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71.
Inactivation of Glutamine Synthetase by Ammonia Shock in the Gram-Positive Bacterium Streptomyces cattleya 总被引:1,自引:0,他引:1 下载免费PDF全文
In cultures of the gram-positive bacterium Streptomyces cattleya, a rapid inactivation of glutamine synthetase was seen after ammonia shock. pH activity curves for ammonia-shocked and control cultures are shown. A peak of glutamine synthetase activity was seen during fermentation for production of the antibiotic thienamycin. 相似文献
72.
M a Belen'ki? S Bountzioukas G Gonzales D Ko K Lederis A L Polenov 《Zhurnal evoliutsionno? biokhimii i fiziologii》1990,26(3):340-346
A significant increase of the content of corticosterone in the blood collected from intravenous cannula or by intracardiac punction has been detected using radioimmunoassay in non-operated and adenohypophysectomized frogs Rana catesbeiana subjected to dehydration in 6.2% mannitol solution during 24 hours. The osmolality of the blood plasma of these animals also increases although less significantly than the growth of plasma corticosterone content. There is a tendency to substantial increase of plasma arginine-vasotocin level prior to the growth of corticosterone level, already after 6 hours of dehydration. Based on the present results and literature data, it is suggested that in adenohypophysectomized frogs lacking endogenous ACTH just the increase of blood arginine-vasotocin level results in a substantial activation of corticosteroid-producing cells of the interrenal gland and in the growth of plasma content of corticosterone. 相似文献
73.
Lipid raft-based membrane compartmentation of a plant transport protein expressed in Saccharomyces cerevisiae 下载免费PDF全文
The hexose-proton symporter HUP1 shows a spotty distribution in the plasma membrane of the green alga Chlorella kessleri. Chlorella cannot be transformed so far. To study the membrane localization of the HUP1 protein in detail, the symporter was fused to green fluorescent protein (GFP) and heterologously expressed in Saccharomyces cerevisiae and Schizosaccharomyces pombe. In these organisms, the HUP1 protein has previously been shown to be fully active. The GFP fusion protein was exclusively targeted to the plasma membranes of both types of fungal cells. In S. cerevisiae, it was distributed nonhomogenously and concentrated in spots resembling the patchy appearance observed previously for endogenous H(+) symporters. It is documented that the Chlorella protein colocalizes with yeast proteins that are concentrated in 300-nm raft-based membrane compartments. On the other hand, it is completely excluded from the raft compartment housing the yeast H(+)/ATPase. As judged by their solubilities in Triton X-100, the HUP1 protein extracted from Chlorella and the GFP fusion protein extracted from S. cerevisiae are detergent-resistant raft proteins. S. cerevisiae mutants lacking the typical raft lipids ergosterol and sphingolipids showed a homogenous distribution of HUP1-GFP within the plasma membrane. In an ergosterol synthesis (erg6) mutant, the rate of glucose uptake was reduced to less than one-third that of corresponding wild-type cells. In S. pombe, the sterol-rich plasma membrane domains can be stained in vivo with filipin. Chlorella HUP1-GFP accumulated exactly in these domains. Altogether, it is demonstrated here that a plant membrane protein has the property of being concentrated in specific raft-based membrane compartments and that the information for its raft association is retained between even distantly related organisms. 相似文献
74.
Willens S Stoskopf MK Martin LD Lewbart GA 《In vitro cellular & developmental biology. Animal》2005,41(8-9):258-263
Summary Anurans are important animal models for studying the effects of anthropogenic chemical contamination of the environment. Two-compartment
Teflon flow-through diffusion cells can be used to study percutaneus absorption of xenobiotics across harvested skin. However,
such an approach currently necessitates that skin be harvested just before experimentation, a requirement that calls for the
continuous growth and housing of living animals. The ability to preserve and store skin would allow more efficient use of
animals and more flexibility in experimental design. To this end, we examined the viability of harvested anuran skin stored
under various protocols consistent with current practices of mammalian skin preservation. Skin from the American bullfrog
maintained 80–85% viability after 28 d, whereas viability of skin from the marine toad was only maintained for 7–10 d. 相似文献
75.
Schwarzenbacher R von Delft F Jaroszewski L Abdubek P Ambing E Biorac T Brinen LS Canaves JM Cambell J Chiu HJ Dai X Deacon AM DiDonato M Elsliger MA Eshagi S Floyd R Godzik A Grittini C Grzechnik SK Hampton E Karlak C Klock HE Koesema E Kovarik JS Kreusch A Kuhn P Lesley SA Levin I McMullan D McPhillips TM Miller MD Morse A Moy K Ouyang J Page R Quijano K Robb A Spraggon G Stevens RC van den Bedem H Velasquez J Vincent J Wang X West B Wolf G Xu Q Hodgson KO Wooley J Wilson IA 《Proteins》2004,56(2):392-395
76.
Ali Sadeghi-Naini Ervis Sofroni Naum Papanicolau Omar Falou Linda Sugar Gerard Morton Martin J. Yaffe Robert Nam Alireza Sadeghian Michael C. Kolios Hans T. Chung Gregory J. Czarnota 《Translational oncology》2015,8(1):25-34
Three-dimensional quantitative ultrasound spectroscopic imaging of prostate was investigated clinically for the noninvasive detection and extent characterization of disease in cancer patients and compared to whole-mount, whole-gland histopathology of radical prostatectomy specimens. Fifteen patients with prostate cancer underwent a volumetric transrectal ultrasound scan before radical prostatectomy. Conventional-frequency (~ 5 MHz) ultrasound images and radiofrequency data were collected from patients. Normalized power spectra were used as the basis of quantitative ultrasound spectroscopy. Specifically, color-coded parametric maps of 0-MHz intercept, midband fit, and spectral slope were computed and used to characterize prostate tissue in ultrasound images. Areas of cancer were identified in whole-mount histopathology specimens, and disease extent was correlated to that estimated from quantitative ultrasound parametric images. Midband fit and 0-MHz intercept parameters were found to be best associated with the presence of disease as located on histopathology whole-mount sections. Obtained results indicated a correlation between disease extent estimated noninvasively based on midband fit parametric images and that identified histopathologically on prostatectomy specimens, with an r2 value of 0.71 (P < .0001). The 0-MHz intercept parameter demonstrated a lower level of correlation with histopathology. Spectral slope parametric maps offered no discrimination of disease. Multiple regression analysis produced a hybrid disease characterization model (r2 = 0.764, P < .05), implying that the midband fit biomarker had the greatest correlation with the histopathologic extent of disease. This work demonstrates that quantitative ultrasound spectroscopic imaging can be used for detecting prostate cancer and characterizing disease extent noninvasively, with corresponding gross three-dimensional histopathologic correlation. 相似文献
77.
Underiner TL Ruggeri B Aimone L Albom M Angeles T Chang H Hudkins RL Hunter K Josef K Robinson C Weinberg L Yang S Zulli A 《Bioorganic & medicinal chemistry letters》2008,18(7):2368-2372
Orally bioavailable, dual inhibitors of TIE-2/VEGF-R2 were identified by elaborating the C3/N13 SAR around a fused pyrrolodihydroindazolocarbazole scaffold. Analogs bearing a C3-thiophencarbonyl group were evaluated in enzymatic and cellular biochemical assays; two orally bioavailable analogs were further profiled in functional assays and found to inhibit microvessel growth in rat aortic explant cultures and inhibit Ang-1-stimulated chemotaxis of HUVECs. 相似文献
78.
Identification, characterization, and localization of a novel kidney polycystin-1-polycystin-2 complex 总被引:9,自引:0,他引:9
Newby LJ Streets AJ Zhao Y Harris PC Ward CJ Ong AC 《The Journal of biological chemistry》2002,277(23):20763-20773
The functions of the two proteins defective in autosomal dominant polycystic kidney disease, polycystin-1 and polycystin-2, have not been fully clarified, but it has been hypothesized that they may heterodimerize to form a "polycystin complex" involved in cell adhesion. In this paper, we demonstrate for the first time the existence of a native polycystin complex in mouse kidney tubular cells transgenic for PKD1, non-transgenic kidney cells, and normal adult human kidney. Polycystin-1 is heavily N-glycosylated, and several glycosylated forms of polycystin-1 differing in their sensitivity to endoglycosidase H (Endo H) were found; in contrast, native polycystin-2 was fully Endo H-sensitive. Using highly specific antibodies to both proteins, we show that polycystin-2 associates selectively with two species of full-length polycystin-1, one Endo H-sensitive and the other Endo H-resistant; importantly, the latter could be further enriched in plasma membrane fractions and co-immunoprecipitated with polycystin-2. Finally, a subpopulation of this complex co-localized to the lateral cell borders of PKD1 transgenic kidney cells. These results demonstrate that polycystin-1 and polycystin-2 interact in vivo to form a stable heterodimeric complex and suggest that disruption of this complex is likely to be of primary relevance to the pathogenesis of cyst formation in autosomal dominant polycystic kidney disease. 相似文献
79.
Grace PM Hurley D Barratt DT Tsykin A Watkins LR Rolan PE Hutchinson MR 《Journal of neurochemistry》2012,122(5):976-994
80.
Stella?PelengarisEmail author Sylvie?Abouna Linda?Cheung Vasiliki?Ifandi Sevasti?Zervou Michael?Khan 《BMC biology》2004,2(1):26