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   61169篇
  免费   3845篇
  国内免费   1045篇
耳鼻咽喉   468篇
儿科学   1461篇
妇产科学   1604篇
基础医学   6921篇
口腔科学   1276篇
临床医学   5060篇
内科学   15213篇
皮肤病学   972篇
神经病学   5530篇
特种医学   2324篇
外国民族医学   2篇
外科学   8578篇
综合类   2125篇
现状与发展   1篇
一般理论   2篇
预防医学   2941篇
眼科学   820篇
药学   4694篇
  8篇
中国医学   980篇
肿瘤学   5079篇
  2023年   516篇
  2022年   1310篇
  2021年   2110篇
  2020年   1283篇
  2019年   1478篇
  2018年   1718篇
  2017年   1371篇
  2016年   1455篇
  2015年   1815篇
  2014年   2411篇
  2013年   2971篇
  2012年   3947篇
  2011年   4004篇
  2010年   2441篇
  2009年   2215篇
  2008年   3547篇
  2007年   3597篇
  2006年   3276篇
  2005年   3200篇
  2004年   2885篇
  2003年   2521篇
  2002年   2254篇
  2001年   1488篇
  2000年   1404篇
  1999年   1342篇
  1998年   600篇
  1997年   456篇
  1996年   482篇
  1995年   355篇
  1994年   353篇
  1993年   291篇
  1992年   732篇
  1991年   619篇
  1990年   585篇
  1989年   585篇
  1988年   487篇
  1987年   438篇
  1986年   431篇
  1985年   346篇
  1984年   283篇
  1983年   232篇
  1982年   148篇
  1981年   125篇
  1980年   121篇
  1979年   231篇
  1978年   132篇
  1977年   116篇
  1974年   130篇
  1973年   129篇
  1972年   128篇
排序方式: 共有10000条查询结果,搜索用时 30 毫秒
121.
122.
Insomnia in psychiatric patients is frequently underestimated in clinical practice. Usually drugs are prescribed for the treatment of this disorder but non-pharmacological intervention can be successfully used. The present study aimed at evaluating the efficacy of a two-session psychoeducational intervention in improving persistent non-organic insomnia and reducing the administration of PRN therapy in severely mentally ill patients. A pre-post study was performed on 36 psychiatric patients admitted to a residential psychiatric unit. The Nocturnal Sleep Onset Scale (NSOS) and Daytime Sleepiness Scale (DSS), the sleep onset latency, the time awake after sleep onset and the numbers of awakenings were gathered 2 weeks before the intervention (T0), immediately prior the intervention (T1), 2 weeks after the last session of the intervention (T2) and a 3-month follow-up (T3). The total number of administrations of PRN therapy from T0 to T1 and from T1 to T2 were also examined. A significant reduction was shown on the NSOS, the sleep onset latency and in the time awake after sleep onset from T1 to T2 and from T1 to T3, while no significant difference was found between T0 and T1. A significant decrease on the mean number of administrations of PRN therapy was also found between 15 days before the intervention (T0-T1) and 15 days after intervention (T1-T2). The initial results of this study seems to suggest the possible efficacy of a short-term psychoeducational intervention on improving persistent non-organic insomnia in severely mentally ill patients. Further control studies are necessary to confirm these findings.  相似文献   
123.
124.
OBJECTIVE: Dilation of aortic annulus, sinuses of Valsalva, and sinotubular junction (STJ) diameters are the characteristic lesions of aortic root aneurysm. The remodeling technique reduces STJ diameter and creates three neosinuses of Valsalva. Alternatively, the reimplantation technique reduces both annulus and STJ diameters to the detriment of aortic root dynamics. Although the remodeling technique is recognized as the most physiological valve-sparing procedure, aortic annulus dilation may jeopardize its results. A standardized approach that combines an external subvalvular aortic prosthetic ring annuloplasty with the remodeling technique is suggested. METHODS: Eighty-three patients underwent an elective aortic root remodeling procedure, either isolated (group 1, n=34) or combined with an external subvalvular aortic prosthetic ring annuloplasty (group 2, n=49). Preoperative aortic regurgitation was 1.59+/-1.1 (group 1) and 1.97+/-1.3 (group 2) (NS). The aortic annulus was more dilated in group 2 than in group 1 (27+/-2.77 mm vs 26.4+/-2.3 mm, p<0.01). Residual aortic regurgitation > or =grade II was the conversion criteria for aortic valve replacement. RESULTS: Operative mortality was 3.6% (n=3). Intraoperative conversion for valve replacement was 32.7% in group 1 (n=11) versus 4.2% in group 2 (n=2) (p<0.001). In group 1, preoperative annulus diameter was larger for converted than for valve-spared patients (27.6+/-1.7 mm vs 25.2+/-1.5 mm, p<0.02). In group 2, implanted aortic ring significantly reduced annulus diameter (20.6+/-1.8 mm) without significant aortic valve gradient (8.3+/-3 mmHg). Follow-up was 17.2+/-13.4 months (group 1) and 10.41+/-7.95 months (group 2). Reoperation for recurrent aortic regurgitation was 13% in group 1 (n=3) versus 4.2% in group 2 (n=2). Echocardiographic follow-up found residual aortic regurgitation < or =grade I in 17 patients in group 1 (90%) versus 43 patients in group 2 (95.5%) and of grade II in two patients in group 1 (10%) and two patients in group 2 (4.5%). CONCLUSION: The addition of external aortic prosthetic ring annuloplasty improves the remodeling technique's operative reproducibility and short-term results. Therefore, its use as a systematical adjunct to the remodeling procedure is suggested. However, further long-term evaluation comparing this valve-sparing procedure to composite graft replacement should define the best surgical strategy for aortic root aneurysm.  相似文献   
125.
126.
127.
AIM: A classification of ischemic stroke subtypes tailored for individual patients is hard to achieve. In 1993, the Trial of Org 10172 in Acute Stroke Treatment (TOAST) group developed a new system to classify the subtypes of ischemic stroke. In our study we applied the TOAST classification to a group of consecutive patients affected by ischemic stroke, to evaluate outcome and factors associated to each stroke subtype. METHODS: To evaluate the prognosis and the associated factors of ischemic stroke subtypes, we classified according to the TOAST classification a cohort of 159 consecutive patients affected by an acute ischemic stroke. We evaluated neurological deficit at admission by Scandinavian Stroke Scale and scored disability at discharge and 6 months after discharge using the Rankin disability scale. We determined 30 days survival and anamnestically evaluated major vascular risk factors. RESULTS: Patients with cardioembolic stroke and stroke of undetermined etiology had a greater neurological deficit on admission and the worst prognosis either in terms of disability or mortality. Lacunar stroke had the least neurological deficit at admission and the best prognosis. Hypercholesterolemia and smoking were more frequent among patients with large artery atherosclerotic stroke. Hypertension, a history of transient ischemic attack and diabetes were more frequent among patients with lacunar stroke. A weak association with hypertension and smoking was observed for cardioembolic stroke. CONCLUSIONS: The TOAST classification is useful in the clinical setting because it identifies ischemic stroke subtypes with different prognosis and with a different profile of associated factors.  相似文献   
128.
129.
Objects Genetic syndromes associated with ependymoma are uncommon, with the exception of NF2. We describe two cases of ependymoma presenting with Klinefelter’s Syndrome (KS) as co-morbid condition. Materials and methods The first patient was diagnosed for KS during pregnancy; he also presented a thyroid agenesis and a deficit of methyltetrahydrofolate reductase (MTHFR); at 30 months of age he was operated on for a grade II ependymoma of IV ventricle; after a multiple-stage surgery, he underwent oral chemotherapy and stereotactic radiotherapy, but after 15 months he presented a local recurrence and died. The second patient was diagnosed for KS at the age of 16 months; at 10 years of age, due to back pain, he underwent an MRI, which showed a cauda equine tumor. He underwent surgery and radiotherapy. Histology was of mixopapillary ependymoma. Conclusion In a review of literature, various neoplasms have been described in association with KS. To our knowledge, these are the first two cases reported of ependymoma associated to KS. A retrospective study of 44 monoinstitutional ependymoma cases demonstrated association with genetic syndromes in 22%.  相似文献   
130.
Di Benedetto  P.  Giorgini  T.  Delneri  C.  Biasutti  E. 《Neurological sciences》2006,27(4):s320-s322
Neurological Sciences - Bladder and urethra are innervated peripherally by pelvic parasympathetic, lumbar sympathetic and pudendal nerves; but a complex of brain networks is involved in the...  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