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   331篇
  免费   28篇
  国内免费   23篇
儿科学   18篇
妇产科学   6篇
基础医学   37篇
口腔科学   9篇
临床医学   38篇
内科学   91篇
皮肤病学   30篇
神经病学   9篇
特种医学   68篇
外科学   9篇
综合类   17篇
预防医学   4篇
药学   30篇
肿瘤学   16篇
  2023年   2篇
  2021年   2篇
  2019年   5篇
  2018年   5篇
  2017年   3篇
  2016年   2篇
  2015年   11篇
  2014年   5篇
  2013年   11篇
  2012年   4篇
  2011年   4篇
  2010年   11篇
  2009年   17篇
  2008年   11篇
  2007年   20篇
  2006年   11篇
  2005年   9篇
  2004年   6篇
  2003年   9篇
  2002年   6篇
  2001年   6篇
  2000年   1篇
  1999年   9篇
  1998年   21篇
  1997年   15篇
  1996年   28篇
  1995年   8篇
  1994年   18篇
  1993年   8篇
  1992年   4篇
  1991年   6篇
  1990年   10篇
  1989年   7篇
  1988年   14篇
  1987年   10篇
  1986年   8篇
  1985年   11篇
  1984年   5篇
  1983年   5篇
  1982年   6篇
  1981年   6篇
  1980年   5篇
  1979年   1篇
  1978年   3篇
  1977年   4篇
  1976年   6篇
  1975年   3篇
排序方式: 共有382条查询结果,搜索用时 15 毫秒
11.
12.
In 2010, the American Society for Bone and Mineral Research (ASBMR) task force defined major and minor features to assist in the case finding and reporting of atypical femoral fractures (AFFs). One major feature that was proposed was a “transverse or short oblique configuration.” Our primary aim was to compare the conventional overall fracture morphology (OFM) with its associated angle (OFMA) and our proposed lateral cortical fracture angle (LCFA) in the assessment of fracture configuration in suspected AFFs and non‐AFFs. The radiographs of 79 patients with AFFs and 39 patients with non‐AFFs were each analyzed by two blinded reviewers to obtain the OFM, OFMA, and LCFA. Using the overall fracture morphology to assess the suspected AFFs resulted in discordance between reviewers in 18 cases (22.8%), of which 5 (6.3%) were discordant between short oblique (>30° to 60°) and long oblique (>60° to 90°) configurations, therefore affecting their classifications as AFFs. By assessing only the critical component within the lateral cortex, all the suspected AFFs fell well within the classification as transverse fractures with a mean LCFA of 4.8° (range 0.3 to 18.0, SD = 4.23). The inter‐reader variability was also lower for LCFA versus OFMA (4.1° versus 6.9°, p = 0.001) when used to assess AFFs. Fracture angles were significantly different in AFFs versus non‐AFFs regardless of whether the OFMA or LCFA methodology was employed, but the greater difference associated with LCFA suggests its greater discriminating power. When LCFA was used in conjunction with 0° to 30° as the criteria for transverse morphology, all the AFFs and non‐AFFs were correctly classified. By using a standardized and precise method in measuring the fracture angle, specifically using only the component of the lateral cortex and limiting to truly transverse fractures, ie, between 0° and 30°, the LCFA is a robust and accurate method to assess the fracture morphology in suspected AFFs. © 2014 American Society for Bone and Mineral Research.  相似文献   
13.
Muta  K; Krantz  SB; Bondurant  MC; Dai  CH 《Blood》1995,86(2):572-580
Stem cell factor (SCF), the ligand for the c-kit tyrosine kinase receptor, markedly stimulates the accumulation of erythroid progenitor cells in vitro. We now report that SCF delays erythroid differentiation among the progeny of individual erythroid progenitors while greatly increasing the proliferation of these progeny. These effects appear to be independent of an effect on maintenance of cell viability. Highly purified day-6 erythroid colony-forming cells (ECFC), consisting mainly of colony-forming units-erythroid (CFU-E), were generated from human peripheral blood burst-forming units-erythroid (BFU-E). Addition of SCF to the ECFC in serum-free liquid culture, together with erythropoietin (EP) and insulin-like growth factor 1 (IGF-1), resulted in a marked increase in DNA synthesis, associated with a delayed peak in cellular benzidine positivity and a delayed incorporation of 59Fe into hemoglobin compared with cultures without SCF. In the presence of SCF, the number of ECFC was greatly expanded during this culture period, and total production of benzidine-positive cells plus hemoglobin synthesis were ultimately increased. To determine the effect of SCF on individual ECFC, single-cell cultures were performed in both semisolid and liquid media. These cultures demonstrated that SCF, in the presence of EP and IGF-1, acted on single cells and their descendants to delay erythroid differentiation while substantially stimulating cellular proliferation, without an enhancement of viability of the initial cells. This was also evident when the effect of SCF was determined using clones of ECFC derived from single BFU-E. Our experiments demonstrate that SCF acts on individual day-6 ECFC to retard erythroid differentiation while simultaneously providing enhanced proliferation by a process apparently independent of an effect on cell viability or programmed cell death.  相似文献   
14.

Background  

Fractures of the intertrochanteric hip are common and the treatment of unstable fractures generally requires an operative approach. In elderly patients, osteoporosis makes internal fixation problematic and frequently contributes to failed fixation and poor clinical results. We have attempted to apply the Less Invasive Stabilization System (LISS) in reverse position for the repair of intertrochanteric hip fractures in elderly patients with osteoporotic bones. A retrospective review is presented of the cases of 28 elderly patients with stable and unstable fractures of the intertrochanteric hip treated using the reverse LISS.  相似文献   
15.

Background  

Until 2005, the Malawi National Tuberculosis Control Programme had been implemented as a vertical programme. Working within the Sector Wide Approach (SWAp) provides a new environment and new opportunities for monitoring the equity performance of the programme. This paper synthesizes what is known on equity and TB in Malawi and highlights areas for further action and advocacy.  相似文献   
16.
Lung cancer is not commonly known to metastasise to the perirenal space, with only five such cases previously published. We present an unusual case of perirenal lung metastases manifesting as diffuse perinephric stranding which to our knowledge has not been described before.  相似文献   
17.
A boy with the dysmorphic features of Noonan's syndrome and pulmonary valve stenosis who had evidence of hypoparathyroidism and abnormal T lymphocyte numbers in the neonatal period is reported. He had a normal karyotype but molecular analysis revealed a submicroscopic deletion within chromosome 22q11, the region deleted in DiGeorge syndrome. Thus this child has both Noonan's syndrome and DiGeorge syndrome; 22q11 is a candidate region for a gene defective in Noonan's syndrome.  相似文献   
18.
Non-insulin-dependent diabetes mellitus (NIDDM) is the commonest form of diabetes. The aim of this study was to evaluate the nature and prevalence of microalbuminuria (MAU) in NIDDM. One hundred and twenty-eight NIDDM patients participated in this study on the prevalence of microalbuminuria and albumin excretion rate (AER). An attempt was made to correlate them to the clinical profile, glycemic control and to diabetic complications. Eighteen patients had MAU with 14.1% prevalence (males--17.5% v/s females--10.8%; NS). Prevalence of MAU was higher in the third and fourth decades of age (28.6%) with a decrease in the fifth decade (12.5%). Prevalence of MAU also increased progressively with duration of diabetes--13 to 14% (< 10 yrs) to 25% (> 10 yrs). High AER in obese patients (13.4 +/- 5.5 v/s 7.9 +/- 1.4 micrograms/min) supports an association of obesity with albuminuria. The prevalence of MAU in patients with borderline and overt hypertension was not statistically different from that in normotensive NIDDM patients. However, NIDDM with borderline hypertension showed high AER 16.2 +/- 5.6 micrograms/min compared to 7.8 +/- 1.3 micrograms/min in normotensives. Prevalence to MAU and AER increased progressively with the deterioration of glycemic control--from 3.3% in well controlled to 18.9% in fairly controlled (P < 0.5) and 31% in poor controlled patients (P < 0.01). Also AER increased significantly from 3.9 +/- 0.8 to 12.3 +/- 4.1 and 18.4 +/- 4.6 micrograms/min, in patients with well to fairly and poorly controlled glycemia respectively. The prevalence of MAU and AER did not correlate with glycated hemoglobin (GHb) levels. The prevalences of peripheral neuropathy (PN) (42.6% v/s 55.6%) were similar in normo- and microalbuminuric patients. Patients with PN had high AER 11.9 +/- 2.7 micrograms/min. Diabetic retinopathy (DR) was equally prevalent in normo- and microalbuminuric NIDDM patients of (20.4% v/s 22.2), and AER was not significantly higher (12.1 +/- 4.3 micrograms/min) in NIDDM with retinopathy. High prevalences of cardiovascular disease (CVD) in MAU-NIDDM (22.2%; NS) was observed compared to normoalbuminuric (9.3%) patients. Also AER was significantly high in NIDDM associated with CVD (21.9 +/- 10.9 micrograms/min; P < 0.025). It can be concluded that, MAU is more prevalent in third and fourth decades and with longer duration of diabetes. Poor glycemic control was identified as a risk factor as in IDDM for development of MAU. MAU was a marker of generalised vascular dysfunction.  相似文献   
19.
20.
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