全文获取类型
收费全文 | 604篇 |
免费 | 33篇 |
专业分类
637篇 |
出版年
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 3篇 |
2016年 | 6篇 |
2015年 | 9篇 |
2014年 | 17篇 |
2013年 | 36篇 |
2012年 | 22篇 |
2011年 | 19篇 |
2010年 | 14篇 |
2009年 | 13篇 |
2008年 | 25篇 |
2007年 | 28篇 |
2006年 | 30篇 |
2005年 | 36篇 |
2004年 | 34篇 |
2003年 | 34篇 |
2002年 | 29篇 |
2001年 | 8篇 |
2000年 | 17篇 |
1999年 | 17篇 |
1998年 | 9篇 |
1997年 | 12篇 |
1995年 | 7篇 |
1994年 | 7篇 |
1993年 | 4篇 |
1992年 | 7篇 |
1991年 | 14篇 |
1990年 | 6篇 |
1989年 | 9篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 12篇 |
1985年 | 16篇 |
1984年 | 10篇 |
1983年 | 9篇 |
1982年 | 4篇 |
1981年 | 9篇 |
1980年 | 8篇 |
1979年 | 8篇 |
1978年 | 12篇 |
1977年 | 9篇 |
1976年 | 11篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1973年 | 4篇 |
1972年 | 4篇 |
1970年 | 8篇 |
1965年 | 2篇 |
排序方式: 共有637条查询结果,搜索用时 0 毫秒
31.
Tachibana T Takagi T Saito ES Tomonaga S Zhang R Koga Y Kido Y Michael Denbow D Furuse M 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2003,135(3):403-409
We examined whether the brain beta 3-adrenergic receptor (B3-AR) is involved in the feeding regulation of chicks. Intracerebroventricular (ICV) injection of BRL37344, a B3-AR agonist, reduced food intake of chicks under ad libitum, but not fasting, feeding conditions. The ICV injection of BRL37344 did not affect chick posture or locomotion activity suggesting that BRL37344 inhibited feeding without induction of sleep-like behavior as caused by norepinephrine. Furthermore, the rectal temperature increased following the ICV injection of BRL37344. Intraperitoneal administration of BRL37344 did not reduce food intake under ad libitum feeding condition. The present study demonstrated that the brain B3-AR is involved in the inhibition of feeding in chicks. We also suggested that activation of the brain affects the energy metabolism in chicks. 相似文献
32.
33.
Rozzo SJ Vyse TJ Menze K Izui S Kotzin BL 《Journal of immunology (Baltimore, Md. : 1950)》2000,164(10):5515-5521
Genes from New Zealand Black and New Zealand White mice have been implicated in the development of a disease similar to human systemic lupus erythematosus. In an attempt to define the MHC class II genes involved in disease, we previously studied similarly designed backcrosses of New Zealand Black mice with C57BL/6 (B6) mice transgenic for Ez genes or with C57BL/10 (B10) mice transgenic for Az genes. Although the transgenes showed no effect on the development of autoantibody production or lupus nephritis in either backcross, surprisingly, there was greatly increased expression of these disease traits in the backcrosses involving B10 compared with B6 mice. These studies therefore implicated genetic contributions in B10 vs B6 backgrounds, despite their 98% identity. A genome-wide linkage analysis uncovered a B10 locus on mid-chromosome 13, which enhanced nephritis and was strongly linked with the production of pathogenic retroviral gp70-anti-gp70 immune complexes when contributed by B10, but not B6, mice. The subsequent identification of a single marker polymorphic between B10 and B6, along with the extreme genetic similarity between the two strains in this region, is likely to permit expedited identification of the lupus-susceptibility gene from this nonautoimmune strain. 相似文献
34.
Murine acquired immunodeficiency syndrome (MAIDS) is characterized by lymphoproliferation, polyclonal B cell activation resulting in the production of autoantibodies, and a progressive immunodeficiency. These are all hallmarks of some autoimmune diseases. Yaa is a Y-chromosome-linked gene that accelerates autoimmune diseases in some autoimmune-prone strains of mice. To further elucidate a possible relationship with autoimmunity, the effect of the Yaa gene on MAIDS was investigated. Analysis of phenotypic and functional disease parameters revealed that Yaa does not accelerate MAIDS disease. This is probably due to the generalized activation of most or all lymphoid cells in MAIDS, which cannot be enhanced by the Yaa gene. This result is in accordance with the selective enhancing effect of the Yaa gene on the immune response against self and foreign antigens in a specific genetic background. It suggests that the autoimmune response associated with MAIDS is a secondary phenomenon. Interestingly, even in wild-type C57BL/6 mice, autoantibody production may contribute overproportionally to the hypergammaglobulinemia associated with MAIDS. 相似文献
35.
To characterize novel genes functioning specifically in mesophyll cells (MCs) or bundle sheath cells (BSCs) of C4 plants, differential screening of a maize cDNA library was conducted using 32P-labeled single-strand cDNAs prepared from MCs and bundle sheath strands (BSS) as probes. Ten genes encoding thylakoid membrane proteins in chloroplasts were identified as MC-abundant genes. These included genes for chlorophyll a/b binding proteins, plastocyanin, PsaD, PsbT, PsbR, PsbO, PsaK, PsaG, PsaN and ferredoxin. Seven genes identified as BSS-abundant genes encoded PEP carboxykinase, salt-inducible SalT homolog, heavy metal-inducible metallothionein-like protein, ABA- and drought-inducible glycine-rich protein, and three proteins of unknown function (one of which was named Bss1). In situ hybridization analyses for several selected genes revealed that mRNAs for the metallothionein-like protein and Bss1 were accumulated specifically in BSCs, and that mRNA for the SalT homolog was accumulated in vascular cells around phloem cells. Results suggest that the functional differentiation of MC chloroplasts accompany preferential expression of these small proteins in photosystem complexes and that BSCs are the major site of stress responses. 相似文献
36.
Ogawa Noriyuki; Yabuta Naohiro; Ueno Yoshihisa; Izui Katsura 《Plant & cell physiology》1998,39(10):1010-1019
Phosphoenolpyruvate carboxylase (PEPC) [EC 4.1.1.31
[EC]
] of plantsundergoes regulatory phosphorylation in response to light ornutritional conditions. However, the nature of protein kinase(s)for this phosphorylation has not yet been fully elucidated.We separated a Ca2+-requiring protein kinase from Ca2+-independentone, both of which can phosphorylate maize leaf PEPC and characterizedthe former kinase after partial purification. Several linesof evidence indicated that the kinase is one of the characteristicCa2+-dependent but calmodulin-independent protein kinase (CDPK).Although the Mr, of native CDPK was estimated to be about 100kDa by gel permeation chromatography, in situ phosphorylationassay of CDPK in a SDS-polyacrylamide gel revealed that thesubunit has an Mr of about 50 kDa suggesting dimer formationor association with other protein(s). Several kinetic parameterswere also obtained using PEPC as a substrate. Although the CDPKshowed an ability of regulatory phosphorylation (Ser-15 in maizePEPC), no significant desensitization to feedback inhibitor,malate, could be observed presumably due to low extent of phosphorylation.The kinase was not specific to PEPC but phosphorylated a varietyof synthetic peptides. The possible physiological role of thiskinase was discussed.
1Present address: NEOS Central Research Laboratory, 1-1 Ohike-machi,Kosei-cho, Shiga, 520-3213 Japan.
2Present address: Chugai Pharmaceutical Co., Ltd., 1-135 Komakado,Gotemba, 412-0038 Japan.
4N.O. and N.Y. contributed equally to this work. 相似文献
37.
Transcription of the Arabidopsis CPD gene, encoding a steroidogenic cytochrome P450, is negatively controlled by brassinosteroids 总被引:9,自引:4,他引:5
38.
Summary We have studied the frequency of trisomics in newly formed zygotes and the proportion of trisomics, k, coming from consanguineous marriages by assuming that recessive genes at a single locus or multiple loci are responsible for the induction of nondisjunction. For mitotic nondisjunction, the value of k increases as the magnitude of consanguinity of the parents increases, but the opposite relationship holds for meiotic nondisjunction. Therefore, it is important to distinguish mitotic and meiotic types in the genetic study of nondisjunction. This seems to be one of the simples tests for detecting the genetic control of nondisjunction. 相似文献
39.
Mehmet Zeynel Cilek Satoshi Hirohata Omer Faruk Hatipoglu Hiroko Ogawa Toru Miyoshi Junko Inagaki Takashi Ohtsuki Hiroshi Harada Shigeshi Kamikawa Shozo Kusachi Yoshifumi Ninomiya 《Cell biology international》2011,35(1):1-8
ADAMTS1 (a disintegrin and metalloproteinase with thrombospondin motifs 1) is an early immediate gene. We have previously reported that ADAMTS1 was strongly induced by hypoxia. In this study, we investigated whether ADAMTS1 promoter‐driven reporter signal is detectable by acute hypoxia. We constructed the GFP (green fluorescent protein) expression vector [AHR (acute hypoxia‐response sequence)‐GFP] under the control of ADAMTS1 promoter and compared it with the constitutive GFP‐expressing vector under the control of CMV (cytomegalovirus promoter‐GFP). We transduced AHR‐GFP and examined whether GFP signals can be detected under the acute hypoxia. When the human umbilical vein [HUVEC (human umbilical vein endothelial cells)] was transduced under normoxia, there were few GFP signals, while CMV‐GFP showed considerable GFP signals. When HUVEC was stimulated with hypoxia, GFP signals from AHR‐GFP gene were induced under hypoxic conditions. Notably, the GFP signals peaked at 3 h under hypoxia. In ischaemic hind limb model, transduced AHR‐GFP showed hypoxic induction of GFP signals. In summary, we have demonstrated that the AHR system induced the reporter gene expression by acute hypoxia, and its induction is transient. This is the first report showing the unique acute hypoxia‐activated gene expression system. 相似文献
40.
Naoya Yoshihara Taiji Sakamoto Takehiro Yamashita Toshifumi Yamashita Keita Yamakiri Shozo Sonoda Tatsuro Ishibashi 《PloS one》2015,10(4)