首页 | 官方网站   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   1001篇
  免费   42篇
  国内免费   4篇
医药卫生   1047篇
  2023年   2篇
  2021年   3篇
  2018年   12篇
  2017年   12篇
  2016年   11篇
  2015年   12篇
  2014年   20篇
  2013年   19篇
  2012年   20篇
  2011年   17篇
  2010年   37篇
  2009年   42篇
  2008年   26篇
  2007年   25篇
  2006年   25篇
  2005年   17篇
  2004年   22篇
  2003年   22篇
  2002年   15篇
  2001年   12篇
  2000年   12篇
  1999年   16篇
  1998年   50篇
  1997年   65篇
  1996年   49篇
  1995年   40篇
  1994年   51篇
  1993年   51篇
  1992年   10篇
  1991年   11篇
  1990年   10篇
  1989年   38篇
  1988年   39篇
  1987年   30篇
  1986年   30篇
  1985年   26篇
  1984年   12篇
  1983年   21篇
  1982年   17篇
  1981年   19篇
  1980年   21篇
  1979年   4篇
  1978年   8篇
  1977年   12篇
  1976年   9篇
  1975年   17篇
  1971年   1篇
  1969年   1篇
  1968年   1篇
  1948年   1篇
排序方式: 共有1047条查询结果,搜索用时 15 毫秒
91.
目的:观察碱性成纤维细胞生长因子对大鼠脑出血后出血灶周围脑组织和出血侧海马bax、bcl-2基因表达的影响,探讨神经营养因子对神经细胞调亡的调控。方法:实验于2006-01/10在广西医科大学医学科学实验中心完成。①取成年清洁级Wistar大鼠72只,雌雄各半,体质量250g左右。②采用脑内囊注射胶原酶建立大鼠脑出血模型,动物于苏醒后按Bederson法进行神经病学评分,评分>3分后入选本实验,入选72只大鼠随机抽签法分为3组,每组24只。碱性成纤维细胞生长因子组按8μg/kg剂量肌肉注射,1次/d;生理盐水组肌肉注射等剂量的生理盐水,1次/d;模型组不作任何干预。③每组分别于干预后1,3,7d随机抽取8只大鼠,麻醉状态下取出血灶周围脑组织和出血侧海马,采用半定量反转录-聚合酶链反应检测调亡调控基因bax mRNA,bcl-2mRNA的表达。结果:在建立脑出血模型中共5只大鼠死亡,随后对死亡动物进行解剖,发现脑内血肿量过大,致脑疝形成而导致死亡,后随机补充动物。72只大鼠进入结果分析。①血肿周围脑组织bax mRNA表达:干预后3d,7d,碱性成纤维细胞生长因子组血肿周围脑组织bax mRNA表达比生理盐水组明显减少(3d:0.54±0.19,0.76±0.23,P<0.05;7d:0.45±0.19,0.71±0.16,P<0.01)。②血肿周围脑组织bcl-2mRNA表达:干预后3d,7d,碱性成纤维细胞生长因子组的血肿周围脑组织bcl-2mRNA表达比生理盐水组明显增高(3d:0.68±0.25,0.39±0.19,P<0.05;7d:0.80±0.21,0.48±0.18,P<0.01)。③出血侧海马bax mRNA表达:干预后3d和7d,碱性成纤维细胞生长因子组的出血侧海马bax mRNA表达比生理盐水组均明显减少(3d:0.54±0.18,0.70±0.11;7d:0.43±0.24,0.69±0.18,P均<0.05)。④出血侧海马bcl-2mRNA表达:干预后3d和7d,碱性成纤维细胞生长因子组的出血侧海马bcl-2mRNA表达比生理盐水组均明显增多(3d:0.66±0.11,0.50±0.15;7d:0.72±0.12,0.52±0.22,P均<0.05)。结论:碱性成纤维细胞生长因子能调节凋亡相关基因,提高大鼠脑出血后大脑脑组织和海马bcl-2mRNA的表达,降低bax mRNA的表达。  相似文献   
92.
93.
Tighe  JE; Daga  A; Calabi  F 《Blood》1993,81(3):592-596
The t(8;21)(q22;q22) is consistently associated with acute myeloid leukemia (AML) M2. Recent data have suggested that breakpoints on chromosome 21 are clustered within a single intron of a novel gene, AML1, just downstream of a region of homology to the runt gene of D melanogaster. In this report, we confirm rearrangement at the same location in at least 12 of 18 patients with t(8;21). Furthermore, we have isolated recombinant clones spanning the breakpoint regions on both the der(8) and the der(21) from one patient. By using a chromosome 8 probe derived from these clones, we show that t(8;21) breakpoints are also clustered on chromosome 8.  相似文献   
94.
Aliment Pharmacol Ther 2011; 34: 656–663

Summary

Background Transient elastography measures liver stiffness, which correlates with the hepatic fibrosis stage and has excellent accuracy for the diagnosis of cirrhosis in patients with chronic hepatitis C. Aim To assess prospectively the kinetics of liver stiffness in treated patients with chronic hepatitis C and compare them with the viral kinetics on treatment and with the final outcome of therapy. Methods 91 patients with chronic hepatitis C with significant fibrosis (>7.0 kPa) at baseline were included. They received therapy with pegylated interferon‐α and ribavirin. The kinetics of liver stiffness were characterized during therapy and thereafter by means of Fibroscan, and compared with the virological responses at weeks 4, 12, 24, end of treatment and 12 and 24 weeks after. Results A significant liver stiffness decrease was observed during therapy, which continued after treatment only in patients who achieved a sustained virological response. In this group, the median intra‐patient decrease relative to baseline at the end of follow‐up was ?3.4 kPa, vs?1.8 kPa in the patients who did not achieve an SVR. Similar dynamics were observed in cirrhotic and non‐cirrhotic patients. In multivariate analysis, only the SVR was associated with long‐term improvement of liver stiffness (odds ratio: 3.10; 95% confidence interval: 1.20–8.02, P = 0.019). Conclusions In patients with advanced fibrosis at the start of therapy, liver stiffness is significantly reduced during treatment, but improvement continues off treatment only in patients who achieve a sustained virological response. Liver stiffness assessment earlier than 6 months after the end of therapy does not appear to be clinically meaningful.
  相似文献   
95.

Background

Diagnostic ultrasonography is used by GPs in approximately 10% of patients of reproductive age with abnormal vaginal bleeding. Transvaginal sonography is recommended as a first-line diagnostic instrument for assessing uterine pathology.

Aim

To assess if findings resulting from openaccess sonography were in agreement with the GPs’ working hypotheses and if these findings contributed to GPs’ management.

Design and setting

Prospective observational cohort study of GPs working in the health district of the Academic Medical Center, Amsterdam and their patients consulting with abnormal vaginal bleeding.

Method

Data on patients’ history, GPs’ primary working hypotheses, and intended management were recorded. After sonography, GPs recorded their actual management.

Results

A total of 122 patients were included by 18 GPs from June 2003 to December 2004. Data from 89 patients were available for analysis. The GPs’ working hypotheses implied ‘no structural pathology’ in 65/89 patients, and ‘fibroids’ in 24/89 patients. Sonographic findings were confirmed in 50/65 patients where ‘no structural pathology’, and in 14/24 of those where ‘fibroids’ were expected. Initially, GPs had intended to refer nine patients to a gynaecologist. Actual management after sonographic assessment was watchful waiting or drug therapy in 57/89 patients. Eighty-nine per cent of these patients had normal sonographic findings. The actual referral rate rose to 27/89 patients. In 17 referred patients, sonographic findings were suggestive of intracavitary abnormalities.

Conclusion

Open-access sonography contributed to more accurate diagnoses and improved GPs’ management of women with abnormal vaginal bleeding.  相似文献   
96.

Background

In November 2006, an email-based health promotion program for pregnant women was implemented nationally in the Netherlands. The program consisted of emails containing quizzes with pregnancy-related questions tailored to the number of weeks of pregnancy. Emails were sent out once every 4 weeks, up to a maximum of nine emails.

Objectives

The aims of the study were (1) to assess the recruitment of participants and their representativeness of the Dutch population and (2) to study differences in recruitment, program use, and program appreciation among women with different levels of education.

Methods

Data from 13,946 pregnant women who enrolled during the first year of the program were included. Upon registration, participants were asked how they found out about the program and subsequently received an email questionnaire to assess demographic, lifestyle, and Internet characteristics. Program use was tracked, and participants were classified into five user groups (inactive to very active). Program appreciation (low, intermediate, and high) was assessed twice with an email questionnaire that was sent after the woman had received her third and sixth quiz email. Information about pregnant women and their characteristics was obtained from Dutch registries to assess representativeness of the study population.

Results

About 8% of the pregnant women in the Netherlands enrolled in the program. Immigrants were underrepresented, and women with a low level of education seemed to be slightly underrepresented. Most women knew about the program from a promotional email sent by the organization (32%), followed by the Internet (22%) and midwives (16%). Women with little education were more often inactive users of the program than were highly educated women (15% vs 11%, P < .001), whereas highly educated women were more often very active users compared with women with little education (25% vs 20%, P< .001). However, women with less education were more likely than women with more education to have a high appreciation of the program after receiving three quiz emails (52% vs 44%, P = .001).

Conclusions

In this real-life setting, pregnant women can be reached through an email-based health promotion program. Selective engagement by education level remains a challenge.  相似文献   
97.
A deletion on one chromosome and a mutant allele on the other may cause an autosomal recessive disease. We report on two patients with mental retardation, dysmorphic features and low catalytic activity of arylsulfatase A. One patient had a pathogenic mutation in the arylsulfatase A gene ( ARSA ) and succumbed to metachromatic leukodystrophy (MLD). The other patient had a pseudoallele, which does not lead to MLD. The presenting clinical features and low arylsulfatase A activity were explained, in each patients, by a deletion of 22q13 and, thereby, of one allele of ARSA .  相似文献   
98.

Background and purpose:

In vitro evidence suggests that metabolism of anandamide by cyclooxygenase-2 (COX-2) may be more important when the primary metabolic pathway [i.e. fatty acid amide hydrolase (FAAH)] is inhibited. Thus, the first aim of the present study was to assess the effects of COX-2 and/or FAAH inhibition, on the cardiovascular actions of anandamide. The second aim was to compare the effects of anandamide with those of the metabolically stable analogue (i.e. methanandamide) and investigate mechanisms involved in responses to the latter in conscious rats.

Experimental approach:

Rats were chronically instrumented for recording blood pressure, heart rate and renal, mesenteric and hindquarters vascular conductances in the freely moving state.

Key results:

Inhibition of FAAH with URB597 (cyclohexycarbamic acid 3′-carbamoyl-biphenyl-3-yl-ester) augmented the haemodynamic actions of anandamide, but there was no effect of COX-2 inhibition with parecoxib, either in the absence or the presence of URB597. Methanandamide caused CB1 receptor-mediated renal and mesenteric vasoconstriction and evoked β2-adrenoceptor-mediated hindquarters vasodilatation.

Conclusions and implications:

No evidence for an involvement of COX-2 in the systemic cardiovascular actions of anandamide could be demonstrated. Vasoconstrictor actions of methanandamide were shown to involve CB1 receptors, whereas no involvement of CB1 receptors in such actions of anandamide has been shown. However, β2-adrenoceptor-mediated hindquarters vasodilatation, independent of CB1 receptors, observed here with methanandamide, has previously been seen with anandamide and differs from previous results with other synthetic cannabinoids for which the response was CB1 receptor-dependent. Thus, mechanisms underlying the cardiovascular actions of endocannabinoids and synthetic analogues appear to be agonist-specific.  相似文献   
99.
100.
Objectives: To assess the influence of clinical status on the association between total plasma bilirubin and unbound bilirubin on death or adverse neurodevelopmental outcomes at 18–22 months corrected age in extremely low birth weight infants. Method: Total plasma bilirubin and unbound bilirubin were measured in 1101 extremely low birth weight infants at 5 ± 1 days of age. Clinical criteria were used to classify infants as clinically stable or unstable. Survivors were examined at 18–22 months corrected age by certified examiners. Outcome variables were death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss, and death prior to follow‐up. For all outcomes, the interaction between bilirubin variables and clinical status was assessed in logistic regression analyses adjusted for multiple risk factors. Results: Regardless of clinical status, an increasing level of unbound bilirubin was associated with higher rates of death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss and death before follow‐up. Total plasma bilirubin values were directly associated with death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss, and death before follow‐up in unstable infants, but not in stable infants. An inverse association between total plasma bilirubin and death or cerebral palsy was found in stable infants. Conclusions: In extremely low birth weight infants, clinical status at 5 days of age affects the association between total plasma bilirubin and death or adverse neurodevelopmental outcomes at 18–22 months of corrected age. An increasing level of UB is associated a higher risk of death or adverse neurodevelopmental outcomes regardless of clinical status. Increasing levels of total plasma bilirubin are directly associated with increasing risk of death or adverse neurodevelopmental outcomes in unstable, but not in stable infants.  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-23

京公网安备 11010802026262号