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   7468篇
  免费   410篇
  国内免费   56篇
耳鼻咽喉   34篇
儿科学   98篇
妇产科学   73篇
基础医学   1237篇
口腔科学   165篇
临床医学   629篇
内科学   1666篇
皮肤病学   86篇
神经病学   822篇
特种医学   249篇
外科学   1186篇
综合类   29篇
现状与发展   1篇
一般理论   2篇
预防医学   402篇
眼科学   198篇
药学   518篇
中国医学   13篇
肿瘤学   526篇
  2023年   43篇
  2022年   148篇
  2021年   319篇
  2020年   137篇
  2019年   206篇
  2018年   210篇
  2017年   131篇
  2016年   182篇
  2015年   217篇
  2014年   303篇
  2013年   335篇
  2012年   591篇
  2011年   592篇
  2010年   328篇
  2009年   277篇
  2008年   496篇
  2007年   493篇
  2006年   457篇
  2005年   431篇
  2004年   431篇
  2003年   365篇
  2002年   331篇
  2001年   50篇
  2000年   38篇
  1999年   49篇
  1998年   48篇
  1997年   60篇
  1996年   33篇
  1995年   31篇
  1994年   20篇
  1993年   19篇
  1992年   32篇
  1991年   38篇
  1990年   34篇
  1989年   35篇
  1988年   29篇
  1987年   53篇
  1986年   32篇
  1985年   30篇
  1984年   23篇
  1983年   16篇
  1979年   19篇
  1978年   19篇
  1976年   14篇
  1975年   15篇
  1974年   11篇
  1973年   14篇
  1972年   15篇
  1971年   13篇
  1968年   12篇
排序方式: 共有7934条查询结果,搜索用时 31 毫秒
1.
2.
3.
OBJECTIVE: Intramuscular (i.m.) ziprasidone treatment has been shown to be effective and well tolerated in reducing the symptoms of acute psychosis in adults. Few data are available as to safety in the elderly. The growing utilization of health services by elderly psychiatric patients warrants an evaluation in this population. METHOD: Consecutive elderly patients (60 years of and older) admitted to a psychogeriatric ward in a large, university-affiliated tertiary psychiatric center were treated by i.m. ziprasidone for acute psychotic agitation. Patients received three days of flexible-dose i.m. ziprasidone. After an initial dose of 10-20 mg, a subsequent dose of 10-20 mg could be given after 12 hours if needed (maximum daily dose: 40 mg). RESULTS: All treatment emergent side effects and adverse events along with the investigators' assessments of severity were systematically recorded as the primary outcome. The Brief Psychiatric Rating Scale (BPRS) and the Behavioral Activity Rating Scale (BARS) were the secondary outcomes. Twenty-one patients, six male and 15 female, mean age 71.4 +/- 1.3 years (range: 60-81 years) were enrolled. All had completed the three days i.m. ziprasidone treatment. There was one adverse event in a patient with untreated benign prostatic hypertrophy who developed urinary retention. Two side effects of mild severity that resolved spontaneously were observed: blurred vision and sedation. The BPRS decreased by 26.8 points after three days of treatment (p = 0.001). The BARS score, reflecting agitation, decreased significantly after each injection, reaching maximal decrease of 2.14 points at completion of study (p = 0.001). CONCLUSION: Intramuscular ziprasidone in this series of elderly patients suggests acceptable safety and efficacy in the management of acute psychotic agitation among elderly patients with schizophrenia.  相似文献   
4.
5.
Background: Tight perioperative control of blood glucose improves the outcome of diabetic patients undergoing cardiac surgery. Because stress response and cardiopulmonary bypass can induce profound hyperglycemia, intraoperative glycemic control may become difficult. The authors undertook a prospective cohort study to determine whether poor intraoperative glycemic control is associated with increased intrahospital morbidity.

Methods: Two hundred consecutive diabetic patients undergoing on-pump heart surgery were enrolled. A standard insulin protocol based on subcutaneous intermediary insulin was given the morning of the surgery. Intravenous insulin therapy was initiated intraoperatively from blood glucose concentrations of 180 mg/dl or greater and titrated according to a predefined protocol. Poor intraoperative glycemic control was defined as four consecutive blood glucose concentrations greater than 200 mg/dl without any decrease in despite insulin therapy. Postoperative blood glucose concentrations were maintained below 140 mg/dl by using aggressive insulin therapy. The main endpoints were severe cardiovascular, respiratory, infectious, neurologic, and renal in-hospital morbidity.

Results: Insulin therapy was required intraoperatively in 36% of patients, and poor intraoperative glycemic control was observed in 18% of patients. Poor intraoperative glycemic control was significantly more frequent in patients with severe postoperative morbidity (37% vs. 10%; P < 0.001). The adjusted odds ratio for severe postoperative morbidity among patients with a poor intraoperative glycemic control as compared with patients without was 7.2 (95% confidence interval, 2.7-19.0).  相似文献   

6.
Pathophysiological aspects of brain edema   总被引:16,自引:0,他引:16  
Summary Two mayor types of brain edema, related to two different pathomechanisms, can be recognized: 1)cytotoxic type-where the main feature is the swelling of cellular elements of brain parenchyma and 2)vasogenic type-where an increased vascular permeability leading to accumulation of edema fluid inthe extracellular spaces plays the principal role. In this type of edema, there is a close interrelationship between extravasation of serum proteins and retention of water in the brain tissue. In theischemic brain edema both cytotoxic and vasogenic mechanisms are involved. A biphasic opening of the blood-brain barrier, associated with vasogenic edema, is observed following release of major cerebral artery occlusion. The first opening of the barrier is related to a reactive hyperemia which follows promptly recirculation. The second opening, recognizable after a delay, is associated with a severe ischemic brain tissue injury.Dedicated to Prof. F. Seitelberger on the occasion of his seventieth birthday  相似文献   
7.
BACKGROUND: The role of local excision for pT2 distal rectal cancer has been challenged because of the observation of high rates of lymph node metastases and local failure. However, neoadjuvant chemoradiation therapy (CRT) has led to increased local disease control and significant tumor downstaging, possibly decreasing rates of lymph node metastases. In this setting, a possible role for local excision of ypT2 has been suggested. METHODS: A total of 401 patients with distal rectal cancer underwent neoadjuvant CRT. Tumor response assessment was performed after at least 8 weeks from CRT completion. One hundred and twelve patients with complete clinical response were not immediately operated on and were excluded from the study, and 289 patients with incomplete clinical response were managed by radical surgery. Patients with final pathological stage ypT2 were analyzed to determine the risk of unfavorable pathological features that could represent unacceptable risk for local failure after local excision. RESULTS: Eighty-eight (30%) patients had ypT2 rectal cancer. Final ypT status was not associated with pretreatment radiological staging (p = 0.62). ypT status was significantly associated with the risk of lymph node metastases, risk of perineural and vascular invasion, and recurrence (p = 0.001). Lymph node metastases were present in 19% of patients with ypT2 rectal cancer. The risk of lymph node metastases in ypT2 was associated with the presence of perineural invasion (47% vs 4%; p = <0.001), vascular invasion (59% vs 6%; p < 0.001), and decreased mean interval CRT surgery (12 vs 18 weeks; p < 0.001), but not with mean tumor size (3.2 vs 3.1 cm; p = 0.8). Disease-free and overall survival rates were significantly better for patients with ypT2N0 (p = 0.02 and 0.006, respectively). Fifty-five (63%) patients with ypT2 had at least one unfavorable pathological feature for local excision (lymph node metastases, vascular or perineural invasion, mucinous type or tumor size >3 cm). CONCLUSION: Lymph node metastases were present in 19% of patients with ypT2 and were significantly associated with poor overall and disease-free survival rates. The risk of lymph node metastases could not be predicted by radiological staging or tumor size. Radical surgery should be considered the standard treatment option for ypT2 rectal cancer after CRT.  相似文献   
8.
The significance of life stress, coping, and social support was examined in relation to depressive symptomatology in a sample of 160 asymptomatic and mildly symptomatic HIV-antibody-positive (HIV+) men. The participants (mean age = 32 years) were interviewed about the life stress that they had experienced in the previous 6  相似文献   
9.
10.
Background: Spinal substantia gelatinosa (SG) is a site of action of administered and endogenous opioid agonists and is an important element in the system of antinociception. However, little is known about the types of neurons serving as specific postsynaptic targets for opioid action within the SG. To study the spinal mechanisms of opioidergic analgesia, the authors compared the action of [mu]-opioid agonist [D-Ala2, N-Me-Phe4, Gly5-ol]-enkephalin (DAMGO) on SG neurons with different intrinsic firing properties.

Methods: Whole cell patch clamp recordings from spinal cord slices of Wistar rats were used to study the sensitivity of SG neurons to DAMGO.

Results: Three groups of neurons with distinct distributions in SG were classified: tonic-, adapting-, and delayed-firing neurons. DAMGO at 1 [mu]m concentration selectively hyperpolarized all tonic-firing neurons tested, whereas none of the adapting- or delayed-firing neurons were affected. The effect of DAMGO on tonic-firing neurons was due to activation of G protein-coupled inward-rectifier K+ conductance, which could be blocked by 500 [mu]m Ba2+ and 500 [mu]m Cs+ but increased by 50 [mu]m baclofen. As a functional consequence of DAMGO action, a majority of tonic-firing neurons changed their pattern of intrinsic firing from tonic to adapting.  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