首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1266篇
  免费   61篇
  国内免费   3篇
耳鼻咽喉   9篇
儿科学   25篇
妇产科学   42篇
基础医学   147篇
口腔科学   45篇
临床医学   111篇
内科学   311篇
皮肤病学   16篇
神经病学   161篇
特种医学   30篇
外科学   164篇
综合类   19篇
预防医学   86篇
眼科学   4篇
药学   76篇
肿瘤学   84篇
  2023年   11篇
  2022年   17篇
  2021年   24篇
  2020年   20篇
  2019年   23篇
  2018年   33篇
  2017年   23篇
  2016年   26篇
  2015年   29篇
  2014年   39篇
  2013年   46篇
  2012年   56篇
  2011年   62篇
  2010年   27篇
  2009年   31篇
  2008年   47篇
  2007年   73篇
  2006年   58篇
  2005年   48篇
  2004年   59篇
  2003年   35篇
  2002年   42篇
  2001年   37篇
  2000年   33篇
  1999年   36篇
  1998年   12篇
  1997年   11篇
  1996年   18篇
  1995年   8篇
  1994年   10篇
  1992年   27篇
  1991年   34篇
  1990年   39篇
  1989年   27篇
  1988年   22篇
  1987年   18篇
  1986年   21篇
  1985年   15篇
  1984年   11篇
  1983年   10篇
  1982年   8篇
  1980年   5篇
  1979年   18篇
  1978年   6篇
  1976年   6篇
  1975年   8篇
  1974年   9篇
  1970年   6篇
  1968年   6篇
  1967年   8篇
排序方式: 共有1330条查询结果,搜索用时 0 毫秒
61.
Semicircular canal orientation in the adult resting rabbit   总被引:1,自引:0,他引:1  
Photographs of rabbits in the alert resting position were used to record head position. Semicircular canals were surgically exposed and points measured along each canal were used to compute the best-fit plane using a least-squares method. Computations of mean best-fit planes showed that the horizontal canals were not carried horizontally in the rabbit. The anteromedial edges were superior by 16 degrees. The anterior canals were vertically oriented and made an angle of 43 degrees to the sagittal plane. The posterior canal was tipped in the anterior direction slightly and also made an acute angle (26 degrees) with the frontal plane. Rabbit semicircular canals deviated significantly from orthogonality. The range was 86 degrees (anterior canals) to 133 degrees (posterior canals). Thus, there were no co-planar canals. Such semicircular canal geometry has implications for the neural circuitry controlling posture in the rabbit.  相似文献   
62.
Short-term measurement of suspended particulate matter has been recently made possible since the release of laser-operating portable instruments. Data of a pilot study of field evaluation of environmental tobacco smoke (ETS) with a portable instrument are reported. We analysed the concentrations of total suspended particle (TSP) and of the fine particles PM10, PM7, PM2.5 and PM1 released indoor from a single cigarette, and their levels inside smoking- and non-smoking-areas of a restaurant. The results indicate that ETS creates high level indoor particulate pollution, with concentrations of PM10 exceeding air quality standards. This kind of field evaluation could allow a more careful assessing of short-term exposure to ETS and its relevance to public health.  相似文献   
63.
64.
The study of the early history of electroencephalography can yield fascinating insights and surprises. A revisit to the work of Mario Gozzano (1898-1986) has proved to be particularly stimulating. His EEG study of 1935 is a classic and should be resurrected from the graveyard of history. Gozzano was an eminent clinical neurologist-epileptologist and chairman of the neurological-psychiatric university departments in Cagliari, Pisa, Bologna and, from 1951 to his retirement, in Rome. He quickly recognized the significance of EEG and produced his major experimental EEG work in the wake of a stay at the Berlin-Buch Brain Institute. His prolonged corticograms of various regions in the rabbit demonstrated striking differences between various cortical areas. Topical cortical strychnine produced spikes (a barely known phenomenon at that time) and the evolution from interictal to ictal spiking. Spikes induced by visual stimuli may be regarded as precursors of evoked potentials. While Hans Berger was a holist ("the brain working as a whole"), Gozzano (influenced by Vogt and Kornmueller) provided EEG support for the localizationists.  相似文献   
65.
This paper assesses the basic steps of management and treatment of dysfunctional uterine bleeding (DUB) - the irregular bleeding arising from anovulation. After menarche, the hypothalamic-pituitary-ovarian axis can take several years to mature resulting in anovulatory and therefore irregular cycles. During an anovulatory cycle, the corpus luteum fails to form, causing failure of normal cyclical progesterone secretion. This results in continuous unopposed production of estradiol, stimulating overgrowth of the endometrium. Without progesterone, the endometrium grows thicker and thicker eventually outgrowing its blood supply, leading to necrosis. The end result is very heavy bleeding.  相似文献   
66.
BACKGROUND: Among the third-generation chemotherapy regimens specifically adapted in the last decade for elderly aggressive non-Hodgkin's lymphoma (NHL) patients, we designed an 8-week cyclophosphamide, mitoxantrone, vincristine, etoposide, bleomycin and prednisone (VNCOP-B) plus granulocyte colony-stimulating factor (G-CSF) regimen which, in a national multicenter trial, induced good complete response (CR) and relapse-free survival rates with only moderate toxic effects. Here we report a prospective, multicenter, randomized trial comparing the efficacy and toxicity of 8- and 12-week regimens of VNCOP-B plus G-CSF. PATIENTS AND METHODS: From February 1996 to June 2001, 306 consecutive previously untreated stage II-IV aggressive NHL patients > or =60 years of age were enrolled from 12 Italian cooperative institutions. Of the 297 evaluable patients, 149 and 148 received 8- and 12-week regimens, respectively, of VNCOP-B. RESULTS: The CR rates were 63% and 56% in the 8- and 12-week groups; at a median of 32 months (range 3-62 months), relapse-free survival rates were 59% and 55%, respectively. Hematological and non-hematological toxicities were similar in both treatment groups. CONCLUSIONS: Our data show that extending induction treatment with the VNCOP-B plus G-CSF regimen from 8 to 12 weeks does not raise the CR rate or provide a more durable remission.  相似文献   
67.
Although non-insulin-dependent diabetes mellitus (NIDDM) is considered a major cause of death, the role of some independent risk factors in diabetic patients is under debate. In fact the prognosis of NIDDM diabetes varies considerably in relation to the individual risk pattern, and the different studies are not directly comparable because of differences in size, age and geography of the samples, and type of statistical analysis. The aim of the study is to identify the independent predictors of mortality in a cohort of subjects with NIDDM, and to verify whether the relative risk (RR) of cardiovascular mortality is different in comparison to that of coeval non-diabetic subjects from a general population. The study includes 683 patients with NIDDM from the Northern Italian town of Pordenone, followed up for 6 years and age- and sex-matched to 683 non-diabetic subjects from a Northern Italian general population. When the two cohorts were compared, NIDDM turned out to be a strong risk factor for cardiovascular mortality (RR: 2.67). Age, coronary artery disease (RR: 1.78), arterial hypertension (RR: 1.39), macro- (RR: 2.97) and microalbuminuria (RR: 2.01) were independent predictors of cardiovascular mortality in the diabetics. In conclusion, survival of diabetic patients is worse than that of non-diabetic coeval subjects. Only few items are able to predict cardiovascular mortality in the diabetics, namely age, hypertension, CAD, macro- and microalbuminuria.  相似文献   
68.
The six-minute walking test (WT) is used in trials and clinical practice as an easy tool to evaluate the functional capacity of chronic heart failure (CHF) patients. As WT measurements are highly variable both between and within individuals, this study aims at assessing the contribution of the different sources of variation and estimating the reproducibility of the test. A statistical model describing WT measurements as a function of fixed and random effects is proposed and its parameters estimated. We considered 202 stable CHF patients who performed two baseline WTs separated by a 30 minute rest; 49 of them repeated the two tests 3 months later (follow-up control). They had no changes in therapy or major clinical events. Another 31 subjects performed two baseline tests separated by 24 hours. Collected data were analysed using a mixed model methodology. There was no significant difference between measurements taken 30 minutes and 24 hours apart (p = 0.99). A trend effect of 17 (1.4) m (mean (SE)) was consistently found between duplicate tests (p < 0.001). REML estimates of variance components were: 5189 (674) for subject differences in the error-free value; 1280 (304) for subject differences in spontaneous clinical evolution between baseline and follow-up control, and 266 (23) for the within-subject error. Hence, the standard error of measurement was 16.3 m, namely 4 per cent of the average WT performance (403 m) in this sample. The intraclass correlation coefficient was 0.96. We conclude that WT measurements are characterized by good intrasubject reproducibility and excellent reliability. When follow-up studies > or = 3 months are performed, unpredictable changes in individual walking performance due to spontaneous clinical evolution are to be expected. Their clinical significance, however, is not known.  相似文献   
69.
The authors report a case of stage 1 ovarian dysgerminoma (OD) in a young woman aged 23 who subsequently underwent conservative surgery. A review of the literature shows that in 80% of cases this neoplasia is present at stage 1A and 85% of patients are under 30, with a 5-year survival rate of 95%. OD treatment should therefore be personalized and, although it continues to be controversial, most authors agree that in young women in whom the disease is limited to one ovary, without lymph node metastases, treatment can be restricted to monolateral adnexectomy, thus assuring the patient's future fertility.  相似文献   
70.
A proper mechanical characterization of soft biological tissues of the human body has a strong impact on several medical applications such as surgical planning, virtual reality simulators, trauma research, and for diagnostic purposes. Adequate experimental data are needed to describe quantitatively the mechanical behaviour of those organs. We present a technique for the acquisition of such data from soft tissues and its post processing, based on a continuum mechanics approach, to determine some parameters of the tissue's mechanical properties. A small tube is applied to the target organ and a weak vacuum is generated inside the tube according to a predefined pressure history. A video camera grabs images of the deformation profile of the aspirated tissue, and a pressure sensor measures the correspondent vacuum level. The images are processed and used to inform the fitting of uniaxial and continuum mechanics models. Whilst the aspiration test device is suitable for in vivo applications, under sterile conditions during open surgery, we hereby present first results obtained by testing cadaveric tissues.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号