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   2509篇
  免费   155篇
  国内免费   6篇
耳鼻咽喉   23篇
儿科学   83篇
妇产科学   54篇
基础医学   245篇
口腔科学   71篇
临床医学   239篇
内科学   544篇
皮肤病学   31篇
神经病学   157篇
特种医学   106篇
外科学   540篇
综合类   40篇
预防医学   119篇
眼科学   63篇
药学   201篇
中国医学   25篇
肿瘤学   129篇
  2023年   32篇
  2022年   91篇
  2021年   119篇
  2020年   91篇
  2019年   102篇
  2018年   92篇
  2017年   73篇
  2016年   85篇
  2015年   95篇
  2014年   101篇
  2013年   122篇
  2012年   178篇
  2011年   166篇
  2010年   82篇
  2009年   92篇
  2008年   163篇
  2007年   143篇
  2006年   116篇
  2005年   138篇
  2004年   109篇
  2003年   88篇
  2002年   89篇
  2001年   39篇
  2000年   53篇
  1999年   35篇
  1998年   20篇
  1997年   15篇
  1996年   12篇
  1995年   12篇
  1994年   11篇
  1993年   3篇
  1992年   10篇
  1991年   12篇
  1990年   10篇
  1988年   7篇
  1987年   6篇
  1986年   3篇
  1985年   5篇
  1984年   5篇
  1982年   2篇
  1981年   3篇
  1979年   7篇
  1977年   2篇
  1976年   2篇
  1974年   2篇
  1973年   4篇
  1972年   4篇
  1971年   5篇
  1969年   3篇
  1967年   3篇
排序方式: 共有2670条查询结果,搜索用时 859 毫秒
1.
2.
Arsenic (As) and cadmium (Cd) have recently emerged as major health concerns owing to their strong association with diabetes mellitus (DM). We aimed to investigate the heavy metals exposure towards incidence of DM at various enzymatic and hormonal levels. Additionally, association of As and Cd with Zinc (Zn, essential metal) was also evaluated. Spot urine samples were collected to assess As, Cd and Zn through ICP-OES. Serum was analyzed by assay method for fasting blood glucose, liver and renal function biomarkers. ELISA was performed to investigate the impact of heavy metals on HbA1c, α-amylase, DPP-IV, IGF-1, leptin, GSH, MDA, SOD, HDL, FFA, TG and interleukin (IL)-6. Association of heavy metals with DM was measured by odds ratio (OR) and level of significance was assessed by Chi-squared test. Unpaired student's t-test was used to compare DM-associated risk factors in heavy metals-exposed and unexposed participants. As and Cd were detectable in 75.4% and 83% participants with mean concentration of 75.5 ppb and 54.5 ppb, respectively. For As exposure, OR in the third quartile was maximum ie 1.34 (95% CI, 0.80 to 2.23), however the result was not statistically significant (P > .05). For Cd exposure, OR in the fourth quartile was considerably high, 1.62 (95% CI, 1.00 to 2.61), with a significant probability value (P < .05). Urinary Cd was negatively associated with Zn. As and Cd exposure increases the incidence of DM in the general population. Impaired hormonal and enzymatic levels in diabetic and non-diabetic exposed participants reflect the multiple organ damage by heavy metal exposure.  相似文献   
3.
4.
BACKGROUND: The epidemiology of superficial venous disease is relatively well defined in the U.K. Caucasian population. By contrast, there are currently no data available for Asians, who comprise 3.6% of the U.K., and 14.1% of this institution's catchment population. The aim of this study was to compare surgery for superficial venous disease in Caucasians and Asians in this institution, in the context of our local population. METHODS: A prospectively gathered database of all 2011 superficial venous operations performed between January 1997 and April 2002 was retrospectively analysed with regard to ethnicity. The ethnic, gender and age composition of our catchment area was determined from U.K. census data. The full institutional records of 100 Asian and 100 randomly selected age and sex-matched Caucasian patients were compared in a case control study. RESULTS: After adjusting for age and gender according to census data, Asians were 40% less likely to undergo superficial venous surgery (SVS). Considering the 2011 operated patients as a whole, Asians were significantly younger and more likely to be male. In the case control study, Asians were significantly less likely to be operated for recurrent disease and significantly more likely to be operated for advanced disease. CONCLUSIONS: Although Asians are significantly less likely to undergo SVS; those that do are more likely to be young, male and operated for skin changes and ulcers. This strongly suggests that the under-representation of Asians is due to cultural, genetic or environmental factors and unmet health care need, rather than a lower prevalence of clinically significant venous disease in the Asian population.  相似文献   
5.
BACKGROUND: There is increasing recognition that high-performance athletes can develop symptomatic arterial flow restriction in one or both (15%) legs due to kinking and/or endofibrosis of their iliac arteries. METHODS: Case report and review based on a Medline search of the literature. RESULTS: A 51-year-old female, 24-hour endurance runner presented with a six-month history of rapidly progressing intermittent claudication affecting her right thigh and calf in the absence of classical risk factors for atherosclerosis. On the basis of invasive and non-invasive investigations, a provisional diagnosis of endofibrosis was made and she was treated successfully with angioplasty. CONCLUSIONS: The epidemiology, optimal investigation and treatment of iliac endofibrosis in endurance athletes is poorly described. Each individual unit's experience is likely to be very small. A European register of such cases would increase our understanding of the condition and improve patient outcomes.  相似文献   
6.
BACKGROUND: Superficial lymphatic malformations are predominantly developmental malformations of infancy, but they may arise at any age. OBJECTIVE: To describe a patient with a late-onset superficial lymphatic malformation. METHODS: Case report and literature review. RESULTS: A 53-year-old woman was evaluated for a colored lesion that developed spontaneously on the anterior abdominal wall. The lesion was treated by surgical excision. Findings on histopathologic examination of the specimen were consistent with superficial lymphatic malformation. There was no recurrence of the lesion at 4 months after the operation. CONCLUSION: Superficial lymphatic malformations can develop in adults spontaneously without the presence of any predisposing condition. Because the majority of such late-onset malformations reported in the literature are localized lesions similar to the one in our patient, surgical removal with inclusion of subcutaneous tissue usually results in cure without recurrence.  相似文献   
7.
A four-day-old male neonate who underwent three exchange transfusions for jaundice owing to ABO incompatibility on three consecutive days is presented. A large intrahepatic hematoma developed as a complication of the third exchange transfusion. The baby fully recovered.  相似文献   
8.
Multiple congenital supratentorial intracerebral cysts occurred in a newborn infant. The cysts, of varying size, content and lining, occupied the cerebral hemispheres. They formed a mosaic pattern on CT scan and left no trace of a recognisable ventricular system. Multiple surgical procedures were performed during the first year of life, and at one year the child was very well and asymptomatic, with two functioning shunts.  相似文献   
9.
AV fistulae are extremely rare complications after hand replantation. In the case presented, the formation of an AV fistula did not occur immediately after the replantation, but after the insertion of the free lateral arm flap to the extensor surface of the replanted hand. This paper discusses the mechanisms responsible for the formation of AV fistulae.  相似文献   
10.
Mycobacterial strains from the Mycobacterium avium complex were compared with each other and with Mycobacterium phlei isolates by restriction endonuclease digestion of chromosomal DNA with SspI and analysis by pulsed-field gel electrophoresis. Characteristic profiles were observed for known typed strains, and five groups were identified. Primary bovine isolates identified as Mycobacterium paratuberculosis by classical methods were shown to fall into both the M. paratuberculosis- and M. avium-like groups. M. paratuberculosis 18 was in the latter category. Two Mycobacterium intracellulare strains of different Schaefer serotypes had different digestion profiles. In addition, this system was exploited for the preparation of DNA probes by the isolation, digestion, and subcloning of DNA fragments separated by pulsed-field gel electrophoresis. Probe JC12 hybridized only to M. avium complex strains, but not to M. phlei, showing characteristic hybridization profiles for each of the groups previously identified by pulsed-field gel electrophoresis. The approach taken in the study lends itself to the comparative analysis of members of the M. avium complex and to the isolation and characterization of DNA probes with specificity for these mycobacteria.  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