全文获取类型
收费全文 | 509篇 |
免费 | 49篇 |
专业分类
558篇 |
出版年
2022年 | 11篇 |
2021年 | 14篇 |
2020年 | 8篇 |
2019年 | 8篇 |
2018年 | 17篇 |
2017年 | 16篇 |
2016年 | 21篇 |
2015年 | 30篇 |
2014年 | 24篇 |
2013年 | 26篇 |
2012年 | 40篇 |
2011年 | 39篇 |
2010年 | 19篇 |
2009年 | 17篇 |
2008年 | 29篇 |
2007年 | 25篇 |
2006年 | 15篇 |
2005年 | 14篇 |
2004年 | 15篇 |
2003年 | 12篇 |
2002年 | 12篇 |
2001年 | 10篇 |
2000年 | 10篇 |
1999年 | 5篇 |
1997年 | 3篇 |
1995年 | 4篇 |
1993年 | 3篇 |
1992年 | 9篇 |
1990年 | 7篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1978年 | 7篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1975年 | 7篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 3篇 |
1971年 | 5篇 |
1970年 | 7篇 |
1969年 | 3篇 |
1968年 | 2篇 |
1967年 | 3篇 |
1966年 | 4篇 |
排序方式: 共有558条查询结果,搜索用时 15 毫秒
91.
The binding of estradiol-horseradish peroxidase conjugate to rat uterine cytosolic estrogen receptor was studied. The conjugate having a steroid to enzyme ratio of 2.8:1 was allowed to bind to protamine precipitated receptor in presence or absence of 100-fold excess of free estradiol. The bound enzyme activity was measured and the data subjected to Scatchard analysis to obtain the dissociation constant and the number of binding sites. Although the binding parameter so obtained differed from values obtained using radiolabelled estradiol, the method may be used for comparative studies. 相似文献
92.
93.
The near ultraviolet and visible light (VL) impinging at an intensity of 2-5 x 10(2) J s-1 m-2 for 2-5 h kills the mitotic and the early S-phase (0- to 15-min-old) amoebae. At the mid- and late S-period only a fraction of cells are killed by VL and G2 phase cells are quite resistant. Amoebae of all cell cycle stages show a delay in the first mitotic division. DNA synthesis, as measured by [3H]thymidine incorporation, is depressed in the VL-exposed early-S amoebae. A concurrent but temporary inhibition in [3H]leucine incorporation also occurs in these cells. However, no significant change in [3H]uridine incorporation has been found. To localize the site of lethal damage, nuclear transplantation studies were undertaken between the control amoebae and the amoebae treated with VL. The nucleus of a VL-exposed early S-phase cell recovers when transplanted immediately after VL exposure into an enucleate G2 cytoplasm but dies if grafted into an enucleat S-phase cytoplasm. The therapeutic effect of the G2 cytoplasm, although at a lower level, is also evident even when the treated early S-phase nucleus is implanted 20 h later, but not after 48 h, into the G2 cytoplasm. The amoeba cytoplasm shows resistance to VL-irradiation, can accept a control nucleus from any cell cycle stage, and function normally. The G2 nucleus also remains apparently unaffected to VL exposure and can survive when it is transfered to the control cytoplasm of any cell-cycle phase. All these findings are discussed in the light of the possible existence of a repair system against VL-induced damage in the G2-phase amoeba. 相似文献
94.
J K Bhattacharjee A F Tucci M Strassman 《Archives of biochemistry and biophysics》1968,123(2):235-239
95.
96.
Homogeneous murine myeloma immunoglobulins (IgA, kappa), M 384, and M 870, bind methyl alpha-D-galactopyranoside and phosphorylcholine at different subsites. Heterologous recombinant immunoglobulins of these two immunoglobulins with M 603 (a homogeneous IgA, kappa with known phosphorylcholine specificity) also bind phosphorylcholine. 相似文献
97.
The present work makes an effort to assess and standardize some redox metabolic and molecular parameters for screening drought tolerant indigenous aromatic rice cultivars of West Bengal, India. PEG-induced dehydration stress during early germination caused disruption of redox-homeostasis and oxidative damage in four IARVs (Jamainadu, Tulaipanji, Sitabhog and Badshabhog) by enhancing the accumulation of pro-oxidants [assessed in terms of oxidation of 2′,7′-dichlorofluorescindiacetate (DCFDA), accumulation of \({\text{O}}_{2}^{ \cdot - }\) and H2O2 and in situ staining of reactive oxygen species (ROS) in germinating tissue], significant reduction of antioxidative defence (total antioxidant and radical scavenging capacity, total thiol content and activities of antioxidative defence enzymes) and aggravating protein oxidation and lipid peroxidation (assessed in terms of free carbonyl content and accumulation of thiobarbituric acid reactive substances). When compared between the indigenous aromatic rice cultivars, a clear trend in differential redox regulatory properties in which ROS-antioxidant interaction acts at metabolic interface for redox homeostasis was observed in the order Badshabhog > Tulaipanji > Sitabhog > Jamainadu. Moreover, when the efficacy of ascorbate–glutathione cycle for scavenging H2O2 generated during dehydration stress was assessed and compared between the landraces exposed to PEG-induced dehydration stress in germinating tissue, it also exhibited almost the same trend with the landrace Tulaipanji and Badsabhog exhibiting maximum and Jamainadu the minimum efficiencies of the redox cycle. The indigenous aromatic rice cultivars Tulaipanji and Badsabhog resist dehydration stress better than the other two landraces due to its early preparedness to combat oxidative stress by up-regulating expression of genes of some enzymes of ascorbate–glutathione cycle along with some other antioxidative enzymes. A model of redox homeostasis in which ROS-antioxidant (ascorbate–glutathione system) acts at metabolic interface for up-regulation of antioxidative gene expression necessary for differential drought stress tolerance among the indigenous aromatic rice varieties is suggested. 相似文献
98.
Binding affinity and in vitro cytotoxicity of harmaline targeting different motifs of nucleic acids: An ultimate drug designing approach 下载免费PDF全文
Paromita Bhattacharjee Tapas Ghosh Sarita Sarkar Prateek Pandya Kakali Bhadra 《Journal of molecular recognition : JMR》2018,31(4)
The work focuses towards interaction of harmaline, with nucleic acids of different motifs by multispectroscopic and calorimetric techniques. Findings of this study suggest that binding constant varied in the order single‐stranded (ss) poly(A) > double‐stranded calf thymus (CT) DNA > double‐stranded poly(G)·poly(C) > clover leaf tRNAPhe. Prominent structural changes of ss poly(A), CT DNA, and poly(G)· poly(C) with concomitant induction of optical activity in the bound achiral alkaloid molecule was observed, while with tRNAPhe, very weak induced circular dichroism perturbation was seen. The interaction was predominantly exothermic, enthalpy driven, and entropy favored with CT DNA and poly(G)·poly(C), while it was entropy driven with poly(A) and tRNAPhe. Intercalated state of harmaline inside poly(A), CT DNA, and poly(G)·poly(C) was shown by viscometry, ferrocyanide quenching, and molecular docking. All these findings unequivocally pointed out preference of harmaline towards ss poly(A) inducing self‐structure formation. Furthermore, harmaline administration caused a significant decrease in proliferation of HeLa and HepG2 cells with GI50 of 28μM and 11.2μM, respectively. Nucleic acid fragmentation, cellular ultramorphological changes, decreased mitochondrial membrane potential, upregulation of p53 and caspase 3, generation of reactive oxygen species, and a significant increase in the G2/M population made HepG2 more prone to apoptosis than are HeLa cells. 相似文献
99.
100.
Tendinopathy diagnosis and treatment monitoring using attenuated total reflectance‐Fourier transform infrared spectroscopy 下载免费PDF全文
Tanmoy T. Bhattacharjee Mariana C. Nicodemo Luciana B. Sant'Anna Emilia A. Lo Schiavo Arisawa Leandro Raniero 《Journal of biophotonics》2018,11(4)
Tendinopathy, an important sports injury afflicting athletes and general public, is associated with huge economic losses. The currently used diagnostic tests are subjective, show moderate sensitivity and specificity; while treatment failures persist despite advances in therapy. This highlights the need for tendinopathy diagnostic and treatment monitoring tools. This study investigates tendon injury, natural healing and effect of treatment using ATR‐FTIR complemented with histopathology. Control (C), injured (I) and treated (T) rat tendons were extracted 3, 7, 14 and 28 days post‐injury/treatment, representing phases of healing; and subjected to hematoxylin & eosin staining as well as spectroscopy. While C showed no change, I‐ and T‐related histological changes could be clearly observed in stained sections. ATR‐FTIR spectra highlighted the biochemical changes within groups. Multivariate analysis could classify C, I and T with 75%; different days between groups with 84%; and different days within group with 65% efficiency. Results suggest that such analysis can not only identify C, I or T but also different phases of healing. Difference between I and T at different time points also suggest change in rate of healing. Further studies may help develop this technique for clinical diagnosis and treatment monitoring in future. 相似文献