全文获取类型
收费全文 | 930篇 |
免费 | 74篇 |
国内免费 | 1篇 |
出版年
2021年 | 6篇 |
2020年 | 21篇 |
2019年 | 41篇 |
2018年 | 35篇 |
2017年 | 12篇 |
2016年 | 15篇 |
2015年 | 22篇 |
2014年 | 23篇 |
2013年 | 51篇 |
2012年 | 30篇 |
2011年 | 31篇 |
2010年 | 23篇 |
2009年 | 16篇 |
2008年 | 39篇 |
2007年 | 32篇 |
2006年 | 35篇 |
2005年 | 33篇 |
2004年 | 25篇 |
2003年 | 27篇 |
2002年 | 28篇 |
2001年 | 25篇 |
2000年 | 20篇 |
1999年 | 25篇 |
1998年 | 20篇 |
1997年 | 14篇 |
1996年 | 25篇 |
1995年 | 22篇 |
1994年 | 9篇 |
1993年 | 14篇 |
1992年 | 30篇 |
1991年 | 11篇 |
1990年 | 14篇 |
1989年 | 31篇 |
1988年 | 10篇 |
1987年 | 20篇 |
1986年 | 13篇 |
1985年 | 11篇 |
1984年 | 11篇 |
1983年 | 8篇 |
1982年 | 7篇 |
1981年 | 10篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1976年 | 8篇 |
1975年 | 5篇 |
1974年 | 8篇 |
1973年 | 7篇 |
1972年 | 6篇 |
1969年 | 6篇 |
排序方式: 共有1005条查询结果,搜索用时 31 毫秒
1.
Malcolm Aitken 《BMJ (Clinical research ed.)》1999,319(7207):401
2.
A double antibody radioimmunoassay technique is described for the measurement of anti-zona antibodies in the peripheral plasma of marmosets actively immunized against intact cow zonae pellucidae. The method has been shown to be a reliable, repeatable indicator of antibody titer, enabling direct comparison of the response obtained between marmosets. This is the first report of a procedure describing the active immunization of a primate against zona antigens, and the first time a radioimmunoassay technique has been used to monitor profiles of anti-cow zona antibody production following active immunization. The method should prove to be a useful tool in the evaluation of zona antigens as agents for immunocontraception. 相似文献
3.
Amino acid sequence surrounding the lipoic acid cofactor of bovine kidney 2-oxoglutarate dehydrogenase complex 总被引:4,自引:0,他引:4
The 2-oxoglutarate dehydrogenase complex was succinylated using 2-oxo[5-14C]glutarate in the presence of N-ethylmaleimide to label the lipoic acid cofactor of the transuccinylase (E2) component. Following peptic digestion, 14C-lipoate-containing peptides were purified and subjected to automated Edman degradation and amino acid analysis. The amino acid sequence surrounding the lipoyllysine residue is reported. 相似文献
4.
5.
A case of chromomycosis in which hyperthermia proved effective is reported. The patient was a 56-year-old male bean curd maker who, without any previous history of minor trauma, developed on the extensor side of the left upper arm an eczematous lesion that underwent gradual radial expansion. The lesion showed a well-defined, 7×10 cm infiltrated erythematous plaque with the central area healed and, at the upper and lower borders, adherent scales and crusts on the surface. Histological examination revealed granulomatous changes in the dermis, as well as sclerotic cells within giant cells and microabscesses. On culturing,Fonsecaea pedrosoi was isolated. The patient was treated with disposable chemical pocket warmers, which were secured over the lesion with a rather tight elastic bandage, so that they kept the affected area warm for 24 hours a day. After a month of such hyperthermic treatment, the erythema and infiltration had decreased considerably, and microscopic examination and culture of the crusts both yielded negative results. Examination of biopsy specimens of the lesion after the third month showed that it had cicatrized. The treatment was stopped after 4 months, and no relapse occurred. We also summarize the published results of local hyperthermic treatment of chromomycosis in Japan. 相似文献
6.
Margot S. Kruskall MD Elizabeth E. Eynon Zuheir Awdeh Chester A. Alper Edmond J. Yunis 《Immunogenetics》1987,26(4-5):216-219
The HLA class I antigen B44 is found in each of two different extended major histocompatibility haplotypes (allele combinations of HLA-B, HLA-DR, and complement genes BF, C2, C4A, and C4B in linkage disequilibrium). Using isoelectric focusing, two variants of HLA-B44 were identified. The basic variant was found in all cell lines with the extended haplotype HLA-B44, DR7, FC31, and the acidic variant in all cell lines with the extended haplotype HLA-B44, DR4, SC30. The occurrence of each antigen variant with a unique extended haplotype explains previous observations concerning the nonrandom association of B44 variants with DR antigens. 相似文献
7.
Embryonal carcinoma-derived growth factor activates protein kinase C in vivo and in vitro. 总被引:4,自引:0,他引:4 下载免费PDF全文
We have recently reported that a polypeptide mitogen, the embryonal carcinoma-derived growth factor (ECDGF), induces phosphorylation of the epidermal growth factor (EGF) receptor in intact C3H 10T 1/2 mouse fibroblasts with concomittant loss of high affinity EGF binding sites. This phenomenon appears to be mediated through an activation of protein kinase C. Several groups have described an acidic 80,000 dalton protein substrate of protein kinase C. In this paper, we demonstrate that the addition of ECDGF or the phorbol ester TPA to intact C3H 10T 1/2 cells results in the enhanced phosphorylation of this 80 kd protein in vivo. Furthermore, this response is demonstrable in vitro. Thus the addition of ECDGF, the phorbol ester TPA, protein kinase C or phosphoinositidase C to crude membranes prepared from C3H 10T 1/2 cells resulted in the enhanced phosphorylation of this protein. Data obtained by phosphopeptide mapping of the 80 kd protein show that the ECDGF-induced activation of protein kinase C in our membrane preparations is comparable with that obtained in vivo. The availability of an in vitro system in which this response is preserved should now allow a detailed biochemical analysis of the steps between binding of a mitogen to its receptor and the activation of protein kinase C. 相似文献
8.
Pathophysiology of pH and Ca2+ in bloodstream and brain 总被引:1,自引:0,他引:1
G G Somjen B W Allen M Balestrino P G Aitken 《Canadian journal of physiology and pharmacology》1987,65(5):1078-1085
The highlights of the literature and our work on tetany and hyperventilation are reviewed. Our studies concern the following: (1) the changes of [Ca2+] in circulating plasma caused by respiratory and "metabolic" acidosis and alkalosis; (2) critical plasma [Ca2+] levels associated with signs of tetany and neuromuscular blockade; (3) changes in cerebral [Ca2+]o caused by hypo- and hyper-calcaemia, and the changes in cerebral [Ca2+]o and pHo caused by acute systemic acidosis and alkalosis; and (4) effects of changing [Ca2+]o and pHo levels on synaptic transmission in hippocampal formation. Our main conclusions are (1) changes of plasma [Ca2+] caused by "metabolic" pH changes are greater than those associated with varying CO2 concentration; (2) acute systemic [Ca2+] changes are associated with small cerebral [Ca2+]o changes; (3) the decreases in systemic and cerebral [Ca2+]o caused by hyperventilation are too small to account for the signs and symptoms of hypocapnic tetany; (4) moderate decrease of [Ca2+]o depresses and its increase enhances synaptic transmission in hippocampal formation; and (5) H+ ions in extracellular fluid have a weak depressant effect on neuronal excitability. CO2 is a strong depressant, which is only partly explained by the acidity of its solution. CO2 concentration is a significant factor in controlling cerebral function. 相似文献
9.
Eight persons with asthma were exposed to seven air conditions varying in temperature (37 degrees C to 49 degrees C [98.6 degrees F to 120.2 degrees F]) and water content (44 mg H2O per liter to 79 mg H2Oper liter) . Normocapnic hyperventilation for three minutes at 40% maximal voluntary ventilation was carried out for each condition. A constant-volume body plethysmograph measured the functional residual capacity and specific airway conductance (SGaw), followed by two forced expiratory manuevers. Measurements were taken before and 1, 5, 10, and 20 minutes after each challenge. Air conditions with 100% relative humidity caused a fall in the SGaw that was maximal in 1 minute. Air conditions at 100% relative humidity caused a greater fall in both the forced expiratory volume in 1 second (FEV1) (P<.05) and the SGaw (P<.005) than did conditions of the same temperature but less water content. At 44 degrees C and 100% relative humidity, the mean percent change in FEV1 and SGaw was -2% and -40%, respectively, at 1 minute after challenge. Of the conditions examined, the optimal temperature was 44 degrees C, and we speculate that the optimal water content is less than 44 mg H2O per liter. Inhaled water concentrations exceeding 44 mg H2O per liter should probably not be used in patients with asthma. 相似文献
10.
Contraceptive potential of antibodies to the zona pellucida 总被引:1,自引:0,他引:1
The notion of a contraceptive vaccine based on gamete-specific surface antigens was first proposed over a decade ago, as the result of in-vitro and in-vivo studies, and in recent years has been the subject of intensive research. In particular, the zona pellucida has attracted much attention as a potential target for immunological intervention in the fertilization process. Such is the rapidly-expanding nature of research into the biochemical and biological characterization of this structure, that a review of the implications for the development of a contraceptive vaccine seems timely. 相似文献