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   2073篇
  免费   133篇
  国内免费   10篇
耳鼻咽喉   14篇
儿科学   64篇
妇产科学   73篇
基础医学   281篇
口腔科学   67篇
临床医学   227篇
内科学   431篇
皮肤病学   61篇
神经病学   120篇
特种医学   88篇
外科学   195篇
综合类   72篇
一般理论   1篇
预防医学   155篇
眼科学   35篇
药学   213篇
中国医学   7篇
肿瘤学   112篇
  2024年   5篇
  2023年   33篇
  2022年   80篇
  2021年   114篇
  2020年   82篇
  2019年   96篇
  2018年   101篇
  2017年   73篇
  2016年   64篇
  2015年   85篇
  2014年   108篇
  2013年   143篇
  2012年   203篇
  2011年   180篇
  2010年   108篇
  2009年   66篇
  2008年   99篇
  2007年   91篇
  2006年   117篇
  2005年   93篇
  2004年   79篇
  2003年   58篇
  2002年   63篇
  2001年   11篇
  2000年   5篇
  1999年   3篇
  1998年   3篇
  1997年   4篇
  1996年   6篇
  1995年   2篇
  1994年   8篇
  1993年   5篇
  1992年   2篇
  1991年   3篇
  1990年   3篇
  1989年   2篇
  1988年   1篇
  1987年   1篇
  1986年   2篇
  1985年   1篇
  1983年   2篇
  1981年   1篇
  1980年   1篇
  1978年   1篇
  1977年   1篇
  1974年   1篇
  1972年   1篇
  1971年   1篇
  1967年   2篇
  1945年   2篇
排序方式: 共有2216条查询结果,搜索用时 15 毫秒
81.
82.
The Asian Pacific Association for the Study of the Liver (APASL) Working Party on Portal Hypertension has developed consensus guidelines on the disease profile, diagnosis, and management of noncirrhotic portal fibrosis and idiopathic portal hypertension. The consensus statements, prepared and deliberated at length by the experts in this field, were presented at the annual meeting of the APASL at Kyoto in March 2007. This article includes the statements approved by the APASL along with brief backgrounds of various aspects of the disease.  相似文献   
83.
Nonsteroidal anti-inflammatory drugs decrease sporadic colorectal carcinoma and adenomas in patients with familial adenomatous polyposis and in rodent models of sporadic colon cancer and familial adenomatous polyposis. Similarly, selective cyclooxygenase 2 inhibitors decrease adenomas in humans and rodents. However, their effects on chronic colitis and colitis-associated neoplasia are unknown. Interleukin 10-/- mice (C57/B6) were fed regular chow (n = 20) or chow with celecoxib (1,500 ppm, n = 18) or rofecoxib (75 ppm, n = 20) for 12 weeks. Twenty-eight percent of the celecoxib group died versus 5% of the control and rofecoxib groups (p < 0.05 compared with control). Celecoxib and rofecoxib increased the incidence of colitis (26% vs. 92% and 68%, p < 0.01), colitis score (0.4 +/- 0.2 vs. 2.5 +/- 0.3 and 2 +/- 0.4, p < 0.01), aberrant crypt foci (0.5 +/- 0.3 vs. 3.7 +/- 2.6 and 2.8 +/- 0.7, p < 0.01), aberrant crypts per mouse (4.11 +/- 2.1 vs. 41.2 +/- 9.7 and 27.1 +/- 7.5, p < 0.01) and dysplasia (11% vs. 54% and 42%, p < 0.01). Similarly, indomethacin (9 ppm, n = 15) increased colitis score, aberrant crypt foci, and dysplasia after 27 days of treatment. Two selective cyclooxygenase 2 inhibitors exacerbate colitis and premalignant changes in the interleukin 10-/- mouse model of chronic colitis and colitis-associated colon carcinoma.  相似文献   
84.
Hypogonadism, found in about one-third of patients with chronic obstructive pulmonary disease (COPD), has potential for decreasing muscle mass and muscle performance. Compared with eugonadal patients, we hypothesized that hypogonadal patients with COPD have decreased respiratory and skeletal muscle performance. Nineteen hypogonadal and 20 eugonadal men with COPD (FEV(1) 1.14 +/- 0.08 and 1.17 +/- 0.11 L [standard error], respectively) were studied. Diaphragmatic contractility, assessed as transdiaphragmatic twitch pressure generated by phrenic nerve stimulation, was similar in hypogonadal and eugonadal patients: 20.6 +/- 2.2 and 19.8 +/- 2.5 cm H(2)O, respectively. During progressive inspiratory threshold loading, hypogonadal and eugonadal patients had similar respiratory muscle endurance times (302 +/- 29 and 313 +/- 48 seconds, respectively) and airway pressure sustained during the last minute of loading (38.2 +/- 3.0 and 40.5 +/- 4.7 cm H(2)O, respectively) (similar to predicted values in healthy subjects). Hypogonadal and eugonadal patients had equivalent limb muscle strength and endurance. During cycle exercise to exhaustion, exercise performance, gas exchange, and respiratory muscle recruitment (estimated by esophageal and gastric pressure swings during tidal breathing) were similar in both groups. In conclusion, hypogonadism does not decrease respiratory or limb muscle performance and exercise capacity in men with moderate-to-severe COPD who, for the most part, are not underweight.  相似文献   
85.

Objectives

The aim of our study was to evaluate minimally invasive techniques for the treatment of anterior circulation aneurysms versus standard surgery, and to calculate the impact of these techniques on health resources, length of stay, and treatment costs.

Methods

A consecutive series of 24 patients with ruptured and 30 with unruptured anterior circulation aneurysms treated with minimally invasive microsurgery (MIM) by the same surgeon was compared with a matched series of standard microsurgeries (SM) conducted for 23 ruptured and 22 unruptured aneurysms. Complication rates, aneurysm obliteration, modified Rankin Scale (mRS) outcomes, length of stay, and treatment costs were assessed.

Results

Surgical complications, aneurysm obliteration rates and mRS outcomes were comparable between MIM and SM groups in ruptured and unruptured aneurysm cohorts. MIM resulted in shorter operative times both in unruptured (102.7?±?4.35 vs 194.7?±?10.26 min, p?<?0.0001) and ruptured aneurysms (124.3?±?827 vs 209?±?13.84 min, p?<?0.0001). Length of stay was reduced in patients with MIM for unruptured aneurysms (1.55?±?24 vs 4.28?±?0.71 days, p?<?0.000,1) but not in those with ruptured aneurysms. MIM reduced treatment costs of unruptured aneurysm patients, mainly through reduced utilization of inpatient resources (non-acute bed costs in CAD: 371.2?±?80.99 vs 1440?±?224.1, p?<?0.0001), whereas costs were comparable in patients with ruptured aneurysms.

Conclusion

Minimally invasive surgery is a safe and effective approach for the treatment of ruptured and unruptured aneurysms of the anterior circulation. In patients with unruptured aneurysms, reduced invasiveness and shorter operative times decreased length of stay, which reflects improved patient postoperative recovery. Overall, this translated into bed resource economy and cost reduction.  相似文献   
86.

Objective

The present study aimed to investigate whether graded doses of Bacopa Monniera (BM) extract could produce antidepressant-like effects in chronic unpredictable stress (CUS) induced depression in rats and its possible mechanism(s).

Methods

Rats were subjected to an experimental setting of CUS. The effect of BM extract treatment in CUS-induced depression was examined using behavioral tests including the sucrose consumption, open field test and shuttle box escape test. The mechanism underlying the antidepressant-like action of BM extract was examined by measuring brain-derived neurotrophic factor (BDNF) protein and mRNA expression in brain tissues of CUS-exposed rats.

Results

Exposure to CUS for 4 weeks caused depression-like behavior in rats, as indicated by significant decreases in sucrose consumption, locomotor activity and escape latency. In addition, it was found that BDNF protein and mRNA levels in the hippocampus and frontal cortex were lower in CUS-treated rats, as compared to controls. Daily administration of the graded doses of BM extract during the 4-week period of CUS significantly suppressed behavioral changes and attenuated the CUS-induced decrease in BDNF protein and mRNA levels in the hippocampus and frontal cortex.

Conclusion

The results suggest that BM extract alleviates depression induced by CUS. Present study also confirms that 80-120 mg/kg doses of BM extract have significantly higher antidepressant-like activity.  相似文献   
87.
BackgroundShoulder pain related to the rotator cuff (RC) is one of the most common and bothersome musculoskeletal complaints. Pharmacologic treatment most often includes acetaminophen and non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen. However, data allowing comparison of the efficacy of these two drugs are very limited. We compared the therapeutic outcomes of acetaminophen and ibuprofen in the management of RC-related pain.MethodsThis was an open-label, two-center, active-control, prospective randomized clinical trial. Participants were assigned randomly to acetaminophen or ibuprofen treatment groups. The acetaminophen dose was 500 mg every 6–8 h, and it was 400–800 mg every 6–8 h for ibuprofen. The impact of the treatment was measured by Shoulder Pain and Disability Index (SPADI), Quick Disabilities of the Arm, Shoulder, and Hand (Quick-DASH) and World Health Organization Quality of Life-BREF (WHOQOL-BREF) questionnaires at baseline and after 6 weeks of therapy.ResultsThirty-three patients completed the study; 20 treated with ibuprofen and 13 with acetaminophen. Patients in both groups were comparable at baseline with regard to SPADI, Quick-DASH, and WHOQOL-BREF scores. After 6 weeks of treatment, patients receiving ibuprofen, but not acetaminophen, reported an improvement in pain severity and functional activity (as measured by SPADI and Quick-DASH). Patients taking acetaminophen, but not ibuprofen, reported improvement in the physical and environmental domains of WHOQOL-BREF scores.ConclusionsIbuprofen and acetaminophen provide benefits to patients suffering from RC-related pain. However, the type of improvement perceived by patients differed between these two medications.  相似文献   
88.
This placebo‐controlled phase II study evaluated the pharmacodynamics, efficacy and safety of 2,2‐dimethylbutyrate (HQK‐1001), a fetal globin gene‐inducing short‐chain fatty acid derivative, administered orally at 15 mg/kg twice daily for 48 weeks in 76 subjects with sickle cell disease (SCD). The median age was 26 years (range: 12–55 years) and 37 subjects (49%) were treated previously with hydroxycarbamide. Sixty subjects (79%) had Hb SS and 16 (21%) had S/β0 thalassemia. The study was terminated after a planned interim analysis showed no significant increase in fetal hemoglobin (Hb F) and a trend for more pain crises in the HQK‐1001 group. For 54 subjects with Week 24 data, the mean absolute increase in Hb F was 0.9% (95% confidence interval (CI): 0.1–1.6%) with HQK‐1001 and 0.2% (95% CI: ?0.7–1.1%) with placebo. Absolute increases in Hb F greater than 3% were noted in 9 of 38 subjects (24%) administered HQK‐1001 and 1 of 38 subjects (3%) administered placebo. The mean changes in hemoglobin at Week 24 were comparable between the two groups. The mean annualized rate of pain crises was 3.5 with HQK‐1001 and 1.7 with placebo. The most common adverse events in the HQK‐1001 group, usually graded as mild or moderate, consisted of nausea, headache, vomiting, abdominal pain, and fatigue. Additional studies of HQK‐1001 at this dose and schedule are not recommended in SCD. Intermittent HQK‐1001 administration, rather than a daily regimen, may be better tolerated and more effective, as shown previously with arginine butyrate, and warrants further evaluation. Am. J. Hematol. 89:709–713, 2014. © 2014 Wiley Periodicals, Inc.  相似文献   
89.
In sickle cell disease (SCD), ocular lesions result from stasis and occlusion of small eye vessels by sickled erythrocytes. Vaso-occlusive disease of the retina can be responsible for nonproliferative (NPR) and proliferative retinopathy (PR). Patients are often asymptomatic until serious complications arise as, vitreous hemorrhage and retinal detachment. This work aimed to study the frequency and pattern of ocular manifestations in Egyptian children and young adults with SCD. In this cross-sectional study, 40 steady state patients (80 eyes) aged 2–28 years (30 children and 10 young adults) with established diagnosis of SCD (26 with homozygous SS and 14 with S/β thalassemia underwent complete ophthalmic examination with dilated fundoscopy. Fluorescein angiography was performed for patients ≥12 years old. The overall frequency of retinal lesions was 47.5 % (46.2 and 50 % of SS and S/β patients respectively). PR and NPR were evident in 32.5 and 27.5 % of all enrolled patients respectively (five patients having both). Peripheral retinal occlusion was a frequent ocular finding in both groups; the youngest patient showing PR was 15 years old. Older age, longer disease duration and splenectomy were significantly more prevalent among patients with PR. Despite lack of visual symptoms, children and young adults are at risk of PR. Frequency of retinal lesions was comparable in SS and S/β patients. Periodic ophthalmologic examination starting at the age of 12 years is recommended for timely-identification of retinal lesions thus minimizing the risk of sight threatening retinopathy.  相似文献   
90.

INTRODUCTION

Retrorectal tumors are uncommon and the etiology diverse. Literature to define the preoperative diagnosis and plan the intraoperative management are uncommon.

PRESENTATION OF CASE

We describe a case of a 44 year old patient with a laparoscopic approach for the removal of a retrorectal tumor and emphasize on the preoperative diagnostics and the intraoperative, minimal invasive approach.

DISCUSSION

Especially because these tumors are rare and often an incidental finding in gynecologic surgery, it is important to know the various differential diagnoses and its consequences with the laparoscopic approach.

CONCLUSION

We suggest the laparoscopic approach in cases of retroperitoneal cysts of unknown origin is ideal also because anatomic structures, mostly nerves, can be easily spared.  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