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   353篇
  免费   24篇
  国内免费   8篇
儿科学   32篇
妇产科学   3篇
基础医学   30篇
口腔科学   10篇
临床医学   29篇
内科学   80篇
皮肤病学   13篇
神经病学   51篇
特种医学   62篇
外科学   22篇
综合类   15篇
预防医学   5篇
眼科学   3篇
药学   10篇
肿瘤学   20篇
  2023年   2篇
  2021年   3篇
  2020年   2篇
  2019年   7篇
  2018年   7篇
  2017年   4篇
  2016年   3篇
  2015年   6篇
  2014年   7篇
  2013年   16篇
  2012年   9篇
  2011年   8篇
  2010年   18篇
  2009年   22篇
  2008年   6篇
  2007年   7篇
  2006年   12篇
  2005年   9篇
  2004年   10篇
  2003年   10篇
  2002年   5篇
  2001年   7篇
  2000年   13篇
  1999年   7篇
  1998年   22篇
  1997年   19篇
  1996年   20篇
  1995年   14篇
  1994年   10篇
  1993年   8篇
  1992年   3篇
  1991年   3篇
  1990年   4篇
  1989年   7篇
  1988年   11篇
  1987年   8篇
  1986年   8篇
  1985年   3篇
  1984年   4篇
  1982年   4篇
  1981年   5篇
  1980年   4篇
  1979年   4篇
  1977年   6篇
  1976年   6篇
  1974年   2篇
  1969年   2篇
  1948年   2篇
  1925年   1篇
  1924年   1篇
排序方式: 共有385条查询结果,搜索用时 15 毫秒
1.
Odanacatib (ODN), a selective oral inhibitor of cathepsin K, was an investigational agent previously in development for the treatment of osteoporosis. In this analysis, the effects of ODN on bone remodeling/modeling and structure were examined in the randomized, double-blind, placebo-controlled, event-driven, Phase 3, Long-term Odanacatib Fracture Trial (LOFT; NCT00529373) and planned double-blind extension in postmenopausal women with osteoporosis. A total of 386 transilial bone biopsies, obtained from consenting patients at baseline (ODN n = 17, placebo n = 23), month 24 (ODN n = 112, placebo n = 104), month 36 (ODN n = 42, placebo n = 41), and month 60 (ODN n = 27, placebo n = 20) were assessed by dynamic and static bone histomorphometry. Patient characteristics at baseline and BMD changes over 5 years for this subset were comparable to the overall LOFT population. Qualitative assessment of biopsies revealed no abnormalities. Consistent with the mechanism of ODN, osteoclast number was higher with ODN versus placebo over time. Regarding bone remodeling, dynamic bone formation indices in trabecular, intracortical, and endocortical surfaces were generally similar in ODN-treated versus placebo-treated patients after 2 years of treatment. Regarding periosteal modeling, the proportion of patients with periosteal double labels and the bone formation indices increased over time in the ODN-treated patients compared with placebo. This finding supported the observed numerical increase in cortical thickness at month 60 versus placebo. In conclusion, ODN treatment for 5 years did not reduce bone remodeling and increased the proportion of patients with periosteal bone formation. These results are consistent with the mechanism of action of ODN, and are associated with continued BMD increases and reduced risk of fractures compared with placebo in the LOFT Phase 3 fracture trial. © 2020 American Society for Bone and Mineral Research.  相似文献   
2.
目的:观察低血糖指数的膳食对2型糖尿病患者氧化应激状态的影响。方法:2004-10/11在上海市静安区二个社区卫生服务中心招募受试者,经医生明确诊断为2型糖尿病、病程超过6个月,体质量指数≥24kg/m2的老年糖尿病志愿者43名,受试者对试验知情同意。采用随机交叉试验随机分配至低血糖指数饮食组和高血糖指数饮食组,每种膳食分别连续使用4周,间隔洗脱期4周,比较试验前后患者超氧化物歧化酶、脂质过氧化产物丙二醛和谷胱甘肽过氧化物酶含量的变化。结果:受试者依从性好,除1人因试验期间发现肿瘤而退出试验,42名志愿者按设计要求完成试验。膳食干预后低血糖指数饮食组和高血糖指数饮食组的超氧化物歧化酶活力分别升高了15.68%和21.33%,丙二醛水平分别下降23.94%和21.55%,谷胱甘肽过氧化物酶活力分别升高了15.74%和17.09%;干预后低血糖指数饮食组丙二醛下降水平与高血糖指数饮食组比较差异有显著性意义(P<0.05),而超氧化物歧化酶和谷胱甘肽过氧化物酶活性两组间差异无显著性意义(P>0.05)。结论:在控制总能量的基础上给予平衡膳食能够改善其氧化应激水平,采用低血糖指数食物有助于氧化应激水平的改善。  相似文献   
3.
The authors developed quantitative radioimmunoassays to allow direct measurement of total human IgG and individual IgG subclasses among antibodies bound to cell surfaces. The assays use four mouse monoclonal radioiodinated antibodies, one that reacts equally well with all four human IgG subclasses and three that are specific for human IgG subclasses 1, 2, or 3. The assays were used to analyze IgG subclass composition in 21 high-titer anti-D samples from Rh-negative volunteers immunized for Rh immunoglobulin production. Anti-D activity was restricted primarily to the IgG1 and IgG3 subclasses. Eleven of 21 sera demonstrated red cell antibodies with a marked predominance of IgG1 (87 +/- 3.6% of total IgG antibody, +/- SEM) and low levels of IgG3 (1.4 +/- 0.73%). In the remaining 10 sera, IgG3 made up a greater proportion of total IgG antibody (32 +/- 3.8%), although IgG1 was still predominant (61 +/- 4.1%). This observed dichotomy in the IgG subclass profiles of different anti-D sera may be a consideration in the selection of anti-D sera for the production of the immunoglobulin used in the prophylaxis of Rh-incompatible pregnancies.  相似文献   
4.
BACKGROUND: The role of L-carnitine (LC) as the requisite carrier of long-chain fatty acids into mitochondria is well established. Human red cells (RBCs), which lack mitochondria, possess a substantial amount of LC and its esters. In addition, carnitine palmitoyl transferase, an enzyme that catalyzes the reversible transfer of the acyl moiety from acyl-coenzyme A to LC is found in RBCs. It has recently been shown that LC and carnitine palmitoyl transferase play a major role in modulating the pathway for the turnover of membrane phospholipid fatty acids in intact human RBCs, and that LC improved the membrane stability of RBCs subjected to high shear stress. RBC membrane lesions occur during storage at 4 degrees C; this study investigated whether the addition of LC (5 mM) to a standard RBC preservative solution (AS-3) affected cellular integrity with 42 days' storage. STUDY DESIGN AND METHODS: A paired (n = 10) crossover design was used for RBCs stored in AS-3 with and without LC. Both in vitro RBC properties reflective of metabolic and membrane integrity and in vivo measures of cell viability (24-hour percentage of recovery and circulating lifespan) were measured at the end of the storage. In addition, the turnover of membrane phospholipid and long-chain acylcarnitine fatty acids and the carnitine content of control and LC-stored RBCs were measured. RESULTS: It was shown that LC was irreversibly taken up by RBCs during storage, with a fourfold increase at 42 days. Furthermore, as found by the use of radiolabeled palmitate, the stored RBCs were capable of generating long-chain acylcarnitine. The uptake of LC during storage was associated with less hemolysis and higher RBC ATP levels and by a significantly greater in vivo viability for LC-stored RBCs than for control-stored RBCs: a mean 24-hour percentage of recovery of 83.9 +/? 5.0 vs. 80.1 +/? 6.0 percent and a mean lifespan of 96 +/? 11 vs. 86 +/? 14 days, respectively (p < 0.05). CONCLUSION: A beneficial effect of the addition of LC to RBCs stored at 4 degrees C was evident. This effect may be related to both biophysical and metabolic actions on the cell membrane.  相似文献   
5.
Most Ig receptors exist as hetero-oligomeric complexes with separate ligand binding (alpha) and signal transducing (beta, gamma, or zeta) subunits. For Fc gamma RIIIa and Fc epsilon RI, association with the FcR gamma-chain is essential for surface expression. However, the human high affinity IgG receptor, hFc gamma RI, was found to be surface- expressed by itself in transient transfection models. We have now analyzed the integrity of hFc gamma RI expression in more detail in stable transfectants. In vitro we noted that, in the absence of FcR gamma-chain, surface expression of hFc gamma RI rapidly declined to background levels, in both IIA1.6 B cells and NIH3T3 fibroblasts. The effect of FcR gamma-chain on hFc gamma RI surface expression in vivo was evaluated by using two newly generated transgenic mouse lines, selectively expressing hFc gamma RI on myeloid cells. These transgenic mice were crossed with FcR gamma-chain-deficient mice. Analysis of blood monocytes and peritoneal macrophages showed that surface expression of hFc gamma RI was reduced by approximately 80%. The remaining approximately 20% of receptors were still capable of binding IgG-opsonized RBC, suggesting FcR gamma-chain not to be critical for hFc gamma RI ligand-binding capacity. Importantly, however, hFc gamma RI signaling capacity was lost in FcR gamma-chain-deficient cells. No phagocytosis could be observed using either ligand sensitized (EA- IgG2a) or CD64-targeted erythrocytes (using a bispecific antibody) in both hFc gamma RI transgenic lines. This documents the FcR gamma-chain to be indispensable for both surface membrane expression and function of human Fc gamma RI in vivo.  相似文献   
6.
7.
8.
9.

Background

Critically-ill trauma patients have a high mortality.

Objective

To study the factors affecting the mortality of ICU trauma patients treated at Al-Ain Hospital, United Arab Emirates (UAE).

Methods

All trauma patients who were admitted to the ICU were prospectively collected over three years (2003–2006). Univariate and multivariate analysis were used to compare patients who died and who did not. Gender, age, nationality, mechanism of injury, systolic blood pressure and GCS on arrival, the need for ventilation, presence of head or chest injuries, AIS for the chest and head injuries and the ISS were studied.

Results

There were 202 patients (181 males). The most common mechanism of injury was road traffic collisions (72.3 %). The overall mortality was 13.9%. A direct logistic regression model has shown that factors that affected mortality were decreased GCS (p < 0.0001), mechanism of injury (p = 0.004) with burns having the highest mortality, increased age (p = 0.004), and increased ISS (p = 0.02). The best GCS that predicted mortality was 5.5 while the best ISS that predicted mortality was 13.5.

Conclusion

Road traffic collision is the most common cause of serious trauma in UAE followed by falls. Decreased GCS was the most significant factor that predicted mortality in the ICU trauma patients.  相似文献   
10.
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