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   1523篇
  免费   90篇
  国内免费   19篇
耳鼻咽喉   17篇
儿科学   90篇
妇产科学   21篇
基础医学   143篇
口腔科学   26篇
临床医学   123篇
内科学   310篇
皮肤病学   27篇
神经病学   72篇
特种医学   137篇
外科学   163篇
综合类   135篇
预防医学   111篇
眼科学   63篇
药学   72篇
中国医学   41篇
肿瘤学   81篇
  2023年   7篇
  2022年   21篇
  2021年   25篇
  2020年   22篇
  2019年   15篇
  2018年   24篇
  2017年   15篇
  2016年   25篇
  2015年   35篇
  2014年   49篇
  2013年   48篇
  2012年   66篇
  2011年   55篇
  2010年   81篇
  2009年   80篇
  2008年   47篇
  2007年   53篇
  2006年   57篇
  2005年   49篇
  2004年   47篇
  2003年   47篇
  2002年   34篇
  2001年   37篇
  2000年   36篇
  1999年   38篇
  1998年   50篇
  1997年   65篇
  1996年   59篇
  1995年   40篇
  1994年   37篇
  1993年   32篇
  1992年   16篇
  1991年   13篇
  1990年   19篇
  1989年   31篇
  1988年   26篇
  1987年   27篇
  1986年   20篇
  1985年   20篇
  1984年   17篇
  1983年   14篇
  1982年   10篇
  1981年   15篇
  1980年   15篇
  1979年   11篇
  1977年   10篇
  1976年   6篇
  1974年   6篇
  1973年   5篇
  1967年   5篇
排序方式: 共有1632条查询结果,搜索用时 15 毫秒
1.
ObjectiveWe examine remission rate probabilities, recovery rates, and residual symptoms across 36 weeks in the Treatment for Adolescents with Depression Study (TADS).MethodThe TADS, a multisite clinical trial, randomized 439 adolescents with major depressive disorder to 12 weeks of treatment with fluoxetine, cognitive–behavioral therapy, their combination, or pill placebo. The pill placebo group, treated openly after week 12, was not included in the subsequent analyses. Treatment differences in remission rates and probabilities of remission over time are compared. Recovery rates in remitters at weeks 12 (acute phase remitters) and 18 (continuation phase remitters) are summarized. We also examined whether residual symptoms at the end of 12 weeks of acute treatment predicted later remission.ResultsAt week 36, the estimated remission rates for intention-to-treat cases were as follows: combination, 60%; fluoxetine, 55%; cognitive–behavioral therapy, 64%; and overall, 60%. Paired comparisons reveal that, at week 24, all active treatments converge on remission outcomes. The recovery rate at week 36 was 65% for acute phase remitters and 71% for continuation phase remitters, with no significant between-treatment differences in recovery rates. Residual symptoms at the end of acute treatment predicted failure to achieve remission at weeks 18 and 36.ConclusionsMost depressed adolescents in all three treatment modalities achieved remission at the end of 9 months of treatment.  相似文献   
2.
Cytokines play a pivotal role in the pathogenesis of degenerative joint disease but also in inflammatory conditions as well as osteoarthritis (OA) and rheumatoid arthritis (RA). A key role is attributed to interleukin-1 and tumor necrosis factor-α. Certain cytokines that can inhibit the activity of catabolic cytokines have great therapeutic potential and are currently being investigated in numerous clinical studies. Available scientific findings indicate that proinflammatory cytokines stimulate cartilage breakdown and blockade of these cytokines can protect the cartilage.  相似文献   
3.
Suppurative corneal ulceration in Bangladesh   总被引:8,自引:0,他引:8  
Suppurative keratitis is an important preventable cause of blindness, particularly in the developing world. This study analyses 142 cases of suppurative keratitis referred to Chittagong Eye Infirmary, Bangladesh. Some 53.5% of cases were bacterial and 35.9% were fungal. The five most common pathogens were: Pseudomonas sp. 24%, Streptococcus pneumoniae 17%, Aspergillus sp. 13%, Fusarium sp. 7% and Curvularia sp. 6%. Gram stain and culture results were consistent in 62.6% of cases. Previous antibiotic treatment was a significant factor for failure of culture isolation and less so for Gram stain failure. On Gram stain, 55.9% of pseudomonal cases were missed, but only 2% of fungal cases were missed. Over all, Gram stain had a sensitivity of 62% and positive predictive value of 84% for bacterial cases, and 98% and 94% for fungal cases, respectively. Fungal ulcers were typically filamentous, but an antecedent history of trauma was not common. The most frequent injury was due to rice grains, but the inoculum appeared to be introduced during eye washing with contaminated water. Pseudomonal ulcers occurred most frequently in the monsoon season, and Fusarium cases were seen only in the hot, dry season.  相似文献   
4.
In corrosion casts of the left anterior descending coronary artery and its branches of higher order, the length, diameter, and number of branches were examined in 20 hearts, from 9 adults, 3 children, 4 new-born and 4 fetuses. We counted 5245 branches in total, thereof 147 branches in the corrosion casts of adult hearts were systematically analyzed, as were 46 branches of children's hearts, 55 branches of the new-born and 35 branches of the fetuses, respectively (left anterior descending coronary arteries and branches of 1st to 6th order). The length of the left coronary arteries and of their branches of 1st and 2nd order increases to almost the same degree as the linear measurements of the hearts. The left anterior descending coronary artery is about four times as long as the 1st order branches and these have twice the length of the 2nd order branches. These differences result from the divergent course of the branches. The results indicate that no significant increase in the number of the 1st to 3rd order branches of the coronary arteries occurs from birth to adulthood in human hearts. During the postnatal growth in human hearts there seems to be no remarkable neogenesis of coronary artery branches of greater diameter. Nearly all of them exist at birth and even in the late fetal period. Their length increases harmonically with the linear measurements of the heart and they become progressively separated. These findings parallel those obtained in a previous study in pigs.  相似文献   
5.
6.
7.
8.
Kuross  SA; Hebbel  RP 《Blood》1988,72(4):1278-1285
Previous studies documented the abnormal association of heme and heme proteins with the sickle RBC membrane. We have now examined RBC ghosts and inside-out membranes (IOM) for the presence of nonheme iron as detected by its formation of a colored complex with ferrozine. Sickle ghosts have 33.8 +/- 18.2 nmol nonheme iron/mg membrane protein, and sickle IOM have 4.3 +/- 3.0 nmol/mg. In contrast, normal RBC ghosts and IOM have no detectable nonheme iron. The combination of heme and nonheme iron in sickle IOM averages nine times the amount of membrane- associated iron in normal IOM. Kinetics of the ferrozine reaction show that some of this nonheme iron on IOM reacts slowly and is probably in the form of ferritin, but most (72% +/- 18%) reacts rapidly and is in the form of some other biologic chelate. The latter iron compartment is removed by deferoxamine and by treatment of IOM with phospholipase D, which suggests that it represents an abnormal association of iron with polar head groups of aminophospholipids. The biologic feasibility of such a chelate was demonstrated by using an admixture of iron with model liposomes. Even in the presence of tenfold excess adenosine diphosphate, iron partitions readily into phosphatidylserine liposomes; there is no detectable association with phosphatidylcholine liposomes. To examine the bioavailability of membrane iron, we admixed membranes and t-butylhydroperoxide and found that sickle membranes show a tenfold greater peroxidation response than do normal membranes. This is not due simply to a deficiency of vitamin E, and this is profoundly inhibited by deferoxamine. Thus, while thiol oxidation in sickle membranes previously was shown to correlate with heme iron, the present data suggest that lipid peroxidation is related to nonheme iron. In control studies, we did not find this pathologic association of nonferritin, nonheme iron with IOM prepared from sickle trait, high-reticulocyte, postsplenectomy, or iron-overloaded individuals. These data provide additional support for the concept that iron decompartmentalization is a characteristic of sickle RBCs.  相似文献   
9.
10.
This study was carried out to determine the ultrastructure and origin of previously described neurotensin-like immunoreactive (NT-LI) nerve fibres in the wall of the carotid sinus of the guinea pig. In our degeneration experiments, these NT-LI axons were unaffected by surgical sympathectomy but disappeared in response to transection of the carotid sinus nerve, thus suggesting a sensory origin. This assumption could be supported by combined retrograde tracing and immunohistochemistry. Primary afferent neurons of the sensory glossopharyngeal (petrosal) ganglion projecting to the carotid sinus were identified by injecting the retrograde fluorescent tracer, Fluoro-Gold, into the sinus wall, and some of these neurons displayed NT-LI. Within the carotid sinus, the terminals of these NT-LI sensory neurons exhibited ultrastructural features characteristic of baroreceptor endings, i.e. axonal swellings filled with mitochondria and closely associated to elastin. However, many endings also fulfilling the ultrastructural criteria for baroreceptors were devoid of immunolabelling. Thus, we conclude that the NT-LI terminals constitute a subgroup rather than the entire population of baroreceptor endings within the guinea pig carotid sinus. With respect to the established pharmacological effects of NT in guinea pig, we propose an involvement of NT-LI fibres in the modulation of baroreception at the peripheral level.  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