全文获取类型
收费全文 | 41004篇 |
免费 | 4064篇 |
国内免费 | 1001篇 |
专业分类
耳鼻咽喉 | 195篇 |
儿科学 | 836篇 |
妇产科学 | 259篇 |
基础医学 | 4400篇 |
口腔科学 | 810篇 |
临床医学 | 5072篇 |
内科学 | 3288篇 |
皮肤病学 | 403篇 |
神经病学 | 2067篇 |
特种医学 | 1837篇 |
外国民族医学 | 3篇 |
外科学 | 1680篇 |
综合类 | 7895篇 |
现状与发展 | 2篇 |
一般理论 | 3篇 |
预防医学 | 8726篇 |
眼科学 | 1389篇 |
药学 | 4448篇 |
153篇 | |
中国医学 | 1614篇 |
肿瘤学 | 989篇 |
出版年
2024年 | 144篇 |
2023年 | 670篇 |
2022年 | 1318篇 |
2021年 | 1717篇 |
2020年 | 1716篇 |
2019年 | 1566篇 |
2018年 | 1458篇 |
2017年 | 1662篇 |
2016年 | 1830篇 |
2015年 | 1584篇 |
2014年 | 2914篇 |
2013年 | 3255篇 |
2012年 | 3044篇 |
2011年 | 3087篇 |
2010年 | 2444篇 |
2009年 | 2065篇 |
2008年 | 2272篇 |
2007年 | 2299篇 |
2006年 | 1922篇 |
2005年 | 1401篇 |
2004年 | 1160篇 |
2003年 | 909篇 |
2002年 | 771篇 |
2001年 | 650篇 |
2000年 | 583篇 |
1999年 | 444篇 |
1998年 | 321篇 |
1997年 | 315篇 |
1996年 | 258篇 |
1995年 | 290篇 |
1994年 | 246篇 |
1993年 | 216篇 |
1992年 | 194篇 |
1991年 | 154篇 |
1990年 | 149篇 |
1989年 | 119篇 |
1988年 | 110篇 |
1987年 | 117篇 |
1986年 | 68篇 |
1985年 | 133篇 |
1984年 | 110篇 |
1983年 | 94篇 |
1982年 | 69篇 |
1981年 | 52篇 |
1980年 | 50篇 |
1979年 | 33篇 |
1978年 | 25篇 |
1977年 | 14篇 |
1976年 | 17篇 |
1973年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
21.
J. G. BLIGH 《Medical education》1992,26(6):497-502
Self-directed learning is a natural way for adults to learn. Vocational training for general practice is a preparation for unsupervised clinical work that will be supported, in the main, by continuing medical education. This study uses the Self-Directed Learning Readiness Scale to investigate factors influencing readiness for such learning among a sample of general practice trainees. Three principal factors emerged from analysis: enjoyment and enthusiasm for learning; a positive self-concept as a learner and a factor suggesting the possibility of a 'reproducing' orientation to learning. These factors may reflect approaches to learning in general rather than these adopted for professional learning, but offer helpful pointers for the development of both vocational training and of continuing medical education. 相似文献
22.
This paper provides for the first time evidence of a consistent difference in the memory structures of novice and expert clinicians. The diagnostic performance of first- and third-year clinical medical students, senior house officers, registrars and consultants on four clinical problems in general medicine was studied. Comparisons were made of all diagnostic interpretations offered and the forceful features (personally important pieces of information which act as a key to particular memory structures which in turn give rise to the clinical interpretation) from which these were derived. Results demonstrate that the numbers of interpretations made and the numbers of forceful features identified did not differ significantly between groups (P greater than 0.05). However, the actual interpretations made in three out of four cases, and the actual forceful features identified in all cases, did differ significantly between groups (P less than 0.05). The numbers of interpretations made by all groups were large and demonstrated enormous variability. Highly individualized multiple responses to clinical information are associated with easy diagnoses. We conclude that there is no difference between groups of differing clinical experience in the breadth of thought but that there are marked differences in the precise content and structure of thought. This allows coherent explanation of variation in diagnostic expertise with clinical experience. The significance of the findings is discussed. 相似文献
23.
The purpose of this study was to assess the impact of an educational intervention on medical students' attitudes toward social and sexual contact with patients by doctors from three medical specialties (general practice, obstetrics/gynaecology and psychiatry). Medical students from two consecutive fifth year classes at one medical school participated in one 3 hour session that included instruction on the standards of the profession that prohibit doctor–patient sexual contact. Students were assigned to either intervention groups or control groups and responded to an anonymous questionnaire (overall response rate 66·8% ; n=141). As many as 14·5% of control group students thought it was (sometimes or usually) appropriate for general practitioners to date their own patients and at least 3% thought it appropriate for members of any of these three medical specialties to engage in sexual contact with their own patients. However, there were no significant differences in attitudes toward hugging, dating or sexual contact with current patients between those who had attended the seminar and the control groups. The session significantly influenced attitudes regarding obstetrician/gynaecologists and psychiatrists hugging and having sexual contact with former patients. These findings are discussed in relation to a need for expansion of such instruction. 相似文献
24.
It is shown that a repetitive pulse sequence consisting of two 90° pulses and gradients in a 1:2 ratio around the second 90° pulse generates interscan shifted stimulated echoes (SSTEs) and intrascan multiple spin echoes (MSEs). Separation of these two types of signals is accomplished using specific gradient crusher schemes. The intensity of the SSTEs is an order of magnitude larger than that of the MSEs and determines the signal contrast if both effects are selected simultaneously. The SSTE sequence generates improved contrast between gray and white matter, even at high field, which is explained in terms of increased inverse T1-weighting for the interscan echo. The MSE image has low signal to noise and no detectable contrast. The effect of interscan diffusion weighting is also discussed. 相似文献
25.
Summary. Divers have worked at 500 m depth in the sea and have reached 700 m in simulated chamber dives. A prerequisite for this has been extensive physiological studies of the body's reactions to pressure and pressure changes. This paper reviews such physiological and pathophysiological studies with emphasis on recent developments. 相似文献
26.
PharmacokineticsofintravenouslyadministeredsodiumdichloroacetateinrabbitsGuBin(顾斌);SongLing(宋岭);JiangYongpei(蒋永培);WenAidong(文... 相似文献
27.
C. James Willig 《Early child development and care》1990,57(1):89-99
The apparently limited classroom application of theories of learning led to an emphasis on detailed observational studies of teachers in action which produced data concerning management and teaching techniques of more obvious use to practising teachers. However, it is argued here that research into children's conceptual development is an essential complement to this initiative. Such research demonstrates the range and quality of children's concepts in areas of learning central to the school curriculum; it describes techniques for disclosing children's concepts; and it identifies the developing pattern of children's thinking which can be used to good effect in arranging appropriate and challenging learning experiences. The importance of clarity of intentions in bringing a sense of purpose and direction to the activities of learning and teaching is also emphasized. 相似文献
28.
M. Sand T. Gambichler G. Moussa F. G. Bechara D. Sand P. Altmeyer K. Hoffmann 《Skin research and technology》2006,12(2):114-118
BACKGROUND/AIMS: It has recently been proposed that the refractive index (RI) measured by means of optical coherence tomography (OCT) may be a valid measure for hydration of skin. In this pilot study, using OCT in vivo, we aimed to investigate the interday variability of RI measurements and acute changes of RI following the application of a moisturizer. METHODS: Twenty healthy Caucasian volunteers were investigated on their forearms using a commercially available OCT system (SkinDex 300, ISIS optronics GmbH, Mannheim, Germany) fitted with an integrated algorithm for the evaluation of the RI. The interday repeatability of the OCT method was determined performing symmetrical measurements on both forearms on day 1, 5, 9, and 13. In order to investigate the acute effect of a moisturizer on RI, OCT assessments were performed before and 10 min after the application of an aqueous lotion with a lipophilic phase. As a control, the contralateral site was investigated in the same way, except for the use of distilled water instead of the lotion. RESULTS: Assessments of interday variability revealed insignificant (P>0.05) variances between the four measurement times as expressed in very small repeatability coefficients (right arm: 0.039; left arm 0.053) and small coefficients of variance (right arm: 1.02%; left arm: 1.38%). With regard to the RIs measured over time, we could not observe significant (P>0.05) differences between the two symmetrical anatomic sites (mean+/-SD of RI: 1.3893+/-0.0142 (right arm); 1.3875+/-0.0192 (left arm)). The acute effect of the moisturizer was indicated by a significant decrease of the RI 5 min after the application of the lotion (1.399+/-0.01 vs. 1.387+/-0.02; difference between means: 0.012; P=0.033; 95% confidence interval: 0.001-0.0023). However the control site treated with distilled water did not show significant differences between the two measurement times (1.387+/-0.013 vs. 1.391+/-0.023; difference between means: -0.004; P=0.57; 95% confidence interval: -0.019-0.011). CONCLUSIONS: In this pilot study, we have demonstrated that RI evaluation via OCT is a promising technique that may be used for the assessment of skin hydration in vivo. However, the direct comparison of OCT with standard methods, ideally such as nuclear magnetic resonance spectroscopy, is necessary. 相似文献
29.
用单克隆抗体测定了移居高原的老年人重返平原后的T细胞亚群的变化结果:①移居西宁(2260m)组、天峻(3000m)组在西宁所测的OKT_3、OKT_4、OKT_8及OKT_4/OKT_8值与在苏州所测的当地老年人无差异。②移居西宁组急返平原后OKT_3、OKT_8水平明显低于返回平原后居住一年以上者(以下简称返回组)(P<0.01~0.001)但OKT_4/OKT_8无差异。③返回组与世居苏州老年人相比,前者OKT_3、OKT_4、OKT_8及OKT_4。OKT_8增高,其中OKT_3、OKT_4增高明显(P<0.01~0.02),作者认为长期移居高原返回平原后T细胞亚群也可能存在一“脱适应”阶段,即机体重新调整重新平衡的一种形式,这一阶段可能需一年以上。 相似文献
30.
N A Johnson S R Stannard D S Rowlands P G Chapman C H Thompson T Sachinwalla M W Thompson 《Diabetic medicine》2006,23(10):1061-1068
AIMS: Metabolic responses to manipulation of the plasma free fatty acid (FFA) concentration were assessed in six healthy men via cross-over design to determine whether FFAs independently influence insulin sensitivity. METHODS: Intramyocellular lipid (IMCL) was measured by proton magnetic resonance spectroscopy and insulin sensitivity via frequently sampled intravenous glucose tolerance test (IVGTT) after 67 h of two identical low carbohydrate/high fat (LC) diets which were used to elevate IMCL and plasma FFAs. To uncouple the influence of FFAs and IMCL on insulin sensitivity, FFAs were suppressed 30 min prior to and during IVGTT in one treatment [LC + nicotinic acid (NA)] by NA ingestion. RESULTS: Vastus lateralis IMCL was significantly elevated in LC (13.3 +/- 1.1 x 10(-3)) and LC + NA (13.5 +/- 1.1 x 10(-3)) (P < 0.01 for both), but was not different between conditions (P > 0.05). Plasma FFAs were raised in LC (0.79 +/- 0.08 mmol/l) and LC + NA (0.80 +/- 0.11 mmol/l) (P < 0.01 for both) and were significantly reduced by NA ingestion prior to (0.36 +/- 0.05 mmol/l, P < 0.01) and during IVGTT (P < 0.05) in LC + NA. Despite marked differences in plasma FFA availability, insulin sensitivity and glucose tolerance were not different between LC and LC + NA (P > 0.05 for both). CONCLUSIONS: Plasma FFAs appear to exert no immediate effect on insulin sensitivity/glucose tolerance independent of their action on intracellular lipid moieties. Further research is required to elucidate the duration of FFA suppression required to restore insulin sensitivity following lipid-induced insulin resistance. 相似文献