全文获取类型
收费全文 | 5027篇 |
免费 | 314篇 |
国内免费 | 3篇 |
出版年
2023年 | 33篇 |
2022年 | 35篇 |
2021年 | 133篇 |
2020年 | 77篇 |
2019年 | 89篇 |
2018年 | 131篇 |
2017年 | 128篇 |
2016年 | 153篇 |
2015年 | 219篇 |
2014年 | 237篇 |
2013年 | 360篇 |
2012年 | 354篇 |
2011年 | 345篇 |
2010年 | 236篇 |
2009年 | 196篇 |
2008年 | 257篇 |
2007年 | 279篇 |
2006年 | 227篇 |
2005年 | 229篇 |
2004年 | 178篇 |
2003年 | 164篇 |
2002年 | 167篇 |
2001年 | 80篇 |
2000年 | 80篇 |
1999年 | 69篇 |
1998年 | 38篇 |
1997年 | 36篇 |
1996年 | 29篇 |
1995年 | 38篇 |
1994年 | 19篇 |
1993年 | 19篇 |
1992年 | 45篇 |
1991年 | 42篇 |
1990年 | 48篇 |
1989年 | 42篇 |
1988年 | 36篇 |
1987年 | 31篇 |
1986年 | 21篇 |
1985年 | 29篇 |
1984年 | 33篇 |
1983年 | 28篇 |
1982年 | 29篇 |
1981年 | 23篇 |
1980年 | 26篇 |
1979年 | 27篇 |
1978年 | 29篇 |
1977年 | 18篇 |
1976年 | 18篇 |
1972年 | 20篇 |
1968年 | 17篇 |
排序方式: 共有5344条查询结果,搜索用时 46 毫秒
991.
Irfan A. Bhat Sivanarayanan T. B. Anjali Somal Sriti Pandey Mukesh K. Bharti Bibhudatta S. K. Panda Indu B. Megha Verma Anand J. Arvind Sonwane G. Sai Kumar Amarpal Vikash Chandra G. Taru Sharma 《Journal of cellular physiology》2019,234(3):2705-2718
This study was conducted to characterize canine bone marrow-derived mesenchymal stem cells (BMSCs); in vivo tracking in mice, and therapeutic evaluation in canine clinical paraplegia cases. Canine BMSCs were isolated, cultured, and characterized in vitro as per International Society for Cellular Therapy criteria, and successfully differentiated to chondrogenic, osteogenic, and adipogenic lineages. To demonstrate the homing property, the pGL4.51 vector that contained luciferase reporter gene was used to transfect BMSCs. Successfully transfected cells were injected around the skin wound in mice and in vivo imaging was done at 6, 12 and 24 hr post MSCs delivery. In vivo imaging revealed that transfected BMSCs migrated and concentrated predominantly toward the center of the wound. BMSCs were further evaluated for allogenic therapeutic potential in 44 clinical cases of spinal cord injuries (SCI) and compared with conventional therapy (control). Therapeutic potential as evaluated by different body reflexes and recovery score depicted significantly better results in stem cell-treated group compared to control group. In conclusion, allogenic canine BMSCs can serve as potent therapeutic candidate in cell-based therapies, especially for diseases like SCI, where the conventional medication is not so promising. 相似文献
992.
Jennifer A. Mietla Dayanjan S. Wijesinghe L. Alexis Hoeferlin Michael D. Shultz Ramesh Natarajan Alpha A. Fowler III Charles E. Chalfant 《Journal of lipid research》2013,54(7):1834-1847
Multiple reports have demonstrated a role for ceramide kinase (CERK) in the production of eicosanoids. To examine the effects of the genetic ablation of CERK on eicosanoid synthesis, primary mouse embryonic fibroblasts (MEFs) and macrophages were isolated from CERK−/− and CERK+/+ mice, and the ceramide-1-phosphate (C1P) and eicosanoid profiles were investigated. Significant decreases were observed in multiple C1P subspecies in CERK−/− cells as compared to CERK+/+ cells with overall 24% and 48% decreases in total C1P. In baseline experiments, the levels of multiple eicosanoids were significantly lower in the CERK−/− cells compared with wild-type cells. Importantly, induction of eicosanoid synthesis by calcium ionophore was significantly reduced in the CERK−/− MEFs. Our studies also demonstrate that the CERK−/− mouse has adapted to loss of CERK in regards to airway hyper-responsiveness as compared with CERK siRNA treatment. Overall, we demonstrate that there are significant differences in eicosanoid levels in ex vivo CERK−/− cells compared with wild-type counterparts, but the effect of the genetic ablation of CERK on eicosanoid synthesis and the serum levels of C1P was not apparent in vivo. 相似文献
993.
994.
995.
The effect of 3 doses of estradiol dipropionate (EDP) on tubal epithelium of immature ovariectomized rhesus monkey (Macaca mulatta) was studied under both light and electron microscopy. EDP at a dose of 5 microgram/kg/day for 6 consecutive days changed differentiation of the epithelial cells into clear and dark cell-types; ciliogenesis, formation of some ciliary buds and even a few cilia were also induced in some clear cells throughout the tubal epithelium. Development of ciliated cells with fully formed ciliary apparatus was accelerated at 10 microgram/kg dosage. The secretory granules (SG) appeared at this dose in some nonciliated cells of the infundibular and ampullary but not the isthmic segments of the tube; some of the infundibular secretory cells, so formed, exhibited even a tendency to secrete. Nearly complete maturation of the tubal epithelium occurred at 20 microgram/kg dose; further signs of secretory activity appeared in all tubal segments. The results indicated that--(i) Nearly complete transformation of tubal epithelium of the immature animal into one of the adult type could be achieved by EDP at a dose not less than 20 microgram/kg under the present conditions. (ii) The response of undifferentiated cells to EDP differed depending upon the location of the epithelial cell within the tube and nature of the cell-type to be formed. (iii) The mode of tubal secretion in this infra-human species was probably apocrine. 相似文献
996.
The permeability of the neutral form of tertiary amine local anesthetics across squid axon membranes was studied by utilizing three different experimental methods: (1) narcotic action of axon excitability was measured by monitoring the time derivative of action potential and the results were analyzed in terms of a diffusion reaction equation of local anesthetics to obtain their permeabilities; (2) the influx of local anesthetic into the axon was measured by use of the radioisotope tracer technique; and (3) the desorption rates of the neutral form of local anesthetics from lipid monolayers were measured and the desorption rate was correlated with permeability.The relative permeabilities obtained for procaine, lidocaine and tetracaine by the above three methods were comparable. The order of relative permeabilities was , and had an inverse correlation with the partition coefficients of anesthetics at oil/water phases. Some discussion concerning the concept of permeability is made when the partition coefficient of a permeant molecule is high. 相似文献
997.
Swarnendu Chandra Nilanjan Chakraborty Amrita Chakraborty Ripen Rai Biswajit Bera 《Archives Of Phytopathology And Plant Protection》2013,46(19):2400-2409
Tea, the second most consumed beverage after water in the world, is produced from the processed tender leaves of tea plants (Camellia sinensis). Production of tea is hindered by various biotic and abiotic stresses. Among the biotic factors, blister blight disease caused by an obligate fungal pathogen, Exobasidium vexans Massee, is a serious problem to the tea industry. The present study was to evaluate the efficacy of elicitor calcium chloride (CaCl2) in inducing resistance in tea plants against blister blight disease. During the pick time of blister incidence at Darjeeling tea garden, the application of CaCl2 at a concentration of 1% resulted in disease inhibition around 71% over the control set. Treatment also resulted in the induction of defence enzymes like peroxidase, polyphenol oxidase, phenylalanine ammonia lyase, β-1,3-glucanase and higher phenol accumulation. Furthermore, the increase in defence molecules also correlated with increase in nitric oxide (NO) generation, a potent defence molecule in plant defence. The result suggests that CaCl2 can used as a potential elicitor in the integrated disease management in organic tea cultivation. 相似文献
998.
Suman Kanungo Sachin N. Desai Ranjan Kumar Nandy Mihir Kumar Bhattacharya Deok Ryun Kim Anuradha Sinha Tanmay Mahapatra Jae Seung Yang Anna Lena Lopez Byomkesh Manna Barnali Bannerjee Mohammad Ali Mandeep Singh Dhingra Ananga Mohan Chandra John D. Clemens Dipika Sur Thomas F. Wierzba 《PLoS neglected tropical diseases》2015,9(3)
BackgroundA bivalent killed whole cell oral cholera vaccine has been found to be safe and efficacious for five years in the cholera endemic setting of Kolkata, India, when given in a two dose schedule, two weeks apart. A randomized controlled trial revealed that the immune response was not significantly increased following the second dose compared to that after the first dose. We aimed to evaluate the impact of an extended four week dosing schedule on vibriocidal response.Conclusions/SignificanceComparable immune responses and safety profiles between the two dosing schedules support the option for increased flexibility of current OCV dosing. Further operational research using a longer dosing regimen will provide answers to improve implementation and delivery of cholera vaccination in endemic and epidemic outbreak scenarios. 相似文献
999.
Pallavi Chandra 《Autophagy》2016,12(3):608-609
Induction of autophagy has been reported as a potential means to eliminate intracellular pathogens. Corroborating that, many studies report inhibition of autophagy as a survival strategy of bacterial pathogens. Incidentally, autophagy at the basal level is critical for survival of host cells including macrophages. We asked how a bacterial pathogen could inhibit autophagy for its survival if the inhibition resulted in cell death. In a recent study we show distinct regulation of autophagy in Mycobacterium tuberculosis (Mtb)-infected macrophages where Mtb containing- and nonMtb-containing autophagosomes show different fates in terms of maturation. We show that upon Mtb infection, there is no dramatic change in the autophagy flux in macrophages. However, autophagosomes that contain the virulent strains of Mtb show selective resilience to the maturation phase of autophagy. Surprisingly, nonMtb-containing autophagosomes in the infected cells continue to mature into autolysosomes. The block in the xenophagy flux is missing in the case of avirulant infections. We show that this selectivity is achieved through selective exclusion of RAB7 from virulent Mtb-containing autophagosomes, thereby restricting the formation of amphisomes. 相似文献
1000.