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981.
A method of cultivating Brucella abortus S19 culture in bioreactor was attempted using three different media. Culture conditions in bioreactor were optimized by varying agitation and aeration parameters. Varying the aeration ranging from 0.5 vvm to 0.8 vvm and agitation rate ranging from 250 rpm to 400 rpm during bacterial growth was found to yield highest viable count within 48 hours of culture period. A count of > 1 x 10(11) CFU per ml within 48 to 60 hours post seeding was obtained consistently in all five consecutive batches (P > 0.05) with 6 x 10(11) CFU per ml being the maximum yield when the organism is grown in soyabean casein digest medium. B. abortus S19 maintained its smooth characteristics throughout its growth in bioreactor. The vaccine prepared with soyabean casein digest medium was found to be potent and safe with a protective index of 3.33 in mice. The vaccine was tested in 10 cattle calves of 3 to 13 months age and all the vaccinated animals were seropositive on 28, 60, 90, 120 and 150 days post-vaccination when analyzed by fluorescence polarization assay (FPA).  相似文献   
982.
Summary Protoplasts fromSclerotium rolfsii were prepared usingTrichoderma harzianum lytic enzymes and immobilized in Ca alginate gels. The immobilized protoplasts when incubated with 1% carboxymethylcellulose in osmotically stabilized induction medium, could secrete endoglucanase and -glucosidase. On repeated use the immobilized preparation retained 36% endoglucanase and 26% -glucosidase activity after 5 cycles.NCL Communication No. 3798  相似文献   
983.
Tumor-associated macrophages are known to influence cancer progression by modulation of immune function, angiogenesis, and cell metastasis, however, little is known about the chemokine signaling networks that regulate this process. Utilizing CT26 colon cancer cells and RAW 264.7 macrophages as a model cellular system, we demonstrate that treatment of CT26 cells with RAW 264.7 conditioned medium induces cell migration, invasion and metastasis. Inflammatory gene microarray analysis indicated CT26-stimulated RAW 264.7 macrophages upregulate SDF-1α and VEGF, and that these cytokines contribute to CT26 migration in vitro. RAW 264.7 macrophages also showed a robust chemotactic response towards CT26-derived chemokines. In particular, microarray analysis and functional testing revealed CSF-1 as the major chemoattractant for RAW 264.7 macrophages. Interestingly, in the chick CAM model of cancer progression, RAW 264.7 macrophages localized specifically to the tumor periphery where they were found to increase CT26 tumor growth, microvascular density, vascular disruption, and lung metastasis, suggesting these cells home to actively invading areas of the tumor, but not the hypoxic core of the tumor mass. In support of these findings, hypoxic conditions down regulated CSF-1 production in several tumor cell lines and decreased RAW 264.7 macrophage migration in vitro. Together our findings suggest a model where normoxic tumor cells release CSF-1 to recruit macrophages to the tumor periphery where they secrete motility and angiogenic factors that facilitate tumor cell invasion and metastasis.  相似文献   
984.
Cutting edge: suppression of T cell chemotaxis by sphingosine 1-phosphate   总被引:7,自引:0,他引:7  
Murine CD4 and CD8 T cells express predominantly types 1 and 4 sphingosine 1-phosphate (S1P) G protein-coupled receptors (designated S1P1 and S1P4 or previously endothelial differentiation gene-encoded 1 and 6) for S1P, which has a normal plasma concentration of 0.1-1 microM. S1P now is shown to enhance chemotaxis of CD4 T cells to CCL-21 and CCL-5 by up to 2.5-fold at 10 nM to 0.1 microM, whereas 0.3-3 microM S1P inhibits this chemotaxis by up to 70%. Chemotaxis of S1P(1), but not S1P(4), transfectants to CXCL1 and CXCL4 was similarly affected by S1P. Activation of CD4 T cells, which decreases S1P receptor expression, suppressed effects of S1P on chemotaxis. Pretreatment of labeled CD4 T cells with S1P before reintroduction into mice inhibited by a maximum of 75% their migration into chemokine-challenged s.c. air pouches. The S1P-S1P(1) receptor axis thus controls recruitment of naive T cells by maintaining their response threshold to diverse lymphotactic factors.  相似文献   
985.
Electrostatic interactions play a key role in enzyme catalytic function. At long range, electrostatics steer the incoming ligand/substrate to the active site, and at short distances, electrostatics provide the specific local interactions for catalysis. In cases in which electrostatics determine enzyme function, orthologs should share the electrostatic properties to maintain function. Often, electrostatic potential maps are employed to depict how conserved surface electrostatics preserve function. We expand on previous efforts to explain conservation of function, using novel electrostatic sequence and structure analyses of four enzyme families and one enzyme superfamily. We show that the spatial charge distribution is conserved within each family and superfamily. Conversely, phylogenetic analysis of key electrostatic residues provide the evolutionary origins of functionality.  相似文献   
986.
A new series of antituberculosis agents 6-9 was designed, synthesized and evaluated for antituberculosis activity against Mycobacterium tuberculosis H37Rv and clinical isolates in an agar dilution method. Compound 9h showed comparable in vitro activity (MIC) to isoniazid against M. tuberculosis H37Rv and clinical isolates (sensitive strains) and superior activity against resistant strains of M. tuberculosis.  相似文献   
987.
The purpose of this editorial is to provide a brief history of National Institutes of Health National Cancer Institute (NCI) workshops as related to quantitative imaging within the oncology setting. The editorial will then focus on the recently supported NCI initiatives, including the Quantitative Imaging Network (QIN) initiative and its organizational structure, including planned research goals and deliverables. The publications in this issue of Translational Oncology come from many of the current members of this QIN research network.  相似文献   
988.
Saraca asoca (Roxb.) Willd. (subfamily Detarioideae, family Fabaceae) is a perennial evergreen sacred medicinal tree classified under ‘vulnerable’ by the IUCN. The chloroplast (cp) genome/plastome which follows uniparental inheritance contains many useful genetic information because of its conservative rate of evolution. The assembled cp genome of S. asoca which maps as a conserved circular structure revealed extensive rearrangement in gene organization, comprising total length 160,003 bp including LSC, SSC, IRa, and IRb, and GC content was 35.26%. Herein a set of rbcL and matK gene were established using molecular phylogenetic analyses for molecular typing of S. asoca.  相似文献   
989.
Growing prosperity and changing diets have contributed to a surge in obesity prevalence in China. Previous research has investigated the relationships between BMI and several socioeconomic, diet‐related, and health‐related variables in China. This study proposes that such relationships are likely to differ along the conditional BMI distribution, and seeks to investigate such quantile‐dependent variation in effects. Special attention is paid to how variables affect the upper tail of the conditional BMI distribution where overweight and obesity concerns are more acute. Quantile regressions (QRs) and ordinary least squares (OLS) regressions are estimated. The sample consists of 3,407 adult individuals aged 20–45 who participated in the China Health and Nutrition Survey (CHNS), 2006. Substantial cross quantile variation is observed in the relationships between several key variables and BMI. The QR shows that the relationship between energy intake and BMI is largely insignificant in the lower and middle quantiles, whereas the upper quantiles show a positive and significant effect substantially larger than predicted by the least squares regression and by previous studies. This implies that a food‐based strategy aimed at limiting energy intake can be an effective way to fight obesity in China. The negative association between smoking and BMI, on the other hand, is found largely to hold only in the lower and middle quantiles, with the upper tail relatively unaffected by smoking status. Thus, smoking cessation policies may not exacerbate obesity.  相似文献   
990.
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