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1.
Temporal changes in the physical properties of healing fractures in rabbits were studied. The mechanical environment at the fracture site was measured and monitored during healing. Animals were sacrificed after 3 to 8 weeks. The results of healing were quantified by whole bone dynamic torsional strength tests. Torque-angle curves were recorded by computer. At maximum torque four parameters were calculated: torque, angle, energy absorbed and stiffness. Torque and stiffness increased while energy remained constant and angle decreased with time. However, values calculated by a constant deformation criteria showed the three strength parameters to increase with time. The rate of increase was highest for stiffness followed by torque and energy. 相似文献
2.
Henry Taylor Jane Teas Thomas Richie Charles Southwick Ram Shrestha 《Primates; journal of primatology》1978,19(2):343-351
In 1,506 hours of field observations on free-ranging rhesus monkeys in Kathmandu Valley, Nepal, in 1974 and 1975 18 cases
of favorable social interactions between adult males and infants were observed. Eleven of these were brief encounters of play
or grooming; seven were more extended cases of male care. One of the latter was a complete adoption of a neonatal orphan by
a dominant male. This adoption was possessive and restrictive and it resulted in the death of the infant by starvation within
three days. A similar adoption involving the same male occurred in 1976 and it also resulted in the death of the infant. Most
of the favorable male-infant interactions occurred during the winter and spring when the infants were 6 to 12 months of age.
These favorable social interactions involved eight males in six different troops, out of a total of about 48 males in 12 troops
in our study population of approximately 600 monkeys. These observations are discussed in light of current sociobiological
theories. 相似文献
3.
Ettinger-Epstein P Tapiolas DM Motti CA Wright AD Battershill CN de Nys R 《Marine biotechnology (New York, N.Y.)》2008,10(1):64-74
The Great Barrier Reef sponge Luffariella variabilis (Poléjaeff 1884) produces a range of potent anti-inflammatory compounds as its major metabolites. These major metabolites—manoalide
monoacetate, manoalide, luffariellin A and seco-manoalide—were monitored temporally and spatially to quantify the potential
yield from wild harvest or aquaculture. Production of the major metabolites was hardwired at the population level with little
variation in space and time over meters to tens of kilometers in the Palm Islands, Queensland, Australia. Manoalide monoacetate
(35 to 70 mg g−1 dry weight of sponge) was consistently the most abundant compound followed by manoalide (15 to 20 mg g−1 dry weight). Luffariellin A and seco-manoalide were 10 to 70 times less abundant and varied between 0 and 3 mg g−1 dry weight. On a larger spatial scale, L. variabilis from Davies Reef and Magnetic Island contained the same rank order and yields of compounds as the Palm Islands, indicating
a generality of pattern over at least 100 km. The “hardwiring” of metabolite production at the population level by L. variabilis was also reflected in the lack of any inductive effect on metabolite production. In addition, individually monitored sponges
produced fixed ratios of the major metabolites over time (years). However, these ratios varied between individuals, with some
individuals consistently producing high levels of manoalide and manoalide monoacetate, providing the potential for selection
of high-yielding stocks. 相似文献
4.
Kinetics of the interaction of a 41-kilodalton macrophage capping protein with actin: promotion of nucleation during prolongation of the lag period 总被引:11,自引:0,他引:11
A 41-kilodalton macrophage capping protein (MCP) has been isolated which is capable of forming complexes with actin monomers in addition to capping the barbed ends of actin filaments (Southwick & DiNubile, 1986). The protein is calcium activated in a fully reversible manner. Using kinetic assays, we determined a capping constant, defined here as a modified Kd, of 1 nM and a Kd of 3-4 microM for MCP-actin monomer complex formation. MCP weakly nucleates actin polymerization: more than 0.5 microM MCP is necessary to shorten the lag period, and 1 microM MCP at an actin/MCP ratio of 10 reduces the average length of actin filaments to about 200 molecules per filament. We determined that the actin nucleus that survives MCP inactivation contains a minimum number of five actin molecules. These experiments also make a point with respect to the interpretation of the prolongation of the lag period. We directly demonstrate that in the presence of an actin binding protein a prolongation of the lag period can be associated with increased nucleation, contrary to the usual interpretation in the literature that it indicates no or decreased nucleation by the actin binding protein. 相似文献
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Salinthone S Singer CA Gerthoffer WT 《American journal of physiology. Gastrointestinal and liver physiology》2004,287(3):G627-G637
Intestinal mucosal cells and invading leukocytes produce inappropriate levels of cytokines and chemokines in human colitis. However, smooth muscle cells of the airway and vasculature also synthesize cytokines and chemokines. To determine whether human colonic myocytes can synthesize proinflammatory mediators, strips of circular smooth muscle and smooth muscle cells were isolated from human colon. Myocytes and muscle strips were stimulated with 10 ng/ml of IL-1beta, TNF-alpha, and IFN-gamma, respectively. Expression of mRNA for IL-1beta, IL-6, IL-8, and cyclooxygenase-2 (COX-2) was induced within 2 h and continued to increase for 8-12 h. Regulated on activation, normal T cell-expressed and -secreted (RANTES) mRNA expression was slower, appearing at 8 h and increasing linearly through 20 h. Expression of all five mRNAs was inhibited by 0.1 microM MG-132, a proteosome inhibitor that blocks NF-kappaB activation. Expression of IL-1beta, IL-6, IL-8, and COX-2 mRNA was reduced by 30 microM PP1, an Src family tyrosine kinase inhibitor, and by 25 microM SB-203580, a p38 MAPK inhibitor. MAPK/extracellular regulated kinase-1 inhibitor PD-98059 (25 microM) was much less effective. In conclusion, human colonic smooth muscle cells can synthesize and secrete interleukins (IL-1beta and IL-6) and chemokines (IL-8 and RANTES) and upregulate expression of COX-2. Regulation of cytokine, chemokine, and COX-2 mRNA depends on multiple signaling pathways, including Src-family kinases, extracellular regulated kinase, p38 MAPKs, and NF-kappaB. SB-203580 was a consistent, efficacious inhibitor of inflammatory gene expression, suggesting an important role of p38 MAPK in synthetic functions of human colonic smooth muscle. 相似文献
10.
Moore JE McCalmont M Xu J Millar BC Heaney N 《Applied and environmental microbiology》2002,68(8):4130-4131
A gram-negative bacillus was isolated from a batch of fruit-flavored bottled water, which had spoiled as a result of bacterial overgrowth (>10(6) CFU/ml). The spoilage organism was extremely difficult to identify phenotypically and was poorly identified as Pasturella sp. (78.7% identification profile) employing the API 20NE identification scheme, which gave the profile 5040000. Molecular identification through PCR amplification of a partial region of the 16S rRNA gene followed by direct automated sequencing of the PCR amplicon allowed identification of the organism. Due to the sequence identity (100%) between the spoilage organism and a reference strain in GenBank, the spoilage isolate was considered to be an Asaia sp., a recently described genus and member of the acetic acid bacteria. This is the first report of Asaia sp. causing spoilage of a foodstuff and highlights the benefits of molecular identification techniques based on 16S rRNA gene sequences in the identification of unusual spoilage organisms. 相似文献