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Richard M. Napier Michael A. Venis Michael A. Bolton Louise I. Richardson Goeffrey W. Butcher 《Planta》1988,176(4):519-526
Binding proteins, thought to be auxin receptors, can be solubilised from maize (Zea mays L.) membranes after acetone treatment. From these crude extracts, receptor preparations of over 50% purity can be obtained by a reliable, straight-forward procedure involving three chromatographic steps — anion exchange, gel filtration and high-resolution anion exchange. Such preparations have been used to immunise rats for subsequent production of monoclonal antibodies. By the further step of native polyacrylamide gel electrophoresis the semi-purified preparations yield homogeneous, dimeric (22-kilodalton, kDa) auxin-binding protein, which has been used to produce a polyclonal rabbit antiserum. The preliminary characterisation of this antiserum and of the five monoclonal antibodies is presented. Two of the monoclonal antibodies specifically recognise the major 22-kDa-binding protein polypeptide whilst the other three recognise, in addition, a minor 21-kDa species. All the monoclonal antibodies recognise the polypeptide rather than the glycan side chain and the polyclonal antiserum also recognises deglycosylated binding protein. The antibodies have been used to quantify the abundance of auxinbinding protein in a number of tissues of etiolated maize seedlings. Root membranes contain 20-fold less binding protein than coleoptile membranes.Abbreviations ABP
auxin-binding protein
- DEAE
diethylaminoethyl
- Ig
immunoglobulin
- kDa
kilodalton
- NAA
naphthalene-1-acetic acid
- Mr
relative molecular mass
- PAGE
polyacrylamide gel electrophoresis
- SDS
sodium dodecyl sulfate 相似文献
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OBJECTIVE--To examine the relation between alcohol consumption and risk factors for coronary heart disease in women. DESIGN--Cross sectional study of a stratified random sample of the population grouped into five categories of habitual alcohol consumption. SETTING--People registered with general practitioners at two large health centres in east Bristol, England. SUBJECTS--1048 women aged 25-69 years. MAIN OUTCOME MEASURES--Fasting plasma concentrations of insulin, total cholesterol, total triglycerides, and high density lipoprotein cholesterol, including its subfractions HDL2 and HDL3, and body mass index. RESULTS--Compared with non-drinkers women consuming a moderate amount of alcohol (1-20 g/day) had lower plasma concentrations of triglycerides, by 0.19 mmol/l (95% confidence interval 0.07 to 0.35); cholesterol, by 0.4 mmol/l (0.19 to 0.61); and insulin, by 1.4 mU/l (0.43 to 1.97) and a lower body mass index, by 1.2 kg/m2 (0.43 to 1.97). They also had higher concentrations of high density lipoprotein cholesterol, by 0.09 mmol/l (0.03 to 0.15); HDL2 cholesterol by 0.05 mmol/l (-0.02 to 0.10) and HDL3 cholesterol, by 0.06 mmol/l (0.06 to 0.11). All these were independent of body mass index, smoking habits, and taking oral contraceptives. CONCLUSIONS--Moderate alcohol consumption is associated with lower levels of cardiovascular risk factors in women. Insulin may have a central role. 相似文献
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D. R. Gamble M. L. Kinsley M. G. FitzGerald R. Bolton K. W. Taylor 《BMJ (Clinical research ed.)》1969,3(5671):627-630
Sera from 123 patients with diabetes mellitus of recent onset, 155 patients with diabetes of more than two years'' duration, and 250 normal persons were collected over a period of two and a half years. All sera were tested for neutralizing antibody to Coxsackie virus types B1–6, and a sample was tested for complement-fixing antibody to a number of viral, rickettsial, and mycoplasmal antigens.In diabetics of recent onset no evidence was found of any excess of antibodies to mumps virus or some common respiratory viruses. Insulin-dependent diabetes within three months of onset were found to have higher antibody titres to Coxsackie B virus, particularly of type B4, than either normal subjects or patients with diabetes of longer duration. 相似文献
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Some pseudomonads produce a toxin that specifically inhibits winter wheat (Triticum aestivum L.) root growth and the growth of several microorganisms. The toxin does not inhibit pea (Pisum sativum) root growth, but the organisms are aggressive root colonizers and their effect on Rhizobium leguminosarum growth, colonization, and nodulation of peas was not known. Peas were grown in Leonard jars in the greenhouse. Pea roots
were inoculated with R. leguminosarum, a toxin-producing Pseudomonas sp., both, or neither (control). The Pseudomonas sp. colonized pea roots more rapidly and in greater number than R. leguminosarum after ten days. In the presence of the Pseudomonas sp., the R. leguminosarum population on the rhizoplane was less at ten days. When the roots were inoculated with both R. leguminosarum and Pseudomonas sp., the number of nodules were greater than when R. leguminosarum was inoculated alone, but nodule dry weight and pea shoot biomass were similar to plants inoculated with only R. leguminosarum. Although these results need confirmation with non-sterile soil and field studies, these preliminary results indicate that
peas will not be affected by wheat root-inhibitory rhizobacteria. 相似文献
8.
Determination of the number and location of the manganese binding sites of DNA quadruplexes in solution by EPR and NMR. 下载免费PDF全文
The paramagnetic metal ion Mn2+ has been used to probe the electrostatic potentials of a DNA quadruplex that has two quartets with an overall fold of the chair type. A quadruplex with a basket type structure has also been examined. The binding of the paramagnetic ion manganese to these quadruplex DNAs has been investigated by solution state electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopies. The EPR results indicate that the DNA aptamer, d(GGTTGGTGTGGTTGG), binds two manganese ions and that the binding constants for each of these sites is approximately 10(5) M-1. The NMR results indicate that the binding sites of the manganese are in the narrow grooves of this quadruplex DNA. The binding sites of the DNA quadruplex formed by dimers of d(GGGGTTTTGGGG) which forms a basket structure are also in the narrow groove. These results indicate that the close approach of phosphates in the narrow minor grooves of the quadruplex structures provide strong binding sites for the manganese ions and that EPR and NMR monitoring of manganese binding can be used to distinguish between the different types of quadruplex structures. 相似文献
9.
Changes in calmodulin and its mRNA accompany reentry of quiescent (G0) cells into the cell cycle 总被引:21,自引:0,他引:21
Release of CHO-K1 cells from plateau or stationary phase and reentry into the cell cycle is specifically and reversibly blocked at two distinct sites by the anticalmodulin drug W13. The first block occurs early during release while the cells are still at G0/G1, whereas the second occurs later in reentry during early S phase. As determined by radioimmunoassay, calmodulin levels undergo changes at three distinct steps in plateau-phase entry and release. First, the entry of exponentially growing cells into plateau phase is accompanied by an increase in the calmodulin level. The second change is a reduction in the calmodulin content of cells within the first hour following release from plateau phase. The third change is the subsequent increase in calmodulin levels, which precedes entry of the cells into S phase. Analysis of calmodulin mRNA levels by dot-blot hybridization demonstrates that the changes in calmodulin protein are preceded by changes in calmodulin mRNA. Furthermore, whereas a decrease in CaM mRNA is observed within the first hour following plateau release, no such decrease is observed for beta-actin mRNA, suggesting that this decrease may be selective for calmodulin. This selectivity is further substantiated by the fact that identical changes in calmodulin and calmodulin mRNA are observed in cells released from plateau by two different techniques. Taken together, these data suggest that calmodulin may play an important role in the reentry of cells into the cell cycle. 相似文献
10.
R W Bolton H Rozmiarek F W Chorpenning 《Journal of immunology (Baltimore, Md. : 1950)》1977,118(4):1154-1158
Normal adult Sprague-Dawley rats were bled serially over a 30-week period and their sera were examined for antibodies to polyglycerophosphate (PGP) by a standardized passive hemolysis test. Levels of "natural" antibodies to PGP fluctuated during this period with a majority of animals exhibiting pronounced cycling of serum antibody levels, however, the individual cycles were not synchronized with each other. Feeding of radiolabeled Gram-positive bacilli to these animals and examination of lymphoid tissue by liquid scintillation counting revealed that the antigen persisted mainly in the mesenteric lymph nodes. A second group of rats was injected i.v. with radiolabeled Gram-positive bacilli and tissues were examined for plaque-forming cells (PFC) of PGP specificity, and the sera were examined by passive hemolysis. Cycling of both anti-PGP antibodies and PFC became synchronized in the injected animals with peaks of serum antibody evident at 16 and 28 days post-injection and splenic PFC peaks at 4 and 16 days post-injection. Cycling was also observed in the mesenteric lymph nodes and bone marrow Examination of lymphoid tissue from the rats injected i.v. revealed that antigen introduced by this route also perisisted mainly in the mesenteric lymph nodes, This report demonstrates individual cycling of natural responses to environmental antigen and to the same determinant in secondary responses, indicating its importance as a regulatory mechanism. 相似文献