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   3703篇
  免费   293篇
  国内免费   13篇
耳鼻咽喉   64篇
儿科学   96篇
妇产科学   47篇
基础医学   496篇
口腔科学   113篇
临床医学   423篇
内科学   715篇
皮肤病学   61篇
神经病学   307篇
特种医学   124篇
外科学   626篇
综合类   39篇
一般理论   4篇
预防医学   327篇
眼科学   70篇
药学   232篇
中国医学   5篇
肿瘤学   260篇
  2023年   23篇
  2022年   35篇
  2021年   89篇
  2020年   59篇
  2019年   94篇
  2018年   106篇
  2017年   85篇
  2016年   94篇
  2015年   94篇
  2014年   118篇
  2013年   188篇
  2012年   237篇
  2011年   279篇
  2010年   169篇
  2009年   129篇
  2008年   200篇
  2007年   198篇
  2006年   208篇
  2005年   224篇
  2004年   199篇
  2003年   163篇
  2002年   155篇
  2001年   58篇
  2000年   48篇
  1999年   49篇
  1998年   28篇
  1997年   29篇
  1994年   17篇
  1993年   20篇
  1992年   30篇
  1991年   22篇
  1990年   16篇
  1989年   27篇
  1988年   28篇
  1987年   35篇
  1986年   17篇
  1985年   16篇
  1984年   22篇
  1983年   19篇
  1978年   17篇
  1975年   18篇
  1974年   24篇
  1973年   25篇
  1972年   19篇
  1971年   20篇
  1970年   22篇
  1969年   16篇
  1968年   19篇
  1967年   18篇
  1966年   24篇
排序方式: 共有4009条查询结果,搜索用时 15 毫秒
1.
Clinical Rheumatology - Prof. Ari Polachek on of the author of the published version of this article missed to add his second affiliation which is the Department of Rheumatology, Tel Aviv Sourasky...  相似文献   
2.
3.
Low-trauma fractures of elderly people are a major public health burden worldwide, and as the number and mean age of older adults in the population continue to increase, the number of fractures is also likely to increase. Epidemiologically, however, an additional concern is that, for unknown reasons, the age-standardized incidence (average individual risk) of fracture has also risen in many populations during the recent decades. Possible reasons for this rise include a birth cohort effect, deterioration in the average bone strength by time, and increased average risk of (serious) falls. Literature provides evidence that the rise is not due to a birth cohort effect, whereas no study shows whether bone fragility has increased during this relatively short period of time. This osteoporosis hypothesis could, however, be tested if researchers would now repeat the population measurements of bone mass and density that were made in the late 1980s and the 1990s. If such studies proved that women's and men's age-standardized mean values of bone mass and density have declined over time, the osteoporosis hypothesis would receive scientific support. The third explanation is based on the hypothesis that the number and/or severity of falls has risen in elderly populations during the recent decades. Although no study has directly tested this hypothesis, a great deal of indirect epidemiologic evidence supports this contention. For example, the age-standardized incidence of fall-induced severe head injuries, bruises and contusions, and joint distortions and dislocations has increased among elderly people similarly to the low-trauma fractures. The fall hypothesis could also be tested in the coming years because the 1990s saw many research teams reporting age- and sex-specific incidences of falling for elderly populations, and the same could be done now to provide data comparing the current incidence rates of falls with the earlier ones.  相似文献   
4.
5.
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   

6.
PURPOSE: To report the use of regional anesthesia and iv nitroglycerin to provide anesthesia and uterine relaxation for three Cesarean deliveries (CD) involving ex utero intrapartum treatment (EXIT) of potentially life-threatening airway obstruction in the newborn. CLINICAL FEATURES: Case 1--a 36-yr-old woman at 38 weeks' gestation was scheduled for an elective CD for fetal skeletal dysplasia and micrognathia. Case 2--a 34-yr-old woman at 35 weeks gestation had a fetal ultrasound revealing fixed neck flexion and micrognathia consistent with fetal arthrogryposis. Case 3--a 27-yr-old woman presented at 38 weeks gestation for CD for severe fetal micrognathia, with mandibular growth below the fifth percentile. For each case, a combined spinal epidural anesthetic was performed with 0.75% bupivacaine, fentanyl and morphine intrathecally followed by placement of a multiorifice epidural catheter. Prior to uterine incision patients received a loading dose followed by an iv infusion of nitroglycerin. Uterine relaxation was sufficient in all cases for delivery of the fetus, and allowed for evaluation by direct laryngoscopy and intubation while maintaining fetal-placental circulation. The surgical procedures were completed without incident. CONCLUSIONS: Anesthesia and uterine relaxation for CD and EXIT procedures can be safely provided with regional anesthesia and iv nitroglycerin.  相似文献   
7.
A survey of hospital emergency rooms in Los Angeles County was conducted in March 1987. Analysis of the distribution of uninsured emergency care patients revealed that private hospitals play a significant frontline role in terms of entry into the hospital system for patients who are unable to pay--almost one-half of such patients were treated in the emergency rooms of private hospitals. Hospitals serving markets in which a higher proportion of residents had incomes below the poverty level provided a greater share of uncompensated emergency room services.  相似文献   
8.
9.
10.
CCR5Delta32 is a deletion mutation in the chemokine receptor CCR5. Liver inflammatory activity was found to be significantly reduced (P = 0.005) in Jewish Israeli patients infected with the hepatitis C virus (HCV) carrying the CCR5Delta32 allele. The CCR5Delta32 allele does not alter susceptibility to HCV infection; however, it may play a role in the progression and outcome of the disease.  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