全文获取类型
收费全文 | 7426篇 |
免费 | 702篇 |
国内免费 | 77篇 |
专业分类
耳鼻咽喉 | 97篇 |
儿科学 | 252篇 |
妇产科学 | 167篇 |
基础医学 | 1208篇 |
口腔科学 | 116篇 |
临床医学 | 803篇 |
内科学 | 1607篇 |
皮肤病学 | 161篇 |
神经病学 | 551篇 |
特种医学 | 527篇 |
外科学 | 825篇 |
综合类 | 168篇 |
一般理论 | 7篇 |
预防医学 | 692篇 |
眼科学 | 172篇 |
药学 | 494篇 |
2篇 | |
中国医学 | 14篇 |
肿瘤学 | 342篇 |
出版年
2021年 | 83篇 |
2020年 | 60篇 |
2019年 | 76篇 |
2018年 | 108篇 |
2017年 | 86篇 |
2016年 | 89篇 |
2015年 | 115篇 |
2014年 | 168篇 |
2013年 | 236篇 |
2012年 | 275篇 |
2011年 | 282篇 |
2010年 | 213篇 |
2009年 | 204篇 |
2008年 | 263篇 |
2007年 | 294篇 |
2006年 | 286篇 |
2005年 | 261篇 |
2004年 | 228篇 |
2003年 | 190篇 |
2002年 | 230篇 |
2001年 | 194篇 |
2000年 | 194篇 |
1999年 | 156篇 |
1998年 | 191篇 |
1997年 | 208篇 |
1996年 | 183篇 |
1995年 | 163篇 |
1994年 | 161篇 |
1993年 | 139篇 |
1992年 | 153篇 |
1991年 | 160篇 |
1990年 | 146篇 |
1989年 | 180篇 |
1988年 | 161篇 |
1987年 | 167篇 |
1986年 | 167篇 |
1985年 | 178篇 |
1984年 | 131篇 |
1983年 | 96篇 |
1982年 | 93篇 |
1981年 | 79篇 |
1980年 | 86篇 |
1979年 | 101篇 |
1978年 | 80篇 |
1977年 | 65篇 |
1976年 | 65篇 |
1975年 | 61篇 |
1974年 | 74篇 |
1973年 | 57篇 |
1972年 | 70篇 |
排序方式: 共有8205条查询结果,搜索用时 15 毫秒
1.
JM Martín† L Calduch† C Monteagudo‡ I Molina† D Ramón† V Alonso† E Jordᆠ《Journal of the European Academy of Dermatology and Venereology》2006,20(4):428-431
Cutaneous plasmacytosis is a rare disorder characterized by a benign proliferation of mature plasma cells that appears as multiple dark-brown to purplish skin lesions, often associated with polyclonal hypergammaglobulinaemia. We present the case of a 55-year-old Caucasian man who suffered from a cutaneous plasmacytosis associated with two different carcinomas. Cutaneous plasmacytosis seems to be a reactive process because most cases reported are not associated with any apparent underlying disease. Nevertheless, because few reported cases were associated with malignancies, screening of additional neoplasms would be justified. 相似文献
2.
3.
Relation between energy expenditure and body composition in man: specific energy expenditure in vivo of fat and fat-free tissue 总被引:2,自引:0,他引:2
L Garby J S Garrow B J?rgensen O Lammert K Madsen P S?rensen J Webster 《European journal of clinical nutrition》1988,42(4):301-305
The relationship between energy expenditure and body composition, in terms of fat and fat-free masses, has previously been described by a variety of predictive regression equations with parameters devoid of physiological content. We present here results obtained by calculating the specific energy expenditure, ie, the energy expenditure per unit of mass, of fat and fat-free tissue on the basis of measurements of the total energy expenditure (EE), the masses of fat (FM), and fat-free (FFM) tissue using the following simple model: EE = k1.FM + k2.FFM where k1 and k2 are the specific energy expenditures of fat and fat-free tissue, respectively. The results of observations on 104 women at rest yielded values for k1 and k2 of 0.31 and 1.35 watts/kg of fat and fat-free mass, respectively, with standard errors of estimate of 0.074 and 0.052 watts/kg, respectively. Analysis of several series of measurements, from other sources and on smaller samples of subjects, yielded similar values at rest but with larger standard errors of estimate. Data from subjects performing varying amounts of work in 24-h measurements showed, as expected, larger values for both tissues. The results explain to a very large extent the well-established relation between resting metabolic rate and body weight, ie, a linear relation with a non-zero intercept. The results also offer a clear-cut explanation for the well known difference in energy expenditure between men and women with the same body weight. 相似文献
4.
5.
Myelinated fiber regeneration after crush injury is retarded in sciatic nerves of aging mice 总被引:2,自引:0,他引:2
To compare nerve regeneration in young adult and aging mice, the right sciatic nerves of 6- and 24-month-old mice were crushed at the sciatic notch. Two weeks later, both groups of mice were perfused with an aldehyde solution, and, after additional fixation, the sciatic nerves were processed so that the transverse sections of each nerve subsequently studied by light and electron microscopy included the entire posterior tibial fascicle 5 mm distal to the crush site. The same level was sectioned in unoperated contralateral nerves; these nerves served as controls. Electron micrographs and the Bioquant Image Analysis System IV were used to measure areas of posterior tibial fascicles and count the number of myelinated axons, the number of unmyelinated axons, and their frequency in Schwann cell units. In aging mice, the total number of regenerating myelinated axons was significantly reduced, but totals of regenerating unmyelinated axons in aging and young adults did not differ significantly. In aging mice, the frequency of Schwann cells that contained a single unmyelinated axon was greater, suggesting that before myelination began, Schwann cell ensheathment of axons also was slowed. After axotomy by a crush injury, the area of the posterior tibial fascicle was less than that in young adults and the distal disintegration of myelin sheath remnants also appeared to be retarded. The results indicate that responses of neurons, axons, and Schwann cells could be important in slowing the regeneration of myelinated fibers found in sciatic nerves from aging mice. 相似文献
6.
Stanley J. Bigos John Holland Carole Holland John S. Webster Michele Battie Judith A. Malmgren 《The spine journal》2009,9(2):147-168
Background contextBack problems (BPs), with their cost and disability, are a substantial burden for individuals, employers, and society.PurposeThis systematic review of controlled trials evaluates the effectiveness of interventions to prevent BP episodes in working age adults.Data sourcesWe searched MEDLINE/EMBASE through May 2007, and COCHRANE/Trials Registry through August 22, 2008 using search terms of back pain, back injuries or sciatica, linked to prevention, control, workplace interventions, or ergonomics and searched article bibliographies.Study selectionFor systematic review inclusion, articles had to describe prospective controlled trials of interventions to prevent BPs in working-age adults, with intervention assignment either to individual participants or preexisting groups. Of 185 articles identified as potentially relevant, 20 trials (11%) met inclusion criteria.Data extractionResearchers extracted relevant information from controlled trials and graded methodological quality. Because of heterogeneity of trials, meta-analysis was not performed.ResultsOnly exercise was found effective for preventing self-reported BPs in seven of eight trials (effect size 0.39 to >0.69). Other interventions were not found to reduce either incidence or severity of BP episodes compared with controls. Negative trials included five trials of education, four of lumbar supports, two of shoe inserts, and four of reduced lifting programs.ConclusionsTwenty high-quality controlled trials found strong, consistent evidence to guide prevention of BP episodes in working-age adults. Trials found exercise interventions effective and other interventions not effective, including stress management, shoe inserts, back supports, ergonomic/back education, and reduced lifting programs. The varied successful exercise approaches suggest possible benefits beyond their intended physiologic goals.Level of evidenceSystematic review Level I evidence. 相似文献
7.
JM Vilanova J Figueras-Aloy J Roselló G Gómez E Gelpí R Jiménez 《Acta paediatrica (Oslo, Norway : 1992)》1998,87(5):588-592
The aim of this study was to evaluate the cerebral synthesis of eicosanoids in the asphyctic newborn and to investigate the relation between the prostanoid profiles in cerebrospinal fluid (CSF) and the appearance and severity of hypoxic-ischaemic encephalopathy (HIE). Levels of 6-keto-PGF 1-α, TXB2 , PGE2 and PGF2-α in CSF were measured in 40 full term newborns during the first day of life. Thirty of these newborns had birth asphyxia and were divided into three groups: 10 without HIE, 12 with mild HIE and 8 with moderate-severe HIE. They were compared to a control group of 10 non-hypoxic newborns. Determinations of the metabolites in CSF were performed by RIA and expressed as pg/ml (mean ± SD). The CSF TXB2 (thromboxane A2 metabolite) in asphyxiated newborns was always higher than in the control group (28.12 ± 10.6), and related to the severity of HIE ( p = 0:005): without HIE (50.84 ± 16.4; p = 0:02), mild HIE (80.65 ± 12.64; p ± 0:01) and moderate-severe HIE (178.14 ± 20.5; p < 0:01). The CSF 6-keto-PGF 1-α (prostacyclin metabolite) in asphyxiated newborns was always higher than in the control group (80.55 ± 12.56), but indirectly related to the severity of HIE: without HIE (240.95 ± 28.12; p < 0:01), mild HIE (183.65 ± 30.1; p < 0:01) and moderate-severe HIE (140.55 ± 25.12; p < 0:01). In the moderate-severe HIE group, the increase in TXB2 was higher than the rise in 6-keto-PGF 1-α . 相似文献
8.
9.
Varicose vein surgery using a pneumatic tourniquet: reduced blood loss and improved cosmesis. 总被引:5,自引:5,他引:0
下载免费PDF全文
![点击此处可从《Annals of the Royal College of Surgeons of England》网站下载免费的PDF全文](/ch/ext_images/free.gif)
J. F. Thompson G. T. Royle P. A. Farrands A. Najmaldin P. C. Clifford J. H. Webster 《Annals of the Royal College of Surgeons of England》1990,72(2):119-122
A prospective controlled randomised study has been performed of 100 consecutive patients undergoing varicose vein surgery. One group underwent saphenofemoral flush ligation and multiple lower leg avulsions with the leg exsanguinated with a Rhys-Davies cuff, and ischaemia maintained with a pneumatic tourniquet. The other group underwent identical surgery but with a 30 degree head down tilt only. Blood loss was significantly less (13.5 +/- 12 ml vs 133 +/- 78 ml; P less than 0.01) and postoperative cosmesis was significantly improved in patients in the tourniquet group. Operating time was similar (27 +/- 11 min vs 30 +/- 13 min) in the two groups. 相似文献
10.
Occurrence of the t(2;5)(p23;q35) in non-Hodgkin's lymphoma 总被引:9,自引:3,他引:6
Weisenburger DD; Gordon BG; Vose JM; Bast MA; Chan WC; Greiner TC; Anderson JR; Sanger WG 《Blood》1996,87(9):3860-3868
Primary CD30(Ki-1)-positive anaplastic large-cell lymphoma (ALCL) is considered by some to be a distinct clinicopathologic entity associated with the t(2;5) (p23;q35). However, the specificity of t(2;5) for ALCL has not been carefully studied. Therefore, we performed a detailed analysis of all cases of ALCL with abnormal cytogenetics results in the Nebraska Lymphoma Study Group registry, as well as all other cases of non-Hodgkin's lymphoma with t(2;5) in the registry. We found the t(2;5) in only five of 10 cases of ALCL, four of whom were young patients. However, we also found the t(2;5) in 11 other cases of nonanaplastic lymphoma, including eight children with typical peripheral T-cell lymphomas of various types. The t(2;5) was also found in three older adults with B-cell lymphomas of various types. Thus, the t(2;5) was not specific for CD30+ ALCL. However, t(2;5) may define a clinicopathologic entity in children and young adults characterized by variable morphologies with a T-cell or indeterminate phenotype, CD30-positivity, nodal disease with frequent extranodal involvement, advanced stage, and an excellent response to therapy, including bone marrow transplantation for relapsed disease. The clinical relevance of the t(2;5) in older patients requires further study. 相似文献