全文获取类型
收费全文 | 3376篇 |
免费 | 241篇 |
出版年
2022年 | 10篇 |
2021年 | 27篇 |
2020年 | 20篇 |
2019年 | 24篇 |
2018年 | 30篇 |
2017年 | 26篇 |
2016年 | 58篇 |
2015年 | 78篇 |
2014年 | 93篇 |
2013年 | 235篇 |
2012年 | 198篇 |
2011年 | 168篇 |
2010年 | 116篇 |
2009年 | 121篇 |
2008年 | 205篇 |
2007年 | 198篇 |
2006年 | 188篇 |
2005年 | 170篇 |
2004年 | 213篇 |
2003年 | 182篇 |
2002年 | 190篇 |
2001年 | 68篇 |
2000年 | 52篇 |
1999年 | 62篇 |
1998年 | 50篇 |
1997年 | 47篇 |
1996年 | 32篇 |
1995年 | 38篇 |
1994年 | 24篇 |
1993年 | 36篇 |
1992年 | 61篇 |
1991年 | 61篇 |
1990年 | 50篇 |
1989年 | 39篇 |
1988年 | 42篇 |
1987年 | 34篇 |
1986年 | 22篇 |
1985年 | 37篇 |
1984年 | 47篇 |
1983年 | 25篇 |
1982年 | 23篇 |
1981年 | 22篇 |
1980年 | 21篇 |
1979年 | 19篇 |
1978年 | 20篇 |
1977年 | 13篇 |
1976年 | 22篇 |
1975年 | 15篇 |
1974年 | 12篇 |
1973年 | 12篇 |
排序方式: 共有3617条查询结果,搜索用时 15 毫秒
981.
Matsuda K Kawaura H Onoue S Kashimoto K Uchiyama M Mochizuki T Kikuyama S 《Zoological science》2003,20(8):1003-1009
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a regulatory neuropeptide which functions as a hypothalamic factor for pituitary hormone release, and as a neurotransmitter, neuromodulator and neurotrophic factor in both frogs and mammals. This study examined the quantitative distribution and chromatographic characterization of immunoreactive PACAP in the central nervous system (CNS) of the bullfrog, Rana catesbeiana, using an enzyme immunoassay (EIA), named avidin-biotin complex detectable EIA for PACAP, and high-performance liquid chromatographic (HPLC) analysis. The brain of adult bullfrogs contained relatively high levels of immunoreactive PACAP (344.63 pmol/g wet weight of tissue). The average concentrations of immunoreactive PACAP in the regions of the telencephalon, diencephalon, tectum, cerebellum, rhombencephalon, and spinal cord were 213.84, 767.14, 524.94, 192.71, 237.67, and 362.04 pmol/g wet weight of tissue, respectively. The concentrations of immunoreactive PACAP increased with the brain development during metamorphosis, and the concentration of immunoreactive PACAP in the brain of tadpoles at the end of metamorphosis was approximately 200 pmol/g wet weight of tissue. The predominant form of immunoreactive PACAP in the CNS of adult and tadpole was eluted closely with synthetic PACAP38, but another smaller immunoreactivity also appeared in a the fraction, which corresponded to the retention time of synthetic PACAP27, as analyzed by reverse-phase HPLC. 相似文献
982.
Tumor mRNA-loaded dendritic cells elicit tumor-specific CD8(+) cytotoxic T cells in patients with malignant glioma 总被引:8,自引:0,他引:8
Kobayashi T Yamanaka R Homma J Tsuchiya N Yajima N Yoshida S Tanaka R 《Cancer immunology, immunotherapy : CII》2003,52(10):632-637
In this study, we demonstrate that tumor mRNA–loaded dendritic cells can elicit a specific CD8+ cytotoxic T-lymphocyte (CTL) response against autologous tumor cells in patients with malignant glioma. CTLs from three patients expressed strong cytolytic activity against autologous glioma cells, did not lyse autologous lymphoblasts or EBV-transformed cell lines, and were variably cytotoxic against the NK-sensitive cell line K-562. Also, DCs-pulsed normal brain mRNA failed to induce cytolytic activity against autologous glioma cells, suggesting the lack of autoimmune response. Two patients' CD8+ T cells expressed a modest cytotoxicity against autologous glioma cells. CD8+ T cells isolated during these ineffective primings secreted large amounts of IL-10 and smaller amounts of IFN- as detected by ELISA. Type 2 bias in the CD8+ T-cell response accounts for the lack of cytotoxic effector function from these patients. Cytotoxicity against autologous glioma cells could be significantly inhibited by anti-HLA class I antibody. These data demonstrate that tumor mRNA–loaded DC can be an effective tool in inducing glioma-specific CD8+ CTLs able to kill autologous glioma cells in vitro. However, high levels of tumor-specific tolerance in some patients may account for a significant barrier to therapeutic vaccination. These results may have important implications for the treatment of malignant glioma patients with immunotherapy. DCs transfected with total tumor RNA may represent a method for inducing immune responses against the entire repertoire of glioma antigens. 相似文献
983.
Subcellular localization of herpes simplex virus type 1 UL51 protein and role of palmitoylation in Golgi apparatus targeting 下载免费PDF全文
Nozawa N Daikoku T Koshizuka T Yamauchi Y Yoshikawa T Nishiyama Y 《Journal of virology》2003,77(5):3204-3216
The herpes simplex virus type 1 (HSV-1) UL51 gene products are virion-associated phosphoproteins with apparent molecular masses of 27, 29, and 30 kDa in HSV-1-infected cells. In this study, we have investigated the intracellular localization and distribution of UL51 protein both in infected cells and in transfected cells expressing only UL51. We found that this protein colocalized closely with Golgi marker proteins such as the Golgi-58K protein and GM130 in transfected cells expressing only UL51. However, in infected cells, the UL51 protein localized to the juxtanuclear region but only partially colocalized with the Golgi maker proteins. Mutant protein analysis revealed that the N-terminal 15 amino acid residues of the UL51 protein sufficed for this Golgi localization property. The UL51 protein redistributed on addition of brefeldin A. This was prevented by pretreatment with 2-deoxyglucose and sodium azide, which results in ATP depletion, but not by pretreatment with NaF and AlCl(3), which activates heterotrimeric G proteins. Moreover, we found that palmitoylation of the UL51 protein through the N-terminal cysteine at position 9 was necessary for its Golgi localization. Protease digestion analysis suggested that the UL51 protein localized on the cytoplasmic face of the membrane in UL51-transfected cells, while in infected cells it localized mainly to the inside of cytoplasmic vesicles and/or the viral envelope. Transmission immunoelectron microscopy revealed an association of UL51 protein-specific labeling with cytoplasmic virions and also with some membranous structure. We infer from these observations that internalization of UL51 protein into the cytoplasmic vesicle and/or virion may occur in association with viral envelopment in HSV-infected cells. 相似文献
984.
Huda MN Chen J Morita Y Kuroda T Mizushima T Tsuchiya T 《Microbiology and immunology》2003,47(6):419-427
We cloned a DNA fragment responsible for drug resistance from chromosome of Vibrio cholerae non-O1. Nucleotide sequence analysis of this fragment revealed the presence of a single open reading frame encoding a protein consisting of 445 amino acid residues. We designated the gene as vcrM. Hydropathy analysis of the deduced amino acid sequence of VcrM suggests the presence of 12 trans-membrane segments. A dendrogram showed that VcrM is a member of the DinF-subfamily within the MATE family of multidrug efflux pumps. Expression of the cloned vcrM gene in drug-hypersensitive Escherichia coli KAM32 cells made them resistant to acriflavine, 4', 6-diamidino-2-phenylindole, Hoechst 33342, rhodamine 6G, tetraphenylphosphonium chloride (TPPCl) and ethidium bromide. Efflux of acriflavine due to VcrM was dependent on Na+ or Li+. Moreover, Na+ efflux was observed with VcrM when TPPCl was added to Na+-loaded cells. Therefore, we conclude that VcrM is a Na+/drug antiporter-type multidrug efflux pump. 相似文献
985.
Intracellular free Ca(2+) regulates diverse cellular processes, including membrane potential, neurotransmitter release, and gene expression. To examine the cellular mechanisms underlying the generation of circadian rhythms, nucleus-targeted and untargeted cDNAs encoding a Ca(2+)-sensitive fluorescent protein (cameleon) were transfected into organotypic cultures of mouse suprachiasmatic nucleus (SCN), the primary circadian pacemaker. Circadian rhythms in cytosolic but not nuclear Ca(2+) concentration were observed in SCN neurons. The cytosolic Ca(2+) rhythm period matched the circadian multiple-unit-activity (MUA)-rhythm period monitored using a multiple-electrode array, with a mean advance in phase of 4 hr. Tetrodotoxin blocked MUA, but not Ca(2+) rhythms, while ryanodine damped both Ca(2+) and MUA rhythms. These results demonstrate cytosolic Ca(2+) rhythms regulated by the release of Ca(2+) from ryanodine-sensitive stores in SCN neurons. 相似文献
986.
Imai S Kanamoto R Yagi I Kotaru M Saeki T Iwami K 《Bioscience, biotechnology, and biochemistry》2003,67(2):383-387
Growing and mature rats were examined for the effect of a change in dietary protein requirements on the induction of liver serine dehydratase (SDH). The rats were fed on diets varying in casein content, and the weight change and nitrogen balance was determined. SDH activity and its gene expression were induced in both growing and mature rats when their protein intake exceeded their nutritional requirements. 相似文献
987.
988.
Mawatari S Ohnishi Y Kaji Y Maruyama T Murakami K Tsutsui K Fujino T 《Bioscience, biotechnology, and biochemistry》2003,67(7):1457-1464
Effects of high dietary cholesterol on erythrocyte membrane lipids were studied. Feeding rats with a diet containing 0.5% cholesterol and 0.15% sodium cholate for two weeks induced changes in erythrocyte membrane lipids including a decrease in cholesterol, an increase in alpha-tocopherol (alpha-Toc) and changes in the fatty acid composition of phospholipids. Oleic acid and linoleic acid increased, while arachidonic acid decreased in phosphatidylcholine. Saturated fatty acids decreased and unsaturated fatty acids increased in phosphatidylethanolamine. Almost the same changes in membrane lipids were also noted after six weeks of feeding rats with the diet. A diet containing 0.5% cholesterol but without sodium cholate caused a decrease in erythrocyte cholesterol and an increase in erythrocyte alpha-Toc after two weeks of feeding, as compared to the basal diet, indicating that high dietary cholesterol, but not sodium cholate, was responsible for these changes in the erythrocyte membrane. 相似文献
989.
Hibino G Nadamoto T Fujisawa F Fushiki T 《Bioscience, biotechnology, and biochemistry》2003,67(1):23-28
We investigated whether the ingestion of the Japanese persimmon (kaki, Diospyros kaki) could lower the human peripheral body temperature. It was found that the temperatures recorded at the foot and wrist were depressed after kaki consumption compared to after the same amount of water consumption. The effects of ingesting freeze-dried kaki and eating a cookie (as its nutritional counterpart) containing the same amount of carbohydrate, protein, fat, and water were compared. A similar temperature-reducing effect of kaki was observed. The recovery of finger temperature after soaking the finger in ice-cooled water was also studied. The temperature recovery was delayed after kaki consumption. It was thus quantitatively demonstrated that ingesting kaki indeed had the effect of lowering (or repressing the rise) of the peripheral human body temperature, as has been traditionally believed in China for many hundreds of years. 相似文献
990.
Summary. The nucleotide sequence of cDNA that encodes hamster d-amino-acid oxidase (DAO) was determined. The cDNA consisted of 1,590 nucleotides and a poly(A) tail. It had an open reading
frame for a protein consisting of 346 amino acid residues. The number of the amino acid residues is the same as that of the
rat DAO. However, the hamster DAO has one residue more than mouse DAO and one residue less than human, pig, rabbit, and guinea
pig DAOs. Amino acid sequence of the hamster DAO was highly similar to those of mouse and rat DAOs: 89% and 88% of the amino
acid residues were identical between the hamster and mouse DAOs and between the hamster and rat DAOs, respectively. The homology
was slightly less between the hamster DAO and the human (81%), pig (78%), rabbit (78%), or guinea pig DAO (82%). It has been
proposed that the mouse and rat DAOs lack an amino acid residue corresponding to the 25th residue of the DAOs of other mammals.
However, a detailed comparison of the amino acid sequences as well as the underlying nucleotide sequences by inclusion of
the hamster ones revealed that the rodent DAOs does not lack the 25th, but the 27th residue.
Received January 16, 2002 Accepted June 20, 2002 Published online November 14, 2002
Authors' address: Dr. Ryuichi Konno, Department of Microbiology, Dokkyo University School of Medicine, Mibu, Tochigi 321-0293, Japan, Fax:
+81-282-86-5616 相似文献