全文获取类型
收费全文 | 5872篇 |
免费 | 426篇 |
国内免费 | 5篇 |
专业分类
6303篇 |
出版年
2024年 | 8篇 |
2023年 | 27篇 |
2022年 | 97篇 |
2021年 | 128篇 |
2020年 | 100篇 |
2019年 | 117篇 |
2018年 | 205篇 |
2017年 | 160篇 |
2016年 | 253篇 |
2015年 | 395篇 |
2014年 | 396篇 |
2013年 | 441篇 |
2012年 | 568篇 |
2011年 | 507篇 |
2010年 | 302篇 |
2009年 | 274篇 |
2008年 | 369篇 |
2007年 | 374篇 |
2006年 | 297篇 |
2005年 | 260篇 |
2004年 | 249篇 |
2003年 | 229篇 |
2002年 | 163篇 |
2001年 | 94篇 |
2000年 | 81篇 |
1999年 | 68篇 |
1998年 | 28篇 |
1997年 | 25篇 |
1996年 | 15篇 |
1995年 | 14篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1971年 | 2篇 |
排序方式: 共有6303条查询结果,搜索用时 0 毫秒
1.
Blocking of acidosis-mediated apoptosis by a reduction of lactate dehydrogenase activity through antisense mRNA expression. 总被引:3,自引:0,他引:3
D Jeong T S Kim J W Lee K T Kim H J Kim I H Kim I Y Kim 《Biochemical and biophysical research communications》2001,289(5):1141-1149
Lactic acid produced from the cells is a potential cause of extra- and intracellular acidification. Due to scarce technical tools, lactic acid that leads to acidification could not be reduced and direct evidence of the relationship between metabolic lactate and apoptosis has not yet been elucidated. In this study, we designed a cellular pH regulation system in CHO cells by a reduction of lactate dehydrogenase (LDH) activity through LDH antisense mRNA expression. This inhibited lactate production and, therefore, acidification of the cytosol. Under HCO3(-)-buffered growth conditions, both the parent CHO cells and the engineered CHO cells maintained their extracellular pH and intracellular pH fairly well. However, upon acidification of the cytosol, only the parent CHO cells underwent apoptosis under HCO3(-)-free conditions. In fact, we observed a number of apoptosis-related events only in control cells, including mitochondrial dysfunction, cytochrome c release, and an increase in caspase-3 enzymatic activity. 相似文献
2.
3.
Leucocytosis was shown to occur in the pulmonate gastropod Biomphalaria glabrata exposed to the trematode Echinostoma lindoense. In these sensitized snails, the leukocyte count in the hemolymph was elevated 3 to 5 days postexposure to miracidia, and prior to complete encapsulation of sporocysts. This increase continued 1 to 5 days after destruction of sensitizing, irradiated E. lindoense sporocysts. Counts returned to normal levels after this period. A significant and more rapid increase in numbers of circulating leukocytes occurred 1 to 6 hr after reexposure of snails to a sensitizing dose of nonirradiated E. lindoense sporocysts. The leukocyte counts usually returned to normal levels after this period, except in snails in which some resensitizing sporocysts remained alive. 相似文献
4.
5.
So Eun Park Jong Cheol Kim Se Jin Lee Mi Rong Lee Sihyeon Kim Dongwei Li Sehyeon Baek Ji Hee Han Jeong Jun Kim Kyung Bon Koo Tae Young Shin Jae Su Kim 《Journal of Asia》2018,21(4):1102-1109
Entomopathogenic fungi have great potential to control agricultural and horticultural insect pests, however optimizing conidial production systems to demonstrate high productivity and stability still needs additional efforts for successful field application and industrialization. Although many virulent entomopathogenic fungal isolates have been viewed as potential candidates in a laboratory environment, very few of the isolates are being used in practice for application in agricultural fields as commercial products. I. javanicus is an entomopathogenic fungus that is parasitic to various diverse coleopteran and lepidopteran insects and thought good candidate as biopesticdes. In this work, the basic characteristics of two entomopathogenic fungi, I. javanica FG340 and Pf04, were investigated in morphological examinations, genetic identification, and virulence against Thrips palmi, and then the feasibility of various grains substrates for conidial production was assessed, particularly focusing on conidial productivity and thermotolerance. Isaria javanica FG340 and Pf04 conidia were solid-cultured on 12 grains for 14?days in a Petri dish. Of the tested Italian millet, perilla seed, millet and barley-based cultures showed high conidial production. The four-grain media yielded >1?×?109 conidia/g of I. javanica FG340 and Pf04. Pf04 strain had enhanced thermotolerance up to 45?°C when cultured on Italian millet. In application, it was easy to make a conidial suspension using the cultured grains, and several surfactants were tested to release the conidia. This work suggests several possible inexpensive grain substrates by which to promote conidial production combined with enhanced stability against exposure to high temperature. 相似文献
6.
Keun Soo Ahn Sung-Tae Hong Yu Na Kang Jung Hyeok Kwon Mi Jeong Kim Tae Jun Park Yong Hoon Kim Tae Jin Lim Koo Jeong Kang 《The Korean journal of parasitology》2012,50(4):357-360
A 25-year-old Uzbek male presented with right upper abdominal pain for 20 days. On radiologic studies, a huge cystic mass was noticed in the right liver which was suspected as parasitic. The patient received right hepatic segmentectomy (segment 7), and the surgically resected mass was confirmed as cystic echinococcosis (CE), measuring 10.5 cm in its diameter. The inner surface of the cyst was bile-stained. The patient was discharged on the 8th hospital day, and was rechecked 6 months after the surgical intervention without any evidence of recurrence. The present report describes findings of an imported case of CE which represented ultrasound images of the ''ball of wool''. 相似文献
7.
Jang do S Lee HJ Lee B Hong BH Cha HJ Yoon J Lim K Yoon YJ Kim J Ree M Lee HC Choi KY 《FEBS letters》2006,580(17):4166-4171
Failure to detect the intermediate in spite of its existence often leads to the conclusion that two-state transition in the unfolding process of the protein can be justified. In contrast to the previous equilibrium unfolding experiment fitted to a two-state model by circular dichroism and fluorescence spectroscopies, an equilibrium unfolding intermediate of a dimeric ketosteroid isomerase (KSI) could be detected by small angle X-ray scattering (SAXS) and analytical ultracentrifugation. The sizes of KSI were determined to be 18.7A in 0M urea, 17.3A in 5.2M urea, and 25.1A in 7M urea by SAXS. The size of KSI in 5.2M urea was significantly decreased compared with those in 0M and 7M urea, suggesting the existence of a compact intermediate. Sedimentation velocity as obtained by ultracentrifugation confirmed that KSI in 5.2M urea is distinctly different from native and fully-unfolded forms. The sizes measured by pulse field gradient nuclear magnetic resonance (NMR) spectroscopy were consistent with those obtained by SAXS. Discrepancy of equilibrium unfolding studies between size measurement methods and optical spectroscopies might be due to the failure in detecting the intermediate by optical spectroscopic methods. Further characterization of the intermediate using (1)H NMR spectroscopy and Kratky plot supported the existence of a partially-folded form of KSI which is distinct from those of native and fully-unfolded KSIs. Taken together, our results suggest that the formation of a compact intermediate should precede the association of monomers prior to the dimerization process during the folding of KSI. 相似文献
8.
Functional analysis of a cold-responsive rice WRKY gene, <Emphasis Type="Italic">OsWRKY71</Emphasis>
9.
SN Park SW Kong MS Park JW Lee E Cho YK Lim MH Choi HS Kim YH Chang JH Shin HS Park SH Choi JK Kook 《Journal of bacteriology》2012,194(19):5445-5446
Fusobacterium nucleatum, one of the major causative bacteria of periodontitis, is classified into five subspecies (nucleatum, polymorphum, vincentii, animalis, and fusiforme) on the basis of the several phenotypic characteristics and DNA homology. This is the first report of the draft genome sequence of F. nucleatum subsp. fusiforme ATCC 51190(T). 相似文献
10.
Kang OH Jeong HJ Kim DK Choi SC Kim TH Nah YH Kim HM Lee YM 《Cell biochemistry and function》2003,21(2):161-167
Trypsin activating both proteinase-activated receptor (PAR) 2 and PAR4 plays an important role in inflammation. We have investigated the potential of trypsin to induce TNF-alpha secretion from the human leukemic mast cell line (HMC-1). HMC-1 cells co-express both PAR2 and PAR4, and their agonist trypsin signals to HMC-1 cells. Trypsin (100 nm), SLIGKV-NH(2) (100 microm, corresponding to the PAR2 tethered ligand), or GYPGQV-NH(2) (100 microm, corresponding to the PAR4 tethered ligand) induced tumour necrosis factor (TNF)-alpha secretion from HMC-1 cells. TNF-alpha secretion by trypsin was significantly blocked by pretreatment with 50 microm PD098059, MEK-1 inhibitor. Furthermore, trypsin stimulated the activation of extracellular signal-regulated kinase (ERK) in HMC-1 cells without any detectable activation of c-Jun N-terminal kinase (JNK) and p38 MAP kinase homologue. These results show that trypsin may induce TNF-alpha secretion following activation of ERK via both PAR2 and PAR4 on HMC-1 cells. 相似文献