全文获取类型
收费全文 | 13775篇 |
免费 | 984篇 |
国内免费 | 28篇 |
专业分类
耳鼻咽喉 | 194篇 |
儿科学 | 471篇 |
妇产科学 | 413篇 |
基础医学 | 1660篇 |
口腔科学 | 319篇 |
临床医学 | 1031篇 |
内科学 | 2915篇 |
皮肤病学 | 291篇 |
神经病学 | 1027篇 |
特种医学 | 663篇 |
外科学 | 2391篇 |
综合类 | 124篇 |
一般理论 | 8篇 |
预防医学 | 1171篇 |
眼科学 | 682篇 |
药学 | 559篇 |
中国医学 | 33篇 |
肿瘤学 | 835篇 |
出版年
2022年 | 129篇 |
2021年 | 265篇 |
2020年 | 141篇 |
2019年 | 247篇 |
2018年 | 337篇 |
2017年 | 237篇 |
2016年 | 249篇 |
2015年 | 270篇 |
2014年 | 375篇 |
2013年 | 532篇 |
2012年 | 692篇 |
2011年 | 773篇 |
2010年 | 464篇 |
2009年 | 435篇 |
2008年 | 715篇 |
2007年 | 682篇 |
2006年 | 683篇 |
2005年 | 648篇 |
2004年 | 582篇 |
2003年 | 594篇 |
2002年 | 511篇 |
2001年 | 347篇 |
2000年 | 371篇 |
1999年 | 376篇 |
1998年 | 123篇 |
1997年 | 117篇 |
1996年 | 99篇 |
1995年 | 87篇 |
1994年 | 77篇 |
1993年 | 85篇 |
1992年 | 231篇 |
1991年 | 227篇 |
1990年 | 254篇 |
1989年 | 250篇 |
1988年 | 207篇 |
1987年 | 223篇 |
1986年 | 203篇 |
1985年 | 200篇 |
1984年 | 182篇 |
1983年 | 149篇 |
1982年 | 74篇 |
1980年 | 77篇 |
1979年 | 116篇 |
1978年 | 108篇 |
1977年 | 85篇 |
1976年 | 94篇 |
1975年 | 77篇 |
1974年 | 97篇 |
1973年 | 92篇 |
1971年 | 86篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Pete Kaiser Tuang Yeow Poh Lisa Rothwell Stuart Avery Sucharitha Balu Uday S Pathania Simon Hughes Marianne Goodchild Shaun Morrell Michael Watson Nat Bumstead Jim Kaufman John R Young 《Journal of interferon & cytokine research》2005,25(8):467-484
As most mechanisms of adaptive immunity evolved during the divergence of vertebrates, the immune systems of extant vertebrates represent different successful variations on the themes initiated in their earliest common ancestors. The genes involved in elaborating these mechanisms have been subject to exceptional selective pressures in an arms race with highly adaptable pathogens, resulting in highly divergent sequences of orthologous genes and the gain and loss of members of gene families as different species find different solutions to the challenge of infection. Consequently, it has been difficult to transfer to the chicken detailed knowledge of the molecular mechanisms of the mammalian immune system and, thus, to enhance the already significant contribution of chickens toward understanding the evolution of immunity. The availability of the chicken genome sequence provides the opportunity to resolve outstanding questions concerning which molecular components of the immune system are shared between mammals and birds and which represent their unique evolutionary solutions. We have integrated genome data with existing knowledge to make a new comparative census of members of cytokine and chemokine gene families, distinguishing the core set of molecules likely to be common to all higher vertebrates from those particular to these 300 million-year-old lineages. Some differences can be explained by the different architectures of the mammalian and avian immune systems. Chickens lack lymph nodes and also the genes for the lymphotoxins and lymphotoxin receptors. The lack of functional eosinophils correlates with the absence of the eotaxin genes and our previously reported observation that interleukin- 5 (IL-5) is a pseudogene. To summarize, in the chicken genome, we can identify the genes for 23 ILs, 8 type I interferons (IFNs), IFN-gamma, 1 colony-stimulating factor (GM-CSF), 2 of the 3 known transforming growth factors (TGFs), 24 chemokines (1 XCL, 14 CCL, 8 CXCL, and 1 CX3CL), and 10 tumor necrosis factor superfamily (TNFSF) members. Receptor genes present in the genome suggest the likely presence of 2 other ILs, 1 other CSF, and 2 other TNFSF members. 相似文献
92.
Although thin fibre muscle afferents possess acid sensing ion channels (ASICs), their contribution to the exercise pressor reflex is not known. This lack of information is partly attributable to the fact that there is no known selective in vivo antagonist for ASICs. Although amiloride has been shown to antagonize ASICs, it also has been shown to antagonize voltage-gated sodium channels, thereby impairing impulse conduction in sensory nerves. Our aim was to test the hypothesis that lactic acid accumulation in exercising muscle acted on ASICs located on thin fibre muscle afferents to evoke the metabolic component of the exercise pressor reflex. To test this hypothesis, we determined in decerebrate cats if amiloride attenuated the pressor and cardioaccelerator responses to static contraction, to tendon stretch and to arterial injections of lactic acid and capsaicin. We found a dose of amiloride (0.5 μg kg−1 ; i.a .) that attenuated the pressor and cardioaccelerator responses to both contraction and lactic acid injection, but had no effect on the responses to stretch and capsaicin. A higher dose of amiloride (5 μg kg−1 , i.a. ) not only blocked the pressor and cardioaccelerator responses to lactic acid and contraction, but also attenuated the responses to stretch and to capsaicin, manoeuvers in which ASICs probably play no significant role. In addition, we found that the low dose of amiloride (0.5 μg kg−1 ) had no effect on the responses of muscle spindles to tendon stretch and to succinylcholine, whereas the high dose (5 μg kg−1 ) attenuated the responses to both. Our data suggest the low dose of amiloride used in our experiments selectively blocked ASICs, whereas the high dose blocked ASICs and impulse conduction in muscle afferents. We conclude that ASICs play a role in the metabolic component of the exercise pressor reflex. 相似文献
93.
The purpose of this study was to investigate the epidemiologic characteristics of the death by poisoning in Korea. We recoded the Death Certificates Database by injury based on the short version of the International Classification of External Causes of Injuries (ICECI). We evaluated the mortality rate by total injury and poisoning, and analyzed the mortality rate by age, gender, year and month, toxic agent, and intent. Adjusted odds ratios were calculated to evaluate the effects of socioeconomic factors on suicidal poisoning death. The total number of death cases by injury was 346,656. The proportion of death cases by injury decreased from 13.53% of all death cases in 1991 to 11.89% in 2001. However, the mortality rate by poisoning increased rapidly from 1998, and then remained stable. The number of suicidal poisoning deaths has gradually increased, and its mortality rate was 6.41 (per 100,000) in 2001. Major toxic agents were pesticides and herbicides (50.90%) in 2001. Adjusted odds ratios of suicidal poisoning versus other poisonings showed significant differences in education attainment, region, and marital status. In conclusion, the mortality rate by poisoning has increased, and the proportion of suicidal poisoning also has increased compared to that of accidental poisoning. 相似文献
94.
A W De Cock L Mendoza A A Padhye L Ajello L Kaufman 《Journal of clinical microbiology》1987,25(2):344-349
Pythium insidiosum sp. nov., the etiologic agent of pythiosis, a cosmopolitan disease of horses, cattle, and dogs, is described and illustrated. 相似文献
95.
A direct extraction of the antigens of group A beta-hemolytic streptococci from 557 throat swabs was performed by a new microtechnique of the nitrous acid extraction method with the Culturette Brand Ten-Minute Strep ID technique from Marion Scientific, Division of Marion Laboratories, Inc., Kansas City, Mo. This group A latex reagent kit contains the reagents for the micronitrous acid extraction of throat swabs and does not require a centrifugation step in its protocol. There was a 99.3% (553 of 557) total agreement between the direct nitrous acid extraction-latex agglutination method and the standard culture method. The direct extraction method yielded an identification of 95.1% (78 of 82) of the group A streptococci identified by the standard method. Throat swabs used for standard culture may also be extracted with nitrous acid for the detection of group A antigen. A 5-min nitrous acid extraction destroys the viability of bacteria associated with normal throat flora as well as group A streptococci and Mycobacterium tuberculosis. This highly rapid method is simple to perform and requires no costly instrumentation. Accordingly, it would be most applicable in a hospital laboratory as well as in a physician's office. 相似文献
96.
Oh S Yoon YW Jang GJ Ahn JB Hong Gp Gang Gh Gang MS Hong Yu Gee JH 《Journal of Korean medical science》2003,18(4):589-591
We report a case of ruptured mycotic aneurysm involving innominate artery requiring an urgent surgical treatment. A 62-yr-old woman presented with fever and dyspnea. Previously, she was diagnosed with colon cancer and received right hemicolectomy and one cycle of adjuvant chemotherapy. On echocardiogram, pericardial effusion was noted and emergency pericardiocentesis was performed. CT scan revealed aortic aneurysm involving ascending aorta and innominate artery, and thrombi surrounding those structures. Patch repair of the defect in the ascending aorta and ringed Goretex graft to bypass the innominate and ascending aorta were performed. We believe that this is the first case of ruptured mycotic aneurysm involving innominate artery. 相似文献
97.
The risk of myocardial infarction after quitting smoking in men under 55 years of age 总被引:10,自引:0,他引:10
L Rosenberg D W Kaufman S P Helmrich S Shapiro 《The New England journal of medicine》1985,313(24):1511-1514
We assessed the effect of quitting cigarette smoking on the incidence of nonfatal myocardial infarction in men under the age of 55 in a case-control study of 1873 men with first episodes of myocardial infarction and 2775 controls. For "current" smokers (men who had smoked in the previous year) as compared with those who had never smoked, the estimated relative risk of myocardial infarction, adjusted for age, was 2.9 (95 per cent confidence interval, 2.4 to 3.4). Among exsmokers (those who had last smoked at least one year previously), the relative-risk estimate declined to a value close to unity for those who had abstained for at least two years; the estimate was 2.0 (1.1 to 3.8) for men who had abstained for 12 to 23 months, and the estimates were about 1.0 for men who had abstained for longer intervals. The results were unchanged by allowance for multiple potential confounding factors. A similar pattern was apparent among exsmokers who had smoked heavily for many years; among those predisposed to a myocardial infarction because of family history, hypertension, or other risk factors; and among those with no apparent predisposition. The results suggest that the risk of myocardial infarction in cigarette smokers decreases within a few years of quitting to a level similar to that in men who have never smoked. 相似文献
98.
Francisella tularensis is a highly infectious gram-negative bacterium with potential for use as a bioweapon. Analysis of the F. tularensis live vaccine strain (LVS) ultrastructure by electron microscopy revealed the presence of long, thin fibers, similar in appearance to type 4 pili. The highly virulent F. tularensis Schu S4 strain was found to contain type 4 pilus genes, and we confirmed that these genes are present and expressed in the LVS. 相似文献
99.
Gil KM Carson JW Porter LS Ready J Valrie C Redding-Lallinger R Daeschner C 《Journal of pediatric psychology》2003,28(5):363-373
OBJECTIVE: To determine the extent to which daily stress and mood are associated with pain, health-care use, and school activity in adolescents with sickle cell disease (SCD). METHOD: Adolescents with SCD (n = 37; aged 13 to 17 years) completed daily diaries assessing pain, stress, mood, activity, and health-care use for up to 6 months. Multilevel modeling was used to analyze the data. RESULTS: Daily increases in stress and negative mood were associated with increases in same-day pain, health-care use, and reductions in school and social activity. Increases in positive mood were associated with decreases in pain, less health-care use, and more activity participation. Notably, pain was predictive of higher stress and lower positive mood on subsequent days. CONCLUSION: Pain in adolescents with SCD is stressful and may lead to alterations in mood states. Understanding the way in which these variables relate to health-care use and activity may lead to improved pain management approaches. 相似文献
100.