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   1305篇
  免费   49篇
  国内免费   11篇
耳鼻咽喉   56篇
儿科学   45篇
妇产科学   16篇
基础医学   133篇
口腔科学   38篇
临床医学   93篇
内科学   240篇
皮肤病学   17篇
神经病学   67篇
特种医学   23篇
外科学   319篇
综合类   45篇
一般理论   1篇
预防医学   84篇
眼科学   57篇
药学   69篇
中国医学   5篇
肿瘤学   57篇
  2023年   8篇
  2022年   34篇
  2021年   38篇
  2020年   24篇
  2019年   35篇
  2018年   46篇
  2017年   32篇
  2016年   20篇
  2015年   39篇
  2014年   60篇
  2013年   69篇
  2012年   90篇
  2011年   101篇
  2010年   47篇
  2009年   59篇
  2008年   78篇
  2007年   78篇
  2006年   82篇
  2005年   92篇
  2004年   66篇
  2003年   62篇
  2002年   45篇
  2001年   16篇
  2000年   11篇
  1999年   16篇
  1998年   11篇
  1997年   5篇
  1996年   4篇
  1993年   6篇
  1992年   11篇
  1991年   14篇
  1990年   4篇
  1989年   2篇
  1988年   2篇
  1986年   2篇
  1985年   5篇
  1984年   4篇
  1982年   4篇
  1979年   3篇
  1978年   2篇
  1977年   3篇
  1973年   2篇
  1970年   4篇
  1969年   5篇
  1935年   2篇
  1933年   2篇
  1932年   3篇
  1930年   4篇
  1927年   2篇
  1904年   1篇
排序方式: 共有1365条查询结果,搜索用时 15 毫秒
991.
Müllerian agenesis, a congenital malformation of the genital tract is the second most common cause of primary amenorrhoea. Its etiology is poorly understood. It may be associated with renal, skeletal or other abnormalities. The diagnosis is often made radiologically or laparoscopically. Three-dimensional ultrasound is a useful diagnostic tool. The hormonal profile and karyotype in these patients are normal. The management varies, but the treatment of choice is non surgical aimed at creating a neovagina. These patients require psychological support due to the implications for reproduction. Here, we present the case of a 24-year-old married woman with primary amenorrhoea with this malformation.  相似文献   
992.
Five cases of toxicity due to consumption of an uncommon wild fruit called Colocynth are described. These cases were seen over a period of 2 years. Severe bouts of bloody diarrhea were encountered in these patients. The plant, its ingredients, the medicinal and other uses, features of toxicity and the management is discussed. Doctors are advised to be aware of this uncommon clinical problem.  相似文献   
993.
Background: Nitric oxide (NO), hydroxyl radical (OH.), superoxide anion (O2 ) and hydrogen peroxide (H2O2) are free-radicals released in oxidative stress. Superoxide dismutase (SOD), glutathione peroxidase (GSHPx) and catalase (CAT) are antioxidant enzymes, mediating defense against oxidative stress. Excess NO and/or defective antioxidants cause lipid peroxidation, cellular dysfunction and death. Age-related maculopathy (ARM) or degeneration (ARMD) is the leading cause of irreversible blindness in developed countries. The etiology is unclear and the molecular factors contributing this disease remain to be specified. Aims: This multicenter, double-blind, cross-sectional study aimed to investigate plasma NO and lipid peroxidation levels with relation to antioxidant enzyme activities in erythrocyte and plasma of patients with ARMD compared with healthy control subjects. Methods: NO, lipid peroxidation (measured as plasma malondialdehyde [MDA] levels) and the catalytic activity of SOD, GSHPx and CAT were measured in a group of 41 patients with maculopathy (19 men, 22 women; 67.12 ± 3.70 years) and compared with 25 age- and sex-matched healthy control subjects without maculopathy (12 men, 13 women; 68.04 ± 3.02 years). NO and MDA levels were measured in plasma, CAT in red blood cells (RBCs), and SOD and GSHPx in both plasma and RBCs. Color fundus photographs were used to assess the presence of maculopathy, and the patients were divided into two groups using clinical examination and grading of photographs; early-ARM (n = 22) and late-ARMD (n = 19). Results: All patients with maculopathy had significantly (p<0.001) higher plasma NO levels over control subjects (mean ± SD, 48.58 ± 8.81 vs. 28.22 ± 3.39 mol/l). Plasma MDA levels in patients and control subjects were 4.99 ± 1.00 and 2.16 ± 0.24 mol/l, respectively, and the difference was significant (p<0.001). On the other hand, SOD and GSHPx activities were significantly lower in both RBCs and plasma of patients with maculopathy than in control subjects (RBCs-SOD, 3509.30 ± 478.22 vs. 5033.30 ± 363.98 U/g Hb, p<0.001; plasma-SOD, 560.95 ± 52.52 vs. 704.76 ± 24.59 U/g protein, p<.001; RBCs-GSHPx, 663.43 ± 41.74 vs. 748.80 ± 25.50 U/g Hb, p<0.001; plasma-GSHPx, 98.26 ± 15.67 vs. 131.80 ± 8.73 U/g protein, p<0.001). RBCs-CAT levels were not different between groups (131.68 ± 12.89 vs. 133.00 ± 13.29 k/g Hb, p=0.811). Late-ARMD patients had significantly lower antioxidant enzyme levels and higher MDA levels when compared with early-ARM patients (for each, p<0.001). In addition, plasma NO and MDA levels were negatively correlated with SOD and GSHPx activities. Conclusions: This study demonstrated for the first time that NO, the most abundant free-radical in the body, might be implicated in the pathophysiology of ARMD in association with decreased antioxidant enzymes and increased lipid peroxidation status.  相似文献   
994.
OBJECTIVE: To create a neovagina and an endocervival canal in two patients with vaginal aplasia and a functioning uterus. DESIGN: Technique and instrumentations. SETTING: University hospital. PATIENT(S): A 31-year-old woman with vaginal aplasia and a double noncommunicating uterus (classified as Mayer-Rokitansky-Kuster-Hauser syndrome) and a 19-year-old woman with partial vaginal aplasia and a functional uterus. INTERVENTION(S): Creation of a neovagina by using the bilateral pudendal thigh fasciocutaneous flap procedure and laparotomy to establish uterovaginal continuity. MAIN OUTCOME MEASURE(S): Clinical follow-up evaluation of restoration of outflow of menstrual blood and coital satisfaction. RESULT(S): Uterovaginal continuity was established in both patients, resulting in normal menstruation. Granulomatous polyps occurred in one patient, and stenosis at the site of anastomosis occurred in the other patient; these conditions were successfully managed. Unimpeded menstrual flow continued after 1 year of follow-up in one patient and 3 years of follow-up in the other patient. CONCLUSION(S): Bilateral fasciocutaneous pudendal thigh flaps permit vaginal reconstruction and a uterovaginal connection in patients with vaginal agenesis and a functional uterus. The main advantages of this technique are that postoperative dilatation is not necessary, sensation is maintained, and the resulting scar is inconspicuous. The main disadvantage is the presence of some sebaceous vaginal secretion and hair in the vaginal lining; the latter can be managed by preoperative and postoperative laser depilation.  相似文献   
995.
This report includes five cases afflicted by chronic mercury poisoning which was observed in Iraq in 1972. All five cases showed the symptomatology of a severe cerebral damage combined with peripheral nerve lesion. The clinical picture reveals an apallic syndrome or a prestage ensuring in the full-blown picture. The combination of CNS lesions with polyneuropathy is typical of mercury poisoning with failure of all brain functions and the appearance of brain stem automatism, combined with severe muscular atrophy. When such conditions are established the remission seems to be impossible. The historical as well as the clinical and morphological facts of the Minamata disease is reviewed. The different stages of chronic mercury poisoning in Iraq are described.  相似文献   
996.
997.
Submandibular gland mucocele should be remembered in the differential diagnosis of swelling at the submandibular triangle. In the cystic lesion of the submandibular area, the biochemical analysis of aspirated material for amylase should be performed. The cases with submandibular gland mucocele should be treated by removing the lesion with both the submandibular and the sublingual glands.  相似文献   
998.
A Hamdi  J Porter  C Prasad 《Brain research》1992,589(2):338-340
The specific binding of [3H]YM-09151-2 was used to investigate the possible differences in age-associated changes in striatal D2 dopamine (DA) receptor properties in genetically obese (fa/fa) Zucker rats and their lean (Fa/?) littermates. The maximal binding sites (Bmax) of D2 DA receptors was found to decline with age in both obese and lean rats; the rate of decline in receptor Bmax was slightly higher in lean than obese rats. However, the Bmax of D2 DA receptor in 6-, 12- and 18-month-old obese rats was significantly lower compared to the age-matched lean rats. These data indicate that obesity decreases the number of striatal D2 DA receptors without affecting the rate at which receptor number decreases with age.  相似文献   
999.
Te forearm distal bone fracture is the most com-mon fracture in children. Scaphoid frac-ture is rare because the scaphoid is largely car-tilaginous in children. Some cases associating both distal radius and scaphoid fractures were reported in the literature. Scaphoid fracture often occurs without displacement and can be easily overlooked. We re-ported a case of children wrist injury combining scaphoid fracture with ipsilateral distal fracture.  相似文献   
1000.
Aspirin reduced plasma concentrations of prostaglandin (PG) F alpha in 11 of 12 children with toddler diarrhoea, and usually, but not always, controlled the symptom. Loperamide consistently controlled toddler diarrhoea in 10 patients but had no effect on plasma PGF alpha. In eight patients experiencing spontaneous remission of symptoms, plasma PGF alpha was significantly lower than during diarrhoeal episodes. These results suggest that (a) toddler diarrhoea is in some cases mediated by PG, and (b) the effect of loperamide is independent of PG levels.  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