全文获取类型
收费全文 | 309篇 |
免费 | 38篇 |
专业分类
347篇 |
出版年
2021年 | 15篇 |
2018年 | 5篇 |
2017年 | 6篇 |
2015年 | 8篇 |
2014年 | 11篇 |
2013年 | 7篇 |
2012年 | 12篇 |
2011年 | 8篇 |
2010年 | 9篇 |
2009年 | 15篇 |
2008年 | 8篇 |
2007年 | 9篇 |
2006年 | 5篇 |
2005年 | 6篇 |
2004年 | 6篇 |
2003年 | 7篇 |
2002年 | 8篇 |
2001年 | 11篇 |
2000年 | 8篇 |
1999年 | 11篇 |
1998年 | 8篇 |
1997年 | 3篇 |
1995年 | 6篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 5篇 |
1983年 | 3篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1973年 | 3篇 |
1969年 | 4篇 |
1968年 | 6篇 |
1966年 | 5篇 |
1964年 | 4篇 |
1963年 | 3篇 |
1939年 | 2篇 |
1935年 | 3篇 |
1930年 | 2篇 |
1928年 | 2篇 |
1926年 | 3篇 |
排序方式: 共有347条查询结果,搜索用时 0 毫秒
101.
Duarte PC Daft BM Conrad PA Packham AE Saville WJ MacKay RJ Barr BC Wilson WD Ng T Reed SM Gardner IA 《The Journal of parasitology》2004,90(2):379-386
The objectives of this study were to evaluate the accuracy of the indirect fluorescent antibody test (IFAT) using serum and cerebrospinal fluid (CSF) of horses naturally and experimentally infected with Sarcocystis neurona, to assess the correlation between serum and CSF titers, and to determine the effect of S. neurona vaccination on the diagnosis of infection. Using receiver-operating characteristic analysis, the areas under the curve for the IFAT were 0.97 (serum) and 0.99 (CSF). Sensitivity and specificity were 83.3 and 96.9% (serum, cutoff 80) and 100 and 99% (CSF, cutoff 5), respectively. Titer-specific likelihood ratios (LRs) ranged from 0.03 to 187.8 for titers between <10 and 640. Median time to conversion was 22-26 days postinfection (DPI) (serum) and 30 DPI (CSF). The correlation between serum and CSF titers was moderately strong (r = 0.6) at 30 DPI. Percentage of vaccinated antibody-positive horses ranged from 0 to 95% between 0 and 112 days after the second vaccination. Thus, the IFAT was reliable and accurate using serum and CSF. Use of LRs potentially improves clinical decision making. Correlation between serum and CSF titers affects the joint accuracy of the IFAT; therefore, the ratio of serum to CSF titers has potential diagnostic value. The S. neurona vaccine could possibly interfere with equine protozoal myeloencephalitis diagnosis. 相似文献
102.
Watanabe H MacKay CA Mason-Savas A Kislauskis EH Marks SC 《The International journal of developmental biology》2000,44(2):201-207
We have shown that in the osteopetrotic rat mutation toothless (tl) osteoblasts are absent from older bone surfaces in mutants and that mutant osteoblasts in vivo lack the prominent stress fiber bundles polarized along bone surfaces in osteoblasts from normal littermates. Our recent data demonstrate that in normal osteoblasts in vitro beta- and gamma-actin mRNAs have different, characteristic intracellular distributions and that tl (mutant) osteoblasts fail to differentially sort these mRNAs. Because bone resorption and formation are highly interdependent and injections of CSF-1, a growth factor, increase bone resorption and growth in tl rats, we examined the effects of CSF-1 treatment on osteoblast survival and ultrastructure in vivo and ability to sort actin mRNAs in vitro. Neonatal CSF-1 treatment of mutants restores osteoblasts on older bone surfaces, normalizes the intracellular distribution of stress fibers in osteoblasts in vivo and promotes normal sorting of beta-actin mRNA in mutant osteoblasts in vitro without normalizing gamma-actin distribution. These data suggest the beta- and gamma-actin mRNAs in osteoblasts are sorted by different mechanisms and that the differential sorting of beta-actin mRNA is related to the characteristic polarization of stress fibers in osteoblasts and their survival on bone surfaces. This experimental system can be used to explore the relationships and regulation of these aspects of cell and tissue biology. 相似文献
103.
Structural analyses reveal phosphatidyl inositols as ligands for the NR5 orphan receptors SF-1 and LRH-1 总被引:32,自引:0,他引:32
104.
105.
In three cases of intrarenal arterial collateral circulation the collateral channels developed between interlobar arteries in diseased kidneys. Probably these originated in hypertrophied spiral vessels that had arisen from the interlobar arteries in the area of the minor calyces. This form of collateral circulation will undoubtedly be recognized more frequently with the increased use of magnification radiography. 相似文献
106.
107.
Quantitative recovery, selective removal and one-step purification of human parotid and leukemic lysozymes by immunoadsorption 总被引:5,自引:0,他引:5
B J MacKay V J Iacono J M Zuckerman E F Osserman J J Pollock 《European journal of biochemistry》1982,129(1):93-98
Immunoadsorption affinity chromatography was used to isolate and purify human lysozyme. The immunoadsorbent was prepared by coupling sheep anti-(human leukemic lysozyme) IgG to epoxy-activated Sepharose 6B. Lyophilized parotid saliva (21) was resuspended in distilled water (325 ml, 50 mg/ml, w/v) and applied to a column which had a capacity to bind 4.25 mg human enzyme. Non-adsorbed material did not contain lysozyme, as determined by enzymatic and immunological analyses. All lysozyme activity present in the applied sample (1.97 mg) bound to and was desorbed from the column by elution with 0.2 M sodium acetate HCl buffer, pH 1.8. The isolated material was homogeneous as determined by cationic and sodium dodecyl sulfate/polyacrylamide gel electrophoresis, ultracentrifugation, amino acid and amino-terminal analyses, and immunoelectrophoretic analysis. The one-step purification procedure yielded a 1370-fold increase in specific activity. Human lysozyme was also selectively purified by this method from an ammonium sulfate precipitate of the urine of a patient with chronic monocytic leukemia. Amino acid and polyacrylamide gel electrophoretic analyses indicated that the purified enzyme was identical to human lysozyme isolated from leukemic urine by classical biochemical techniques. 相似文献
108.
Development of yellow mustard (Sinapis alba L.) with superior quality traits (low erucic and linolenic acid contents, and low glucosinolate content) can make this species as a potential oilseed crop. We have recently isolated three inbred lines Y1127, Y514 and Y1035 with low (3.8%), medium (12.3%) and high (20.8%) linolenic acid (C18∶3) content, respectively, in this species. Inheritance studies detected two fatty acid desaturase 3 (FAD3) gene loci controlling the variation of C18∶3 content. QTL mapping revealed that the two FAD3 gene loci responsible for 73.0% and 23.4% of the total variation and were located on the linkage groups Sal02 and Sal10, respectively. The FAD3 gene on Sal02 was referred to as SalFAD3.LA1 and that on Sal10 as SalFAD3.LA2. The dominant and recessive alleles were designated as LA1 and la1 for SalFAD3.LA1, and LA2 and la2 for SalFAD3.LA2. Cloning and alignment of the coding and genomic DNA sequences revealed that the SalFAD3.LA1 and SalFAD3.LA2 genes each contained 8 exons and 7 introns. LA1 had a coding DNA sequence (CDS) of 1143 bp encoding a polypeptide of 380 amino acids, whereas la1 was a loss-of-function allele due to an insertion of 584 bp in exon 3. Both LA2 and la2 had a CDS of 1152 bp encoding a polypeptide of 383 amino acids. Allele-specific markers for LA1, la1, LA2 and la2 co-segregated with the C18∶3 content in the F2 populations and will be useful for improving fatty acid composition through marker assisted selection in yellow mustard breeding. 相似文献
109.
110.