全文获取类型
收费全文 | 31383篇 |
免费 | 2173篇 |
国内免费 | 116篇 |
专业分类
耳鼻咽喉 | 238篇 |
儿科学 | 1011篇 |
妇产科学 | 631篇 |
基础医学 | 4231篇 |
口腔科学 | 902篇 |
临床医学 | 3207篇 |
内科学 | 6034篇 |
皮肤病学 | 410篇 |
神经病学 | 3325篇 |
特种医学 | 1140篇 |
外国民族医学 | 6篇 |
外科学 | 4475篇 |
综合类 | 369篇 |
一般理论 | 51篇 |
预防医学 | 2290篇 |
眼科学 | 1121篇 |
药学 | 2275篇 |
中国医学 | 51篇 |
肿瘤学 | 1905篇 |
出版年
2022年 | 170篇 |
2021年 | 417篇 |
2020年 | 267篇 |
2019年 | 435篇 |
2018年 | 529篇 |
2017年 | 432篇 |
2016年 | 475篇 |
2015年 | 527篇 |
2014年 | 743篇 |
2013年 | 1249篇 |
2012年 | 1908篇 |
2011年 | 2091篇 |
2010年 | 1133篇 |
2009年 | 1086篇 |
2008年 | 2003篇 |
2007年 | 2280篇 |
2006年 | 2192篇 |
2005年 | 2222篇 |
2004年 | 2114篇 |
2003年 | 2097篇 |
2002年 | 2004篇 |
2001年 | 264篇 |
2000年 | 210篇 |
1999年 | 276篇 |
1998年 | 453篇 |
1997年 | 405篇 |
1996年 | 309篇 |
1995年 | 328篇 |
1994年 | 314篇 |
1993年 | 307篇 |
1992年 | 218篇 |
1991年 | 195篇 |
1990年 | 176篇 |
1989年 | 147篇 |
1988年 | 151篇 |
1987年 | 138篇 |
1986年 | 174篇 |
1985年 | 172篇 |
1984年 | 290篇 |
1983年 | 264篇 |
1982年 | 335篇 |
1981年 | 304篇 |
1980年 | 316篇 |
1979年 | 156篇 |
1978年 | 188篇 |
1977年 | 196篇 |
1976年 | 123篇 |
1975年 | 130篇 |
1974年 | 112篇 |
1973年 | 83篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
101.
102.
The external genitalia of one perimenarcheal and five adult female white handed-gibbons (Hylobates (H.) lar) were examined to clarify their gross anatomy. It was found that the vulval structures were complex and exhibited inter-individual variation in arrangement. This complexity appears to result from an ontogenetic process by which the tissues of the vaginal rim (the labia minora) bud-off and extrude extensions toward the vagina immediately prior and subsequent to menarche. Two of these lobular structures surround the urethral meatus with associated prepuce and frenulum and vestigial labia majora, undergo cycles of tumescence and detumescence during intermenstrual intervals. The complex form of the external genitalia and the presence of a swelling cycle are unusual for a monogamous species, are contrary to current applications of sexual selection theory, and raise questions about the significance of mate choice in hominoid evolution. 相似文献
103.
The level of psychiatric morbidity and perceived sources of stress among police officers were investigated using the General Health Questionnaire (GHQ) and a stress situation questionnaire, which were sent to 171 officers. Half of the responders were invited to attend group counselling sessions weekly for 12 weeks. Outcome measures studied were a second GHQ completed at the end of the treatment period and the amounts of sick leave taken in the 12-week period before, during and after the treatment period. The results were that 61 people returned the first GHQ of whom 59 were male and of whom 14 were classed as ‘cases’. Of the 31 assigned to the treatment group, 22 attended at least one session. Responses to the stress situation questionnaire and the content of counselling sessions tended to confirm the impression that internal aspects of the organization were viewed as prime sources of stress and dissatisfaction. There were no significant changes in GHQ score within or between groups, nor were there significant differences in the amount of sick leave taken. Nevertheless the sessions appeared to be valued and we conclude that this sort of intervention is at least feasible. We recommend that similar studies measure psychiatric morbidity during treatment and at follow-up, rather than immediately after finishing, when reactions to this termination are prominent. 相似文献
104.
Dr. Ronald L. Bauer MD Michael L. Palmer MD Andrea M. Bauer MSN RN CS Hector R. Nava MD Harold O. Douglass Jr. MD 《Annals of surgical oncology》1994,1(3):183-188
Background: The purpose of this study was to evaluate the tumor characteristics and treatment associated with an improved overall survival in patients with adenocarcinoma of the small intestine.
Methods: The records of all patients with primary adenocarcinoma of the small bowel seen between January 1971 and December 1991 were reviewed retrospectively. The study comprised 38 patients, 22 (58%) with duodenal tumors, 11 (29%) with jejunal tumors, and five (13%) with ileal tumors.
Results: Although not statistically significant, the patients with duodenal adenocarcinoma lived longer than the patients with jejunal or ileal lesions (p=0.77). The overall survival was 23% and seemed to correlate best with absence of lymph node metastases (p=0.04) and pancreaticoduodenectomy for localized duodenal tumors (p=0.04). The patient's age, duration of symptoms, disease-free interval, tumor location, type of recurrence, and histologic grade did not significantly influence survival.
Conclusions: The lethality of small-intestinal adenocarcinoma appears to be related to a delay in diagnosis and treatment. When a definitive surgical procedure is performed before lymph node metastases appear, the patient's chance for long-term survival is greatly improved.Presented at the 46th Annual Cancer Symposium of The Society of Surgical Oncology, Los Angeles, California, March 18–21, 1993. 相似文献
105.
Ronald B. Stewart Ronald G. Marks Phillip D. Padgett William E. Hale 《Pharmacoepidemiology and drug safety》1994,3(1):23-29
The objective of the work was to identify changes in antidepressant drug use and determine if the prevalence of antidepressant use has changed over 14 years. A longitudinal analysis comparing antidepressant drug use at 14 yearly intervals from 1978–79 to 1991–92 was undertaken using the longitudinal health screening program of ambulatory elderly participants (Florida Geriatric Research Program). Participants included all subjects screened in the Florida Geriatric Research Program from 1 August 1978 to 31 July 1992. The outcome measures were self-reported antidepressant drug use. Approximately 3.0 per cent (range of 2.3 to 3.2 per cent over 14 yearly intervals) of participants in this program reported the use of an antidepressant drug. There was no statistically significant change in antidepressant use between 1978–79 and 1991–92 (p > 0.6630). Across all study intervals women reported more frequent use of antidepressant drugs than men. In 1991–92, amitriptyline and imipramine represented over 50 per cent of all antidepressant drug use in this elderly population. Less than 6 per cent of all antidepressant drug use was for fluoxetine, the newest selective serotonin uptake inhibitor. The majority of elderly patients are receiving older tertiary amine tricyclic antidepressants such as amitriptyline, imipramine and doxepin that are not the preferred drugs for the elderly. Educational programs are needed to improve antidepressant prescribing for geriatric patients. 相似文献
106.
107.
R.P. Butt J.P. Huggins D. Greiling B. Hopkins S. Gaboardi D. Winslow M. Ronald S. Lewis S. Ward E. Levett J. Owen F. Burslem M. Collis S. Bailey P.V. Fish G. Whitlock S. Billotte K. James A. Mcelroy J. Blagg 《International journal of experimental pathology》2004,85(1):A20-A21
Introduction Fibrosis is a component of many tissue pathologies leading to loss of normal tissue function, primarily due to excessive collagen deposition. Collagen is deposited following cleavage of the C- and N- terminal peptides from the pro-collagen molecule. The cleavage of the globular C-peptide by PCP reduces solubility of the fibrillar collagen molecule, resulting in deposition of insoluble collagen. Increased insoluble collagen deposition is a feature of all organ fibroses, with inhibition of this process, a key potential anti-fibrotic mechanism. The aim of this work was to discover potent and selective PCP inhibitors as experimental, topically applied, anti-fibrotic drugs for clinical evaluation.
Materials and methods PCP was cloned from human osteosarcoma cells and enzymatic activity demonstrated using a PCP-specific peptide cleavage assay. Activities were confirmed by measuring cleavage of [3 H]C-peptide from type-I pro-collagen. A cell-based fibroplasias model was employed to demonstrate compound efficacy using collagen deposition, liberated C-peptide and histological endpoints. The activities of PCP inhibitors in fibroblast and epithelial in vitro cell proliferation and migration assays, and selectivity vs. a panel of MMPs were also determined.
Discussion In summary, we have identified and characterized potent and selective inhibitors of PCP for progression to clinical studies for investigation as a treatment paradigm for fibrotic disease.
Materials and methods PCP was cloned from human osteosarcoma cells and enzymatic activity demonstrated using a PCP-specific peptide cleavage assay. Activities were confirmed by measuring cleavage of [
Discussion In summary, we have identified and characterized potent and selective inhibitors of PCP for progression to clinical studies for investigation as a treatment paradigm for fibrotic disease.
Results 相似文献
108.
109.
110.
Microvascular function in viable myocardium after chronic infarction does not influence fractional flow reserve measurements. 总被引:1,自引:0,他引:1
Koen M Marques Paul Knaapen Ronald Boellaard Adriaan A Lammertsma Nico Westerhof Frans C Visser 《Journal of nuclear medicine》2007,48(12):1987-1992
Fractional flow reserve (FFR) is an index of coronary stenosis severity. FFR is the ratio of hyperemic myocardial flow in the stenotic area to maximal flow in that same territory without stenosis and can be measured with a pressure wire. In patients with prior infarction, measuring FFR in infarct-related arteries may be different for 2 reasons: a smaller mass of viable myocardium depending on the stenotic infarct-related artery and greater microvascular resistance in the infarcted area than in the reference area. When microvascular resistance does not differ between the infarcted and the reference areas, FFR should equal relative flow reserve (RFR). RFR is the ratio of myocardial blood flow in the stenotic area to blood flow in a normally perfused reference area, at maximal hyperemia. H(2)(15)O PET measures myocardial flow within only the viable areas of an infarct and can be used to measure RFR. The present study assessed in patients with chronic myocardial infarction whether microvascular resistance in the infarct is different from that in the reference area. Therefore, the correlation between FFR and RFR using H(2)(15)O PET was studied. METHODS: In the catheterization laboratory, FFR was measured in the infarct-related artery and a reference coronary artery. The H(2)(15)O PET study and FFR measurements were performed on the same day in 22 patients. RESULTS: In 27 patients, the mean interval between the PET study and infarction was 3.3 y. Most patients had an anterior infarction, and the mean ejection fraction was 44%. The mean FFR and RFR values were 0.75 +/- 0.16 and 0.74 +/- 0.18, respectively. A significant correlation (r = 0.81; P < 0.0001) was found between FFR and RFR. The linear regression line was close to the line of identity. CONCLUSION: In patients with chronic myocardial infarction and a reduced ejection fraction, a good correlation was found between FFR measurements in the infarct-related artery and RFR. Because the linear regression line between FFR and RFR was close to the line of identity, one can conclude that microvascular resistance in the viable myocardium does not differ from that in the reference area. 相似文献