a predictive ecological risk assessment (ERA). WOE is the process of considering strengths and weaknesses of various pieces of information in order to inform a decision being made among competing alternatives. A predictive ERA uses existing information relating cause and effect to estimate the probability that today's action X will lead to tomorrow's adverse outcome Y. There appears to be no practical guidance for use of WOE in predictive assessments. We therefore propose a strategy for using a WOE approach, within an ERA framework, to weigh and integrate outcomes from various lines of evidence to estimate the probability of an adverse outcome in an assessment endpoint. An ERA framework is necessary to connect the results of an assessment to the management goals of concern to decision-makers and stakeholders. Within that framework, a WOE approach provides a consistent and transparent means of interpreting the myriad types of data and information gathered during a complex ecological assessment. Impediments to application of WOE are discussed, including limited regulatory guidance, limited prior regulatory use, and persistent reliance on threshold-based decision-making. 相似文献
956.
Prakitchai Chotewutmontri Barry D. Bruce 《The Journal of biological chemistry》2015,290(12):7602-7621
Previously, we identified the N-terminal domain of transit peptides (TPs) as a major determinant for the translocation step in plastid protein import. Analysis of Arabidopsis TP dataset revealed that this domain has two overlapping characteristics, highly uncharged and Hsp70-interacting. To investigate these two properties, we replaced the N-terminal domains of the TP of the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase and its reverse peptide with a series of unrelated peptides whose affinities to the chloroplast stromal Hsp70 have been determined. Bioinformatic analysis indicated that eight out of nine peptides in this series are not similar to the TP N terminus. Using in vivo and in vitro protein import assays, the majority of the precursors containing Hsp70-binding elements were targeted to plastids, whereas none of the chimeric precursors lacking an N-terminal Hsp70-binding element were targeted to the plastids. Moreover, a pulse-chase assay showed that two chimeric precursors with the most uncharged peptides failed to translocate into the stroma. The ability of multiple unrelated Hsp70-binding elements to support protein import verified that the majority of TPs utilize an N-terminal Hsp70-binding domain during translocation and expand the mechanistic view of the import process. This work also indicates that synthetic biology may be utilized to create de novo TPs that exceed the targeting activity of naturally occurring sequences. 相似文献
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958.
Human cytomegalovirus UL18 alleviated human NK-mediated swine endothelial cell lysis 总被引:2,自引:0,他引:2
Kim JS Choi SE Yun IH Kim JY Ahn C Kim SJ Ha J Hwang ES Cha CY Miyagawa S Park CG 《Biochemical and biophysical research communications》2004,315(1):144-150
Human cytomegalovirus UL18, a MHC class I homologue, is known to serve as a natural killer cell (NK) decoy and to ligate NK inhibitory receptors to prevent lysis of an infected target cell. To explore whether the cell surface expression of UL18 represents a potential immune suppressive approach to evade NK-mediated cytotoxicity in the prevention of xenograft rejection, we examined the effect of the UL18 expression in vitro upon human NK-mediated cytotoxicity against swine endothelial cells (SECs). UL18 expression on SECs by a retroviral vector (PLNCX2) significantly suppressed NK-mediated SEC lysis by approximately 25-100%. The protective effect of UL18 could be mediated through ILT-2 inhibitory receptor on NKs. Additionally, the interaction between UL18 and NKs resulted in the significant reduction of IFN-gamma production. This study demonstrates that UL18 can serve as an effective tool for the evasion of NK-mediated cytotoxicity and for the inhibition of IFN-gamma production during xenograft rejection. 相似文献
959.
Silk scaffolds connected with different naturally occurring biomaterials for prostate cancer cell cultivation in 3D 下载免费PDF全文
Anne Bäcker Olga Erhardt Lukas Wietbrock Natalia Schel Bettina Göppert Marian Dirschka Paul Abaffy Thomas Sollich Angelica Cecilia Friederike J. Gruhl 《Biopolymers》2017,107(2):70-79
In the present work, different biopolymer blend scaffolds based on the silk protein fibroin from Bombyx mori (BM) were prepared via freeze‐drying method. The chemical, structural, and mechanical properties of the three dimensional (3D) porous silk fibroin (SF) composite scaffolds of gelatin, collagen, and chitosan as well as SF from Antheraea pernyi (AP) and the recombinant spider silk protein spidroin (SSP1) have been systematically investigated, followed by cell culture experiments with epithelial prostate cancer cells (LNCaP) up to 14 days. Compared to the pure SF scaffold of BM, the blend scaffolds differ in porous morphology, elasticity, swelling behavior, and biochemical composition. The new composite scaffold with SSP1 showed an increased swelling degree and soft tissue like elastic properties. Whereas, in vitro cultivation of LNCaP cells demonstrated an increased growth behavior and spheroid formation within chitosan blended scaffolds based on its remarkable porosity, which supports nutrient supply matrix. Results of this study suggest that silk fibroin matrices are sufficient and certain SF composite scaffolds even improve 3D cell cultivation for prostate cancer research compared to matrices based on pure biomaterials or synthetic polymers. 相似文献
960.
Doan H. Nguyen Roger W. Beuerman Christine L. Halbert Qiangwei MA Guang Sun 《In vitro cellular & developmental biology. Animal》1999,35(4):198-204
Summary To establish an immortalized lacrimal gland epithelial cell line, the orbital lacrimal glands of normal New Zealand White
rabbits were multiply injected with an immortalizing amphotropic retroviral vector (LXSN16E6E7) containing the E6 and E7 genes
of human papillomavirus type 16. Lacrimal glands were removed after 2 d and acinar epithelial cells were isolated and cultured
on Matrigel-coated 60 mm2 plates containing DMEM-F12 supplemented with 5% Nu-serum V. Transformed cells were selected in G418 sulfate for 7 d and passaged.
Morphology of the immortalized cells was similar to that described for normal acinar cells both in vivo and in vitro, with
rough endoplasmic reticulum and secretory granules. These characteristics remained unchanged and the cells continued to exhibit
typical polygonal epithelioid structure. The cells have been maintained in culture for 14 mo. and have gone through 58 passages
without loss of proliferation or epithelial cell characteristics. Immunohistochemistry and Western blots showed positive reactivity
to secretory component, transferrin, and transferrin receptor, which are typical proteins found in the lacrimal gland. Functional
analysis by stimulation with a cholinergic agonist, carbachol (100 μM), resulted in a significant release of protein. This is the first report of an immortalized rabbit lacrimal epithelial cell.
These cells will provide a valuable tool for the molecular analysis of lacrimal gland epithelial cell functions. 相似文献