全文获取类型
收费全文 | 255篇 |
免费 | 42篇 |
出版年
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 10篇 |
2013年 | 19篇 |
2012年 | 14篇 |
2011年 | 18篇 |
2010年 | 15篇 |
2009年 | 9篇 |
2008年 | 12篇 |
2007年 | 19篇 |
2006年 | 8篇 |
2005年 | 14篇 |
2004年 | 10篇 |
2003年 | 18篇 |
2002年 | 15篇 |
2001年 | 8篇 |
2000年 | 8篇 |
1999年 | 13篇 |
1998年 | 7篇 |
1997年 | 2篇 |
1995年 | 4篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 3篇 |
1968年 | 2篇 |
1934年 | 1篇 |
排序方式: 共有297条查询结果,搜索用时 15 毫秒
1.
The regularity of a basketlike surrounding of parenchymatous parts of the liver by portal branches proves the lobular organization of the liver. The wall formation of the portal basket (corbicula portalis) is demonstrated by several figures. 相似文献
2.
Maren Preuss Pilar Díaz-Tapia Heroen Verbruggen Giuseppe C. Zuccarello 《Journal of phycology》2023,59(5):950-962
Parasitic red algae are an interesting system for investigating the genetic changes that occur in parasites. These parasites have evolved independently multiple times within the red algae. The functional loss of plastid genomes can be investigated in these multiple independent examples, and fine-scale patterns may be discerned. The only plastid genomes from red algal parasites known so far are highly reduced and missing almost all photosynthetic genes. Our study assembled and annotated plastid genomes from the parasites Janczewskia tasmanica and its two Laurencia host species (Laurencia elata and one unidentified Laurencia sp. A25) from Australia and Janczewskia verruciformis, its host species (Laurencia catarinensis), and the closest known free-living relative (Laurencia obtusa) from the Canary Islands (Spain). For the first time we show parasitic red algal plastid genomes that are similar in size and gene content to free-living host species without any gene loss or genome reduction. The only exception was two pseudogenes (moeB and ycf46) found in the plastid genome of both isolates of J. tasmanica, indicating potential for future loss of these genes. Further comparative analyses with the three highly reduced plastid genomes showed possible gene loss patterns, in which photosynthetic gene categories were lost followed by other gene categories. Phylogenetic analyses did not confirm monophyly of Janczewskia, and the genus was subsumed into Laurencia. Further investigations will determine if any convergent small-scale patterns of gene loss exist in parasitic red algae and how these are applicable to other parasitic systems. 相似文献
3.
We used the incorporation of 14C-uridine into RNA of incubating kidney fragments from normal control rats to evaluate RNA metabolism. Sera from unilaterally nephrectomized rats (uni) obtained 20 hrs post-operatively stimulate 14C-uridine incorporation into RNA significantly more than sera from sham-operated rats (sham). Differently, sera from uni and sham rats have little influence on specific activities of endogenous uridine nucleotide pool in renal fragments. Renal extracts were obtained by homogenizing kidneys in saline. Extracts from kidneys of uni and sham rats 20 hrs post operation depress incorporation markedly, and each depresses to a similar extent, but kidney extracts dilute the specific activities of uridine pools. Correcting for the latter dilution demonstrates that kidney extracts alone have little effect on 14C-uridine incorporation into RNA. We then followed the results when these sera and extracts were combined. Compared to fragments incubating in sham sera and sham extracts, substitution of uni extracts or both uni extracts and uni sera enhances 14C-uridine into renal RNA, whether or not results are corrected for changes in the specific activities of the uridine pools. We conclude that after uninephrectomy there is a concurrent elevation in circulating renotropin and a tissue activating factor in the remaining kidney. The tissue factor can only form an excitor to 14C-uridine incorporation into RNA when serum is present. The rat renotropic system that enhances incorporation of 3H-thymidine into DNA also can stimulate 14C-uridine incorporation into renal RNA. 相似文献
4.
C H Hsu T W Kurtz H G Preuss J M Weller 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1975,149(2):470-472
The radioactive microsphere technique is a simple method for measurement of RBF and intrarenal blood flow distribution in the rat that does not require surgical manipulation of the kidney or general anesthesia. The results are reproducible and compatible with other established techniques. 相似文献
5.
The micronutrient content of most cereal grains is low and responsible for malnutrition deficiencies in millions of people who rely on grains as their primary food source. Any strategy that can increase the micronutrient content of grain will have significant benefits to world health. We identified a gene from barley encoding a cell wall protein with multiple histidine (His)-rich motifs interspersed with short arabinogalactan-protein (AGP) domains and have called it Hordeum vulgare His-rich AGP (HvHRA1). Sequence analysis shows that His-rich AGPs are rare in plants and that the number of His-rich and AGP domains differ between cereals and dicots. The barley and wheat encoded proteins have more than 13 His-rich domains, whereas the putative rice orthologue has only 5 His-rich regions. His-rich motifs are well-established metal-binding motifs; therefore, we developed transgenic (Tx) rice plants that constitutively overexpress barley HvHRA1. There was no significant effect on plant growth or grain yield in Tx plants. Purification of AGPs from wild-type and Tx plants showed that only Tx plants contained detectable levels of a His-rich AGP. Calcein assay shows that the AGP fraction from Tx plants had increased binding affinity for Cu(2+) . Micronutrient analysis of brown and white rice showed that the grain nutrient yield for Fe, Zn and Cu was higher in two Tx lines compared to their respective nulls, although the differences were not statistically significant. This approach highlights the potential of the plant apoplast (cell wall) for storage of key nutrients through overexpression of genes for metal-binding proteins. 相似文献
6.
The fact that the Corpora sesamoidea have never been precisely defined has led to a series of small cartilaginous bodies in the larynx being thus designated, for want of a better solution. Since the corpora sesamoidea have been identified as capsular bodies, however, originating in or in connection with a synovial capsule, there remained only one laryngeal cartilage which appeared to fulfill all the criteria of sesamoid cartilage, namely the papilionaceous cartilage found in all alar species from Monotremata to Carnivora, and which comparative anatomists term proarytaenoid cartilage. If Goeppert's findings are regarded as having an additional functional significance, then it is clear that this cartilage too, like cartilagines interarytaenoidea, postarytaenoidea (dorsoarytaenoidea in the dog?) pararytaenoidea, cunciformis, corniculata, intercorniculata and triticea, is a connecting cartilage. 相似文献
7.
Hung-Hsin Chen Douglas M. Shaw Lauren E. Petty Misa Graff Ryan J. Bohlender Hannah G. Polikowsky Xue Zhong Daeeun Kim Victoria L. Buchanan Michael H. Preuss Megan M. Shuey Ruth J.F. Loos Chad D. Huff Nancy J. Cox Julie A. Bastarache Lisa Bastarache Kari E. North Jennifer E. Below 《American journal of human genetics》2021,108(1):194-201
8.
Ellen Preuss Manuela Hugle Romy Reimann Marcel Schlecht Simone Fulda 《The Journal of biological chemistry》2013,288(49):35287-35296
The PI3K/mammalian Target of Rapamycin (mTOR) pathway is often aberrantly activated in rhabdomyosarcoma (RMS) and represents a promising therapeutic target. Recent evaluation of AZD8055, an ATP-competitive mTOR inhibitor, by the Preclinical Pediatric Testing Program showed in vivo antitumor activity against childhood solid tumors, including RMS. Therefore, in the present study, we searched for AZD8055-based combination therapies. Here, we identify a new synergistic lethality of AZD8055 together with ABT-737, a BH3 mimetic that antagonizes Bcl-2, Bcl-xL, and Bcl-w but not Mcl-1. AZD8055 and ABT-737 cooperate to induce apoptosis in alveolar and embryonal RMS cells in a highly synergistic fashion (combination index < 0.2). Synergistic induction of apoptosis by AZD8055 and ABT-737 is confirmed on the molecular level, as AZD8055 and ABT-737 cooperate to trigger loss of mitochondrial membrane potential, activation of caspases, and caspase-dependent apoptosis that is blocked by the pan-caspase inhibitor Z-VAD-fmk. Similar to AZD8055, the PI3K/mTOR inhibitor NVP-BEZ235, the PI3K inhibitor NVP-BKM120 and Akt inhibitor synergize with ABT-737 to trigger apoptosis, whereas no cooperativity is found for the mTOR complex 1 inhibitor RAD001. Interestingly, molecular studies reveal a correlation between the ability of different PI3K/mTOR inhibitors to potentiate ABT-737-induced apoptosis and to suppress Mcl-1 protein levels. Importantly, knockdown of Mcl-1 increases ABT-737-induced apoptosis similar to AZD8055/ABT-737 cotreatment. This indicates that AZD8055-mediated suppression of Mcl-1 protein plays an important role in the synergistic drug interaction. By identifying a novel synergistic interaction of AZD8055 and ABT-737, our findings have important implications for the development of molecular targeted therapies for RMS. 相似文献
9.
This study was conducted to examine the psycho-emotional effects of repeated oral exposure to capsaicin, the principal active component of chili peppers. Each rat received 1 mL of 0.02% capsaicin into its oral cavity daily, and was subjected to behavioural tests following 10 daily administrations of capsaicin. Stereotypy counts and rostral grooming were significantly increased, and caudal grooming decreased, in capsaicin-treated rats during the ambulatory activity test. In elevated plus maze test, not only the time spent in open arms but also the percent arm entry into open arms was reduced in capsaicin-treated rats compared with control rats. In forced swim test, although swimming duration was decreased, struggling increased in the capsaicin group, immobility duration did not differ between the groups. Repeated oral capsaicin did not affect the basal levels of plasma corticosterone; however, the stress-induced elevation of plasma corticosterone was prolonged in capsaicin treated rats. Oral capsaicin exposure significantly increased c-Fos expression not only in the nucleus tractus of solitarius but also in the paraventricular nucleus. Results suggest that repeated oral exposure to capsaicin increases anxiety-like behaviours in rats, and dysfunction of the hypothalamic-pituitary-adrenal axis may play a role in its pathophysiology. 相似文献
10.
KB Cullberg T Christiansen SK Paulsen JM Bruun SB Pedersen B Richelsen 《Obesity (Silver Spring, Md.)》2013,21(3):454-460