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   5255篇
  免费   316篇
  国内免费   54篇
耳鼻咽喉   51篇
儿科学   92篇
妇产科学   276篇
基础医学   553篇
口腔科学   91篇
临床医学   543篇
内科学   1183篇
皮肤病学   59篇
神经病学   406篇
特种医学   132篇
外科学   664篇
综合类   95篇
一般理论   2篇
预防医学   241篇
眼科学   297篇
药学   453篇
中国医学   28篇
肿瘤学   459篇
  2023年   25篇
  2022年   71篇
  2021年   149篇
  2020年   59篇
  2019年   116篇
  2018年   160篇
  2017年   99篇
  2016年   117篇
  2015年   159篇
  2014年   197篇
  2013年   247篇
  2012年   404篇
  2011年   370篇
  2010年   281篇
  2009年   211篇
  2008年   302篇
  2007年   317篇
  2006年   316篇
  2005年   273篇
  2004年   236篇
  2003年   200篇
  2002年   175篇
  2001年   164篇
  2000年   158篇
  1999年   131篇
  1998年   27篇
  1997年   36篇
  1996年   25篇
  1995年   23篇
  1994年   25篇
  1993年   11篇
  1992年   80篇
  1991年   55篇
  1990年   67篇
  1989年   40篇
  1988年   29篇
  1987年   39篇
  1986年   27篇
  1985年   26篇
  1984年   18篇
  1983年   9篇
  1981年   9篇
  1980年   16篇
  1979年   20篇
  1978年   16篇
  1977年   9篇
  1975年   10篇
  1973年   8篇
  1972年   12篇
  1971年   8篇
排序方式: 共有5625条查询结果,搜索用时 15 毫秒
991.
992.
Follistatin is a glycoprotein with various biologic functions that plays a role in adipocyte differentiation, muscle stimulation, anti-inflammation, and energy homeostasis. Thyroid hormones influence energy expenditure, glucose, and lipid metabolism. The association between serum follistatin level and thyroid function statuses has seldom been evaluated.The objectives of this study were to compare serum follistatin concentrations in different thyroid function statuses and to evaluate the associations between serum follistatin and free thyroxine (fT4) levels.In this study, 30 patients with hyperthyroidism (HY group) and 30 euthyroid individuals (EU group) were recruited. The patients of HY group were treated with antithyroid regimens as clinically indicated, whereas no medication was given to EU group. The demographic and anthropometric characteristics, biochemical data, serum levels of follistatin, and thyroid function of both groups at baseline and at the 6th month were compared. Data of all patients were pooled for the analysis of the associations between the levels of follistatin and fT4.At baseline, the HY group had significantly higher serum follistatin levels than the EU group (median [Q1, Q3]: 1.81 [1.33, 2.78] vs 1.13 [0.39, 1.45] ng/mL, P < 0.001). When treated with antithyroid regimens, the follistatin serum levels in HY group decreased to 1.54 [1.00, 1.88] ng/mL at the 6th month. In all patients, the serum levels of follistatin were positively associated with fT4 levels at baseline (β = 0.54, P = 0.005) and at the 6th month (β = 0.59, P < 0.001). The association between follistatin and fT4 levels remained significant in the stepwise multivariate regression analysis, both initially and at the 6th month.In comparison to the EU group, patients with hyperthyroidism had higher serum follistatin levels, which decreased after receiving antithyroid treatment. In addition, the serum follistatin concentrations were positively associated with serum fT4 levels in patients with hyperthyroidism or euthyroidism.  相似文献   
993.
Context Oxidative stress plays a key role in neurodegenerative disorders, including Parkinson’s disease (PD). Rice fermented with Monascus purpureus Went (Monascaceae) NTU 568 (red mould rice) was found to contain antioxidants, including dimerumic acid (DMA) and deferricoprogen (DFC).

Objective The effects of DMA and DFC on 6-hydroxydopamine (6-OHDA)-induced cytotoxicity and potential protective mechanisms in differentiated PC-12 pheochromocytoma cells were investigated.

Materials and methods DMA (0–60?μM) or DFC (0–10?μM) was co-treated with 6-OHDA (200?μM, 24?h exposure) in differentiated PC-12 cells. Cell viability and intercellular reactive oxygen species (ROS) were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and 2′,7′-dichlorofluorescein-diacetate (DCFH-DA) assays, respectively. Cell apoptosis was determined by DNA fragmentation analysis and propidium iodide staining by flow cytometry. Western blot analysis was used to measure the levels of cell protein expression.

Results DMA and DFC significantly increased cell viability to 72% and 81% in 6-OHDA-induced differentiated PC-12 cell cultures, respectively. Furthermore, DMA and DFC reduced 6-OHDA-induced formation of extracellular and intercellular ROS by 25% and 20%, respectively, and decreased NADPH oxidase-2 expression in differentiated PC-12 cells. DMA and DFC inhibited 6-OHDA-induced apoptosis and decreased activation of caspase-3 via regulation of Bcl-2-associated X protein (Bax) and Bcl-2 protein expression in differentiated PC-12 cells.

Conclusion DMA and DFC may protect against 6-OHDA toxicity by inhibiting ROS formation and apoptosis. These results showed that the metabolites from M. purpureus NTU 568 fermentation were potential therapeutic agents for PD induced by oxidative damage and should be encouraged for further research.  相似文献   
994.
995.
996.

Background

Patient-reported outcomes, such as the Erectile Dysfunction Inventory of Treatment Satisfaction (EDITS) index, are essential for successful evaluation and treatment of patients with erectile dysfunction.

Aim

To enrich interpretation of the EDITS index score and to complement the existing 0 to 100 scoring.

Methods

This supplemental analysis evaluated EDITS questionnaire data (11 items; index score range = 0–100; higher scores indicate more treatment satisfaction) after completion of an 8-week double-blinded trial of 279 men 18 to 65 years old with erectile dysfunction randomized to sildenafil 100 mg, sildenafil 50 mg, or placebo. Response options for each EDITS item were grouped into “success” (the 2 most satisfied or favorable responses) and “no success” (the remaining 3 responses). The binary response (success or no success) for each item was expressed as a function of overall EDITS score in a simple logistic regression model with all treatments combined.

Outcomes

Odds ratios and success probabilities (using Wald χ2 tests) were calculated for specified point differences and total EDITS index scores, respectively.

Results

EDITS index score increases corresponded with significant increases in odds of success in different EDITS aspects (P < .0001 for all comparisons). For instance, a 10-point EDITS index score difference was associated with odds ratios of 11.3, 42.0, 17.7, and 6.8 for overall treatment satisfaction, treatment meeting expectations, satisfaction with treatment quickness, and satisfaction with how long treatment lasts, respectively. For a given EDITS index score, likelihood of success was determined for different aspects of treatment satisfaction. For example, a mean EDITS index score of 78 (sildenafil 100 mg; SD = 18) corresponded to 96%, 88%, 94%, and 88% chances of success for the 4 EDITS items referenced earlier, respectively. Corresponding probabilities for a mean EDITS index score of 50 (placebo; SD = 18) were 3%, less than 0.1%, 1%, and 4%, respectively.

Clinical Implications

Interpretation of the EDITS index score can be augmented using key aspects of treatment satisfaction as reported by the patient.

Strengths and Limitations

This analysis used a well-established anchor-based approach to interpret EDITS index scores. The methodology used and corresponding results are appropriate for clinical practice and clinical trial settings. Limitations include data evaluation only for the Patient EDITS and not the complementary Partner EDITS and use of data from a clinical trial enrolling a well-defined patient population only in stable relationships.

Conclusion

These results enable a meaningful interpretation of EDITS index scores, facilitating decision making by stakeholders for better-informed health care choices.Cappelleri JC, Tseng L-J, Stecher V, Goldstein I. Enriching the Interpretation of the Erectile Dysfunction Inventory of Treatment Satisfaction: Characterizing Success in Treatment Satisfaction. J Sex Med 2018;15:732–740.  相似文献   
997.
998.
Alzheimer's disease (AD) progresses insidiously from the preclinical stage to dementia. While people with subjective cognitive decline (SCD) have normal cognitive performance, some may be in the preclinical stage of AD. Neurofibrillary tangles appear first in the transentorhinal cortex, followed by the entorhinal cortex in the clinically silent stage of AD. We expected the earliest changes in subjects with SCD to occur in medial temporal subfields other than the hippocampal proper. These selective structural changes would affect specific memory subcomponents. We used the Family Picture subtest of the Wechsler Memory Scale‐III, which was modified to separately compute character, activity, and location subscores for episodic memory subcomponents. We recruited 43 subjects with SCD, 44 subjects with amnesic mild cognitive impairment, and 34 normal controls. MRI was used to assess cortical thickness, subcortical gray matter volume, and fractional anisotropy. The results demonstrated that SCD subjects showed significant cortical atrophy in their bilateral parahippocampus and perirhinal and the left entorhinal cortices but not in their hippocampal regions. SCD subjects also exhibited significantly decreased mean fractional anisotropy in their bilateral uncinate fasciculi. The diminution of cortical thickness over the mesial temporal subfields corresponded to brain areas with early tangle deposition, and early degradation of the uncinate fasciculus was in accordance with the retrogenesis hypothesis. The parahippocampus and perirhinal cortex contribute mainly to context association memory while the entorhinal cortex, along with the uncinate fasciculus, contributes to content‐related contextual memory. We proposed that context association and related memory structures are vulnerable in the SCD stage.  相似文献   
999.
1000.
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