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1.
The transport and phosphorylation of gluconate in E. coli occurs through two systems (GntI and GntII) which duplicate activities. bioH-asddeletion mutants do not grow on media with gluconate as sole carbon source because they lack the GntI system and do not express GntII. Although E. coli C177 is a Δ(bioH-asd) mutant, it carries the pyrB linked mutation gnt177 that enables it to metabolize this substrate through inducible expression of the GntII system. Several gntS derivatives which are unable to grow on gluconate were isolated from E. coli C177 by spontaneous curing of the transposon Tn10 previously inserted at the gntS locus (zjf::Tn10, min 95.3). A representative gntS mutant, E. coli TI141A retained the ability to take up gluconate but had lost the thermosensitive gluconokinase activity (gene gntV, min 96.9). Furthermore, it could be demonstrated that gntV is repressed in E. coli TI141A. The results indicate that gntS might specify a trans-acting positive regulator involved in the control of at least the expression of the thermosensitive gluconokinase (GntII), instead of a gluconate uptake system as it was previously postulated. Likewise, these results can be used to reconsider whether the locus altered by the gnt177 lesion is allelic with that of the GntII permease instead of a regulator, as it was originally postulated. 相似文献
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Nicholas J Laping Jeffrey I Everitt Kendall S Frazier Mark Burgert Melisa J Portis Caprice Cadacio Leslie I Gold Cheryl L Walker 《Clinical cancer research》2007,13(10):3087-3099
PURPOSE: Transforming growth factor beta (TGF-beta), which generally stimulates the growth of mesenchymally derived cells but inhibits the growth of epithelial cells, has been proposed as a possible target for cancer therapy. However, concerns have been raised that whereas inhibition of TGF-beta signaling could be efficacious for lesions in which TGF-beta promotes tumor development and/or progression, systemic pharmacologic blockade of this signaling pathway could also promote the growth of epithelial lesions. EXPERIMENTAL DESIGN: We examined the effect of a TGF-beta inhibitor on mesenchymal (leiomyoma) and epithelial (renal cell carcinoma) tumors in Eker rats, which are genetically predisposed to develop these tumors with a high frequency. RESULTS: Blockade of TGF-beta signaling with the ALK5/type I TGF-beta R kinase inhibitor, SB-525334, was efficacious for uterine leiomyoma; significantly decreasing tumor incidence and multiplicity, and reducing the size of these mesenchymal tumors. However, SB-525334 was also mitogenic and antiapoptotic for epithelial cells in the kidney and exacerbated the growth of epithelial lesions present in the kidneys of these animals. CONCLUSION: Although pharmacologic inhibition of TGF-beta signaling with SB-525334 may be efficacious for mesenchymal tumors, inhibition of this signaling pathway seems to promote the development of epithelial tumors. 相似文献
3.
Plasmids containing the inosine monophosphate dehydrogenase gene CaIMH3 from Candida albicans strain ATCC 32354 transform their host to resistance against mycophenolic acid (MPA). The transformants maintain the plasmids at a high copy number (20–40 per cell) and express the CaIMH3 gene at very high levels relative to untransformed controls. The plasmid copy number can be controlled by the concentration of MPA in the media. The transformation procedure is reproducible and the efficiency of transformation is high, up to 15,000 per microgram. Unrearranged plasmids are readily recovered by transforming total DNA from transformants back into Escherichia coli. C. albicans genes cloned into the plasmid are expressed at elevated levels relative to untransformed controls. A derivative vector containing the CaMAL2 promoter and termination sequences expresses the CaERG11 ORF at high levels and confers moderate resistance to fluconazole. These shuttle vectors should facilitate global genomics approaches in C. albicans that have been hampered by its diploid genome. 相似文献
4.
Jeremías Bayón Melisa Santá-Álvarez Raymundo Ocaranza-Sánchez Carlos González-Juanatey 《Revista portuguesa de cardiologia》2018,37(12):1009.e1-1009.e3
We present first-in-human treatment with bioabsorbable magnesium scaffolds for percutaneous coronary intervention in a patient with nickel allergy. We present images from angiography and optical coherence tomography at three months. We also review the current status of these novel devices. 相似文献
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Ayelen L. Gomez Melisa B. Delconte Gabriela A. Altamirano Lucia Vigezzi Veronica L. Bosquiazzo Luís F. Barbisan Jorge G. Ramos Enrique H. Luque Mónica Muñoz-de-Toro Laura Kass 《Hormones & cancer》2017,8(2):78-89
The development of the mammary gland is a hormone-regulated event. Several factors can dysregulate its growth and make the gland more susceptible to cellular transformation. Among these factors, perinatal exposure to xenoestrogens and hormone replacement therapy has been associated with increased risk of developing breast cancer. Here, we assessed the effects induced by estrogen replacement therapy (ERT) in ovariectomized (OVX) middle-aged rats and whether perinatal exposure to diethylstilbestrol (DES) or bisphenol A (BPA) modified these effects in the mammary gland. Pregnant rats were orally exposed to vehicle, 5 μg DES/kg/day, or 0.5 or 50 μg BPA/kg/day from gestational day 9 until weaning. Then, 12-month-old offspring were OVX and treated with 17β-estradiol for 3 months. Morphological changes and the percentage of epithelial cells that proliferated or expressed estrogen receptor alpha (ESR1) and progesterone receptor (PR) were analyzed in mammary gland samples of 15-month-old animals. ERT induced lobuloalveolar hyperplasia and ductal cysts in the mammary gland of middle-aged rats, associated with a higher proliferation index of epithelial cells. Perinatal exposure to DES followed by ERT increased the number of cysts and induced the formation of fibroadenoma and ductal carcinoma in situ, without modifying the expression of ESR1 or PR. Also, after 3 months of ERT, BPA-exposed rats had a higher incidence of ductal hyperplasia and atypical lobular hyperplasia than animals under ERT alone. In conclusion, perinatal exposure to xenoestrogens increases the susceptibility of the mammary gland to develop cysts and hyperplastic lesions when confronted with ERT later in life. 相似文献
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Pérez Aisa A Nuevo J López Morante AA González Galilea A Martin de Argila C Aviñoa Arreal D Feu F Borda Celaya F Gisbert JP Pérez Roldan F Gonzalvo Sorribes JM Palazón Azorín JM Ponce Romero M Castro Fernández M Catalina Rodriguez MV Gallego Montañés S Calvet X Rodrigo Saez L Montoro Huguet M González Méndez Y Sierra Hernández A Sánchez Hernández E Dominguez Muñoz E Pérez Cuadrado E Muñoz M Lanas A 《Gastroenterologia y hepatologia》2012,35(7):468-475