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   711篇
  免费   32篇
  国内免费   9篇
耳鼻咽喉   1篇
儿科学   20篇
妇产科学   16篇
基础医学   133篇
口腔科学   8篇
临床医学   64篇
内科学   133篇
皮肤病学   6篇
神经病学   66篇
特种医学   71篇
外科学   52篇
综合类   4篇
预防医学   34篇
眼科学   10篇
药学   79篇
中国医学   4篇
肿瘤学   51篇
  2023年   6篇
  2022年   8篇
  2021年   19篇
  2020年   15篇
  2019年   17篇
  2018年   23篇
  2017年   20篇
  2016年   25篇
  2015年   14篇
  2014年   31篇
  2013年   43篇
  2012年   55篇
  2011年   50篇
  2010年   35篇
  2009年   31篇
  2008年   60篇
  2007年   61篇
  2006年   72篇
  2005年   45篇
  2004年   43篇
  2003年   34篇
  2002年   24篇
  2001年   4篇
  2000年   2篇
  1999年   1篇
  1998年   1篇
  1997年   2篇
  1995年   1篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1989年   4篇
  1988年   1篇
  1974年   1篇
  1971年   1篇
排序方式: 共有752条查询结果,搜索用时 15 毫秒
1.
We show the systemic administration of low levels of TSH increases bone volume and improves bone microarchitecture and strength in aged OVX rats. TSH's actions are mediated by its inhibitory effects on RANKL-induced osteoclast formation and bone resorption coupled with stimulatory effects on osteoblast differentiation and bone formation, suggesting TSH directly affects bone remodeling in vivo. INTRODUCTION: Thyroid-stimulating hormone (TSH) receptor haploinsufficient mice with normal circulating thyroid hormone levels have reduced bone mass, suggesting that TSH directly affects bone remodeling. We examined whether systemic TSH administration restored bone volume in aged ovariectomized (OVX) rats and influenced osteoclast formation and osteoblast differentiation in vitro. MATERIALS AND METHODS: Sprague-Dawley rats were OVX at 6 months, and TSH therapy was started immediately after surgery (prevention mode; n = 80) or 7 mo later (restoration mode; n = 152). Hind limbs and lumbar spine BMD was measured at 2- or 4-wk intervals in vivo and ex vivo on termination at 8-16 wk. Long bones were subjected to microCT, histomorphometric, and biomechanical analyses. The direct effect of TSH was examined in osteoclast and osteoblast progenitor cultures and established rat osteosarcoma-derived osteoblastic cells. Data were analyzed by ANOVA Dunnett test. RESULTS: In the prevention mode, low doses (0.1 and 0.3 microg) of native rat TSH prevented the progressive bone loss, and importantly, did not increase serum triiodothyroxine (T3) and thyroxine (T4) levels in aged OVX rats. In restoration mode, animals receiving 0.1 and 0.3 microg TSH had increased BMD (10-11%), trabecular bone volume (100-130%), trabecular number (25-40%), trabecular thickness (45-60%), cortical thickness (5-16%), mineral apposition and bone formation rate (200-300%), and enhanced mechanical strength of the femur (51-60%) compared with control OVX rats. In vitro studies suggest that TSH's action is mediated by its inhibitory effects on RANKL-induced osteoclast formation, as shown in hematopoietic stem cells cultivated from TSH-treated OVX rats. TSH also stimulates osteoblast differentiation, as shown by effects on alkaline phosphatase activity, osteocalcin expression, and mineralization rate. CONCLUSIONS: These results show for the first time that systemically administered TSH prevents bone loss and restores bone mass in aged OVX rats through both antiresorptive and anabolic effects on bone remodeling.  相似文献   
2.
The aim of this cross-sectional study was to estimate the prevalence of different subtypes of idiopathic focal dystonia in the population of Belgrade (Serbia), Yugoslavia. On December 31, 2001, the crude prevalence of all studied types of dystonia (focal, segmental, and multifocal) in Belgrade was 13.6 per 100,000 population (11.8 per 100,000 for men and 15.2 per 100,000 for women). Type-specific prevalence for focal dystonia was 11.2 per 100,000. The prevalence for cervical dystonia, blepharospasm, writer's cramp and laryngeal dystonia were 5.9 per 100,000, 1.9 per 100,000, 1.9 per 100,000, and 1.1 per 100,000, respectively.  相似文献   
3.
Adrenocorticotrophic hormone (ACTH) is essential for developmental maturation of numerous organ systems during the fetal period and for adaptation to environmental challenges. Immunocytochemical and stereological methods were used in the present study to examine the effects of dexamethasone (Dx) administration during pregnancy on fetal rat pituitary ACTH-producing cells. Doses of 0.5, 0.5 and 1.0 mg Dx/kg body weight/day were given to the dams on 3 consecutive days starting on day 16 of gestation. Morphometric analysis of the ACTH-producing cells of fetuses at 21 days of gestation revealed significant inhibition by 24% and 27%, respectively, of cell volume and cell number after maternal Dx administration, whereas the volume of cell nuclei and volume density of ACTH-stained cells were insignificantly decreased. Immunocytochemical analysis showed reduced numbers, sizes and immunopositivity of ACTH cells of 21-day-old fetuses from Dx-treated dams as compared with the control group. Maternal Dx treatment in the period of intense differentiation of the hypothalamo-hypophyseal-adrenal system had an inhibitory effect on fetal function and proliferative activity of ACTH-producing cells at 21 days of gestation. Thus, inhibition of activity of fetal ACTH-producing cells may lead to adrenal suppression, modified activity of the hypothalamo-pituitary-adrenal axis and reduced body weight possibly causing lasting functional abnormalities.  相似文献   
4.
BACKGROUND: The role of Daxx, in particular its ability to promote or hinder apoptosis, still remains controversial. In order to elucidate the functional relevance of Daxx in the extrinsic signaling of malignant lymphocytes Jurkat T-cells were stably transfected with a Daxx-expressing vector or with the respective Daxx-negative control vector. RESULTS: Assessing first the impact of Daxx expression on the rate of proliferation we demonstrate that overexpression of Daxx alone is not sufficient to alter proliferation in neoplastic lymphocytes. Nevertheless, expression of Daxx down-regulates anti-apoptotic Bcl-2 and up-regulates pro-apoptotic BID. In addition, Daxx-overexpressing Jurkat cells exhibit a decreased expression of the pro-caspase-8, -10, -9 and -3 and a concomitant increase of the inhibitors of apoptosis proteins survivin, XIAP, cIAP-1 and -2. We further demonstrate, that upon incubation with various chemotherapeutic agents these Daxx-induced molecular alterations sensitize Jurkat T-cells to the apoptosis-inducing effects of specific chemotherapeutic agents. CONCLUSIONS: We here outline the molecular changes elicited by Daxx on major components of the apoptotic cascade of malignant lymphocytes and demonstrate the capacity of Daxx to sensitize these cells to the apoptosis-inducing effect of various chemotherapeutic agents.  相似文献   
5.
6.
Antiphospholipid syndrome (APS) has been defined as a clinical and laboratory entity. Laboratory criteria include the presence of anticardiolipin antibodies (aCL) and/or lupus anticoagulant (LA), collectively termed as antiphospholipid antibodies (aPL). However, there has been a rising interest in antibodies against so-called protein cofactors, particularly in beta(2)-glycoprotein I. In the early 90s, annexins were considered as target antigens for aPL, but at present the exact role of antibodies against annexins (aANX) remains puzzling. This review is concerned with annexin V or annexin A5 (ANXA5), a widespread member of the annexin family, and antibodies directed towards it. We have endeavoured to summarise essential information about the detection of anti-annexin V antibodies (aANXA5) and their clinical relevance. This review has also brought together some relevant published data concerning the structure, physiological role and therapeutic potential of ANXA5.  相似文献   
7.
8.
BACKGROUND: The aim of this study was to investigate the frequency of C677T methylenetetrahydrofolate reductase (MTHFR) mutation in healthy Croatian volunteers and in patients with atherosclerosis. METHODS: The C677T MTHFR gene mutation was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 640 subjects, residents of the Zagreb city or Zagreb surroundings. Control group (n=298) was healthy blood donors. Patients (n=342) were divided into two groups of those with coronary heart disease, CAD (n=247) and those with >60% carotid stenosis, CS (n=95). RESULTS: CC genotype was recorded in 45% of healthy volunteers and 46% of patients (46.3% with CS and 46.2% with CAD). TC genotype was found in 49% of healthy volunteers and 45% of patients (46.3% with CS and 44.9% with CAD). There was no significant difference (p>0.05) from the control group in the genotype or allele frequency either for the overall group of patients with atherosclerosis or for the patient subgroups. CONCLUSION: The preliminary study of MTHFR polymorphism in control subjects and cardiovascular disease/carotid stenosis patients revealed that in Croats there was a low frequency of TT genotype (6% in controls vs. 9% in patients) and T allele (31% for cases and controls). Additionally, our results did not show significantly higher frequency of MTHFR mutation in CAD and CS studied groups.  相似文献   
9.
Elevated glucocorticoid level in the gravid female circulation affects number of endocrine functions in fetuses and offspring. In this research female rats were injected with dexamethasone (Dx) in three consecutive daily doses of 1.0, 0.5, 0.5 mg/kg body weight, starting from day 16 of pregnancy. The influence of this treatment on the pituitary adrenocorticotrophic (ACTH) cells and adrenal glands of 19-day-old fetuses was examined immunocytochemically and by morphometric analysis. Moreover, the proliferative activity of adrenocortical cells was estimated after application of the mitotic inhibitor Oncovine. Administration of Dx to pregnant rats induced a decline of fetal ACTH cell immunopositivity and significant decreases of ACTH cell volume (23%, p<0.05), volume density (41%, p<0.05), and its number per unit area (17%, p<0.05) in comparison to the control 19-day-old fetuses. Reduced proliferative activity of adrenocortical cells (31%; p<0.05) in zona glomerulosa, as well as the volume of this zone were detected. The volume and number of fetal adrenocortical cells in the inner zone and chromoblasts were not significantly reduced after Dx treatment of pregnant rats. These results show that maternal Dx administration in the period when the fetal hypothalamo-pituitary-adrenal (PA) axis begins its function inhibited the PA axis. Reduced ACTH cell function and mitotic activity led to suppression of adrenocortical cell multiplication in zona glomerulosa, the region of the adrenal cortex where most proliferating cells were found in control 19-day-old fetuses. Thus, increased glucocorticoid levels during late pregnancy caused developmental modifications involving the fetal PA axis, which could be the basis of the altered endocrine responsiveness in adult life.  相似文献   
10.

Aim

To assess the effectiveness of the long-term group psychotherapy in the treatment of posttraumatic stress disorder (PTSD) in war veterans on the basis of clinical picture of PTSD, associated neurotic symptoms, and adopted models of psychological defense mechanisms.

Methods

Prospective cohort study involved 59 war veterans who participated in dynamic-oriented supportive group psychotherapy for five years. The groups met once a week for 90 minutes. Forty-two veterans finished the program. The Clinician-Administered PTSD Scale structured interview was used to assess the intensity of PTSD. Crown-Crisp Index was used to evaluate other neurotic symptoms, and Life Style Questionnaire was used to assess the defense mechanisms. The assessments were done at the beginning of psychotherapy, after the second, and after the fifth year of treatment. Comorbid diagnoses, hospitalizations, and outpatient clinic treatments were also recorded.

Results

Long-term group psychotherapy reduced the intensity of PTSD symptoms in our patients (the difference between Clinician-Administered PTSD Scale score at the beginning and the end of treatment, F = 9.103, P = 0.001). Other neurotic symptoms and the characteristic profile of defense mechanisms did not change significantly during the course of treatment. Predominant defense mechanisms were projection (M = 82.0 ± 14.4) and displacement (M = 69.0 ± 16.8). None of the symptoms or defense mechanisms present at the beginning of the treatment changed significantly after two or five years of treatment. The number of diagnosed major depressive episodes, which increased after the second year of psychotherapy, decreased by the end of treatment.

Conclusion

Psychotherapy can reduce the intensity of PTSD symptoms, but the changes in the personality of veterans with PTSD are deeply rooted. Traumatic experiences lead to the formation of rigid defense mechanisms, which cannot be significantly changed by long-term group psychotherapy.A traumatic experience greatly changes the perception of inner and outer world in a patient with posttraumatic stress disorder (PTSD) (1). Feelings of deep isolation, alienation, helplessness, and distrust, together with interpersonal problems and socially dysfunctional behavior, are the main psychological components of PTSD (1). Group psychotherapy, therefore, has the central role in the integrated psychiatric treatment of patients with PTSD (2).Since 1980, when the term “posttraumatic stress disorder” was introduced in psychiatric nomenclature, numerous studies have been conducted to establish the most appropriate psychotherapeutic methods for treating this disorder (3). Although recent guidelines recommend cognitive-behavioral approach, it seems that this type of therapy cannot be successfully applied in all war veterans, especially not in those with chronic PTSD (2-5). Deeply rooted changes in personality, which disturb biological, psychological, and social equilibrium, require long-term therapy. The corrective emotional experience and the feeling of security in a therapeutic group setting strengthen the healthy parts of the self, and neutralize and reintegrate the destructive ones (6). Dynamic-oriented group therapy is commonly used because the number of patients who need psychological help is relatively high, the availability of group therapists is limited, and the range of indications for this type of therapy is broad (2).After the 1991-1995 war in Croatia, the number of war veterans asking for psychiatric help has been increasing. In the first encounters with these patients, psychiatrists prescribed psychopharmaceuticals more often than short psychotherapeutic interventions. However, they soon realized that PTSD symptoms were recurring after an initial improvement and that the disorder had a strong and lasting impact on the patients'' professional, social, and family life. It was obvious that initially applied treatment methods could not successfully meet veterans’ needs for continuous and accessible mental health care. A more comprehensive and effective psychotherapeutic approach had to be adopted (6,7).Our aim was to assess the effectiveness of long-term group psychotherapy in the treatment of war veterans with PTSD by evaluating the clinical picture of PTSD, associated neurotic symptoms, and adopted models of psychological defense mechanisms after two and five years of treatment.  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