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   1644篇
  免费   168篇
  国内免费   45篇
耳鼻咽喉   4篇
儿科学   96篇
妇产科学   67篇
基础医学   229篇
口腔科学   25篇
临床医学   205篇
内科学   347篇
皮肤病学   14篇
神经病学   100篇
特种医学   145篇
外科学   197篇
综合类   51篇
一般理论   1篇
预防医学   171篇
眼科学   11篇
药学   126篇
中国医学   5篇
肿瘤学   63篇
  2021年   17篇
  2019年   12篇
  2018年   19篇
  2016年   19篇
  2015年   20篇
  2014年   29篇
  2013年   51篇
  2012年   54篇
  2011年   44篇
  2010年   51篇
  2009年   48篇
  2008年   58篇
  2007年   79篇
  2006年   55篇
  2005年   44篇
  2004年   47篇
  2003年   59篇
  2002年   48篇
  2001年   42篇
  2000年   50篇
  1999年   36篇
  1998年   65篇
  1997年   54篇
  1996年   46篇
  1995年   38篇
  1994年   24篇
  1993年   31篇
  1992年   45篇
  1991年   33篇
  1990年   44篇
  1989年   52篇
  1988年   47篇
  1987年   47篇
  1986年   38篇
  1985年   51篇
  1984年   24篇
  1983年   30篇
  1982年   18篇
  1981年   19篇
  1980年   19篇
  1979年   24篇
  1978年   25篇
  1977年   21篇
  1976年   13篇
  1975年   20篇
  1974年   10篇
  1973年   13篇
  1972年   15篇
  1971年   10篇
  1968年   9篇
排序方式: 共有1857条查询结果,搜索用时 31 毫秒
1.
Idiopathic retroperitoneal fibrosis. A retrospective analysis of 60 cases   总被引:5,自引:0,他引:5  
Sixty patients with idiopathic retroperitoneal fibrosis presenting between 1965 and 1984 are reviewed. Their mean age at presentation was 56 years and the male:female ratio was 3:1. The commonest presenting symptoms were flank and abdominal pain, weight loss, nausea and polyuria. Physical examination was usually normal, expect for the presence of hypertension. Anaemia and elevation of erythrocyte sedimentation rate were usually present. Proteinuria was found in less than a third of patients at presentation and significant bacteriuria was uncommon. The correct diagnosis was made or suspected in very few patients before referral. The cumulative actuarial survival rate was 86% at 1 year and 78% at 2 years. Seventeen patients died; they were significantly older and more uraemic at the time of referral than those who survived. A few patients did well with either corticosteroid therapy or ureterolysis alone. In the majority, both operation and steroid treatment were necessary. In bilateral obstruction with residual function in both kidneys, bilateral ureterolysis proved superior to unilateral operation (each followed by steroid therapy) in conserving renal function. Operation alone or steroid therapy alone should be considered in cases where steroids or surgery respectively present particular hazards. The less traumatic unilateral operation should be considered in poor risk patients and in those whose renal function is absent on one side. In many survivors, disease activity has persisted for many years. Life-long follow-up is recommended.  相似文献   
2.
BACKGROUND: Sore throat is a common symptom presented to general practitioners (GPs), and there remains controversy about the appropriate use of antibiotics. AIM: To compare, in a randomized controlled trial, the effectiveness of penicillin, cefixime and placebo on symptom resolution in patients presenting with a sore throat in general practice. METHOD: Twenty-two GPs in Avon recruited 154 patients, aged 16-60 years, presenting to their GP with a sore throat, and for whom the GP would normally prescribe an antibiotic. Patients were randomized to one of three groups: penicillin V 250 mg four times a day; cefixime 200 mg daily; and placebo. Each was prescribed for five days. The main outcome measures were a diary of symptom resolution over seven days and eradication of group A beta-haemolytic streptococcus (GABHS). RESULTS: Of the 103 (67%) patients who completed symptom diaries, 40 were allocated to receive penicillin, 29 cefixime and 34 placebo. In the analysis including all patients, symptom resolution was greater by day 3 in the cefixime group than in the placebo group. Penicillin did not improve symptom resolution by day 3 compared with placebo, and cefixime was not statistically significantly different from penicillin. There were significant differences in the proportion of patients using analgesia at day 3, with the proportion being lowest in the cefixime group. The results for the subgroup of patients without GABHS were similar to those for all patients; in particular, the only statistically significant difference was between cefixime and placebo. Although numbers were too small for statistical significance, among patients with GABHS the effects of penicillin and cefixime were similarly raised in relation to placebo. CONCLUSION: Compared with placebo, cefixime can improve the rate of resolution of symptoms in patients with a sore throat who are selected for antibiotic treatment by their GP. The unexpected finding that cefixime was of benefit compared with placebo for patients without GABHS suggests that bacteria other than GABHS may be important in the pathogenesis of sore throat.  相似文献   
3.
Traditionally, neuropsychological deficits due to Sickle Cell Disease (SCD) have been understudied in adults. We have begun to suspect, however, that symptomatic and asymptomatic Cerebrovascular Events (CVE) may account for an alarming number of deficits in this population. In the current brief review, we critically evaluated the pediatric and adult literatures on the neurocognitive effects of SCD. We highlighted the studies that have been published on this topic and posit that early detection of CVE via neurocognitive testing, neuropsychiatric evaluations, and neuroimaging may significantly reduce adult cognitive and functional morbidities.  相似文献   
4.
The predictive validity of infant neuromotor evaluation by the Movement Assessment of Infants (MAI) was investigated in low-birthweight infants. Motor performance at four and eight months was examined in relation to neurodevelopmental outcome at 18 months of age. Correlations were equally strong between total MAI risk scores at four and eight months and performance on the Bayley Scales. Muscle tone observations were more discriminating at four months, and automatic reactions and volitional movement were most predictive at eight months. The MAI was highly sensitive to neurodevelopmental abnormality at four and eight months and more sensitive than the Bayley Motor Scale; both assessment tools had lower specificity at eight months. The high false-positive rate is attributed to transient neuromotor abnormalities and immaturity of motor function in low-birthweight infants with normal outcome.  相似文献   
5.
6.
We used arthrotomography to study the glenoid labrum in 114 patients. Sixty-nine of the patients had anatomic instability of the shoulder (including recurrent dislocation and subluxation of the shoulder), and 45 patients had functional instability of the shoulder (denoted by chronic pain, clicking of the joint, and the sensation that an unstable condition exists without the objective signs of it). Labral tears were revealed arthrotomographically in 86% of the patients with anatomic instability, while only 40% of the patients with functional instability had labral abnormalities, and these were primarily of minor severity. Fifty-six patients (44 of whom had anatomic instability; 12, functional instability) required surgery. The surgical findings were correlated with the arthrotomographic findings, and no false-positive results were revealed. However, arthrotomography demonstrated only part of the pathologic condition of two patients. These results confirm that there is a strong correlation between labral pathologic conditions and anatomic instability of the shoulder. Arthrotomographic studies have a great impact on the selection of therapy in cases of both anatomic and functional instability of the shoulder.  相似文献   
7.
Unilateral epidural analgesia occurring in a parturient three times in successive pregnancies is reported. Possible causes are reviewed, and clinical and radiological evidence in support of the most likely explanation are presented.  相似文献   
8.
A case of Fournier's gangrene of the scrotum is reported in a 31-year old man who had outpatient vasectomy during an intercurrent diarrheal illness. The surgery was done through a midline incision, under local anesthesia of plain 2% lignocaine, with a preoperative chlorhexidine scrub. Although his scrotum was red and swollen within 3 hours, he did not have medical care until admission to hospital 48 hours later. At admission he had Fournier's gangrene of the scrotum and penis, Gram-negative septic shock, and acute renal failure. In the intensive care unit he was treated with continuous dialysis, parenteral metronidazole, benzylpenicillin, Ceftazidime and inotropes. He had a cardiorespiratory arrest after emergency radical debridement. After resuscitation he developed adult respiratory distress syndrome and disseminated intravascular coagulation. Pathological exam showed necrosis of the dermis and subcutaneous layers, thrombosis and beta-hemolytic streptococci. After adding gentamicin and vancomycin, 2 weeks of ventilator care, 4 more surgical debridements, a left orchidectomy, and a despite a grossly abnormal EEG recording, the man regained consciousness and recovered. His scrotal and penile skin re-epithelialized over 3 months. Patients requesting vasectomy should be assessed for local and systemic illness before performing the procedure.  相似文献   
9.
10.
Characterization of the mitogenic signal from an oncogene ras protein   总被引:1,自引:0,他引:1  
Wild-type or cellular RAS proteins function at the end of the G1 phase of the cell cycle, but they cannot signal quiescent cells to start cycling. By contrast, the oncogenic or "activated" RAS proteins produced by certain mutant ras genes can start quiescent cells cycling and appear to be involved in a large fraction of human cancers. One of these "activated" RAS proteins is the temperature-sensitive viral K-RAS protein produced by tsKSV-NRK rat kidney fibroblasts. Reactivating this viral K-RAS protein in serum-starved quiescent cells by lowering the temperature from a non-permissive 41 degrees C to a permissive 36 degrees C is a powerful mitogenic signal which starts the progression of cells through the various stages of the cell cycle even in the absence of serum growth factors. This first signal is associated with transient surges of cytosolic Ca2+ and membrane-associated protein kinase C activity, but is not mediated by signals from the protein-tyrosine kinase receptors of known K-RAS-induced autocrine mitogens such as TGF alpha and PDGF. While the importance of the Ca2+ transient is uncertain, the transient surge of membrane-associated protein kinase C activity appears to be involved in the process by which the viral RAS protein triggers the G0 to G1 transition. The need for the viral K-RAS protein does not end with this first signal. The protein also operates briefly at the end of the G1 phase and then, after chromosome replication, it also stimulates events necessary for the initiation of mitosis.  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