全文获取类型
收费全文 | 1570篇 |
免费 | 397篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 12篇 |
儿科学 | 52篇 |
妇产科学 | 37篇 |
基础医学 | 184篇 |
口腔科学 | 13篇 |
临床医学 | 459篇 |
内科学 | 309篇 |
皮肤病学 | 11篇 |
神经病学 | 356篇 |
特种医学 | 62篇 |
外科学 | 228篇 |
综合类 | 7篇 |
一般理论 | 1篇 |
预防医学 | 124篇 |
眼科学 | 4篇 |
药学 | 41篇 |
肿瘤学 | 78篇 |
出版年
2023年 | 58篇 |
2022年 | 27篇 |
2021年 | 39篇 |
2020年 | 56篇 |
2019年 | 45篇 |
2018年 | 70篇 |
2017年 | 116篇 |
2016年 | 94篇 |
2015年 | 109篇 |
2014年 | 120篇 |
2013年 | 146篇 |
2012年 | 60篇 |
2011年 | 56篇 |
2010年 | 97篇 |
2009年 | 121篇 |
2008年 | 48篇 |
2007年 | 53篇 |
2006年 | 52篇 |
2005年 | 45篇 |
2004年 | 37篇 |
2003年 | 42篇 |
2002年 | 33篇 |
2001年 | 31篇 |
2000年 | 31篇 |
1999年 | 19篇 |
1998年 | 42篇 |
1997年 | 26篇 |
1996年 | 37篇 |
1995年 | 27篇 |
1994年 | 24篇 |
1993年 | 11篇 |
1992年 | 17篇 |
1991年 | 21篇 |
1990年 | 18篇 |
1989年 | 14篇 |
1988年 | 22篇 |
1987年 | 13篇 |
1986年 | 7篇 |
1985年 | 5篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 7篇 |
1975年 | 7篇 |
1974年 | 4篇 |
1973年 | 11篇 |
1972年 | 5篇 |
1971年 | 8篇 |
1970年 | 4篇 |
1969年 | 5篇 |
1966年 | 6篇 |
排序方式: 共有1978条查询结果,搜索用时 15 毫秒
1.
PT Foley A Ganeshan S Anthony R Uberoi 《Journal of Medical Imaging and Radiation Oncology》2010,54(1):9-16
This is a retrospective review of the results at our institution of using multi-detector CT angiography (CTA) to localise lower gastrointestinal (GI) bleeding. We hypothesised that in our patient population: (i) CTA was unlikely to demonstrate bleeding in patients who were haemodynamically stable; (ii) in haemodynamically unstable patients in whom CTA was undertaken, the results could be used to select patients who would benefit from catheter angiography; and (iii) in haemodynamically unstable patients in whom CTA was undertaken, a subgroup of patients could be identified who would benefit from primary surgical treatment, avoiding invasive angiography completely. A retrospective review was conducted of the clinical records of all patients undergoing CTA for lower GI haemorrhage at our institution between 1 January 2005 and 30 June 2007. Out of the 20 patients examined, 10 had positive CTAs demonstrating the bleeding site. Nine were haemodynamically unstable at the time of the study. Four patients with positive CT angiograms were able to be treated directly with surgery and avoided invasive angiography. Ten patients had negative CTAs. Four of these were haemodynamically unstable, six haemodynamically stable. Only one required intervention to secure haemostasis, the rest stopped spontaneously. No haemodynamically stable patient who had a negative CTA required intervention. CTA is a useful non-invasive technique for localising the site of lower GI bleeding. In our patient population, in the absence of haemodynamic instability, the diagnostic yield of CTA was low and bleeding was likely to stop spontaneously. In haemodynamically unstable patients, a positive CTA allowed patients to be triaged to surgery or angiography, whereas there was a strong association between a negative CTA and spontaneous cessation of bleeding. 相似文献
2.
Boris A. Zelle MD Andrea S. Herzka MD Christopher D. Harner MD James J. Irrgang PhD PT ATC 《Operative Techniques in Orthopaedics》2005,15(1):76
Clinical outcomes data can be used to facilitate patient management decisions, assess clinician and organizational performance, and to provide evidence for the effectiveness of surgery and rehabilitation. The validity of the inferences made from outcomes data are dependent on the validity of the outcomes measures themselves and the circumstances under which the data were collected, analyzed, and interpreted. Clinical outcomes may include measures of impairment of body structure and function, activity limitation, and participation restriction. However, because the relationship between impairment and the resulting activity limitation and participation restriction is not direct, and because activity limitations and participation restrictions are of the utmost concern to the athlete, the primary clinical outcome should be measures of activity limitation and participation restriction. Activity limitation and participation restriction may be measured either through direct observation of performance or by general or specific measures of health related quality of life. Clinical outcomes data must be collected systematically to ensure valid inferences from the data. 相似文献
3.
4.
S T O'Dwyer H R Michie T R Ziegler A Revhaug R J Smith D W Wilmore 《Archives of surgery (Chicago, Ill. : 1960)》1988,123(12):1459-1464
To investigate the effects of endotoxin on gut barrier function, we performed paired studies of intestinal permeability in healthy humans (N = 12) receiving intravenous Escherichia coli endotoxin (4 ng/kg) or 0.9% saline solution. Two nonmetabolizable sugars, lactulose and mannitol, which are standard permeability markers, were administered orally, 30 minutes before and 120 minutes after the test injection. The 12-hour urinary excretion of these substances after endotoxin/saline solution administration was used to quantitate intestinal permeability. After endotoxin administration systemic absorption and excretion of lactulose increased almost two-fold (mean +/- SEM, 263 +/- 36 mumol per 12 hours vs 145 +/- 19 mumol per 12 hours during saline studies). Similar but less marked alterations in mannitol absorption and excretion occurred after endotoxin injection (5.7 +/- 0.3 mmol per 12 hours vs 4.9 +/- 0.3 mmol per 12 hours). When individual 12-hour lactulose excretion after endotoxin administration was related to the magnitude of systemic responses, a significant relationship occurred between lactulose excretion and elaboration of norepinephrine and between lactulose excretion and minimum white blood cell count. These data suggest that a brief exposure to circulating endotoxin increases the permeability of the normal gut. These observations are consistent with the hypothesis that during critical illness, prolonged or repeated exposure to systemic endotoxins or associated cytokines may significantly compromise the integrity of the gastrointestinal mucosal barrier. 相似文献
5.
In-vitro maturation of human germinal vesicle stage oocytes: role of cumulus cells and epidermal growth factor in the culture medium 总被引:21,自引:6,他引:21
Goud PT; Goud AP; Qian C; Laverge H; Van der Elst J; De Sutter P; Dhont M 《Human reproduction (Oxford, England)》1998,13(6):1638-1644
In-vitro maturation (IVM) of oocytes is a promising technique to reduce the
costs and avert the side-effects of gonadotrophin stimulation for in-vitro
fertilization (IVF). The pregnancy rates from oocytes matured in vitro are
much lower than those of in-vivo stimulation cycles indicating that
optimization of IVM remains a challenge. Therefore, we investigated the
effect of supplementation of the medium with gonadotrophins, oestradiol and
epidermal growth factor (EGF) and the effect of retaining or removing the
cumulus cells on nuclear and cytoplasmic maturation of immature oocytes.
Human germinal vesicle (GV) oocytes obtained after gonadotrophin
stimulation for intracytoplasmic sperm injection (ICSI) were cultured in a
complex defined medium either supplemented with gonadotrophins, oestradiol
and physiological concentrations of EGF (2 ng/ml) or gonadotrophins and
oestradiol alone. The cumulus cells were either removed or kept intact. In
GV stage oocytes cultured without cumulus (group I) significantly more
oocytes reached the metaphase II (MII) stage at 30 h in media supplemented
with EGF (64.3 versus 33.9%, P < 0.003). For oocytes cultured with
intact cumulus (group II), more oocytes reached MII at 30 h than in group
I, but there was no difference in medium with or without EGF
supplementation (81.8 and 79.8% respectively). Cytoplasmic maturation of
MII oocytes was judged from their capability to activate and fertilize
after ICSI. In group I, the rates of activation and normal fertilization
were similar. However, in group II, significantly more oocytes underwent
normal fertilization in the EGF-supplemented than the unsupplemented group
(71.7 versus 45.6%, P < 0.05). The cleavage rates of the fertilized
oocytes were similar in the sibling oocyte subgroups cultured with or
without EGF supplementation, but the overall cleavage rates were higher in
cumulus-intact compared to cumulus-denuded oocytes (88.9 versus 47.8%, P
< 0.001). Thus, supplementation of the maturation medium with EGF and
maintenance of the cumulus during culture improve the nuclear and
cytoplasmic maturation of human oocytes in vitro.
相似文献
6.
Image analysis derived ploidy and proliferation indices in soft tissue sarcomas: comparison with clinical outcome. 下载免费PDF全文
AIMS--To compare prognostic information obtained by image analysis cytometry of paraffin wax embedded soft tissue sarcomas with conventional assessment. METHODS--A CAS 200 image analyser was used to determine DNA content of Feulgen stained cytology preparations and tissue sections and to quantify immunostaining by Ki67 and PC10 antibodies. A mitotic count in 50 high power fields was undertaken and histological grade assigned by the Trojani system. Clinical details including follow up and outcome were obtained by case note review. The Kruskal-Wallis one way analysis test, Spearman rho significance test, Kaplan-Meier method, and log-rank test were applied in statistical analysis. RESULTS--Ploidy status, DNA index, 2.5c exceeding rate, 5c exceeding rate, mitotic count and Trojani grade all correlated significantly with clinical outcome. The relation between Ki67 index and outcome did not reach significance. The PC10 index and outcome were not related. Only 2.5c exceeding rate, 5c exceeding rate, and mitotic count correlated significantly with Trojani grade. CONCLUSIONS--DNA content determination of soft tissue sarcomas by image analysis provides quantifiable information of benefit in prediction of outcome. Larger series are required to determine the independent value of ploidy. In this study quantification of anti-Ki67 and anti-PC10 immunostaining was not of prognostic benefit) by contrast with mitotic count and Trojani grade. 相似文献
7.
Histometry of lymphoid infiltrate in the thyroid of primary thyrotoxicosis patients. Relation of extent of thyroiditis to preoperative drug treatment and postoperative hypothyroidism. 总被引:1,自引:0,他引:1 下载免费PDF全文
R J Young M B Sherwood J G Simpson A G Nicol W Michie J S Beck 《Journal of clinical pathology》1976,29(5):398-402
The thyroids of primary thyrotoxicosis patients prepared for partial thyroidectomy with propranolol contained much more lymphoid infiltrate than those prepared with carbimazole. No relation was found between the extent of lymphoid infiltrate in the thyroid and the development of postoperative hypothyroidism either between or within the two drug treatment groups. This study has shown that the extent of thyroid infiltrate should not be used as the major factor in predicting hypothyroidism after subtotal thyroidectomy for primary thyrotoxicosis. 相似文献
8.
William R. Leonard PT Katzmarzyk Anthony G. Comuzzie Michael H. Crawford Rem I. Sukernik 《American journal of human biology》1994,6(3):339-350
This study examines physical growth and nutritional status in a sample of 478 (247 males; 231 females) Evenki herders of Central Siberia. The Evenki display slow growth in stature and body weight, particularly during late childhood and adolescence. Adult males fall below the U.S. 5th percentiles for both stature and body weight. Adult females are below the 5th percentile for stature and approximate the 15th percentile for weight. Despite their diminutive size, the Evenki appear to have adequate energy reserves, as indicated by their skinfold measurements, which range between the U.S. 15th and 50th percentiles. Among adults, women are relatively heavier and fatter than men and tend to increase in weight and fatness with age. Poor growth in the Evenki does not appear to be directly attributable to limited food availability. Rather, it is hypothesized that elevated metabolic requirements, associated with adaptation to a high latitude ecosystem, are responsible for limiting the amount of energy that is allocated to growth. Relatively high levels of adiposity in adult females appear to be the product of changes in activity patterns and fertility levels that resulted after the collectivization of the Evenki. © 1994 Wiley-Liss, Inc. 相似文献
9.
10.
Recessively inherited L-DOPA-responsive parkinsonism in infancy caused by a point mutation (L205P) in the tyrosine hydroxylase gene 总被引:4,自引:0,他引:4