全文获取类型
收费全文 | 746篇 |
免费 | 36篇 |
出版年
2023年 | 2篇 |
2021年 | 7篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 11篇 |
2017年 | 6篇 |
2016年 | 10篇 |
2015年 | 18篇 |
2014年 | 19篇 |
2013年 | 56篇 |
2012年 | 46篇 |
2011年 | 57篇 |
2010年 | 30篇 |
2009年 | 27篇 |
2008年 | 37篇 |
2007年 | 44篇 |
2006年 | 49篇 |
2005年 | 46篇 |
2004年 | 56篇 |
2003年 | 48篇 |
2002年 | 51篇 |
2001年 | 9篇 |
2000年 | 10篇 |
1999年 | 8篇 |
1998年 | 21篇 |
1997年 | 9篇 |
1996年 | 11篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 2篇 |
1976年 | 3篇 |
1975年 | 5篇 |
1974年 | 1篇 |
1969年 | 1篇 |
1965年 | 1篇 |
1963年 | 2篇 |
1961年 | 1篇 |
排序方式: 共有782条查询结果,搜索用时 15 毫秒
111.
Remote sensing technologies have been advanced continuously to a certain level for multi-scale applications to ease social and political concerns resulting from food security. In this study, an integrated monitoring, sensing and modeling system for estimating CO2 fixation and grain yields using a photosynthetic sterility model was developed. Input data for model computation include observed meteorological data, numerical prediction reanalysis data, and satellite data such as solar radiation, land-cover and Normalized Difference Vegetation Index (NDVI) on a continental scale. Model validation requires crop yields and the Crop Situation Index (CSI) was provided by the Japanese government. It also demonstrates the application potential of this system to grain fields of paddy rice, winter wheat, and maize in Southeast Asia. The carbon hydrate in grains has the same chemical formula as that of cellulose in grain vegetation. The partition of sequestered CO2 into grain, straw, and root portions of plant biomass weight was computed. The present photosynthesis model was evaluated using the mass of carbon included in the harvested grains of provincial crop production. Results indicate that the proposed system successfully estimates the photosynthesis fixation of rice reasonably well in Japan and China through the analysis of carbon in grains. However, the model tends to underestimate the photosynthesis rates for winter wheat and maize. The parameterization of radiation response function and the temperature response functions for low-temperature sterility need to be improved in the future. 相似文献
112.
Atsuhiro Matsumoto Takanori Kanai Yohei Mikami Po–Sung Chu Nobuhiro Nakamoto Hirotoshi Ebinuma Hidetsugu Saito Toshiro Sato Hideo Yagita Toshifumi Hibi 《PloS one》2013,8(4)
Retinoid-related orphan receptor (ROR) γt is known to be related to the development and function of various immunological compartments in the liver, such as Th17 cells, natural killer T (NKT) cells, and innate lymphoid cells (ILCs). We evaluated the roles of RORγt-expressing cells in mouse acute hepatitis model using RORγt deficient (RORγt−/−) mice and RAG-2 and RORγt double deficient (RAG-2−/− × RORγt−/−) mice. Acute hepatitis was induced in mice by injection with carbon tetrachloride (CCl4), to investigate the regulation of liver inflammation by RORγt-expressing cells. We detected RORC expression in three compartments, CD4+ T cells, NKT cells, and lineage marker-negative SCA-1+Thy1high ILCs, of the liver of wild type (WT) mice. CCl4-treated RORγt−/− mice developed liver damage in spite of lack of RORγt-dependent cells, but with reduced infiltration of macrophages compared with WT mice. In this regard, ILCs were significantly decreased in RAG-2−/− × RORγt−/− mice that lacked T and NKT cells. Surprisingly, RAG-2−/− × RORγt−/− mice developed significantly severer CCl4-induced hepatitis compared with RAG-2−/− mice, in accordance with the fact that hepatic ILCs failed to produce IL-22. Lastly, anti-Thy1 monoclonal antibody (mAb), but not anti-NK1.1 mAb or anti-asialo GM1 Ab administration exacerbated liver damage in RAG-2−/− mice with the depletion of liver ILCs. Collectively, hepatic RORγt-dependent ILCs play a part of protective roles in hepatic immune response in mice. 相似文献
113.
Nathan D. Mathewson Orr Ashenberg Itay Tirosh Simon Gritsch Elizabeth M. Perez Sascha Marx Livnat Jerby-Arnon Rony Chanoch-Myers Toshiro Hara Alyssa R. Richman Yoshinaga Ito Jason Pyrdol Mirco Friedrich Kathrin Schumann Michael J. Poitras Prafulla C. Gokhale L. Nicolas Gonzalez Castro Marni E. Shore Kai W. Wucherpfennig 《Cell》2021,184(5):1281-1298.e26
114.
115.
Kazuko Iwamoto Shuichi Kamo Yuichi Takada Ayana Ieda Takatoshi Yamashita Toshiro Sato Nobuhiro Zaima Tatsuya Moriyama 《Biochemistry and Biophysics Reports》2018
Soyasapogenol is a soyasaponin aglycone, which has been suggested to exert a more potent function than the glycoside form. In this study, the effect of soyasapogenol A and B on cultured adipocyte cell function was investigated using mouse 3T3-L1 adipocyte cells. 3T3-L1 cells were treated with insulin, dexamethasone, and 3-isobutyl-1-methylxanthine for differentiation to adipocytes, and the cells were then cultured in the presence of soyasapogenol A or B (6.25 or 12.5 µM). The media were harvested and refreshed every 2 d. After a 10 d culture, the cells were harvested and the triglyceride content of the cells was determined. The triglyceride content of soyasapogenol B-treated cells was significantly lower than those of vehicle-treated cells. Glycerol and free fatty acid levels in the soyasapogenol-treated cell media were higher than those in vehicle cells. However, there was no difference in the level of adipose triglyceride lipase among soyasapogenol A-, soyasapogenol B-, and vehicle-treated cells. The secreted adiponectin and resistin levels of soyasapogenol-treated cell media were also different compared with those of vehicle-treated cells. Especially, the secreted resistin level in soyasapogenol B-treated cell media was obviously reduced compared with that of vehicle-treated cells. Taken together, these results suggest that soyasapogenol B exerted an anti-obesity and anti-diabetic effect on adipocytes by lowering the cellular triglyceride level by accelerating triglyceride lipolysis with reduced resistin secretion. 相似文献
116.
117.
Takashi Seino Shintaro Kawasaki Mariko Shimokawa Hiroki Tamagawa Kohta Toshimitsu Masayuki Fujii Yuki Ohta Mami Matano Kosaku Nanki Kenta Kawasaki Sirirat Takahashi Shinya Sugimoto Eisuke Iwasaki Junichi Takagi Takao Itoi Minoru Kitago Yuko Kitagawa Takanori Kanai Toshiro Sato 《Cell Stem Cell》2018,22(3):454-467.e6
118.
Plasma and erythrocyte enzyme activities were measured in ddY mice supplemented with dietary selenium (Se) from baker's yeast (Saccharomyces serevisiae) or selenious acid at 0.3 ppm Se content. Glutathione peroxidase (GSHpx) activities increased significantly in erythrocytes from mice supplemented with dietary Se. It was concluded that addition of dietary Se as food additive is very effective for activation of GSHpx in mice. 相似文献
119.
Reported is the preparation of wheat germ (WG) hydrolyzate with potent angiotensin I‐converting enzyme (ACE) inhibitory activity, and the characterization of peptides responsible for ACE inhibition. Successful hydrolyzate with the most potent ACE inhibitory activity was obtained by 0.5 wt.%–8 h Bacillus licheniformis alkaline protease hydrolysis after 3.0 wt.%–3 h α‐amylase treatment of defatted WG (IC50; 0.37 mg protein ml−1). The activity of WG hydrolyzate was markedly increased by ODS and subsequent AG50W purifications (IC50; 0.018 mg protein ml−1). As a result of isolations by high performance liquid chromatographies, 16 peptides with the IC50 value of less than 20 μm , composed of 2–7 amino acid residues were identified from the WG hydrolyzate. Judging from the high content (260 mg in 100 g of AG50W fraction) and powerful ACE inhibitory activity (IC50; 0.48 μm ), Ile‐Val‐Tyr was identified as a main contributor to the ACE inhibition of the hydrolyzate. Copyright © 1999 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
120.
Hiroyama T Sudo K Aoki N Miharada K Danjo I Fujioka T Nagasawa T Nakamura Y 《Cell biology international》2008,32(1):1-7
Clinical application of human embryonic stem (ES) cells will require the establishment of methods for their culture, either in the presence or absence of human-derived feeder cells. We have tested the ability of non-immortalized cultured cells derived from human umbilical cord (HUC cells) to support ES cell culture. A primate ES cell line that had been established and maintained with mouse embryonic fibroblasts was cultured on HUC cells for >3 months (HUC-maintained ES cells). These cells retained their expression of alkaline phosphatase, SSEA-4, Oct-3/4, and to a lesser extent Nanog, but did not express Rex-1. Nevertheless, HUC-maintained ES cells could produce ectoderm-, mesoderm- and endoderm-derived cells in teratomata that they formed in immunodeficient mice. We show that HUC-maintained ES cells could give rise to hematopoietic cells, although this ability of HUC cells varied among HUC cell populations derived from different neonates. HUC cells are promising as human material with which to maintain ES cells in a state that retains their ability to produce mature cells, including hematopoietic cells. 相似文献