全文获取类型
收费全文 | 11505篇 |
免费 | 1233篇 |
国内免费 | 64篇 |
专业分类
耳鼻咽喉 | 96篇 |
儿科学 | 316篇 |
妇产科学 | 305篇 |
基础医学 | 1683篇 |
口腔科学 | 266篇 |
临床医学 | 1363篇 |
内科学 | 1991篇 |
皮肤病学 | 146篇 |
神经病学 | 1168篇 |
特种医学 | 521篇 |
外国民族医学 | 1篇 |
外科学 | 1667篇 |
综合类 | 195篇 |
一般理论 | 6篇 |
预防医学 | 1214篇 |
眼科学 | 190篇 |
药学 | 803篇 |
中国医学 | 15篇 |
肿瘤学 | 856篇 |
出版年
2022年 | 85篇 |
2021年 | 178篇 |
2020年 | 95篇 |
2019年 | 158篇 |
2018年 | 182篇 |
2017年 | 153篇 |
2016年 | 157篇 |
2015年 | 218篇 |
2014年 | 277篇 |
2013年 | 386篇 |
2012年 | 564篇 |
2011年 | 536篇 |
2010年 | 254篇 |
2009年 | 279篇 |
2008年 | 522篇 |
2007年 | 510篇 |
2006年 | 495篇 |
2005年 | 504篇 |
2004年 | 469篇 |
2003年 | 434篇 |
2002年 | 395篇 |
2001年 | 357篇 |
2000年 | 393篇 |
1999年 | 347篇 |
1998年 | 146篇 |
1997年 | 149篇 |
1996年 | 137篇 |
1995年 | 119篇 |
1994年 | 122篇 |
1993年 | 105篇 |
1992年 | 273篇 |
1991年 | 238篇 |
1990年 | 264篇 |
1989年 | 268篇 |
1988年 | 241篇 |
1987年 | 222篇 |
1986年 | 219篇 |
1985年 | 230篇 |
1984年 | 171篇 |
1983年 | 144篇 |
1982年 | 123篇 |
1981年 | 103篇 |
1980年 | 96篇 |
1979年 | 147篇 |
1978年 | 129篇 |
1977年 | 109篇 |
1976年 | 102篇 |
1974年 | 102篇 |
1973年 | 108篇 |
1970年 | 80篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Rous-associated virus type 7 induces a syndrome in chickens characterized by stunting and obesity. 总被引:3,自引:1,他引:3
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Infection of 10-day-old chicken embryos with an avian retrovirus. Rous-associated virus type 7, resulted in a disease characterized by stunting and hyperlipidemia. By 20 days after hatch, infected chickens were smaller than hatchmates and developed ataxia and obesity over the next 30 days. Histological examinations of livers from infected chickens revealed a diffuse panlobular fatty infiltrate involving an accumulation of fat in microdroplets. Electron microscopic examinations of livers from infected chickens revealed hepatocytes with swollen mitochondria that lacked cristae. The thyroid and pancreas were infiltrated with lymphoblastoid cells by 1 week after hatch. An examination of the blood revealed a mild anemia, a frank lipemia, and high levels of uric acid. This syndrome induced by Rous-associated virus type 7 in chickens may be useful for elucidating the nature of several diseases, including that found in the fatty liver and kidney syndrome of chickens and that observed in a strain of obese chickens. 相似文献
92.
The clinical-grade 42-kilodalton fragment of merozoite surface protein 1 of Plasmodium falciparum strain FVO expressed in Escherichia coli protects Aotus nancymai against challenge with homologous erythrocytic-stage parasites 总被引:4,自引:0,他引:4
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Darko CA Angov E Collins WE Bergmann-Leitner ES Girouard AS Hitt SL McBride JS Diggs CL Holder AA Long CA Barnwell JW Lyon JA 《Infection and immunity》2005,73(1):287-297
A 42-kDa fragment from the C terminus of major merozoite surface protein 1 (MSP1) is among the leading malaria vaccine candidates that target infection by asexual erythrocytic-stage malaria parasites. The MSP1(42) gene fragment from the Vietnam-Oak Knoll (FVO) strain of Plasmodium falciparum was expressed as a soluble protein in Escherichia coli and purified according to good manufacturing practices. This clinical-grade recombinant protein retained some important elements of correct structure, as it was reactive with several functional, conformation-dependent monoclonal antibodies raised against P. falciparum malaria parasites, it induced antibodies (Abs) that were reactive to parasites in immunofluorescent Ab tests, and it induced strong growth and invasion inhibitory antisera in New Zealand White rabbits. The antigen quality was further evaluated by vaccinating Aotus nancymai monkeys and challenging them with homologous P. falciparum FVO erythrocytic-stage malaria parasites. The trial included two control groups, one vaccinated with the sexual-stage-specific antigen of Plasmodium vivax, Pvs25, as a negative control, and the other vaccinated with baculovirus-expressed MSP1(42) (FVO) as a positive control. Enzyme-linked immunosorbent assay (ELISA) Ab titers induced by E. coli MSP1(42) were significantly higher than those induced by the baculovirus-expressed antigen. None of the six monkeys that were vaccinated with the E. coli MSP1(42) antigen required treatment for uncontrolled parasitemia, but two required treatment for anemia. Protective immunity in these monkeys correlated with the ELISA Ab titer against the p19 fragment and the epidermal growth factor (EGF)-like domain 2 fragment of MSP1(42), but not the MSP1(42) protein itself or the EGF-like domain 1 fragment. Soluble MSP1(42) (FVO) expressed in E. coli offers excellent promise as a component of a vaccine against erythrocytic-stage falciparum malaria. 相似文献
93.
The effect of sweetness on the efficacy of carbohydrate supplementation during exercise in the heat.
James Carter Asker E Jeukendrup David A Jones 《Revue canadienne de physiologie appliquée》2005,30(4):379-391
The aim of the present study was to investigate potential mechanisms responsible for the improvement in prolonged exercise capacity in hot environments with exogenous carbohydrate. Eight endurance-trained men (VO(2)max 60.5 +/- 2.4 ml.kg(-1).min(-1), mean +/- SE) cycled to exhaustion on three occasions at 60% VO(2)max at an ambient temperature of 35 degrees C. They ingested either a sweet 6.4% carbohydrate solution (SC), a nonsweet 6.4% carbohydrate solution (NSC), or water (W). Exercise capacity was significantly increased with SC and NSC compared to W, the improvements corresponding to 15.8% and 11.8%, respectively. No difference in exercise capacity was seen between SC and NSC solutions. Plasma glucose concentrations were higher during the SC and NSC trials compared to W, significantly so at 10 min and at fatigue. Rates of carbohydrate oxidation were higher in the SC and NSC trials, although the rates never declined below 2.1 +/- 0.2 g.min(-1) in the W trial. There was no difference in the rate of rise of rectal temperature between trials, but there was a trend for subjects to fatigue at higher temperatures during the two carbohydrate trials. In conclusion, exogenous carbohydrate, independent of sweetness, improves exercise capacity in the heat compared to water alone. 相似文献
94.
Effects of transmission-blocking monoclonal antibodies on different isolates of Plasmodium falciparum. 总被引:4,自引:3,他引:4
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
P M Graves R Carter T R Burkot J Rener D C Kaushal J L Williams 《Infection and immunity》1985,48(3):611-616
The strain diversity in Plasmodium falciparum has been studied with respect to gamete surface antigens which are the targets of transmission-blocking antibodies. Of 12 isolates tested, 11 were positive by immunofluorescence with the three monoclonal antibodies studied. The exception was a Liberian isolate, two clones of which were found to react with only one of the three monoclonal antibodies. Antibodies IIC5-B10 and IA3-B8, which previously have been shown to act synergistically to block infectivity of 7G8, a Brazilian clone of P. falciparum, acted in an exactly similar way with another Brazilian isolate, It.D12, and an isolate from Thailand. In the presence of complement either IA3-B8 or a third antibody, IID2-A10, strongly suppressed infectivity of It.D12 as well as 7G8, but neither isolate was strongly suppressed by IIC5-B10. IA3-B8 and IID2-A10 did not react by immunofluorescence or immunoprecipitation with gametes of L.E5; IIC5-B10 reacted positively with L.E5 gametes in these tests. In the absence of complement, the combination of IA3-B8 and IIC5-B10 did not suppress infectivity of L.E5 to mosquitoes. In contrast to its effect on gametocytes of other isolates, IIC5-B10 in the presence of complement strongly suppressed infectivity of L.E5 to mosquitoes. These results imply that IA3-B8 and IIC5-B10 react with two structurally distinct epitopes on the surface of gametes of P. falciparum and that the properties of both epitopes on gametes of L.E5 differ from those on gametes of the other isolates tested. 相似文献
95.
Cerebrospinal fluids (CSFs) were examined for the presence of a cytopathogenic component by an in vitro assay. No abnormal proteins were detected in CSF which produced cytopathic effects. The cytopathic effect was associated with high-molecular-weight material which was resistant to enzyme treatment. The effect persisted after extensive ultraviolet irradiation. The presence of the cytopathic effect was associated with increased CSF enolase levels. 相似文献
96.
The morphology of immune reactions in normal, thymectomized and reconstituted mice: I. The response to sheep erythrocytes 总被引:16,自引:0,他引:16
下载免费PDF全文
![点击此处可从《Immunology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A. J. S. Davies R. L. Carter Elizabeth Leuchars Valerie Wallis P. C. Koller 《Immunology》1969,16(1):57-69
The response to sheep red blood cells has been studied in the lymph nodes draining their site of injection in normal mice, and in thymectomized, irradiated, bone-marrow injected mice with and without a reconstituting thymus graft. By using a chromosome marker to differentiate between cells derived from the bone-marrow and thymus graft it has proved possible to show that the immune response should be thought of in terms of at least two cell populations. Cells of thymic origin are stimulated to mitotic activity in the interfollicular cortex, and their activity precedes both antibody production and morphological signs of activity in the follicular regions. Mitotic divisions of cells of bone-marrow origin reached a peak a day later than did the thymic cells and their activity was sustained. Follicular enlargement and germinal centre production were coincident in time both with antibody production and bone-marrow cell mitotic activity. Lymph nodes of animals lacking a thymic influence showed only minor changes after antigenic stimulation and these were restricted to the follicular regions. There appeared to be only a small quantitative difference between the responses of normal and of reconstituted animals. 相似文献
97.
K. B. Carter J. K. Drury J. R. Richards 《Medical & biological engineering & computing》1976,14(4):465-470
Calorimetry, using the gradient layer technique, has become well established in the study of energy metabolism. The use of a commercially constructed gradient layer box within a calorimetry system designed to measure directly and indirectly the metabolic sequelae of thermal injury in rats, is described. Variations in the signal output were discovered. These were found to be dependent upon:
- stability of the ambient temperature
- stability of the gradient layer box water jacket temperature
- position and size of the calibrating heat source.
98.
99.
The 16189 variant of mitochondrial DNA occurs more frequently in C282Y homozygotes with haemochromatosis than those without iron loading 总被引:3,自引:1,他引:3
Livesey KJ Wimhurst VL Carter K Worwood M Cadet E Rochette J Roberts AG Pointon JJ Merryweather-Clarke AT Bassett ML Jouanolle AM Mosser A David V Poulton J Robson KJ 《Journal of medical genetics》2004,41(1):6-10
Background:Patients with hereditary haemochromatosis (HH) are usually homozygous for the C282Y mutation in the HFE gene. They have variable expression of iron overload and present with a variety of complications, including liver disease, diabetes, arthropathy, fatigue, and cardiomyopathy. The mitochondrial 16189 variant is associated with diabetes, dilated cardiomyopathy, and low body fat at birth, and might contribute to genetic predisposition in further multifactorial disorders. The objective of this study was to determine the frequency of the 16189 variant in a range of patients with haemochromatosis, who had mutations in the HFE gene.
Methods:Blood DNA was analysed for the presence of the 16189 variant in British, French, and Australian C282Y homozygotes and controls, with known iron status, and in birth cohorts.
Results:The frequency of the mitochondrial 16189 variant was found to be elevated in individuals with haemochromatosis who were homozygous for the C282Y allele, compared with population controls and with C282Y homozygotes who were asymptomatic (42/292 (14.4%); 102/1186 (8.6%) (p = 0.003); and 2/64 (3.1%) (p = 0.023), respectively).
Conclusions:Iron loading in C282Y homozygotes with HH was exacerbated by the presence of the mitochondrial 16189 variant.
相似文献100.
Microarray based comparative genomic hybridisation (array-CGH) detects submicroscopic chromosomal deletions and duplications in patients with learning disability/mental retardation and dysmorphic features 总被引:24,自引:2,他引:24
下载免费PDF全文
![点击此处可从《Journal of medical genetics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Shaw-Smith C Redon R Rickman L Rio M Willatt L Fiegler H Firth H Sanlaville D Winter R Colleaux L Bobrow M Carter NP 《Journal of medical genetics》2004,41(4):241-248
The underlying causes of learning disability and dysmorphic features in many patients remain unidentified despite extensive investigation. Routine karyotype analysis is not sensitive enough to detect subtle chromosome rearrangements (less than 5 Mb). The presence of subtle DNA copy number changes was investigated by array-CGH in 50 patients with learning disability and dysmorphism, employing a DNA microarray constructed from large insert clones spaced at approximately 1 Mb intervals across the genome. Twelve copy number abnormalities were identified in 12 patients (24% of the total): seven deletions (six apparently de novo and one inherited from a phenotypically normal parent) and five duplications (one de novo and four inherited from phenotypically normal parents). Altered segments ranged in size from those involving a single clone to regions as large as 14 Mb. No recurrent deletion or duplication was identified within this cohort of patients. On the basis of these results, we anticipate that array-CGH will become a routine method of genome-wide screening for imbalanced rearrangements in children with learning disability. 相似文献