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   361篇
  免费   26篇
  国内免费   2篇
耳鼻咽喉   2篇
儿科学   8篇
妇产科学   24篇
基础医学   23篇
口腔科学   6篇
临床医学   21篇
内科学   58篇
皮肤病学   12篇
神经病学   14篇
特种医学   8篇
外科学   84篇
综合类   10篇
预防医学   50篇
眼科学   3篇
药学   28篇
中国医学   3篇
肿瘤学   35篇
  2023年   4篇
  2022年   5篇
  2021年   19篇
  2020年   7篇
  2019年   7篇
  2018年   18篇
  2017年   13篇
  2016年   16篇
  2015年   6篇
  2014年   24篇
  2013年   23篇
  2012年   35篇
  2011年   31篇
  2010年   17篇
  2009年   10篇
  2008年   13篇
  2007年   15篇
  2006年   15篇
  2005年   21篇
  2004年   18篇
  2003年   16篇
  2002年   5篇
  2001年   1篇
  2000年   2篇
  1999年   1篇
  1997年   1篇
  1996年   1篇
  1993年   1篇
  1992年   4篇
  1991年   2篇
  1990年   5篇
  1989年   3篇
  1988年   4篇
  1987年   1篇
  1986年   4篇
  1985年   4篇
  1984年   2篇
  1983年   2篇
  1981年   2篇
  1980年   1篇
  1979年   2篇
  1978年   2篇
  1977年   1篇
  1976年   1篇
  1974年   1篇
  1970年   1篇
  1969年   1篇
  1966年   1篇
排序方式: 共有389条查询结果,搜索用时 937 毫秒
1.
Summary. Eleven normotensive diabetics with noninsulin-dependent diabetes mellitus (NIDDM) (mean age 52.5 SD 8.2 years) and 11 controls (mean age 47.4 SD 8.9 years) had their ambulatory blood pressure and heart rate recorded non-invasively by the Oxford Medilog System in standard hospital conditions. The results were averaged as hourly means of systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MAP), and heart rate (HR) for the 24-h period and similarly for the ‘awake’ period (14.16 h) and the ‘asleep’ period (8–10 h). Hourly means for diabetics and controls showed no differences in blood pressure and heart rate over the 24 h. During sleep, control subjects showed a significant drop in SBP (P < 0.001), DBP (P < 0.001), MAP (P < 0.001) and HR (P < 0.001). However, this nocturnal dip in blood pressure could not be demonstrated in the diabetic group. Blood pressure variability was significantly increased in diabetics compared to controls during waking hours (P < 0.01). These results indicate that in noninsulin-dependent diabetics during sleep there is loss of the nocturnal dip of BP seen in normal subjects, and they have increased BP variability. These may be contributing factors to the development of hypertension and the accelerated target organ damage (TOD) seen in diabetes.,  相似文献   
2.
OBJECTIVE: In women presenting with threatened preterm labor, both fetal fibronectin and sonographic measurement of cervical length have been shown to distinguish between true and false labor. The aim of this study was to determine whether the combination of both tests provides a better prediction than the individual tests alone. METHODS: We examined 195 women with singleton pregnancies presenting at 24-36 (median 31) weeks of gestation with regular and painful uterine contractions, intact membranes and cervical dilatation of less than 3 cm. On admission to the hospital fetal fibronectin positivity in cervicovaginal secretions was determined and transvaginal sonographic measurement of cervical length was carried out. The results were not made available to the attending obstetrician. The primary outcome measure was delivery within 7 days of presentation. RESULTS: Delivery within 7 days occurred in 51.4% (18 of 35) of those with cervical length below 15 mm and 0.6% (1 of 160) of those with cervical length of 15 mm or more, in 21.2% (18 of 85) of the fibronectin positive group and in 0.9% (1 of 110) of the fibronectin negative group. There was a significant association between cervical length and the incidence of fibronectin positivity (r = -0.921, P = 0.003). Logistic regression analysis demonstrated that the only significant contributor to the prediction of delivery within 7 days was cervical length, with no significant contribution from fibronectin positivity, ethnic origin, maternal age, gestational age, body mass index, parity, previous history of preterm delivery, cigarette smoking, or use of tocolytics. CONCLUSIONS: In women with threatened preterm labor assessment of fetal fibronectin in cervicovaginal secretions does not improve the prediction of delivery within 7 days provided by the sonographic measurement of cervical length.  相似文献   
3.
OBJECTIVE: To investigate the interobserver agreement on the intrapartum ultrasonographic definition of the fetal occipital position. METHODS: In 60 singleton pregnancies in labor at term the fetal occipital position was determined by transabdominal ultrasound by two appropriately trained sonographers who were not aware of each other's findings. The Bland-Altman plot was performed and the 95% limits of agreement were calculated. Logistic regression analysis was used to investigate the association between complete agreement in the fetal occipital position between the two observers and maternal and labor characteristics. RESULTS: The two observers had complete agreement on the fetal occipital position in 22/60 (36.7%) cases and disagreement by 15 degrees and 30 degrees in 31 (51.7%) and seven (11.6%) cases, respectively. The mean of the differences between the two observers was 0.25 degrees and the 95% limits of agreement were -28.9 degrees (-32.2 degrees to -25.6 degrees) to 29.4 degrees (26.1 degrees to 32.7 degrees). There were no significant associations between complete agreement and maternal and labor characteristics. CONCLUSION: The interobserver agreement on sonographically determined fetal occipital position during labor is within 15 degrees in nearly 90% of cases and within 30 degrees in all cases.  相似文献   
4.
Reversible hepatic dysfunction associated with rhabdomyolysis   总被引:2,自引:0,他引:2  
Hepatic dysfunction was observed in 34 patients with nontraumatic rhabdomyolysis. The serum levels of lactic dehydrogenase were markedly elevated in all patients. The peak values occurred within 72 h of hospitalization. There was no significant difference among patients with (9,044 +/- 1,154 U/l) and without acute renal failure (ARF; 9,125 +/- 3,067 U/l). Similarly, marked elevation in both alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were observed within 72 h after admission to the hospital. They were significantly higher in patients with ARF (ALT: 4,718 +/- 785 vs. 2,496 +/- 927 U/l, p less than 0.01; AST: 3,635 +/- 820 vs. 1,352 +/- 624 U/l, p less than 0.01). Hyperbilirubinemia was noted in 13 of 22 (60%) patients with ARF and in 5 of the 12 (41%) of those without ARF. Serum levels of bilirubin ranged from 2.6 to 14.3 mg/dl. Prothrombin time was prolonged in 4 of 12 (33%) without ARF and in 14 of 22 (63%) of patients with ARF. This abnormality lasted from 1 to 13 days. The magnitude and duration of hyperbilirubinemia and abnormal prothrombin time were similar in patients with and without ARF. Hepatic dysfunction appears to occur in about 25% of patients with rhabdomyolysis. The pathogenesis of these abnormalities is not well defined and may be multifactorial. Hyperpyrexia, hypotension and proteases released from injured muscle may each or all be contributory. These hepatic derangements are reversible.  相似文献   
5.
A polyclonal antibody-based enzyme-linked immunosorbent assay (ELISA) method was developed for the N-methylcarbamate insecticide bendiocarb (2,2-dimethyl-1,3-benzodioxol-4-yl methylcarbamate). Two novel haptens having dimethylbenzodioxyl and dimethylbenzofuranyl groups connected to oxyacetyl-γ-aminobutanoic acid and oxyacetyl-β-alanine spacer arm respectively were synthesised. The first hapten was conjugated to carrier proteins to make antigens that were used to raise polyclonal antibodies in rabbits. The antibodies specifically recognised bendiocarb and its metabolite 2,2-dimethyl-1,3-benzodiox-4-ol with an IC50 value of 9 ppb (ng ml-1). The assay was standardised using the competitive ELISA format at 0.0625 µg antibody concentration and at 1/10k pesticide-HRP dilution. Matrix effect studies were carried out in four vegetable and cereal food samples. Matrix effect elimination in cabbage, cauliflower and rice was achieved by simple dilution of the extract. Five different approaches were attempted to achieve matrix clean up in paddy rice. C-18 column and gel permeation column chromatography (GPC) helped in the matrix removal. The spike and recovery studies for all the four food samples gave a recovery in the range of 75-95%, thus indicating the efficiency of the matrix elimination procedures developed.  相似文献   
6.
Alliance governance is a form of governance developed in industry settings and more recently applied to healthcare. The core idea behind alliance governance is to involve the many stakeholders in the system to collaboratively develop a joint programme that promotes an integrated and whole of systems approach to care. Little is known about the model in healthcare, nor what those involved in an alliance should be focused upon. Using a modified Delphi method, this research presents a set of components that research participants agreed should underpin development of an effective alliance governance arrangement.These characteristics include a systems perspective—a truly shared governance protocol based on a shared vision and a common purpose; performance measurement—collecting and using real-time data that depicts the realities of an end-to-end system to establish better and more achievable goals based on alliance performance; a relational perspective to promote trust, respect and collaboration amongst alliance members, who historically have been competing for contracts and resources; structural changes that enable and promote a shared governance system; and, finally, equity and inclusion to ensure a diverse alliance which promotes diversity of ideas, and involvement of all stakeholders in the decision making process. This research is relevant to policymakers seeking to develop effective alliance-type arrangements as well as to those involved in the practice of alliance governance.  相似文献   
7.
Partial left ventriculectomy (PLV) has been introduced as an alternative surgical therapy for patients with end-stage dilated cardiomyopathy. The physiological benefits of PLV are relatively unknown. Therefore, the objective of this study was to determine the acute effects of PLV by measuring cardiac function before and after PLV. Aortic and left ventricular pressures and aortic flow were measured in eight patients. Continuous, beat-to-beat data were recorded and compared pre-PLV and post-PLV with and without inferior vena cava (IVC) occlusions. PLV increased cardiac output (0.93+/-0.5, p = 0.01) as a result of increased stroke volume (5.12+/-4.24, p = 0.06) and heart rate (14.5+/-8.44, p = 0.02). Contractility (+/- dP/dt, 240.33+/-74.28, p = 0.001) and external work (650.8+/-320.4, p = 0.01) were also improved. Left ventricular end-diastolic elastance (0.15+/-0.14, p = 0.10) nearly doubled after PLV. Our results indicated an improved cardiac function as measured by increased cardiac output, stroke volume, ejection fraction (EF), and contractility.  相似文献   
8.
In a group of 35 patients with relapsed and/or chemo-resistant non-Hodgkin's lymphoma (NHL), low-dose total body irradiation (LTBI) (+involved-field radiotherapy to bulky sites) achieved a complete remission rate of 29%, 2-years progression-free survival of 32% and a median progression-free survival of 12 months. The 2-year survival was 42% and the median survival was 17 months. Immuno-staining and flow cytometry of peripheral blood in 14 patients showed that LTBI leads to a significant increase in the percentage of CD4+ cells with a consequent significant increase in the CD4+/CD8+ ratio. High lymphocytic percent and a high percentage of CD4+ cells before LTBI were significantly correlated with longer response duration and overall survival. These data may suggest that the palliative potential of LTBI should be investigated as an alternative to chemotherapy in NHL patients. The pre-treatment percentage of lymphocytes and CD4+ cells may be used as predictors for response to LTBI.  相似文献   
9.
Timing in peak gait values shifts slightly between gait trials. When averaged, the standard deviation (S.D.) in gait data may increase due to this inter-trial variability unless normalization is carried out beforehand. The objective of this study was to determine how curve registration, an alignment technique, can reduce inter-subject variability in gait data without perturbing the curve characteristics. Twenty young, healthy men participated in this study each providing a single gait trial. Gait was assessed by means of a four-camera high-speed video system synchronized to a force plate. A rigid body three-segment model was used in an inverse dynamic approach to calculate three-dimensional muscle powers at the hip, knee and ankle. Curve registration was applied to each of the 20 gait trials to align the peak powers. The mean registered peak powers increased by an average of 0.10±0.13 W/kg with the highest increases in the sagittal plane at push-off. After performing curve registration, the RMS values decreased by 13.6% and the greatest reduction occurred at the hip and knee, both in the sagittal plane. No important discontinuities were reported in the first and second derivatives of the unregistered and registered curves. Curve registration did not have much effect on the harmonic content. This would be an appropriate technique for application prior to any statistical analysis using able-bodied gait patterns.  相似文献   
10.
Objectives. Cardiac surgery patients are excluded from SAPS2 but included in SAPS3. Neither score is evaluated for this exclusive population; however, they are used daily. We hypothesized that SAPS3 may be superior to SAPS2 in outcome prediction in cardiac surgery patients. Design. All consecutive patients undergoing cardiac surgery between January 2007 and December 2010 were included in our prospective study. Both models were tested with calibration and discrimination statistics. We compared the AUC of the ROC curves by DeLong's method and calculated OCC values. Results. A total of 5207 patients with mean age of 67.2 ± 10.9 years were admitted to the ICU. The mean length of ICU stay was 4.6 ± 7.0 days and the ICU mortality was 5.9%. The two tested models had acceptable discriminatory power (AUC: SAPS2: 0.777–0.875; SAPS3: 0.757–893). SAPS3 had a low AUC and poor calibration on admission day. SAPS2 had poor calibration on Days 1–6 and 8. Conclusions. Despite including cardiac surgery patients, SAPS3 was not superior to SAPS2 in our analysis. In this large cohort of ICU cardiac surgery patients, performance of both SAPS models was generally poor. In this subset of patients, neither scoring system is recommended.  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