全文获取类型
收费全文 | 2561篇 |
免费 | 147篇 |
国内免费 | 1篇 |
出版年
2022年 | 10篇 |
2021年 | 23篇 |
2020年 | 11篇 |
2019年 | 19篇 |
2018年 | 24篇 |
2017年 | 39篇 |
2016年 | 47篇 |
2015年 | 78篇 |
2014年 | 93篇 |
2013年 | 248篇 |
2012年 | 142篇 |
2011年 | 130篇 |
2010年 | 109篇 |
2009年 | 96篇 |
2008年 | 163篇 |
2007年 | 176篇 |
2006年 | 201篇 |
2005年 | 176篇 |
2004年 | 186篇 |
2003年 | 156篇 |
2002年 | 127篇 |
2001年 | 18篇 |
2000年 | 14篇 |
1999年 | 29篇 |
1998年 | 27篇 |
1997年 | 27篇 |
1996年 | 27篇 |
1995年 | 27篇 |
1994年 | 30篇 |
1993年 | 24篇 |
1992年 | 23篇 |
1991年 | 17篇 |
1990年 | 21篇 |
1989年 | 11篇 |
1988年 | 21篇 |
1987年 | 13篇 |
1986年 | 10篇 |
1985年 | 15篇 |
1984年 | 15篇 |
1983年 | 7篇 |
1982年 | 11篇 |
1981年 | 14篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1978年 | 9篇 |
1977年 | 5篇 |
1976年 | 9篇 |
1975年 | 6篇 |
1974年 | 3篇 |
1973年 | 3篇 |
排序方式: 共有2709条查询结果,搜索用时 156 毫秒
101.
Akiko Shibui Ayako Takamori Mohammed E.M. Tolba Aya Nambu Eri Shimura Sachiko Yamaguchi Chizu Sanjoba Hajime Suto Katsuko Sudo Ko Okumura Sumio Sugano Hideaki Morita Hirohisa Saito Kenji Matsumoto Susumu Nakae 《Biochemistry and Biophysics Reports》2016
IL-25, IL-33 and TSLP, which are produced predominantly by epithelial cells, can induce production of Th2-type cytokines such as IL-4, IL-5 and/or IL-13 by various types of cells, suggesting their involvement in induction of Th2-type cytokine-associated immune responses. It is known that Th2-type cytokines contribute to host defense against malaria parasite infection in mice. However, the roles of IL-25, IL-33 and TSLP in malaria parasite infection remain unclear. Thus, to elucidate this, we infected wild-type, IL-25?/?, IL-33?/? and TSLP receptor (TSLPR)?/? mice with Plasmodium berghei (P. berghei) ANKA, a murine malaria strain. The expression levels of IL-25, IL-33 and TSLP mRNA were changed in the brain, liver, lung and spleen of wild-type mice after infection, suggesting that these cytokines are involved in host defense against P. berghei ANKA. However, the incidence of parasitemia and survival in the mutant mice were comparable to in the wild-type mice. These findings indicate that IL-25, IL-33 and TSLP are not critical for host defense against P. berghei ANKA. 相似文献
102.
Mikako Saito Asako Kaneda Hajime Shigeto Nobuaki Hanata Keiko Otokuni Hideaki Matsuoka 《Cytotechnology》2016,68(4):987-998
In order to produce insulin-secreting cells with a high value of glucose-stimulated insulin secretion (GSIS) from mouse embryonic stem cells, we have developed an optimized 5-stage protocol by referring to culture conditions so far reported elsewhere. This protocol is characterized by 4 points: (1) use of an activin-free medium in the first stage, (2) use of gelatin/fibronectin coated culture dishes in 1–4 stages throughout, (3) removal of undifferentiated cells by cell sorter at the end of 4th stage, and (4) sedimental culture in the 5th stage. GSIS value of the produced cells reached 2.4, that was at a higher rank of those so far reported. The produced cells were transplanted in diabetes model mice but no remedy effect was observed. Then transplantation was conducted in pre-diabetes model mice, in which GSIS was impaired without affecting insulin producing function. The transplantation of 5 × 106 cells resulted in a marked improvement of glucose tolerance within 20 days. This effect decreased but was still observed at 120 days post-transplantation. This demonstrates the feasibility of the novel optimized protocol. 相似文献
103.
Takefumi Yamashita Eiichi Mizohata Satoru Nagatoishi Takahiro Watanabe Makoto Nakakido Hiroko Iwanari Yasuhiro Mochizuki Taisuke Nakayama Yuji Kado Yuki Yokota Hiroyoshi Matsumura Takeshi Kawamura Tatsuhiko Kodama Takao Hamakubo Tsuyoshi Inoue Hideaki Fujitani Kouhei Tsumoto 《Structure (London, England : 1993)》2019,27(3):519-527.e5
104.
Koyama Satoshi Fujita Hiroyuki Shimosato Takeshi Kamijo Aki Ishiyama Yasufumi Yamamoto Eri Ishii Yoshimi Hattori Yukako Hagihara Maki Yamazaki Etsuko Tomita Naoto Nakajima Hideaki 《Probiotics and antimicrobial proteins》2019,11(1):295-298
Probiotics and Antimicrobial Proteins - Probiotic-rich foods are consumed without much restriction. We report here, a case of septic shock caused by yogurt derived Lactobacillus species in a... 相似文献
105.
The objective of this study was to develop an ideal freezing extender and method for rat epididymal sperm cryopreservation. Epididymal sperm collected from 30 Wistar males was frozen, and experiments were conducted to study its post-thaw characteristics when freezing with raffinose-free buffer or various concentrations of raffinose and egg yolk dissolved in distilled and deionised water, PBS, or modified Krebs–Ringer bicarbonate (mKRB)-based extender. Different concentrations of glycerol, Equex STM, or sodium dodecyl sulfate (SDS) dissolved in either PBS or mKRB containing egg yolk were also tested. Based on the data from these experiments, further experiments tested how different sugars such as raffinose, trehalose, lactose, fructose, and glucose dissolved in mKRB with Equex STM, SDS and egg yolk supplementation affected the post-thaw characteristics of cryopreserved sperm. Cryosurvival of frozen-thawed sperm were judged by microscopic assessment of the sperm motility index (SMI), and acrosome integrity was measured using FITC-PNA staining. Thawed sperm were subjected to 3 h of a thermal resistance test. Beneficial effects on the post-thaw survival of sperm were obtained when 0.1 M raffinose in mKRB was used with 0.75% Equex STM, 0.05% SDS, and 20% egg yolk. Sperm cryopreserved with this treatment exhibited a higher motility index and maintained greater SMI and acrosome integrity throughout incubation when compared to sperm frozen in various concentrations of other cryoprotectants and trehalose, lactose, fructose, glucose. In conclusion, cryopreservation in an extender solution of raffinose dissolved in mKRB containing Equex STM, SDS and egg yolk greatly enhances the freezability of rat epididymal sperm. 相似文献
106.
This protocol details a method for monitoring glucose uptake into single, living mammalian cells using a fluorescent D-glucose derivative, 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-D-glucose (2-NBDG), as a tracer. The specifically designed chamber and superfusion system for evaluating 2-NBDG uptake into cells in real time can be combined with other fluorescent methods such as Ca2+ imaging and the subsequent immunofluorescent classification of cells exhibiting divergent 2-NBDG uptake. The whole protocol, including immunocytochemistry, can be completed within 2 d (except for cell culture). The procedure for 2-NBDG synthesis is also presented. 相似文献
107.
Polyglutamine (polyQ) expansion mutation causes conformational, neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases. These diseases are characterized by the aggregation of misfolded proteins, such as amyloid fibrils, which are toxic to cells. Amyloid fibrils are formed by a nucleated growth polymerization reaction. Unexpectedly, the critical nucleus of polyQ aggregation was found to be a monomer, suggesting that the rate-limiting nucleation process of polyQ aggregation involves the folding of mutated protein monomers. The monoclonal antibody 1C2 selectively recognizes expanded pathogenic and aggregate-prone glutamine repeats in polyQ diseases, including Huntington's disease (HD), as well as binding to polyleucine. We have therefore assayed the in vitro and in vivo aggregation kinetics of these monomeric proteins. We found that the repeat-length-dependent differences in aggregation lag times of variable lengths of polyQ and polyleucine tracts were consistently related to the integration of the length-dependent intensity of anti-1C2 signal on soluble monomers of these proteins. Surprisingly, the correlation between the aggregation lag times of polyQ tracts and the intensity of anti-1C2 signal on soluble monomers of huntingtin precisely reflected the repeat-length dependent age-of-onset of HD patients. These data suggest that the alterations in protein surface structure due to polyQ expansion mutation in soluble monomers of the mutated proteins act as an amyloid-precursor epitope. This, in turn, leads to nucleation, a key process in protein aggregation, thereby determining HD onset. These findings provide new insight into the gain-of-function mechanisms of polyQ diseases, in which polyQ expansion leads to nucleation rather than having toxic effects on the cells. 相似文献
108.
Hajime HRAMATSU Kiyoshi KYONO Atsushi YAMAMOTO Kazuhiko SAEKI Hideaki SHIMA Shigeru SUGIYAMA 《Acta biochimica et biophysica Sinica》2007,(5)
Dipeptidyl peptidase Ⅳ (DPPIV), which belongs to the prolyl oligopeptidase family of serine proteases, is known to have a variety of regulatory biological functions and has been shown to be implicated in type 2 diabetes. It is therefore important to develop selective human DPPIV (hDPPIV) inhibitors. In this study, we determined the crystal structure of apo hDPPIV at 1.9 A resolution. Our high-resolution crystal structure of apo hDPPIV revealed the presence of sodium ion and glycerol molecules at the active site. In order to elucidate the hDPPIV binding mode and substrate specificity, we determined the crystal structure of hDPPIV-diprotin B (Val-Pro-Leu) complex at 2.1 A resolution, and clarified the difference in binding mode between diprotin B and diprotin A (Ile-Pro-Ile) into the active site of hDPPIV. Comparison between our crystal structures and the reported apo hDPPIV structures revealed that positively charged functional groups and conserved water molecules contributed to the interaction of ligands with hDPPIV. These results are useful for the design of potent hDPPIV inhibitors. 相似文献
109.
Hirotoshi Motoda Takayuki Sasaki Yoshio Kano Peter R Ryan Emmanuel Delhaize Hideaki Matsumoto Yoko Yamamoto 《Plant signaling & behavior》2007,2(6):467-472
The wheat ALMT1 gene encodes an aluminum (Al)-activated malate transport protein which confers Al-resistance. We investigated the membrane topology of this plasma-membrane localized protein with immunocytochemical techniques. Several green fluorescent protein (GFP)-fused and histidine (His)-tagged chimeras of ALMT1 were prepared based on a computer-predicted secondary structure and transiently expressed in cultured mammalian cells. Antibodies raised to polypeptide epitopes of ALMT1 were used in conjunction with the antibody to the His-tags to determine the topology of ALMT1. This study shows that the ALMT1 protein contains six transmembrane domains with the amino and carboxyl termini located on the extracellular side of the plasma membrane.Key Words: ALMT1, aluminum resistance, immunofluorescent staining, malate transporter, topology, Triticum aestivum 相似文献
110.
Tanida Kotomi Shimada Mihoko Khor Seik-Soon Toyoda Hiromi Kato Kayoko Kotorii Nozomu Kotorii Tatayu Ariyoshi Yu Kato Takao Hiejima Hiroshi Ozone Motohiro Uchimura Naohisa Ikegami Azusa Kume Kazuhiko Kanbayashi Takashi Imanishi Aya Kamei Yuichi Hida Akiko Wada Yamato Kuroda Kenji Miyamoto Masayuki Hirata Koichi Takami Masanori Yamada Naoto Okawa Masako Omata Naoto Kondo Hideaki Kodama Tohru Inoue Yuichi Mishima Kazuo Honda Makoto Tokunaga Katsushi Miyagawa Taku 《Sleep and biological rhythms》2022,20(1):137-148
Sleep and Biological Rhythms - Idiopathic hypersomnia (IH) is a rare sleep disorder characterized by excessive daytime sleepiness, great difficulty upon awakening, and prolonged sleep time. In... 相似文献