全文获取类型
收费全文 | 2027篇 |
免费 | 138篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 56篇 |
妇产科学 | 49篇 |
基础医学 | 368篇 |
口腔科学 | 37篇 |
临床医学 | 189篇 |
内科学 | 413篇 |
皮肤病学 | 19篇 |
神经病学 | 71篇 |
特种医学 | 236篇 |
外科学 | 397篇 |
综合类 | 14篇 |
一般理论 | 1篇 |
预防医学 | 96篇 |
眼科学 | 2篇 |
药学 | 117篇 |
肿瘤学 | 105篇 |
出版年
2021年 | 21篇 |
2020年 | 15篇 |
2019年 | 20篇 |
2018年 | 31篇 |
2017年 | 26篇 |
2016年 | 22篇 |
2015年 | 28篇 |
2014年 | 29篇 |
2013年 | 51篇 |
2012年 | 67篇 |
2011年 | 73篇 |
2010年 | 39篇 |
2009年 | 54篇 |
2008年 | 69篇 |
2007年 | 75篇 |
2006年 | 69篇 |
2005年 | 76篇 |
2004年 | 65篇 |
2003年 | 53篇 |
2002年 | 52篇 |
2001年 | 57篇 |
2000年 | 57篇 |
1999年 | 53篇 |
1998年 | 32篇 |
1997年 | 41篇 |
1996年 | 43篇 |
1995年 | 35篇 |
1994年 | 33篇 |
1993年 | 22篇 |
1992年 | 53篇 |
1991年 | 48篇 |
1990年 | 66篇 |
1989年 | 70篇 |
1988年 | 65篇 |
1987年 | 69篇 |
1986年 | 63篇 |
1985年 | 76篇 |
1984年 | 43篇 |
1983年 | 39篇 |
1982年 | 41篇 |
1981年 | 34篇 |
1980年 | 23篇 |
1979年 | 27篇 |
1978年 | 28篇 |
1977年 | 20篇 |
1976年 | 15篇 |
1975年 | 10篇 |
1974年 | 15篇 |
1973年 | 14篇 |
1967年 | 11篇 |
排序方式: 共有2179条查询结果,搜索用时 46 毫秒
61.
62.
63.
Consecutive adult patients (n = 70) referred for investigation of suspected asthma were reinvestigated after 5 years with the same diagnostic procedures (airway symptom score, spirometry, methacholine test) as used at the initial investigation. The same diagnostic criteria for asthma, asthma-like disorder (current asthma-like symptoms but negative asthmatests)and chronicobstructive pulmonary disease (COPD) were used at both visits. At the first visit 39/70 patients (56%) fulfilled the asthma criteria, 21/70 (27%) fulfilled the asthma-like criteria and 5/70 (7%) the COPD criteria. Due to lack of current symptoms 5/70 (7%) could not be classified. 5/70 patients (7%) were smokers, however, in the majority (72%) smoke was not tolerated as it induced asthma-like symptoms. At the investigation, 5 years later, 30/39 patients (76%) still fulfilled the asthma criteria and 12/21 patients (57%) still fulfilled the asthma-like criteria. At the 5-year investigation, 10% of patients in the asthma group now fulfilled the asthma-like criteria and 10% of patients in the asthma-like group fulfilled the asthma criteria. It is concluded that asthma as well an asthma-like syndrome may persist for 5 years or more. It is also concluded thatthe two disorders are closely related as patients in the asthma group over time could move into the diagnostic criteria ofthe asthma-like disorder and vice versa. 相似文献
64.
Esophageal injury during mediastinoscopy is a rare and easily overlooked complication. In this paper 2 complicated cases, one associated with a pulmonary artery lesion, are reported. Both patients eventually recovered. The principles of management are discussed based on these cases. 相似文献
65.
Structure of genes for virus-associated RNAI and RNAII of adenovirus type 2. 总被引:31,自引:0,他引:31 下载免费PDF全文
G Akusj?rvi M B Mathews P Andersson B Vennstr?m U Pettersson 《Proceedings of the National Academy of Sciences of the United States of America》1980,77(5):2424-2428
A DNA sequence, 552 base pairs in length, encoding the two "virus-associated" (VA) RNAs of adenovirus type 2 is presented. Comparison of the oligonucleotide maps of VA RNAI and VA RNII with the established sequence permits identification of the genes for these RNAs. VA RNAI is 157-160 nucleotides long and VA RNAII 158-163 nucleotides long, depending on the exact length of their heterogeneous 3' end. The genes are separated by a spacer of about 98 nucleotides. The RNAs exhibit scattered regions of primary sequence homology and can adopt secondary structures which resemble each other closely in their configuration and stability. VA RNAII is also capable of assuming a different configuration that is energetically more favorable. The data suggest that the two RNA genes may have arisen by duplication of an ancestral gene and that the folding of the RNA chain may be of importance for the function of VA RNAs. Hypothetical RNA polymerase III recognition sequences and the coding potential of the region are discussed. 相似文献
66.
Pettersson C Fogelstrand L Rosengren B Ståhlman S Hurt-Camejo E Fagerberg B Wiklund O 《Journal of internal medicine》2008,264(2):155-165
Background. Lipolysis of lipoproteins by secretory phospholipase A2 group V (sPLA2‐V) promotes inflammation, lipoprotein aggregation and foam cell formation – all considered as atherogenic mechanisms. Objective. In this study, we compared the susceptibility to sPLA2‐V lipolysis of VLDL and LDL from individuals with type 2 diabetes and the metabolic syndrome (T2D‐MetS) and from healthy controls. Design. VLDL and LDL were isolated from 38 T2D‐MetS subjects and 38 controls, treated pair‐wise. Extent of sPLA2‐V lipolysis was measured as release of nonesterified free fatty acids (NEFA). In a subset of the subjects, lipoprotein composition was determined as a relationship between lipid and apolipoprotein components. Results. Mean paired increase in sPLA2‐V lipolysis after 1 h for T2D‐MetS versus control was 2.0 μmol NEFA l?1 for VLDL (P = 0.004) and 0.75 μmol NEFA l?1 for LDL (P = 0.001). There were also substantial differences in lipoprotein composition between the groups. T2D‐MetS VLDL had higher triglyceride and cholesterol contents than control VLDL. T2D‐MetS LDL was smaller and contained more triglycerides and less cholesterol than control LDL. Both VLDL and LDL from T2D‐MetS subjects also contained more apolipoprotein CIII per particle. Conclusion. VLDL and LDL from T2D‐MetS individuals were more susceptible to sPLA2‐V lipolysis than those from control individuals. This may result in elevated levels of NEFA and lysophosphatidylcholine, both in circulation and in LDL, possibly contributing to the elevated inflammatory state and increased risk of cardiovascular diseases seen in these individuals. 相似文献
67.
68.
Rebecca E. Graff Andreas Pettersson Rosina T. Lis Natalie DuPre Kristina M. Jordahl Elizabeth Nuttall Jennifer R. Rider Michelangelo Fiorentino Howard D. Sesso Stacey A. Kenfield Massimo Loda Edward L. Giovannucci Bernard Rosner Paul L. Nguyen Christopher J. Sweeney Lorelei A. Mucci 《The Prostate》2015,75(9):897-906
69.
We have identified a black individual with homozygous sickle cell anemia who is the silent carrier of alpha-thalassemia (genotype - alpha/alpha alpha) due to heterozygosity for the leftward deletion alpha-thal-2 haplotype. This deletion has not been described previously in a black subject and is the only leftward deletion that we have found among 255 alpha-thal-2 chromosomes from sickle cell subjects. Its effects on the clinical, hematologic, biosynthetic, and cellular pathology of sickle cell anemia resemble those reported for the common alpha-thalassemia genotypes of the black population. 相似文献
70.
The basic helix-loop-helix-PAS protein ARNT functions as a potent coactivator of estrogen receptor-dependent transcription 下载免费PDF全文