全文获取类型
收费全文 | 82篇 |
免费 | 3篇 |
国内免费 | 7篇 |
专业分类
92篇 |
出版年
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2016年 | 1篇 |
2015年 | 5篇 |
2014年 | 8篇 |
2013年 | 9篇 |
2012年 | 5篇 |
2011年 | 4篇 |
2010年 | 4篇 |
2009年 | 5篇 |
2008年 | 5篇 |
2007年 | 2篇 |
2006年 | 2篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 2篇 |
2000年 | 7篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1994年 | 1篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1977年 | 1篇 |
1974年 | 2篇 |
排序方式: 共有92条查询结果,搜索用时 0 毫秒
11.
The asexual nature of the first cortical reorganization of conjugation in Stylonychia was analyzed by comparing the effect of amputation performed at different stages of early conjugation to that performed on vegetative cells at different stages of the cell cycle. Amputation of vegetative cells delineated a point of commitment to binary fission at 0.51–0.57 of the cell cycle. Cells amputated before this point were induced to undergo the regenerative mode of asexual development, but those amputated after this point continued with binary fission. In parallel, during conjugation a similar commitment was made around the time of formation of tight mating-pairs: early conjugants amputated around this time might undergo regeneration, and those operated on after this stage continued with the first cortical reorganization as in typical conjugants. The two mates of a pair might differ in their response to amputation, suggesting that the timing of commitment to the first cortical reorganization is not related to the events of conjugation, but rather is individually determined in the vegetative cycle of the cells before they pair up in mating. These observations provide support for the notion that the first cortical reorganization of conjugants is homologous to the asexual mode of cortical development in dividers, according to the theory of developmental heterochrony in the sexual reproduction of hypotrichs. The timing of commitment to the first cortical reorganization was found to temporally correlate with the entrance of the micronuclei into meiosis. Since the first cortical reorganization can proceed without the micronucleus, this raises the possibility that initiation of micronuclear meiosis is closely coupled with, and may be determined by, the commitment to the first cortical reorganization. 相似文献
12.
14.
15.
甾体1,4-脱氢和11α-羟基化反应的两种不同微生物转化 总被引:2,自引:1,他引:2
Two kinds of micro-organism, Arthrobacter sp. AX86(1,4-dehdrogenator)and Absidia sp. A28(11α-hydroxylator) were used in this experiment. Two different fermentation techniques were performed to accomplish the multiple conversional reactions for producing 16β-methyl-11α, 17α, 21-trihydroxy-1,4-pregnadiene-3,20-dione (Ⅲ) from 16β-methyl-3β, 17α,21-trihydroxy-5α-pregnane-20-one-21-acetate(1) 1)To produce product(Ⅲ)by means of a two-step fermentation method which were independently performed first by Arthrobacter and next by Abslaia, and 2)the product was obtained by a sequential fermentation system of aforesaid two micro-organisms in a single fermentor without isolation of the intermediates from the mixture. Our results showed that in both fermentation systems high yield of product was obtained. However, according to the technical simplicity, shorter duration of fermentation cycle and efficient yield of product, the second method is better than the first one. 相似文献
16.
Sofie De Cooman Nathalie De Mey Bram BC Dewulf Rik Carette Thierry Deloof Maurice Sosnowski Andre M De Wolf Jan FA Hendrickx 《BMC anesthesiology》2008,8(1):1-6
Background
Current analgesics have drawbacks such as delays in acquisition, lag-times for effect, and side effects. We recently presented a preliminary report of a new analgesic method involving a two-minute sciatic nerve press, which resulted in immediate short-term relief of pain associated with dental and renal diseases. The present study investigated whether this technique was effective for pain associated with other disease types, and whether the relief was effective for up to one hour.Methods
This randomized, placebo-controlled, parallel-group trial was conducted in four hospitals in Anhui Province, China. Patients with pain were sequentially recruited by participating physicians during clinic visits, and 135 patients aged 15 – 80 years were enrolled. Dental disease patients included those with acute pulpitis and periapical abscesses. Renal disease patients included those with kidney infections and/or stones. Tumor patients included those with nose, breast, stomach and liver cancers, while Emergency Room patients had various pathologies. Patients were randomly assigned to receive a "sciatic nerve press" in which pressure was applied simultaneously to the sciatic nerves at the back of both thighs, or a "placebo press" in which pressure was applied to a parallel region on the front of the thighs. Each fist applied a pressure of 11 – 20 kg for 2 minutes. Patients rated their level of pain before and after the procedure.Results
The "sciatic nerve press" produced immediate relief of pain in all patient groups. Emergency patients reported a 43.5% reduction in pain (p < 0.001). Significant pain relief for dental, renal and tumor patients lasted for 60 minutes (p < 0.001). The peak pain relief occurred at the 10 – 20th minutes, and the relief decreased 47% by the 60th minutes.Conclusion
Two minutes of pressure on both sciatic nerves produced immediate significant short-term conduction analgesia. This technique is a convenient, safe and powerful method for the short-term treatment of clinical pain associated with a diverse range of pathologies.Trial registration
Current Controlled Trials ACTRN012606000439549 相似文献17.
18.
Omaira Vera Lizcano Sarah Stela Resende Yonne F Chehuan Marcus VG Lacerda Cristiana FA Brito Mariano G Zalis 《Memórias do Instituto Oswaldo Cruz》2014,109(7):948-951
The molecular basis of Plasmodium vivax chloroquine (CQ) resistance
is still unknown. Elucidating the molecular background of parasites that are
sensitive or resistant to CQ will help to identify and monitor the spread of
resistance. By genotyping a panel of molecular markers, we demonstrate a similar
genetic variability between in vitro CQ-resistant and sensitive phenotypes of
P. vivax parasites. However, our studies identified two
loci (MS8 and MSP1-B10) that could be used to discriminate
between both CQ-susceptible phenotypes among P. vivax isolates in
vitro. These preliminary data suggest that microsatellites may be used to identify
and to monitor the spread of P. vivax-resistance around the
world. 相似文献
19.
对多种生物薄样品和标样进行电子探针X射线能谱显微定量分析,分别以电子束轰击后样品的O Kα峰计数和介于4.2-6.2keV区间的连续X-射线计数变化监测质量损失,结果显示样品O Kα峰计数减少幅度大于连续X-射线计数减少幅度,在相同的分析条件下,各样品质量损失程度不相同(P<0.05)。培养肝癌细胞冷冻干燥超薄切片、明胶冷冻干燥超薄切片、BSA薄膜、氨基塑料超薄切片、红细胞冷冻干燥超薄切片和卵黄高磷蛋白薄膜样品的质量损失分别为33%、28%、26%、18%、13%和13%,以上结果提示:以O Kα峰计数的减少监测样品的质量损失较敏感,在进行生物薄试样定量EPMA时应对各样品的质量损失进行相应校正。 相似文献
20.
Workers dominate male production in the neotropical bumblebee Bombus wilmattae (Hymenoptera: Apidae)