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   2279篇
  免费   140篇
  国内免费   9篇
耳鼻咽喉   3篇
儿科学   30篇
妇产科学   12篇
基础医学   216篇
口腔科学   43篇
临床医学   128篇
内科学   599篇
皮肤病学   253篇
神经病学   101篇
特种医学   64篇
外科学   540篇
综合类   7篇
预防医学   112篇
眼科学   4篇
药学   149篇
肿瘤学   167篇
  2023年   15篇
  2022年   20篇
  2021年   41篇
  2020年   16篇
  2019年   26篇
  2018年   74篇
  2017年   59篇
  2016年   66篇
  2015年   52篇
  2014年   76篇
  2013年   84篇
  2012年   126篇
  2011年   116篇
  2010年   56篇
  2009年   55篇
  2008年   89篇
  2007年   80篇
  2006年   77篇
  2005年   79篇
  2004年   84篇
  2003年   63篇
  2002年   75篇
  2001年   82篇
  2000年   92篇
  1999年   109篇
  1998年   40篇
  1997年   24篇
  1996年   20篇
  1995年   9篇
  1994年   11篇
  1993年   13篇
  1992年   60篇
  1991年   67篇
  1990年   53篇
  1989年   61篇
  1988年   44篇
  1987年   28篇
  1986年   30篇
  1985年   32篇
  1984年   22篇
  1983年   21篇
  1979年   20篇
  1978年   17篇
  1977年   17篇
  1975年   13篇
  1974年   11篇
  1972年   14篇
  1970年   11篇
  1969年   9篇
  1968年   9篇
排序方式: 共有2428条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
The second derivative of the finger photoplethysmogram (SDPTG) has been used as a non-invasive examination for arterial stiffness. The present study sought to elucidate independent determinants of the SDPTG among various cardiovascular risk factors in middle-aged Japanese men. The SDPTG was obtained from the cuticle of the left-hand forefinger in 973 male workers (mean age: 44+/-6 years) during a medical checkup at a company. The SDPTG indices (b/a and d/a) were calculated from the height of the wave components. Multiple logistic regression analyses revealed that the independent determinants of an increased b/a (highest quartile of the b/a) were age (odds ratio [OR]: 1.12 per 1-year increase, 95% confidence interval [CI]: 1.09-1.15), hypertension (OR: 1.65, 95% CI: 1.03-2.65), dyslipidemia (OR: 1.51, 95% CI: 1.09-2.09), impaired fasting glucose/diabetes mellitus (OR: 2.43, 95% CI: 1.16-5.07), and a lack of regular exercise (OR: 2.00, 95% CI: 1.29-3.08). Similarly, independent determinants of a decreased d/a (lowest quartile of the d/a) were age (OR: 1.11 per 1-year increase, 95% CI: 1.08-1.14), hypertension (OR: 3.44, 95% CI: 2.20-5.38), and alcohol intake 6 or 7 days per week (OR: 2.70, 95% CI: 1.80-4.06). No independent association was observed between the SDPTG indices and blood leukocyte count or serum C-reactive protein levels. In conclusion, the SDPTG indices reflect arterial properties affected by several cardiovascular risk factors in middle-aged Japanese men. The association between inflammation and the SDPTG should be evaluated in further studies.  相似文献   
6.
Since humans are under ceaseless orthostatic stress, the mechanism to maintain arterial pressure (AP) under orthostatic stress against gravitational fluid shift is of great importance. We hypothesized that (1) orthostatic stress resets the arterial baroreflex control of sympathetic nerve activity (SNA) to a higher SNA, and (2) resetting of the arterial baroreflex contributes to preventing postural hypotension. Renal SNA and AP were recorded in eight anaesthetized, vagotomized and aortic-denervated rabbits. Isolated intracarotid sinus pressure (CSP) was increased stepwise from 40 to 160 mmHg with increments of 20 mmHg (60 s for each CSP level) while the animal was placed supine and at 60 deg upright tilt. Upright tilt shifted the CSP–SNA relationship (the baroreflex neural arc) to a higher SNA, shifted the SNA–AP relationship (the baroreflex peripheral arc) to a lower AP, and consequently moved the operating point to marked high SNA while maintaining AP. A simulation study suggests that resetting in the neural arc would double the orthostatic activation of SNA and increase the operating AP in upright tilt by 10 mmHg, compared with the absence of resetting. In addition, upright tilt did not change the CSP–AP relationship (the baroreflex total arc). A simulation study suggests that although a downward shift of the peripheral arc could shift the total arc downward, resetting in the neural arc would compensate this fall and prevent the total arc from shifting downward to a lower AP. In conclusion, upright tilt increases SNA by resetting the baroreflex neural arc. This resetting may compensate for the reduced pressor responses to SNA in the peripheral cardiovascular system and contribute to preventing postural hypotension.  相似文献   
7.
A 40-year-old man who lived in a wooden house built 30 years ago presented with complaints of fever, dry cough and dyspnea. Chest X-ray findings showed interstitial shadows throughout bilateral lung fields. After admission, high-dose administration of 3000 mg of methylprednisolone was performed because of deterioration of chest X-ray shadows and symptoms. In a week, clinical data and symptoms improved. Findings of BAL fluid on admission revealed a relative increase of lymphocytes, neutrophils and mast cells, and pathological findings of transbronchial lung biopsy revealed non-caseous granulation and alveolitis. Precipitating antibodies and indirect fluorescent antibodies against Trichosporon cutaneum and Cryptococcus neoformans had positive reactions and T. cutaneum was isolated and identified from the patient's house. A diagnosis of summer-type hypersensitivity pneumonitis was made according to the criteria advocated by Ando et al. This seemed to be a rare case of summer-type hypersensitivity pneumonitis prolonged after isolation from his normal living environment, successfully treated by high-dose administration of steroid.  相似文献   
8.
A 28-year-old woman developed numbness and weakness of the hands and arms when she was 8 months pregnant, and weakness worsened gradually. However, weakness started to spontaneously subside immediately after delivery and she felt almost recovered several hours later. But weakness and numbness recurred one week after delivery and she was admitted to our hospital. Neurological examination revealed moderate weakness and disturbance of the deep and cutaneous sensations in the upper and lower extremities, and marked decrease of the deep tendon reflexes. The upper extremities were more severely affected. Nerve conduction study showed marked decrease in the motor conduction velocities. Cerebrospinal fluid showed increase of protein without pleocytosis. Teased preparation of the biopsied sural nerve showed occasional internodal segments with thin myelination, indicating demyelination and remyelination. A diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy was made. Treatment with prednisolone markedly improved the weakness and hyporeflexia as well as the cerebrospinal fluid protein. Postpartum rapid remission may have been produced by rapid increase of endogenous steroid hormone in the blood by its massive excretion during delivery.  相似文献   
9.
Tuberculous aneurysms of the aorta need early diagnosis and prompt surgical intervention because if untreated, they lead to severe consequences. We report herein, a case of a 63 year old woman who underwent successful resection of a tuberculous pseudoaneurysm which had ruptured into the left upper lobe of the lung after a punch biopsy, performed under bronchoscopy, had caused severe bleeding. Subsequent CT and MRI examinations suggested a fistula between the mass and the aorta and proved useful in establishing the diagnosis of a pseudoaneurysm. We wish to emphasize the need for bronchoscopy to be done carefully because of the risk of inducing massive hemoptysis.  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