全文获取类型
收费全文 | 303篇 |
免费 | 14篇 |
出版年
2022年 | 3篇 |
2021年 | 9篇 |
2020年 | 4篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 3篇 |
2015年 | 10篇 |
2014年 | 9篇 |
2013年 | 14篇 |
2012年 | 15篇 |
2011年 | 12篇 |
2010年 | 11篇 |
2009年 | 10篇 |
2008年 | 11篇 |
2007年 | 17篇 |
2006年 | 9篇 |
2005年 | 11篇 |
2004年 | 9篇 |
2003年 | 10篇 |
2002年 | 10篇 |
2001年 | 9篇 |
2000年 | 14篇 |
1999年 | 11篇 |
1998年 | 7篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1990年 | 4篇 |
1989年 | 7篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 1篇 |
1976年 | 5篇 |
1975年 | 6篇 |
1974年 | 3篇 |
1973年 | 7篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1968年 | 4篇 |
1967年 | 1篇 |
1912年 | 1篇 |
1911年 | 2篇 |
排序方式: 共有317条查询结果,搜索用时 343 毫秒
61.
Functional morphology including the origin, insertion, and innervation of the respiratory muscles in relation to buccal pressure pump and opercular suction pumps in a fresh-water bottom dwelling siluroid fish, Bagarius bagarius have been studied. Histochemical studies were made on the succinic dehydrogenase activity of adductor mandibulae, retractor tentaculi, levator operculi, dilatator operculi, adductor operculi, intermandibularis, interhyoideus, hyohyoideus superior and constrictor branchialis. The intensity of reaction reveals the presence of three types of muscle fibres in some of the respiratory muscles. The muscle containing red muscle fibres are mostly innervated by the branches of the VIIth cranial nerve. The retractor tentaculi consists of superficial white muscle fibres and the interior part is dominated by red muscle fibres. The muscles (adductor operculi, levator operculi, dilatator operculi, interhyoideus, hyohyoideus superior) concerned with the opercular suction pumps are of mixed type and consist of white and red muscle fibres, whereas adductor mandibulae and intermandibularis are made up entirely of white muscle fibres. The adductor muscle bundles of the constrictor branchialis, which are responsible for movement of gill filaments, are dominated by the red muscle fibres. The abductor part, however, is made up entirely of white muscle fibres. 相似文献
62.
Emily E. Puckett Emma Sherratt Matthew Combs Elizabeth J. Carlen William Harcourt‐Smith Jason Munshi‐South 《Ecology and evolution》2020,10(11):4739-4748
Urbanization exposes species to novel environments and selection pressures that may change morphological traits within a population. We investigated how the shape and size of crania and mandibles changed over time within a population of brown rats (Rattus norvegicus) living in Manhattan, New York, USA, a highly urbanized environment. We measured 3D landmarks on the cranium and mandible of 62 adult individuals sampled in the 1890s and 2010s. Static allometry explained approximately 22% of shape variation in crania and mandible datasets, while time accounted for approximately 14% of variation. We did not observe significant changes in skull size through time or between the sexes. Estimating the P‐matrix revealed that directional selection explained temporal change of the crania but not the mandible. Specifically, rats from the 2010s had longer noses and shorter upper molar tooth rows, traits identified as adaptive to colder environments and higher quality or softer diets, respectively. Our results highlight the continual evolution to selection pressures. We acknowledge that urban selection pressures impacting cranial shape likely began in Europe prior to the introduction of rats to Manhattan. Yet, our study period spanned changes in intensity of artificial lighting, human population density, and human diet, thereby altering various aspects of rat ecology and hence pressures on the skull. 相似文献
63.
64.
65.
Tendulkar SR Saikumari YK Patel V Raghotama S Munshi TK Balaram P Chattoo BB 《Journal of applied microbiology》2007,103(6):2331-2339
AIMS: Isolation of bacterial antagonist for use in the biological control of phytopathogenic fungi like rice blast fungus, Magnaporthe grisea, and to further purify and characterize the antifungal molecule produced by the antagonist. METHODS AND RESULTS: Bacterial antagonist exhibiting highest antifungal activity against the rice blast fungus M. grisea was isolated from soil and identified as Bacillus licheniformis BC98. Besides M. grisea, the isolate also inhibited the growth of other phytopathogens such as Curvularia lunata and Rhizoctonia bataticola. Biologically active fractions were isolated from the culture filtrate and further fractionated by reverse-phase high-performance liquid chromatography (HPLC) enabling detailed structural characterization of a component of molecular mass 1035 Da. The active peptide was identified as surfactin after 500 MHz (1)H NMR analysis. Microscopic analysis of the effect of the antagonist on M. grisea revealed bulbous hyphae showing patchy and vacuolated cytoplasm when observed under the electron microscope. CONCLUSIONS: The antagonistic lipopeptide secreted by B. licheniformis BC98 and identified as surfactin, induced morphological changes in M. grisea, inhibiting its further growth, and thus exhibiting fungicidal activity. SIGNIFICANCE AND IMPACT OF THE STUDY: The antagonist inhibits germination of M. grisea, a potent rice phytopathogen, and therefore appears to be a potential candidate for control of rice blast disease. 相似文献
66.
Huang S Garbaccio RM Fraley ME Steen J Kreatsoulas C Hartman G Stirdivant S Drakas B Rickert K Walsh E Hamilton K Buser CA Hardwick J Mao X Abrams M Beck S Tao W Lobell R Sepp-Lorenzino L Yan Y Ikuta M Murphy JZ Sardana V Munshi S Kuo L Reilly M Mahan E 《Bioorganic & medicinal chemistry letters》2006,16(22):5907-5912
Through a comparison of X-ray co-crystallographic data for 1 and 2 in the Chek1 active site, it was hypothesized that the affinity of the indolylquinolinone series (2) for Chek1 kinase would be improved via C6 substitution into the hydrophobic region I (HI) pocket. An efficient route to 6-bromo-3-indolyl-quinolinone (9) was developed, and this series was rapidly optimized for potency by modification at C6. A general trend was observed among these low nanomolar Chek1 inhibitors that compounds with multiple basic amines, or elevated polar surface area (PSA) exhibited poor cell potency. Minimization of these parameters (basic amines, PSA) resulted in Chek1 inhibitors with improved cell potency, and preliminary pharmacokinetic data are presented for several of these compounds. 相似文献
67.
Dai-Shi Su John J. Lim Elizabeth Tinney Bang-Lin Wan Mary Beth Young Kenneth D. Anderson Deanne Rudd Vandna Munshi Carolyn Bahnck Peter J. Felock Meiqing Lu Ming-Tain Lai Sinoeun Touch Gregory Moyer Daniel J. DiStefano Jessica A. Flynn Yuexia Liang Rosa Sanchez Sridhar Prasad Youwei Yan Neville J. Anthony 《Bioorganic & medicinal chemistry letters》2009,19(17):5119-5123
68.
Jagesh K. Tiwari Anilabh D. Munshi Ravinder Kumar Raghu N. Pandey Ajay Arora Jayant S. Bhat Amish Kumar Sureja 《Acta Physiologiae Plantarum》2010,32(1):103-114
A pot experiment with 17 diverse genotypes of cucumber with four levels of salt stress viz., 0, 2, 4 and 6 dS m?1 was carried out during 2006. ANOVA revealed significant differences amongst genotypes and genotype × salt stress interaction indicating the genetic variability and differential response of the genotypes to different salt stress levels. The salt stress adversely affected the biochemical parameters; effects were severe under 4 dS m?1. No genotype could survive at 6 dS m?1. Sodium content, Na+–K+ ratio, proline, reducing sugars, phenol and yield reduction (%) increased significantly as the salt stress increased. Potassium, chlorophyll, membrane stability index and fruit yield decreased significantly under salt stress in all genotypes. However, the genotypes CRC-8, CHC-2 and G-338 showed lower accumulation of sodium, lesser depletion of potassium, lower Na+–K+ ratio and higher accumulation of proline, reducing sugars, phenols, better membrane stability and lower yield reduction (%) under salt stress, while CH-20 and DC-1 were sensitive to salt stress. Thus, a combination of traits such as higher membrane stability, lower Na+–K+ ratio, higher osmotic concentration and selective uptake of useful ions and prevention of over accumulation of toxic ions contribute to salt stress tolerance in cucumber. These traits would be useful selection criteria during salt stress breeding in cucumber. 相似文献
69.
Hemaka A. Rajapakse Philippe G. Nantermet Harold G. Selnick James C. Barrow Georgia B. McGaughey Sanjeev Munshi Stacey R. Lindsley Mary Beth Young Phung L. Ngo M. Katherine Holloway Ming-Tain Lai Amy S. Espeseth Xiao-Ping Shi Dennis Colussi Beth Pietrak Ming-Chih Crouthamel Katherine Tugusheva Qian Huang Min Xu Adam J. Simon Joseph P. Vacca 《Bioorganic & medicinal chemistry letters》2010,20(6):1885-1889
The optimization of tertiary carbinamine derived inhibitors of BACE1 from its discovery as an unstable lead to low nanomolar cell active compounds is described. Five-membered heterocycles are reported as stable and potency enhancing linkers. In the course of this work, we have discovered a clear trend where the activity of inhibitors at a given assay pH is dependent on pKa of the amino group that interacts directly with the catalytic aspartates. The potency of compounds as inhibitors of Αβ production in a cell culture assay correlated much better with BACE1 enzyme potency measured at pH 7.5 than at pH 4.5. 相似文献
70.
Surabhi Dangi-Garimella Amanda J. Redig Mario A. Shields Mohammed A. Siddiqui Hidayatullah G. Munshi 《The Journal of biological chemistry》2010,285(36):28363-28372
Membrane type 1-matrix metalloproteinase (MT1-MMP, MMP14), which is associated with extracellular matrix (ECM) breakdown in squamous cell carcinoma (SCC), promotes tumor formation and epithelial-mesenchymal transition. However, in this report we demonstrate that MT1-MMP, by cleaving the underlying ECM, causes cellular aggregation of keratinocytes and SCC cells. Treatment with an MMP inhibitor abrogated MT1-MMP-induced phenotypic changes, but decreasing E-cadherin expression did not affect MT1-MMP-induced cellular aggregation. As ROCK1/2 can regulate cell-cell and cell-ECM interaction, we examined its role in mediating MT1-MMP-induced phenotypic changes. Blocking ROCK1/2 expression or activity abrogated the cellular aggregation resulting from MT1-MMP expression. Additionally, blocking Rho and non-muscle myosin attenuated MT1-MMP-induced phenotypic changes. Moreover, SCC cells expressing only the catalytically active MT1-MMP protein demonstrated increased cellular aggregation and increased myosin II activity in vivo when injected subcutaneously into nude mice. Together, these results demonstrate that expression of MT1-MMP may be anti-tumorigenic in keratinocytes by promoting cellular aggregation. 相似文献