全文获取类型
收费全文 | 37870篇 |
免费 | 2766篇 |
国内免费 | 119篇 |
专业分类
耳鼻咽喉 | 364篇 |
儿科学 | 1032篇 |
妇产科学 | 667篇 |
基础医学 | 5470篇 |
口腔科学 | 647篇 |
临床医学 | 3972篇 |
内科学 | 8091篇 |
皮肤病学 | 774篇 |
神经病学 | 3888篇 |
特种医学 | 1389篇 |
外国民族医学 | 11篇 |
外科学 | 5206篇 |
综合类 | 435篇 |
一般理论 | 30篇 |
预防医学 | 3067篇 |
眼科学 | 729篇 |
药学 | 2640篇 |
中国医学 | 93篇 |
肿瘤学 | 2250篇 |
出版年
2023年 | 309篇 |
2022年 | 502篇 |
2021年 | 975篇 |
2020年 | 674篇 |
2019年 | 898篇 |
2018年 | 1070篇 |
2017年 | 854篇 |
2016年 | 966篇 |
2015年 | 1017篇 |
2014年 | 1387篇 |
2013年 | 1711篇 |
2012年 | 2692篇 |
2011年 | 2799篇 |
2010年 | 1583篇 |
2009年 | 1309篇 |
2008年 | 2138篇 |
2007年 | 2288篇 |
2006年 | 2179篇 |
2005年 | 1973篇 |
2004年 | 1867篇 |
2003年 | 1571篇 |
2002年 | 1465篇 |
2001年 | 608篇 |
2000年 | 609篇 |
1999年 | 555篇 |
1998年 | 338篇 |
1997年 | 255篇 |
1996年 | 254篇 |
1995年 | 225篇 |
1994年 | 190篇 |
1993年 | 147篇 |
1992年 | 318篇 |
1991年 | 296篇 |
1990年 | 304篇 |
1989年 | 242篇 |
1988年 | 245篇 |
1987年 | 273篇 |
1986年 | 283篇 |
1985年 | 268篇 |
1984年 | 222篇 |
1983年 | 175篇 |
1982年 | 124篇 |
1979年 | 236篇 |
1978年 | 160篇 |
1977年 | 138篇 |
1976年 | 120篇 |
1974年 | 128篇 |
1973年 | 138篇 |
1972年 | 119篇 |
1971年 | 119篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
Bourn David; Carter Simon A.; Mason Susan; Evans D.Gareth R.; Strachan Tom 《Human molecular genetics》1994,3(5):813-816
The recent identification of the NF2 tumour suppressor genehas enabled large scale screening for pathological mutationsin the gene. We have sought germline mutations In the NF2 geneby SSCP and heteroduplex analysis of cDNA and genomic DNA samplesfollowed by cloning and sequencing of mutant alleles. In thepresent report we describe 11 putative pathological mutations,including five nonsense mutations, three short insertions ordeletions cauing frameshifts and three missense mutations. Moststop mutations and frameshift mutations were found In Individualsexpressing a severe phenotype while one of the three missensemutations was associated with a mild phenotype. Four unrelatedNF2 patients of the 93 tested were found to have identical nonsensemutations caused by a C to T transition (C169) in a CpG dinucleotide,which is a potential mutational hotspot in the NF2 tumour suppressorgene. 相似文献
92.
A K Simon E Seipelt J Sieper 《Proceedings of the National Academy of Sciences of the United States of America》1994,91(18):8562-8566
A major immunoregulatory mechanism in inflammatory infections and allergic diseases is the control of the balance of cytokines secreted by Th1/Th2 subsets of T helper (Th) cells. This might also be true in autoimmune diseases; a Th2 pattern that prevents an effective immune response in infections with intracellular bacteria may favor immunosuppression in autoimmune disease. The pattern of cytokine expression was compared in the synovial tissue from patients with a typical autoimmune disease, rheumatoid arthritis, and with a disorder with similar synovial pathology but driven by persisting exogenous antigen, reactive arthritis. We screened 12 rheumatoid and 9 reactive arthritis synovial tissues by PCR and in situ hybridization for their expression of T-cell cytokines. The cytokine pattern differs significantly between the two diseases; rheumatoid arthritis samples express a Th1-like pattern whereas in reactive arthritis interferon gamma expression is accompanied by that of interleukin 4. Studying the expression of cytokines by in situ hybridization confirmed the results found by PCR; they also show an extremely low frequency of cytokine-transcribing cells. In a double-staining experiment, it was demonstrated that interleukin 4 is made by CD4 cells. These experiments favor the possibility of therapeutic intervention in inflammatory rheumatic disease by means of inhibitory cytokines. 相似文献
93.
94.
95.
A definition and systems view of anaerobic capacity 总被引:3,自引:0,他引:3
Simon Green 《European journal of applied physiology》1994,69(2):168-173
The purpose of this paper is both to define terms used in exercise physiology, i.e. anaerobic capacity, anaerobic work capacity and anaerobic potential, and develop a systems perspective of anaerobic capacity. Philosophical argument is used to support the proposed definitions and systems view, which is an approach to assist in the universal acceptance of such terms amongst scientific investigators, coaches and athletes, and provide a focus on physiological mechanisms associated with anaerobic capacity which may be the subject of future investigation. 相似文献
96.
The renal adaptations that maintain potassium homeostasis in diffuse forms of glomerular disease are not well defined. Thus, handling of potassium by superficial nephron segments was examined in a rat model of antiglomerular basement membrane nephritis. Sampling the same nephron successively from the end and beginning of the distal tubule and the end of the proximal tubule allowed a segmental analysis. Despite a 40% reduction in GFR, potassium excretion in the glomerulonephritis animals was normal due to an increase in FEK. The proximal tubule and loop segment did not contribute to the enhanced FEK seen in these animals. In contrast, potassium entry along the distal tubule was significantly greater in the experimental group averaging 13.7 +/- 4.3 pmol/min compared to 1.2 +/- 1.7 pmol/min in controls (P less than 0.01). Multiple linear regression analysis showed that distal tubule potassium entry at any level of flow was enhanced in glomerulonephritis compared to controls (P less than 0.0001). Plasma aldosterone levels were similar in both groups of animals. Thus, the adaptation to potassium excretion seen in glomerulonephritis is partly achieved by the distal tubule through flow-rate independent mechanisms and appears to be independent of plasma aldosterone levels. 相似文献
97.
98.
A crucial component of cardiac rehabilitation programs is exercise therapy. The purpose of this paper is to describe the benefits of exercise and the role of nursing within these programs. Rehabilitation programs must be individualized by identifying different patient populations and appropriate nursing diagnoses. Thereby, benefits of the program are maximized in order to improve the individual's quality of life. 相似文献
99.
OBJECTIVES: Clinical trials and community-based studies often include the Center for Epidemiologic Studies-Depression scale (CES-D) as a measure of depression outcome. We compared responses to symptom-related items on the CES-D by depressed stroke and primary-care patients for several purposes: 1) to illustrate the use of Item Response Theory (IRT)-based (Rasch) models for comparing scale functioning across different patient subgroups; and 2) to inform clinicians and outcome researchers about scale functioning and depressive symptomatology in stroke- compared with primary care-based depression. METHODS: Two data sources were analyzed, including 32 depressed patients who were 3 months poststroke, and 366 depressed primary-care patients. Presence of depression was based on a CES-D score 16 or higher. Rasch models were used to assess item fit and compare item hierarchies between depressed primary-care and stroke patients. RESULTS: Item hierarchies were similar for poststroke depression and primary care-based depression. Interpersonal disruption items were the most difficult to endorse for both groups. No items misfit the scale in primary-care depression. Items relating to restless sleep, unfriendliness, and crying slightly misfit the scale in stroke patients, that is, may measure a different trait. Differential item functioning (DIF) between the groups was identified for items relating to appetite, restless sleep, crying, and feeling disliked. CONCLUSIONS: Results generally supported the use of the CES-D as measure of depression outcome, particularly in primary care-based depression. DIF may imply that slightly different clusters of depressive symptoms are reported by depressed stroke patients compared with primary care, but this is conjectural given the small stroke sample size and the same items have been previously associated with bias in studies of large nonstroke samples. This study found Rasch models to be useful tools to investigate scale performance for different clinical applications. 相似文献
100.