全文获取类型
收费全文 | 13383篇 |
免费 | 1181篇 |
国内免费 | 1445篇 |
出版年
2024年 | 45篇 |
2023年 | 216篇 |
2022年 | 505篇 |
2021年 | 801篇 |
2020年 | 619篇 |
2019年 | 685篇 |
2018年 | 688篇 |
2017年 | 561篇 |
2016年 | 726篇 |
2015年 | 821篇 |
2014年 | 1063篇 |
2013年 | 1063篇 |
2012年 | 1206篇 |
2011年 | 1072篇 |
2010年 | 682篇 |
2009年 | 658篇 |
2008年 | 688篇 |
2007年 | 612篇 |
2006年 | 471篇 |
2005年 | 422篇 |
2004年 | 395篇 |
2003年 | 319篇 |
2002年 | 328篇 |
2001年 | 209篇 |
2000年 | 177篇 |
1999年 | 109篇 |
1998年 | 80篇 |
1997年 | 90篇 |
1996年 | 51篇 |
1995年 | 68篇 |
1994年 | 53篇 |
1993年 | 38篇 |
1992年 | 47篇 |
1991年 | 44篇 |
1990年 | 51篇 |
1989年 | 54篇 |
1988年 | 23篇 |
1987年 | 24篇 |
1986年 | 16篇 |
1985年 | 20篇 |
1984年 | 18篇 |
1983年 | 24篇 |
1982年 | 21篇 |
1981年 | 11篇 |
1980年 | 13篇 |
1979年 | 13篇 |
1978年 | 18篇 |
1977年 | 15篇 |
1976年 | 12篇 |
1973年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Application of 1% methol, which, along with cold, activates specific thermosensitive ionic channels, changes the number of functioning cold receptors on the skin of the forearm similarly to the cold exposure test; however, it does not affect the number of heat receptors and does not significantly change the threshold of cold sensation. Group variants of responses to menthol that indicate individual differences in the sensitivity of skin receptors to the effects of methol and cold have been found. The results obtained give grounds to suggest that, from the variant of response to menthol (a decrease, increase, or absence of changes in the number of functioning cold receptors 5 min after menthol application), it is possible to predict specific features of response to cold. 相似文献
2.
3.
Yeqi Nian Jasper Iske Ryoichi Maenosono Koichiro Minami Timm Heinbokel Markus Quante Yang Liu Haruhito Azuma Jinrui Yang Reza Abdi Hao Zhou Abdallah Elkhal Stefan G. Tullius 《Aging cell》2021,20(2)
Age impacts alloimmunity. Effects of aging on T‐cell metabolism and the potential to interfere with immunosuppressants have not been explored yet. Here, we dissected metabolic pathways of CD4+ and CD8+ T cells in aging and offer novel immunosuppressive targets. Upon activation, CD4+ T cells from old mice failed to exhibit adequate metabolic reprogramming resulting into compromised metabolic pathways, including oxidative phosphorylation (OXPHOS) and glycolysis. Comparable results were also observed in elderly human patients. Although glutaminolysis remained the dominant and age‐independent source of mitochondria for activated CD4+ T cells, old but not young CD4+ T cells relied heavily on glutaminolysis. Treating young and old murine and human CD4+ T cells with 6‐diazo‐5‐oxo‐l‐norleucine (DON), a glutaminolysis inhibitor resulted in significantly reduced IFN‐γ production and compromised proliferative capacities specifically of old CD4+ T cells. Of translational relevance, old and young mice that had been transplanted with fully mismatched skin grafts and treated with DON demonstrated dampened Th1‐ and Th17‐driven alloimmune responses. Moreover, DON diminished cytokine production and proliferation of old CD4+ T cells in vivo leading to a significantly prolonged allograft survival specifically in old recipients. Graft prolongation in young animals, in contrast, was only achieved when DON was applied in combination with an inhibition of glycolysis (2‐deoxy‐d‐glucose, 2‐DG) and OXPHOS (metformin), two alternative metabolic pathways. Notably, metabolic treatment had not been linked to toxicities. Remarkably, immunosuppressive capacities of DON were specific to CD4+ T cells as adoptively transferred young CD4+ T cells prevented immunosuppressive capacities of DON on allograft survival in old recipients. Depletion of CD8+ T cells did not alter transplant outcomes in either young or old recipients. Taken together, our data introduce an age‐specific metabolic reprogramming of CD4+ T cells. Targeting those pathways offers novel and age‐specific approaches for immunosuppression. 相似文献
4.
E. P. Isakova Yu. I. Deryabina N. N. Gessler T. A. Belozerskaya Ya. M. Rabinovich 《Applied Biochemistry and Microbiology》2010,46(3):318-323
Cell respiratory activity of protoplasts obtained from the wild type of Neurospora crassa and photoreceptor complex WCC—white collar 1 (wc-1) and white collar 2 (wc-2)—mutants of Neurospora crassa strains was investigated. Respiration inhibition by KCN in the presence of 25 mM succinate was similar in all strains and
did not exceed 83–85% against control. The significant induction of KCN-resistant respiratory pathway occurred under 1% glucose
oxidation in wc-1 and wc-2 mutants if compared with the wild type strains. The inhibitors of the main (cytochrome) pathway of electron transfer in mitochondria—1
mM KCN and antimycin A (4 μg/ml)—blocked the respiration rate of the protoplasts from N. crassa wild type by 75%, while the cell respiration of wc-1 and wc-2 strains was suppressed by approximately 50%. The specific inhibitor of alternative oxidase—10 mM salicylhydroxamic acid (SHAM)—in
combination with the blockers of mitochondrial electron transfer chain caused the total suppression of respiratory activity
of protoplasts in all studied strains. It is supposed that an increase of KCN-resistance in WCC mutants under glucose oxidation
is connected with alternative oxidase activation as the result of failure in reception and signal transduction of active oxygen
species. 相似文献
5.
6.
7.
Many animals exhibit different behaviors in different seasons. The photoperiod can have effects on migration, breeding, fur growth, and other processes. The cyclic growth of the fur and feathers of some species of mammals and birds, respectively, is stimulated by the photoperiod as a result of hormone-dependent regulation of the nervous system. To further examine this phenomenon, we evaluated the Arbas Cashmere goat (Capra hircus), a species that is often used in this type of research. The goats were exposed to an experimentally controlled short photoperiod to study the regulation of cyclic cashmere growth. Exposure to a short photoperiod extended the anagen phase of the Cashmere goat hair follicle to increase cashmere production. Assessments of tissue sections indicated that the short photoperiod significantly induced cashmere growth. This conclusion was supported by a comparison of the differences in gene expression between the short photoperiod and natural conditions using gene chip technology. Using the gene chip data, we identified genes that showed altered expression under the short photoperiod compared to natural conditions, and these genes were found to be involved in the biological processes of hair follicle growth, structural composition of the hair follicle, and the morphogenesis of the surrounding skin appendages. Knowledge about differences in the expression of these genes as well as their functions and periodic regulation patterns increases our understanding of Cashmere goat hair follicle growth. This study also provides preliminary data that may be useful for the development of an artificial method to improve cashmere production by controlling the light cycle, which has practical significance for livestock breeding. 相似文献
8.
9.
Ya. O. Loginov G. G. Khudaigulov S. P. Chetverikov A. I. Melent’ev O. N. Loginov 《Applied Biochemistry and Microbiology》2011,47(3):311-314
Highly viscous polysaccharide (250–350 kDa) of an alginate nature with a predominance of α-L-guluronic acid (M/G = 0.22) was
obtained from Azotobacter vinelandi. The yield of polysaccharide was 20.5 ± 0.5 g/l when cultured in a medium containing molasses at a viscosity of the cultural
liquid of over 30000 cSt. The biopolymer is stable at pH 4.0–9.0 in a wide temperature range and well soluble in highly mineralized
water; it retains a high viscosity level and can be used in the petroleum industry for enhanced oil recovery. 相似文献
10.