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   10529篇
  免费   685篇
  国内免费   32篇
耳鼻咽喉   202篇
儿科学   277篇
妇产科学   325篇
基础医学   1516篇
口腔科学   266篇
临床医学   1128篇
内科学   2174篇
皮肤病学   167篇
神经病学   1138篇
特种医学   474篇
外科学   1489篇
综合类   100篇
一般理论   2篇
预防医学   543篇
眼科学   160篇
药学   471篇
中国医学   20篇
肿瘤学   794篇
  2023年   60篇
  2022年   151篇
  2021年   248篇
  2020年   155篇
  2019年   208篇
  2018年   227篇
  2017年   151篇
  2016年   233篇
  2015年   255篇
  2014年   343篇
  2013年   428篇
  2012年   639篇
  2011年   643篇
  2010年   400篇
  2009年   336篇
  2008年   547篇
  2007年   547篇
  2006年   562篇
  2005年   493篇
  2004年   469篇
  2003年   438篇
  2002年   389篇
  2001年   280篇
  2000年   277篇
  1999年   214篇
  1998年   106篇
  1997年   75篇
  1996年   100篇
  1995年   83篇
  1994年   69篇
  1993年   80篇
  1992年   153篇
  1991年   159篇
  1990年   138篇
  1989年   124篇
  1988年   113篇
  1987年   104篇
  1986年   93篇
  1985年   92篇
  1984年   75篇
  1983年   63篇
  1982年   49篇
  1981年   45篇
  1979年   73篇
  1978年   46篇
  1977年   54篇
  1975年   47篇
  1974年   53篇
  1973年   48篇
  1972年   62篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Sniff nasal inspiratory pressure (SNIP) measurement is a volitional noninvasive assessment of inspiratory muscle strength. A maximum of 10 sniffs is generally used. The purpose of the present study was to investigate whether the maximum SNIP improved after the tenth sniff. In total, 20 healthy volunteers and 305 patients with various neuromuscular and lung diseases were encouraged to perform 40 and 20 sniffs, respectively. The best SNIP among the first 10 sniffs was lower than the best SNIP among the next 10 sniffs in the healthy volunteers and patients. The SNIP improvement after the twentieth sniff was marginal. In conclusion, a learning effect persists after the tenth sniff. The current authors suggest using 10 additional sniffs when the best result of the first 10 sniffs is slightly below normal, or when sniff nasal inspiratory pressure is used to monitor a progressive decline in inspiratory muscle strength.  相似文献   
2.
3.
Ten years experience with acute peritoneal dialysis in 39 preterm-, newborn and small infants shows advantage and low risk of surgically implanted single dacron cuffed silicone catheters compared to trocar catheters.  相似文献   
4.
A rotating contact lens holder for the three-mirror Goldmann lens permits circular examination of the fundus or chamber angle without having to change the position of the fingers on the edge of the lens. The contact lens holder consists of an outer polygonal ring hold by the thumber and index finger. An inner rotating ring holds the contact lens. Continuous rotation of the contact lens is performed with the free middle Finger. This device permits circular examination of the retina without interruption of fixation. The instrument improves not only the speed but also the reliability of the examination.  相似文献   
5.
Cerebral infarction is rare in premature newborns and is most commonly the result of arterial embolization from the placenta. A focal echodense area was identified on prenatal cranial ultrasonography (US) in a premature infant (34 weeks of gestation). After birth, cerebral infarction was confirmed by magnetic resonance imaging (MRI). The clinical findings, imaging findings and pathogenesis are discussed. New diagnostic methods such as MRI show to be a useful approach in the neonatal period facilitating recognition of cerebrovascular accidents also in low-birth-weight infants.  相似文献   
6.
PURPOSE: To investigate whether balloon angioplasty of the superficial femoral artery (SFA) increases serum levels of C5a and whether C5a predicts risk of restenosis. METHODS: C5a antigen was measured at baseline and 8 hours after intervention in 131 consecutive patients (76 women; median age 72 years) with intermittent claudication who underwent successful primary SFA balloon angioplasty. Patients were followed for a median 10 months [interquartile range (IQR) 6 to 14] for the occurrence of >50% restenosis by duplex ultrasound. RESULTS: Median C5a levels increased significantly from 39.7 ng/mL (IQR 27.8 to 55.0) at baseline to 53.8 ng/mL (IQR 35.6 to 85.1, p<0.001) 8 hours post intervention. During the follow-up period, 70 (53%) patients developed restenosis. Increasing levels of C5a (quartiles) at baseline were significantly associated with an increased risk for restenosis (p=0.0092). Adjusted hazard ratios (95% confidence intervals) for restenosis with increasing quartiles of baseline serum C5a levels were 1.24 (0.60 to 2.58), 1.93 (0.95 to 3.93), and 2.08 (1.02 to 4.21), respectively, compared to the lowest quartile. This effect was independent of nonspecific inflammation as reflected by plasma levels of C-reactive protein. CONCLUSION: Inflammatory mechanisms play a major role in the development of restenosis after angioplasty. The complement component C5a exerts strong chemotactic and proinflammatory effects. Enhanced complement activation prior to PTA, as measured by higher levels of C5a, was significantly associated with restenosis after SFA balloon angioplasty. Pathways of complement inhibition thus may be worth investigating with respect to improving patency rates.  相似文献   
7.
8.
One method used to control costs in community cardiovascular disease surveillance is to limit the number of electrocardiograms (ECGs) used to validate acute myocardial infarction (AMI). The Minnesota Heart Survey investigated the impact of decreasing the maximum number of ECGs analyzed on classification of ECG pattern and final AMI diagnosis (definite, probable, none). A 50% sample of all 1980 acute CHD hospital discharge records (ICD-9 code 410 or 411) from 30 of 31 Twin Cities hospitals were abstracted. Comparing results using all available ECGs in the record (maximum of 12) with those obtained using up to 4 ECGs showed little differences in the ECG classification or final AMI diagnosis.  相似文献   
9.
Although intellectual impairment is common in patients with myotonic dystrophy, this aspect of the disease has received relatively little research attention. We examined 41 patients with myotonic dystrophy using objective neuropsychological procedures and magnetic resonance imaging. Ten patients (24%) had severe and generalized intellectual dysfunction, while lesser or no cognitive impairment characterized the remaining patients. Degree of intellectual impairment was not related to neuromuscular status or sex. Patients with severe intellectual disturbance had significantly earlier onset of both myotonia and weakness and were more likely to inherit the disease from their mother. Magnetic resonance imaging findings indicated that while degree of cerebral atrophy was not related to severity of intellectual impairment, skull thickness, focal white matter lesions, and anterior temporal lobe abnormalities were significantly more common in patients with severely disturbed intellect. This study reports a number of previously unreported cerebral magnetic resonance imaging findings associated with intellectual impairment in myotonic dystrophy, but the etiology of these changes awaits neuropathologic examination.  相似文献   
10.
Background: Pimecrolimus cream 1% has proven to be well‐tolerated and effective in controlled clinical studies in patients with atopic dermatitis (AD). In a 15‐week patient self‐observation study, safety and efficacy was investigated in the daily practice. Patients and methods: 3502 patients with AD (mean age 26.2 ± 18 years, 62% female) received pimecrolimus cream 1% from 810 physicians in the German Federal Republic.The severity of the disease was assessed at baseline, two times during the 15‐week observation period and at the end of treatment.Patients recorded daily the degree of erythema and pruritus. At the end of treatment, safety and efficacy were assessed by the physician based on patient's daily records and by the patient. Results: The percentage of patients with severe or massive AD decreased from 25% to 7%, whereas the percentage of patients without or with mild symptoms increased from 9% to 55%.The efficacy of treatment was rated by physicians as good or very good in 83.5% of cases and by 79% of patients.At baseline 35% of the patients were free of flares as compared to 75% at the end of therapy. Disease control was better in patients who followed the recommended treatment algorithm for pimecrolimus cream.Tolerability was mostly rated as good or very good. Conclusion: Treatment with pimecrolimus cream 1% for patients with AD is well‐tolerated and effective in daily practice.  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