全文获取类型
收费全文 | 884篇 |
免费 | 48篇 |
专业分类
932篇 |
出版年
2024年 | 3篇 |
2023年 | 11篇 |
2022年 | 28篇 |
2021年 | 33篇 |
2020年 | 17篇 |
2019年 | 27篇 |
2018年 | 26篇 |
2017年 | 26篇 |
2016年 | 36篇 |
2015年 | 35篇 |
2014年 | 61篇 |
2013年 | 76篇 |
2012年 | 53篇 |
2011年 | 65篇 |
2010年 | 45篇 |
2009年 | 28篇 |
2008年 | 39篇 |
2007年 | 35篇 |
2006年 | 40篇 |
2005年 | 31篇 |
2004年 | 24篇 |
2003年 | 15篇 |
2002年 | 18篇 |
2001年 | 7篇 |
2000年 | 13篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1992年 | 12篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 12篇 |
1987年 | 9篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1980年 | 3篇 |
1979年 | 8篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1975年 | 6篇 |
1974年 | 6篇 |
1973年 | 5篇 |
1971年 | 5篇 |
1969年 | 2篇 |
1967年 | 2篇 |
排序方式: 共有932条查询结果,搜索用时 0 毫秒
1.
2.
Fourier transform infrared (FTIR) spectroscopic imaging is an emerging microscopy modality for clinical histopathologic diagnoses as well as for biomedical research. Spectral data recorded in this modality are indicative of the underlying, spatially resolved biochemical composition but need computerized algorithms to digitally recognize and transform this information to a diagnostic tool to identify cancer or other physiologic conditions. Statistical pattern recognition forms the backbone of these recognition protocols and can be used for highly accurate results. Aided by biochemical correlations with normal and diseased states and the power of modern computer-aided pattern recognition, this approach is capable of combating many standing questions of traditional histology-based diagnosis models. For example, a simple diagnostic test can be developed to determine cell types in tissue. As a more advanced application, IR spectral data can be integrated with patient information to predict risk of cancer, providing a potential road to precision medicine and personalized care in cancer treatment. The IR imaging approach can be implemented to complement conventional diagnoses, as the samples remain unperturbed and are not destroyed. Despite high potential and utility of this approach, clinical implementation has not yet been achieved due to practical hurdles like speed of data acquisition and lack of optimized computational procedures for extracting clinically actionable information rapidly. The latter problem has been addressed by developing highly efficient ways to process IR imaging data but remains one that has considerable scope for progress. Here, we summarize the major issues and provide practical considerations in implementing a modified Bayesian classification protocol for digital molecular pathology. We hope to familiarize readers with analysis methods in IR imaging data and enable researchers to develop methods that can lead to the use of this promising technique for digital diagnosis of cancer. 相似文献
3.
V K Singh H K Kalra K Yamaki T Abe L A Donoso T Shinohara 《Journal of immunology (Baltimore, Md. : 1950)》1990,144(4):1282-1287
S-Antigen (S-Ag) is a well characterized 45,000 m.w. photoreceptor cell protein. When injected into susceptible animal species, including primates, it induces an experimental autoimmune uveitis, a predominantly T cell-mediated autoimmune disease of the retina and uveal tract of the eye, and of the pineal gland. In this study we found an amino acid sequence homology between a uveitopathogenic site of S-Ag, several viral proteins and one additional nonviral protein. An experimental autoimmune uveitis and pinealitis was induced in Lewis rats with these different synthetic peptides, corresponding to the amino sequence of hepatitis B virus DNA polymerase, gag-pol polyprotein of Baboon endogenous virus and gag-pol polyprotein of AKV murine leukemia virus and potato proteinase inhibitor IIa, which contain three or more consecutive amino acids identical to peptide M in S-Ag. Lymph node cells from rats immunized with either peptide M or the different synthetic peptides showed a significant degree of cross-reaction. Mononuclear cells from monkeys (Macaca fascicularis) immunized with peptide M also showed significant proliferation when incubated with either peptide M or synthetic peptides as measured by in vitro lymphocyte mitogenesis assay using [3H]TdR. Based on our findings we conclude that a viral infection may sensitize the mononuclear cells that can cross-react with self proteins by a mechanism termed molecular mimicry. Tissue injury from the resultant autoantigenic event can take place in the absence of the infectious virus that initiated the immune response. 相似文献
4.
Jawahar Kalra Dave Lautner K. Lorne Massey Kailash Prasad 《Molecular and cellular biochemistry》1988,84(2):233-238
Summary The effect of oxygen free radicals, generated by xanthine and xanthine oxidase, was studied on the release of lysosomal hydrolase from rat liver lysosomes in vitro. A lysosomal enriched subcellular fraction was prepared, using differential centrifugation technique, from the homogenate of rat liver. The biochemical purity of the lysosomal fraction was established by using the markers of different cellular organelles. Oxygen free radicals were generated in vitro by the addition of xanthine and xanthine oxidase. The release of lysosomal hydrolase (-glucuronidase) from the lysosomal fraction was measured. There was a 3 to 4 fold increase in the release of -glucuronidase activity in the presence of xanthine and xanthine oxidase when compared to that in the absence of xanthine and xanthine oxidase. In the presence of superoxide dismutase (SOD), a scavenger of oxygen free radicals, the xanthine and xanthine oxidase system was unable to induce the release of -glucuronidase activity from the lysosomes. Sonication (2 bursts for 15 sec each) and Lubrol (2 mg/10 mg lysosomal protein) treatment, which are known to cause membrane disruption, also induced the release of -glucuronidase from lysosomal fraction. This release of -glucuronidase by sonication and lubrol treatment was not prevented by SOD. These data indicate that lysosomal disruption is a consequence of oxygen free radicals, generated by xanthine and xanthine oxidase.Abbreviations HEPES
N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid
- EGTA
Ethylene Glycol Bis-(-aminoethyl ether)N,N,-N,N-tetracetic acid
- Tris
Tris (hydroxymethyl) aminomethane
- SOD
Superoxide Dismutase 相似文献
5.
G Singh M M Singh S C Maitra W Elger V Kalra S N Upadhyay S R Chowdhury V P Kamboj 《Journal of reproduction and fertility》1988,83(1):73-83
RU-38486 or ZK-98734 treatment (3 mg/day, s.c.) to intact or hysterectomized adult female rats on Days 5-7 post coitum induced changes characteristic of luteolysis. Ultrastructurally, the luteal cells exhibited an extensive vacuolization of the cytoplasm and perinuclear areas, degeneration of mitochondrial cristae, massive accumulation of lipid droplets, increase in number of lysosome like granules and heterochromatinization of the nucleus. In general, RU-38486 induced more marked degeneration of the luteal cells than did ZK-98734. There was also a significant decrease in peripheral plasma progesterone concentrations in treated rats. We suggest that these antiprogestagens act via inhibition of luteal function in addition to their antagonism at the uterine progesterone receptor level. 相似文献
6.
S P Kalra L G Allen A Sahu P S Kalra W R Crowley 《Journal of steroid biochemistry》1988,30(1-6):185-193
We report that the two classes of regulatory neuropeptides, neuropeptide Y (NPY) and endogenous opioid peptides (EOP), modulate luteinizing hormone (LH) release in diverse fashion in gonad-intact rats. Each neuropeptide acts at two loci, the hypothalamus and pituitary, to excite (NPY) or inhibit (EOP) LH release. At the hypothalamic level, NPY stimulates luteinizing hormone releasing hormone (LHRH) release, a response mediated by alpha 2-adrenoreceptors and amplified in the presence of adrenergic agonists. At the pituitary level, NPY acts in concert with LHRH to amplify the LH response. In contrast, EOP inhibit LHRH release by decreasing the supply of excitatory adrenergic signals in the vicinity of LHRH neurons in the preoptic-tuberal pathway, and at the pituitary level, they decrease LH release in response to LHRH. Further, the gonadal steroidal milieu facilitates NPY neurosecretion and postsynaptic expression of NPY in concert with adrenergic system; a similar clear-cut facilitatory effect of gonadal steroids on EOP secretion is not yet obvious. Our additional studies imply that the EOP system has the potential to increase sensitivity towards gonadal steroids and that to induce the preovulatory LH surge the neural clock may decrease the inhibitory EOP tone prior to the critical period on proestrus. This antecedent neural event allows the excitatory adrenergic and NPY signals to evoke LHRH secretion at a higher frequency approximating that seen in ovariectomized rats. Further studies are under way to delineate the steroid-induced subcellular events that integrate the action of these regulatory peptides in the control of the episodic LHRH secretion pattern which sustains basal and cyclic gonadotropin release in the rat. 相似文献
7.
S.P. Pathak J.W. Bhattacherjee N. Kalra S. Chandra 《Journal of applied microbiology》1988,65(4):347-352
The seasonal distribution of Aeromonas hydrophila in water and recovery rate from live river fish was investigated. The highest isolation rates of A. hydrophila occurred in water during the late winter followed by a progressive decline in density during the summer and monsoon seasons. The organism was recovered from fish throughout the period from which it was concluded that they form a reservoir which is unrelated to their density in water. The enterotoxigenicity of some environmental strains was tested in suckling mice and rabbit ileal loop. 相似文献
8.
Serum antioxidant enzyme activity in Parkinson's disease 总被引:2,自引:0,他引:2
Jawahar Kalra Ali H. Rajput Subrahmanyam V. Mantha Kailash Prasad 《Molecular and cellular biochemistry》1992,110(2):165-168
Summary The activities of superoxide dismutase (SOD; EC 1.15.1.1) and glutathione peroxidase (GSHPx; EC 1.11.1.9.), the enzymes that metabolize the superoxide anion and hydrogen peroxide, respectively, were measured in serum
from healthy subjects and patients with Parkinson's disease (PD). The activities of SOD and GSHPx in patients with PD were higher than those in normal healthy individuals. These results suggest that the increased activities
of these enzymes could be due to oxidative stress in the initial stages of this disease. 相似文献
9.
K. Prasad J. B. Gupta J. Kalra B. Bharadwaj 《Molecular and cellular biochemistry》1992,111(1-2):55-59
It has been suggested that oxygen free radicals (OFR) depress the excitation-contraction coupling in cardiac muscle. It is possible that a decrease in the cardiac contractility in the failing heart may be due to an increased OFR producing activity of polymorphonuclear (PMN) leukocytes. We studied the OFR producing activity (chemiluminescence) of PMN leukocytes from blood in dogs with heart failure due to chronic volume overload. The animals were divided into two groups: I) normal, (n = 10): II) dogs with mitral insufficiency (MI) of 6 to 9 months duration, (n = 10). Hemodynamic studies were done to establish the presence of heart failure. Blood samples were collected to measure PMN leukocyte chemiluminescence. There was a decrease in the cardiac index and index of myocardial contractility (dp/dt/IIP) and an increase in the left ventricular end-diastolic pressure in dogs with MI indicating left ventricular failure. The peak chemiluminescent activity of the PMN leukocytes in blood of dogs with failure was about four folds greater than that in the blood from normal dogs. These results suggest that there may be an increased OFR generation in dogs with volume overload heart failure. The decrease in the myocardial contractility in the failing heart might be due to an increase in the OFR produced by the PMN leukocytes. 相似文献
10.
On Day 5 of pregnancy, before the blastocyst migrates to the uterus, one uterine horn was ligated to restrict the trophoblast to the lumen ipsilateral to the corpus luteum. The numbers of placentomes (caruncles and cotyledons) were reduced by half, but neither at 120 nor at 140 days of pregnancy (term 147 days) did the weights of placentae and fetuses of treated ewes differ significantly from those of control ewes. Amongst uterus-ligated animals prepared for chronic study, the rate of uterine blood flow (electromagnetic flow transducer, ml/min) to the pregnant horn was higher than in control ewes, as was the concentration of progestagens in maternal peripheral blood. There may be a compensatory response that causes hypertrophy of placentomes and that increases blood flow to the uterine horn containing placental tissue. 相似文献