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   2735207篇
  免费   193101篇
  国内免费   7940篇
耳鼻咽喉   36462篇
儿科学   91348篇
妇产科学   76329篇
基础医学   383223篇
口腔科学   74876篇
临床医学   247034篇
内科学   541078篇
皮肤病学   65881篇
神经病学   223330篇
特种医学   107851篇
外国民族医学   819篇
外科学   409436篇
综合类   51329篇
现状与发展   5篇
一般理论   971篇
预防医学   209123篇
眼科学   60151篇
药学   198691篇
  10篇
中国医学   5449篇
肿瘤学   152852篇
  2019年   21082篇
  2018年   32659篇
  2017年   26204篇
  2016年   29202篇
  2015年   33748篇
  2014年   44223篇
  2013年   63876篇
  2012年   88561篇
  2011年   88951篇
  2010年   53271篇
  2009年   52633篇
  2008年   81403篇
  2007年   86807篇
  2006年   88705篇
  2005年   91599篇
  2004年   89838篇
  2003年   83407篇
  2002年   76600篇
  2001年   130938篇
  2000年   132648篇
  1999年   113712篇
  1998年   31824篇
  1997年   28305篇
  1996年   28586篇
  1995年   27804篇
  1994年   25443篇
  1993年   23719篇
  1992年   89113篇
  1991年   85894篇
  1990年   83306篇
  1989年   80466篇
  1988年   73617篇
  1987年   72097篇
  1986年   67507篇
  1985年   64006篇
  1984年   47439篇
  1983年   40045篇
  1982年   23263篇
  1981年   20600篇
  1979年   41714篇
  1978年   29148篇
  1977年   24592篇
  1976年   22635篇
  1975年   24633篇
  1974年   29110篇
  1973年   27446篇
  1972年   25817篇
  1971年   24033篇
  1970年   22119篇
  1969年   21319篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
APACHE II score and abdominal sepsis. A prospective study   总被引:7,自引:0,他引:7  
Therapeutic trials for intra-abdominal sepsis require pretreatment stratification; physiologic scoring has been recently proposed for this purpose. We have prospectively tested the validity of one such scoring system, namely, the Acute Physiology and Chronic Health Evaluation (APACHE II). As part of a larger database, we correlated APACHE II scores with mortality in 100 patients hospitalized for generalized peritonitis or abdominal abscess. Use of steroids was recorded because of our suspicion that steroids increase mortality but blunt the physiologic response to sepsis. Thirty-one patients died, including 12 of 19 patients receiving steroids. Stepwise discriminant analysis revealed that the APACHE II score and steroid use were each independently associated with the rate of mortality. We report a prospective validation of pretreatment APACHE II scoring in abdominal sepsis. Steroid use is an independent risk factor.  相似文献   
993.
The use of additional epidural sympathetic block during and after microvascular surgery in the lower extremities to prevent vasospasm is generally agreed on. However, a significant fall in the perfusion rate of the transplants was seen after application of bupivacaine (Marcain) via the epidural catheter. This effect has, to our knowledge, not been described before and is probably caused by the sympathectomy effect of this type of analgesia.  相似文献   
994.
995.
In a randomised, double-blind study, 20 women with idiopathic detrusor instability and associated symptoms were treated with terodiline 25 mg bd, placebo, and emepronium bromide 200 mg tds--each drug being given for 3 weeks with placebo as wash-out period before cross-over. The results were evaluated according to drug preference, frequency charts and elimination of detrusor instability on cystometry. Serum levels of both drugs were monitored as control of tablet intake. The preference for terodiline to placebo was statistically significant: 14/3 women (P less than 0.05), and the majority of women (12/4) preferred terodiline to emepronium. Terodiline also gave a small but significant reduction in 24 h micturition frequency and eliminated detrusor instability in almost 50% of the patients (P less than 0.05). Side effects were frequent but mild in all three treatment periods. It was concluded that terodiline offers an alternative in the treatment of female detrusor instability.  相似文献   
996.
Multiple trauma is often associated with blunt thoracic injuries. Especially lung contusion can result in respiratory insufficiency and therefore a higher mortality rate. In our prospective study comparing 8 multiple trauma patients with and without associated lung contusion, we found that respiratory function was already significantly disturbed (decrease of paO2/FiO2 and increase of AaDO2, a rise in extravascular lung water (EVLW) both early after trauma and also with a second peak following the 4th day. This group (LK) developed significantly more cases of respiratory distress (ARDS). The disturbance of respiratory function seen initially was interpreted as a consequence of the direct mechanical impact, leading to the formation of interstitial fluid and hematoma. The frequent development of ARDS in the LK-group probably results from a pronounced activation of cellular and humoral mechanisms and therefore an enforced injury of the pulmonary capillary bed. A significant increase of pulmonary infections or the development of sepsis was not seen in the LK-group and is probably not responsible for the higher ARDS-rate in this group.  相似文献   
997.
998.
The skeletal manifestations of malignant carcinoid seem not to have been reported in the orthopedic literature. Bronchial and hindgut carcinoid tumors are less numerous than midgut tumors but metastasize to bone much more frequently. Carcinoid skeletal deposits are usually osteoblastic and most commonly affect the axial skeleton. The radiologic appearance is frequently indistinguishable from prostatic skeletal metastases or chronic sclerosing osteomyelitis. Two cases of skeletal metastases from midgut carcinoid are reported to demonstrate that metastases from carcinoid should be considered in the differential diagnosis of either bone malignancy or chronic sclerosing osteomyelitis.  相似文献   
999.
The influence of the pore size of Nucleopore diffusion-chamber filters on the rate of proliferation and differentiation of periosteal cells in muscle was studied in 44 growing rabbits. Periosteal grafts were placed in chambers (16-19 in each experimental group) sealed with filters with a pore size of 0.4, 0.6, 0.8, 1.0, or 2.0 micron. Each chamber was implanted into the paraspinal muscle of the rabbit, where it remained for 16 weeks. The osteochondrogenic activity of the graft grew linearly when the pore size increased from 0.4 to 1.0 micron. In the chambers with a pore size of 2.0 micron, both bone and cartilage were found in only one chamber. Bone and cartilage were not found outside any of the chambers. The present results showed that the pore size of the filters significantly affected the ability of the periosteal graft to form bone and cartilage.  相似文献   
1000.
We report spectrophotometric methods for quantifying sodium and potassium in serum and plasma without sample pretreatment or solvent-extraction steps. The methods are based on novel chromogenic ionophores characterized by molecular structures highly preorganized for binding, which result in exceptionally high sensitivity and selectivity (negligible responses to sodium at 80 to 200 mmol/L in the potassium assay and to potassium at 0 to 10 mmol/L in the sodium assay). The within-run imprecisions are comparable with those for ion-selective electrodes (for K, 1.0% at 4.5 mmol/L; for Na, 1.1% at 136 mmol/L); the analytical range is 2-10 mmol/L for potassium, 80-170 mmol/L for sodium. The results for greater than 100 patients' samples correlated well with results obtained with ion-selective electrodes (r = 0.99 for K, 0.97 for Na). The ready-to-use aqueous reagents will be available under the trade name of ChromoLyte for use with Technicon's RA family of clinical analyzers.  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