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   3002篇
  免费   181篇
  国内免费   14篇
耳鼻咽喉   20篇
儿科学   106篇
妇产科学   34篇
基础医学   579篇
口腔科学   98篇
临床医学   316篇
内科学   495篇
皮肤病学   51篇
神经病学   346篇
特种医学   90篇
外科学   312篇
综合类   14篇
预防医学   290篇
眼科学   26篇
药学   203篇
肿瘤学   217篇
  2023年   23篇
  2022年   14篇
  2021年   60篇
  2020年   45篇
  2019年   71篇
  2018年   85篇
  2017年   55篇
  2016年   75篇
  2015年   86篇
  2014年   111篇
  2013年   144篇
  2012年   233篇
  2011年   246篇
  2010年   125篇
  2009年   149篇
  2008年   196篇
  2007年   193篇
  2006年   204篇
  2005年   214篇
  2004年   166篇
  2003年   144篇
  2002年   154篇
  2001年   52篇
  2000年   30篇
  1999年   35篇
  1998年   40篇
  1997年   20篇
  1996年   16篇
  1995年   14篇
  1994年   19篇
  1993年   17篇
  1992年   11篇
  1991年   11篇
  1990年   9篇
  1989年   14篇
  1988年   11篇
  1987年   9篇
  1986年   6篇
  1985年   9篇
  1984年   5篇
  1983年   7篇
  1982年   4篇
  1979年   3篇
  1978年   4篇
  1977年   3篇
  1976年   4篇
  1970年   5篇
  1968年   3篇
  1965年   3篇
  1930年   3篇
排序方式: 共有3197条查询结果,搜索用时 296 毫秒
1.
2.
Background: Postoperative pain mostly results from sensitization of afferent fibers at injury sites driving central sensitization. Recently, peripheral processes have gained attention as mechanisms of hyperalgesia, and prostaglandins are among highly sensitizing agents. To date, perioperative administration of a single local dose of nonsteroidal antiinflammatory drugs has shown inconclusive efficacy. Rather than a single bolus, the current study evaluates the postoperative analgesic effect of diclofenac continuous intrawound infusion after elective cesarean delivery.

Methods: Ninety-two parturients were randomly allocated to receive a 48-h continuous intrawound infusion with 240 ml containing 300 mg diclofenac, 0.2% ropivacaine, or saline. In the ropivacaine and saline groups, patients also received 75 mg intravenous diclofenac every 12 h for 48 h. Postoperative evaluation included intravenous morphine consumption by patient-controlled analgesia and visual analog pain scores. Punctate mechanical hyperalgesia surrounding the wound and presence of residual pain after 1 and 6 months were also assessed.

Results: Continuous diclofenac infusion significantly reduced postoperative morphine consumption (18 mg; 95% confidence interval, 12.7-22.2) in comparison with saline infusion and systemic diclofenac (38 mg; 95% confidence interval, 28.8-43.7) (P = 0.0009) without unique adverse effects. Postoperative analgesia produced by local diclofenac infusion was as effective as local ropivacaine infusion with systemic diclofenac.  相似文献   

3.
We correlated MRI features with histopathological findings in an HIV-positive patient with vacuolar myelopathy. On MRI symmetrical nonenhancing high-signal areas in the posterior columns on T2-weighted images result from extensive vacuolation visible on histological sections. Received: 18 November 1997 Accepted: 23 March 1997  相似文献   
4.
Pneumocandin B0 (6) and six related lipopeptides are antifungal and anti-Pneumocystis carinii agents from mutants of Zalerion arboricola, whose structures were determined mainly on the basis of spectroscopic analysis. They belong, along with pneumocandin A0 (L-671,329) previously isolated from these laboratories, to the echinocandin class of antifungal agents. The product from base-catalyzed ring opening involving the hemiaminal position of the dihydroxyornithine residue of B0, has been clearly defined as 6b. Modifications were limited to the 3-hydroxy-4-methylproline, 3,4-dihydroxyhomotyrosine and 4,5-dihydroxyornithine residues of pneumocandin A0.  相似文献   
5.
6.
E. Faist  M. W. Wichmann 《Der Chirurg》1997,68(11):1066-1070
Zusammenfassung. Der klinische Verlauf bei polytraumatisierten Patienten wird durch das h?ufige Auftreten schwerwiegender immunologischer Komplikationen beeintr?chtigt. Die Immunantwort auf schweres Trauma kann durch die vermehrte Freisetzung proinflammatorischer Mediatoren über das „systemic inflammatory response syndrome (SIRS)“ zum Mehrorganversagen [„multisystem organ failure (MOF)“] führen, welches mit einer Letalit?t von bis zu 80 % behaftet ist. Charakteristisch für die Entwicklung des Multiorganversagens ist das Auftreten des „remote organ failure (ROF)“, eine Fehlfunktion von Organen, die durch das eigentliche Trauma keinen direkten Schaden erlitten haben. Diese Arbeit gibt einen kurzen überblick über die neueren Entwicklungen auf dem Gebiet der tierexperimentell-immunologischen Traumaforschung und geht eingehend auf den aktuellen Stand der klinisch-immunologischen Traumaforschung ein. Insbesondere wird die Bedeutung der sog. pro- und antiinflammatorischen Cytokine bei der Entstehung von SIRS, MOF und ROF er?rtert. Trotz der vielen Fortschritte auf dem Gebiet der klinischen Immunologie und der vielf?ltigen Informationen über die Trauma-induzierten Immunfunktionsst?rungen müssen jedoch noch viele offene Fragen gel?st werden, bevor die immunologischen Ver?nderungen nach schwerem Trauma durch immunmodulatorische Therapieans?tze nachhaltig positiv beeinflu?t werden k?nnen.   相似文献   
7.
OBJECTIVE: The purpose of this study was to investigate whether Dizziness Handicap Inventory (DHI) score is related to postural performance as assessed by dynamic posturography. STUDY DESIGN: Retrospective study. SETTING: Outpatient in a tertiary referral center. PATIENTS: Ninety-two complete unilateral vestibular loss patients, categorized into 3 groups according to the postlesion stage: 1 to 2 months (n = 32; age, 47.6 +/- 10.7 yr), 4 to 7 months (n= 23; 47.1 +/- 8.37 yr), and 1 year and older (n = 37; 49.2 +/- 9.5 yr). MAIN OUTCOME MEASURES: Dizziness Handicap Inventory and dynamic balance measured with a seesaw platform moving either in the anterior-posterior or in the mediolateral direction. RESULTS: The mean DHI score was 25.8 +/- 18.7 and the range was 0 to 68. Dizziness Handicap Inventory scores did not differ significantly between the different unilateral vestibular loss groups studied. No difference was detected between the groups for the 3 subscores (emotional, functional, and physical), except that the older-than-1-year group had a significantly higher physical score than the 2 others. No correlation was found between DHI scores and postural indicators for either direction of the platform. However, patients unable to maintain balance when the seesaw platform moved in the mediolateral direction had significantly higher DHI scores than those who did not fall. CONCLUSION: Even if they are not directly related, we suggest that DHI and dynamic posturography are complementary approaches for appreciating the vestibular compensation process and are thus useful for postoperative counseling for vestibular loss patients.  相似文献   
8.
We have investigated the distribution of vasopressin binding sites in the brain of male and female adult mice using a radio-iodinated ligand and film autoradiography. Vasopressin receptors were uncovered in various regions of the brain including the basal nucleus of Meynert, the substantia innominata, the hypothalamic paraventricular nucleus, the substantia nigra pars compacta and the hypoglossal nucleus. A sex-related difference in the expression of vasopressin receptors was seen in the medial preoptic area/anterior hypothalamus corresponding to the rat sexually dimorphic nucleus in the rat and in the hypothalamic mammillary nuclei. In both structures the autoradiographic labeling is more intense in females than in males. These observations confirm that vasopressin binding sites are present in the hypothalamic preoptic area of most species examined so far and that sex-related expression of neuropeptide receptors could trigger sex-related behavioral differences.  相似文献   
9.
The sensitivity of single-photon emission computed tomography (SPECT) in evaluating posterior mculation infarcts compared with that of computed tomography (CT) or magnetic resonance imaging (MRI) remains unknown. In a hospital-based population, the authors studied SPECT, CT, and MRI in 35 consecutive patients presentmg with acute infarction clinically localized in the thalamus (7), posterior cerebral artery (PCA) territory (15), bramtem (19), and cerebellum (3) Multiple infarcts were noted m 8 patients. Overall, the SPECT sensitivity was lower than that of MRI (21% vs 93%, p ~ 0 004) and CT (42% vs 65%, p = 0 046) The SPECT and CT sensitivities were not Significantly different (67% vs 73%) for PCA Infarcts. Performed within 24 hours, SPECT showed a relevant hypoperfusion in all PCA mfarcts. For brainstem infarcts, CT (33%, p = 0 074) and MRI (91 %, p = 0.004) were more sensitive than SPECT, which showed no hemispheric hypoperfusion. The sensitivity of the three imaging techniques was 100% for large cerebellar infarcts. For the small group of thalamic infarcts, the SPECT, CT, and MRI sensitivities were 14, 71, and 100%, respectively. Thus, SPECT compared to CT and MRI is not helpful in the subacute phase to localize PCA and cerebellar infarcts and is of limited value for thalamic infarcts. In the first hours, the absence of cerebral hypoperfusion in brainstem mfarcts may help to differentiate them from hemispheric infarcts usually associated with profound hypoperfusion.  相似文献   
10.
In this study, a replicative fowl adenovirus serotype 1 (CELO) recombinant expressing chicken interferon-gamma (ChIFN-gamma) was constructed. In the engineered recombinant, the ChIFN-gamma gene was placed under the control of cytomegalovirus (CMV) promoter. The ChIFN-gamma expression cassette was inserted in the right end of the CELO genome (D fragment), which was able to carry the largest insertion of foreign DNA without affecting the replication functions of the vector. The recombinant ChIFN-gamma (rChIFN-gamma) produced in the CELO-virus expression system was characterized by comparing its biologic activities with that of rChIFN-gamma produced via the baculovirus expression system (Bac-ChIFN-gamma). CELO-ChIFN-gamma inhibited the replication of cytolytic virus in chicken embryo fibroblasts (CEFs) and activated macrophages in a better manner than did Bac-ChIFN-gamma . Moreover, the in vitro and in vivo stability of the CELO-derived rChIFN-gamma was considerably higher than that of the Bac-ChIFN-gamma. The CELO-ChIFN-gamma recombinant vector was able to replicate in vitro in the loghorn male hepatoma (LMH) hepatocyte cell line and to produce detectable levels of recombinant cytokine in supernatant as early as 90 min post-infection. Therefore, the CELO-virus expression system is an appropriate system for high-level expression of biologically active and stable ChIFN-gamma.  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