全文获取类型
收费全文 | 2212篇 |
免费 | 127篇 |
国内免费 | 2篇 |
出版年
2023年 | 3篇 |
2022年 | 14篇 |
2021年 | 28篇 |
2020年 | 11篇 |
2019年 | 19篇 |
2018年 | 55篇 |
2017年 | 23篇 |
2016年 | 36篇 |
2015年 | 68篇 |
2014年 | 85篇 |
2013年 | 139篇 |
2012年 | 154篇 |
2011年 | 137篇 |
2010年 | 114篇 |
2009年 | 103篇 |
2008年 | 140篇 |
2007年 | 171篇 |
2006年 | 160篇 |
2005年 | 130篇 |
2004年 | 139篇 |
2003年 | 118篇 |
2002年 | 153篇 |
2001年 | 20篇 |
2000年 | 18篇 |
1999年 | 23篇 |
1998年 | 37篇 |
1997年 | 27篇 |
1996年 | 24篇 |
1995年 | 14篇 |
1994年 | 18篇 |
1993年 | 19篇 |
1992年 | 14篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 11篇 |
1988年 | 10篇 |
1987年 | 9篇 |
1986年 | 3篇 |
1985年 | 9篇 |
1984年 | 10篇 |
1983年 | 4篇 |
1982年 | 12篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1975年 | 5篇 |
1971年 | 3篇 |
1966年 | 2篇 |
1963年 | 2篇 |
排序方式: 共有2341条查询结果,搜索用时 24 毫秒
171.
172.
Ohnishi Y Nagase M Ichiyanagi T Kitamoto Y Aimi T 《Applied microbiology and biotechnology》2007,76(5):1069-1078
173.
Hayashi A Aoyagi H Kinjyo K Yoshimura T Tanaka H 《Applied microbiology and biotechnology》2007,75(6):1437-1446
Screening method of microorganisms that utilized the symbiotic association between insect (Nasutitermes takasagoensis: Nt) and intestinal microorganisms was developed. The existence of desired microorganisms that grew by degrading difficult-to-degrade
materials in the gut was detected using survivability of Nt as an indicator. The desired microorganisms were isolated from
the survived Nt. It was thought that guts of Nt behave as continuous culture systems whereby microorganisms that cannot degrade
diet components are washed out, whereas those that can degrade it are retained and concentrated in the gut. About 60% of Nt
fed with phenol artificial diet (PAD) died within 7 days, while 4% of termites survived for 9 days. The structure of intestinal
microorganisms of the survived Nt fed with PAD differed from the bacterial communities obtained from enrichment culture (which
contained phenol) of wood-feeding Nt. Relatively high colonies (650-times) were detected in the gut of Nt fed on phenol artificial
diet compared with those obtained when Nt was fed on wood. Seven denaturing gradient gel electrophoresis (DGGE) bands were
detected from gut of wood-feeding Nt, whereas 11 DGGE-bands were detected from that of phenol-feeding Nt. Out of 11 DGGE-bands,
5 of them were sequenced, and bacterial species including phenol-degrading bacteria were identified. 相似文献
174.
Bovine beta-lactoglobulin (betaLG) binds a variety of hydrophobic ligands, though precisely how is not clear. To understand the structural basis of this promiscuous binding, we studied the interaction of betaLG with palmitic acid (PA) using heteronuclear NMR spectroscopy. The titration was monitored using tryptophan fluorescence and a HSQC spectrum confirmed a 1:1 stoichiometry for the PA-betaLG complex. Upon the binding of PA, signal disappearances and large changes in chemical shifts were observed for the residues located at the entrance and bottom of the cavity, respectively. This observation indicates that the lower region makes a rigid connection with PA whereas the entrance is more flexible. The result is in contrast to the binding of PA to intestinal fatty acid-binding protein, another member of the calycin superfamily, in which structural consolidation occurs upon ligand binding. On the other hand, the ability of betaLG to accommodate various hydrophobic ligands resembles that of GroEL, in which a large hydrophobic cavity and flexible binding site confer the ability to bind various hydrophobic substrates. Considering these observations, it is suggested that, in addition to the presence of the hydrophobic cavity, the plasticity of the entrance region makes possible the binding of hydrophobic ligands of various shapes. Thus, in contrast to the specific binding seen for many enzymes, betaLG provides an example of binding with low specificity but high affinity, which may play an important role in protein-ligand and protein-protein networks. 相似文献
175.
176.
177.
We examined the expression profiles of vasoactive intestinal contractor/endothelin-2 (VIC/ET-2) at both gene and peptide level in skin irradiated with different ultraviolet wavelengths. We found that VIC/ET-2 gene expression is sensitive only to ultraviolet-C (UVC) irradiation and has an immediate response. These results provide direct evidence that high doses of UVC irradiation induce an increase in gene expression and protein production of VIC/ET-2 and endothelin (ET) receptors in a dose-dependent manner in epidermal keratinocytes. We suggest that VIC/ET-2 can play an essential role in the maintenance, protection and hyperpigmentation of the epidermis exposed to UVC irradiation from artificial or natural sources. 相似文献
178.
An Inhibitory Role of Nitric Oxide in the Dynamic Regulation of the Blood-Brain Barrier Function 总被引:1,自引:0,他引:1
Yamauchi A Dohgu S Nishioku T Shuto H Naito M Tsuruo T Sawada Y Kataoka Y 《Cellular and molecular neurobiology》2007,27(3):263-270
1. The present study aimed at elucidating the effect of nitric oxide (NO) on blood-brain barrier (BBB) function with mouse
brain capillary endothelial (MBEC4) cells.
2. Histamine (20–100 μM) evoked NO production (1.6–7 μM) in MBEC4 cells in a dose-dependent manner.
3. The permeability coefficient of sodium fluorescein for MBEC4 cells and the cellular accumulation of rhodamine 123 in MBEC4
cells were increased dose-dependently by the addition of NO solutions (14 and 28 μM) every 10 min during a 30-min period.
4. The present study demonstrated that NO increased the permeability and inhibited the P-glycoprotein efflux pump of brain
capillary endothelial cells, suggesting that NO plays an inhibitory role in the dynamic regulation of the BBB function. 相似文献
179.
Ishikawa T Terai S Urata Y Marumoto Y Aoyama K Murata T Mizunaga Y Yamamoto N Nishina H Shinoda K Sakaida I 《Cell and tissue research》2007,327(3):463-470
We previously reported that fibroblast growth factor 2 (FGF2) facilitated the differentiation of transplanted bone marrow
cells (BMCs) into hepatocytes. Our earlier study also demonstrated that administration of FGF2 in combination with bone marrow
transplantation (BMT) synergistically activated tumor necrosis factor-alpha signaling and significantly improved liver function
and prognosis more than BMT alone. However, the way that it affected the extracellular matrix remained unclear. Here, we investigated
the effect of FGF2 treatment together with BMT on liver fibrosis in mice treated with carbon tetrachloride (CCl4). Transplantation of BMCs and concurrent treatment with FGF2 caused a statistically significant reduction in CCl4-induced liver fibrosis that was accompanied by strong expression of matrix metalloproteinase 9 as compared with FGF2-only
treatment or BMT alone. Moreover, in this process, the proliferation of bone-marrow-derived cells was accelerated without
causing apoptosis. Thus, the administration of FGF2 in combination with BMT synergistically improves CCl4-induced liver fibrosis in mice. This treatment has the potential of being an effective therapy for patients with liver cirrhosis.
This study was supported by Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (nos. 16390211
and 16590597) and for translational research from the Ministry of Health, Labor and Welfare (H-trans-5 and H17-Special-015). 相似文献
180.
Iino N Matsunaga T Harada T Igarashi S Koyama I Komoda T 《Cell and tissue research》2007,328(2):355-363
Alkaline phosphatase (AP) isozymes are surfactant-associated proteins (SPs). Since several different AP isozymes have been
detected in the pneumocytes of lung cancer patients, we attempted to identify the relationship between pulmonary surfactant
aggregate subtypes and AP isozymes. Pulmonary surfactant aggregates were isolated from carcinoma and non-carcinoma tissues
of patients with non-small cell carcinoma of the lung. Upon analysis, ultraheavy, heavy, and light surfactant aggregates were
detected in the non-carcinoma tissues, but no ultraheavy surfactant aggregates were found in the carcinoma tissues. Surfactant-associated
protein A (SP-A) was detected as two bands (a 27-kDa band and a 54-kDa band) in the ultraheavy, heavy, and light surfactant
aggregates found in the non-carcinoma tissues. Although both SP-A bands were detected in the heavy and light surfactant aggregates
from adenocarcinoma tissues, the 54-kDa band was not detected in squamous cell carcinoma tissues. Liver AP (LAP) was detected
in the heavy and light surfactant aggregates from both non-carcinoma and squamous carcinoma tissues, but not in heavy surfactant
aggregates from adenocarcinoma tissues. A larger amount of bone type AP (BAP) was found in light surfactant aggregate fractions
from squamous cell carcinomas than those from adenocarcinoma tissues or non-carcinoma tissues from patients with either type
of cancer. LAP, BAP, and SP-A were identified immunohistochemically in type II pneumocytes from non-carcinoma tissues and
adenocarcinoma cells, but no distinct SP-A staining was observed in squamous cell carcinoma tissues. The present study has
thus revealed several differences in pulmonary surfactant aggregates and AP isozymes between adenocarcinoma tissue and squamous
cell carcinoma tissue. 相似文献