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   3006篇
  免费   335篇
  国内免费   4篇
耳鼻咽喉   41篇
儿科学   90篇
妇产科学   92篇
基础医学   396篇
口腔科学   90篇
临床医学   333篇
内科学   798篇
皮肤病学   57篇
神经病学   262篇
特种医学   115篇
外科学   375篇
综合类   98篇
一般理论   1篇
预防医学   230篇
眼科学   29篇
药学   177篇
肿瘤学   161篇
  2022年   15篇
  2021年   34篇
  2020年   36篇
  2019年   44篇
  2018年   51篇
  2017年   47篇
  2016年   48篇
  2015年   39篇
  2014年   65篇
  2013年   100篇
  2012年   145篇
  2011年   153篇
  2010年   128篇
  2009年   104篇
  2008年   129篇
  2007年   165篇
  2006年   169篇
  2005年   145篇
  2004年   146篇
  2003年   120篇
  2002年   91篇
  2001年   87篇
  2000年   100篇
  1999年   102篇
  1998年   55篇
  1997年   39篇
  1996年   40篇
  1995年   50篇
  1994年   36篇
  1993年   46篇
  1992年   87篇
  1991年   60篇
  1990年   62篇
  1989年   55篇
  1988年   48篇
  1987年   62篇
  1986年   38篇
  1985年   39篇
  1984年   43篇
  1983年   28篇
  1982年   15篇
  1981年   21篇
  1980年   18篇
  1979年   23篇
  1978年   29篇
  1977年   24篇
  1976年   16篇
  1975年   17篇
  1973年   15篇
  1971年   17篇
排序方式: 共有3345条查询结果,搜索用时 15 毫秒
1.
2.
A Decade of Change in Obesity Surgery   总被引:4,自引:0,他引:4  
Background: The International (formerly National) Bariatric Surgery Registry began collecting data in January 1986. The aim of this study was to examine changes in the practice of surgical treatment of severe obesity that occurred during the decade of 1986 through 1995, as observed in the IBSR data. Methods: All data submitted to the IBSR during the decade were transferred to the IBM mainframe computer for analysis. Characteristics of operative type populations were compared over time using analysis of variance (ANOVA) for age, body mass index (BMI), operative weight and Chi-square (χ2) test for gender. Results: There has been a steady increase over the decade in mean patient weight. The operations used have changed from predominantly ‘simple’ operations to more frequent use of ‘complex’ operations. Within the categories of ‘simple’ and ‘complex’, an increase in the variety of operations occurred. As a group, patients with ‘simple’ operations have been heavier, more often male and public pay patients than those who have undergone ‘complex’ operations. One year weight loss was greater for Roux-en-Y gastric bypass (RGB) than vertical banded gastroplasty (VBG), but follow-up rates were too low to study the relative merits of the operations used. The reported incidence of operative mortality and serious complications (leak with peritonitis, abscess and pulmonary embolism) remained low. Conclusions: These observations and their implications can be summarized in three statements which relate to action for improved patient care in the beginning of the new century: (1) increasing weight of candidates for surgical treatment during this decade indicates the need for earlier use of operative treatment before irreversible complications of obesity can develop; (2) low risk of obesity surgery, decreasing postoperative hospital stay, and early weight control support the continued and increased use of surgical treatment; (3) continued widespread use of both ‘simple’ and ‘complex’ operations with increased modifications of standard RGB and VBG procedures emphasizes the need for standardized long-term data and analyses regarding both weight control and postoperative side-effects.  相似文献   
3.
4.

Background  

The objective of this study was to examine missed opportunities for participation in a prevention of mother-to-child transmission (PMTCT) programme in three sites in South Africa. A rapid anthropological assessment was used to collect in-depth data from 58 HIV-positive women who were enrolled in a larger cohort study to assess mother-to-child HIV transmission. Semi-structured interviews were conducted with the women in order to gain an understanding of their experiences of antenatal care and to identify missed opportunities for participation in PMTCT.  相似文献   
5.
We used a quantitative immunoassay to examine the effects of human serum and immunoglobulins on neurofilament protein expression in cultures of chick spinal neurons. Compared with cultures grown in the presence of serum from healthy controls or patients with other neurologic disorders, ALS serum lowered the level of neurofilament proteins. Effects were similar with or without muscle-derived neurotrophic factors; there was no specificity for motor neurons. No neurotoxic activity was found in immunoglobulin fractions, and there was no evidence of circulating antibodies that might neutralize muscle-derived neurotrophic factors or induce cytolysis of spinal neurons.  相似文献   
6.
One hundred patients with malignant biliary obstruction underwent palliative therapy by means of percutaneous transhepatic placement of 114 biliary endoprostheses. All patients were then followed up for at least 18 months or until death. Retrospective evaluation of the 95 patients who died showed an average survival time of 5.0 months. The five remaining patients have survived an average of 29.8 months. During the 1st week after stent insertion, a second manipulation was performed to improve stent function in nine patients. Overall, 14 (12.3%) of the stents became obstructed and six (5.2%) migrated; 86 patients required no further therapy for biliary obstruction or stent malfunction. The 30-day mortality rate was 12%; none of the deaths were directly attributable to a complication of the stent placement procedure.  相似文献   
7.
8.
INTRODUCTION: Levetiracetam (LEV) is approved for use as add-on therapy in adult patients with partial epilepsy. It is apparent from clinical trials that up to 8% of previously drug-resistant patients may be rendered seizure-free by adding-on levetiracetam. As yet there is no way of predicting these unexpectedly responsive patients. We set out to identify our previously refractory patients who had demonstrated unexpected responsiveness to add-on therapy with levetiracetam, and compared these to patients who had not responded to the drug. We then attempted to characterise any clinical features that differentiated these groups of patients. METHODS: We included all patients with a history of present or previous exposure to levetiracetam who had been unresponsive to at least two other prior anti-epileptic drugs (AEDs) and recorded their demographic and clinical data. We divided response into (a) 'seizure-free' (seizure-free for a minimum of 6 months after commencing LEV); (b) 'partial > 50%' (greater than 50% reduction in seizures for a minimum of 6 months after commencing LEV); (c) 'honeymoon' (seizure-free for less than 6 months after commencing LEV and then returned towards baseline frequency); and (d) 'no-response'. For the purpose of analysis we considered the 'seizure-free' and 'partial > 50%' groups as 'responders', and the 'no response' group as 'non responders'. RESULTS: 344 patients were included in the analysis. Fifty-six patients (16.3%) were rendered seizure-free on levetiracetam. Idiopathic generalised epilepsy and post-traumatic partial epilepsy were more common in the responder than the non-responder group (p = 0.005 and 0.05 respectively). Lamotrigine was used significantly more often in combination with levetiracetam in responders than non-responders (p = 0.003). The mean daily dose of levetiracetam was lower in responders than non-responders. DISCUSSION: A higher than expected number of previously drug resistant patients was rendered seizure-free by add-on therapy with levetiracetam. Those who respond best appear to do so at relatively low doses and our data suggest the possibility of a beneficial pharmacodynamic interaction between levetiracetam and lamotrigine. We were unable to identify any clinical factors that clearly predicted which patients would become seizure-free and we hypothesise that response may be determined by genetic or molecular factors. All drug-resistant patients, including those being assessed for surgery, should be considered for a trial of levetiracetam, regardless of their epilepsy classification.  相似文献   
9.
Administration of repetitive sublethal doses of either recombinant human tumor necrosis factor (TNF) or recombinant murine gamma-interferon (IFN) to non-tumor-bearing (NTB) rats caused a significant decline in food intake and body weight. After 3 days rats became resistant to the anorectic and weight loss effects of TNF but maintained persistent diminished food intake and diminished body weight gain while receiving recombinant murine IFN. Passive immunization against recombinant rat gamma-interferon allowed cachectic tumor-bearing (TB) rats to eat more food, have a lesser decline in body weight, live longer, and tolerate larger tumors than similar TB rats given nonspecific control antibody. TB rats treated with an antisera to recombinant murine TNF, which was 100% protective when given to NTB rats 6 h before a lethal endotoxin challenge, did not differ significantly from TB rats treated with control antibody with respect to food intake, body weight, survival, or tumor size. Serum levels of TNF or IFN were not detectable in cachectic tumor-bearing rats. The data indicate that the administration of exogenous IFN can simulate cachexia in NTB rats and that passive immunization against it can partially reverse the cachectic changes associated with cancer and prolong survival. These findings suggest that gamma-interferon may be an important mediator of cachexia in this rat tumor model.  相似文献   
10.
Current emphasis on reducing length of hospital stay has stimulated a review of the philosophical, clinical, and administrative approaches to brief psychiatric hospitalization of children. A model of time-limited hospitalization on an eight-bed children's unit was designed to stabilize the patients and triage them back to appropriate levels of community aftercare within 28 days. Clinical and administrative strategies used to facilitate this process included a community-based case manager for each patient, focused clinical intervention, and strong parent involvement. The treatment model was generally successful in meeting the goals of hospitalization. Of 212 admissions over three years, 37 percent of the patients at discharge continued to need complex, multi-modal treatments, and 63 percent were referred for less intensive outpatient care.  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