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   1085篇
  免费   76篇
  国内免费   7篇
耳鼻咽喉   4篇
儿科学   21篇
妇产科学   24篇
基础医学   194篇
口腔科学   14篇
临床医学   92篇
内科学   215篇
皮肤病学   22篇
神经病学   117篇
特种医学   17篇
外科学   82篇
综合类   3篇
一般理论   2篇
预防医学   86篇
眼科学   13篇
药学   106篇
中国医学   1篇
肿瘤学   155篇
  2024年   2篇
  2023年   12篇
  2022年   32篇
  2021年   62篇
  2020年   21篇
  2019年   48篇
  2018年   33篇
  2017年   21篇
  2016年   33篇
  2015年   48篇
  2014年   71篇
  2013年   65篇
  2012年   126篇
  2011年   105篇
  2010年   52篇
  2009年   34篇
  2008年   78篇
  2007年   60篇
  2006年   46篇
  2005年   65篇
  2004年   45篇
  2003年   40篇
  2002年   38篇
  2001年   4篇
  2000年   2篇
  1999年   2篇
  1998年   8篇
  1997年   2篇
  1996年   2篇
  1995年   1篇
  1993年   1篇
  1992年   1篇
  1991年   2篇
  1988年   1篇
  1984年   1篇
  1981年   1篇
  1974年   1篇
  1973年   1篇
  1970年   1篇
排序方式: 共有1168条查询结果,搜索用时 171 毫秒
71.
72.
The sterilizing agent commonly used to sterilize materials for an isolator is a peracetic acid (PA) and hydrogen peroxide (HP) mixture. The permeation of this agent through ambulatory pumps should reveal a potential toxic risk for the patient and a stability modification of the drug by a pH change. Six wrapped and six unwrapped ambulatory pumps from each laboratory were introduced in the transfer chamber for the sterilizing process over 2 h 45 min. The presence of PA and HP were determined by using analytical strips. If the analytical strips of HP were positive, the level of HP was determined by using a specific spectrometric kit. No acid permeation was found in all wrapped pumps. Acid permeation was found in two samples of Ultraflow unwrapped series and in one unwrapped sample of Easypump series by the analytical strips. In other unwrapped samples, no acid permeation was detected. In four unwrapped ambulatory pumps (Accufuser, Infusor, Ultraflow, and Easypump), the analytical strips of HP were positive in the range of 0.5 to 25 mg/L, varying by laboratory. In only one sample (Surefuser), no detection of HP was found. The quantitative dosage of HP by spectrophotometry confirmed the permeation risk inside all pumps except the Surefuser. Our investigation shows that the permeation risk inside ambulatory pumps is real when pumps are unwrapped and exposed at high levels to PA and HP mixture. The results of our study recommend retaining the wrapping for the peracetic acid sterilization of the ambulatory pumps.  相似文献   
73.
PURPOSE: To describe the safety, complications, and liver regeneration associated with the left liver after embolization of the right portal vein (PV) in patients with hepatocellular carcinoma (HCC) developed in the setting of advanced liver fibrosis and cirrhosis. MATERIALS AND METHODS: Forty patients (31 men, nine women; mean age, 62 years) with HCC underwent PV embolization over a 4-year period. Embolization was performed from a left PV percutaneous access with use of n-butyl cyanoacrylate (NBCA) mixed with iodized oil. Computed tomography (CT) volumetry was performed before and 1 month after PV embolization to measure the left lobe volume as well as the functional liver ratio defined by the ratio between the left lobe and the total liver volume minus tumoral volume. PV pressure and liver enzyme levels were compared before and 1 month after the procedure and complications were registered. Factors potentially affecting regeneration (age, sex, diabetes, chemoembolization, functional liver ratio before PV embolization, and Knodell histologic score) were evaluated by one-way and stepwise regression analysis. RESULTS: PV embolization could be achieved successfully in all cases. Two patients had partial PV thrombosis on the 1-month follow-up CT and two patients developed transient ascites after PV embolization. The left lobe volume increase was 41% +/- 32% after PV embolization and the functional liver ratio increased from 28% +/- 10% to 36% +/- 10% (P < .0001). Hypertrophy of the left lobe was greater in patients with a low functional liver ratio before PV embolization and those with an F3 fibrosis score. Other factors had no influence on left lobe regeneration. CONCLUSION: PV embolization with use of NBCA is feasible in patients with advanced fibrosis and cirrhosis. Hypertrophy of the left lobe of the liver after PV embolization has a statistically significant correlation with lower functional liver ratio and lower degrees of fibrosis.  相似文献   
74.
75.
Context  The incidence of nonmelanoma skin cancer is increasing rapidly among elderly persons, but little is known about its incidence in the population younger than 40 years. Objectives  To estimate the sex- and age-specific incidences of basal cell carcinoma and squamous cell carcinoma in persons younger than 40 years in Olmsted County, Minnesota, and to evaluate change in incidence over time; to describe the clinical presentation, rate of recurrence and metastasis, and histologic characteristics of these tumors in this population-based sample. Design  Population-based retrospective incidence case review. Setting  Residents of Olmsted County, Minnesota, a population with comprehensive medical records captured through the Rochester Epidemiology Project. Participants  Patients younger than 40 years with basal cell carcinoma or squamous cell carcinoma diagnosed between 1976 and 2003. Main Outcome Measures  Incident basal cell carcinomas and squamous cell carcinomas and change in incidence of these tumors over time. Results  During the study period, 451 incident basal cell carcinomas were diagnosed in 417 patients and 70 incident squamous cell carcinomas were diagnosed in 68 patients. Of these tumors, 328 were histologically confirmed basal cell carcinomas and 51 were histologically confirmed squamous cell carcinomas. Overall, the age-adjusted incidence of basal cell carcinoma per 100 000 persons was 25.9 (95% confidence interval [CI], 22.6-29.2) for women and 20.9 (95% CI, 17.8-23.9) for men. The incidence of basal cell carcinoma increased significantly during the study period among women (P<.001) but not men (P = .19). Nodular basal cell carcinoma was the most common histologic subtype; 43.0% of tumors were solely nodular basal cell carcinoma and 11.0% had a mixed composition, including the nodular subtype. The incidence of squamous cell carcinoma was similar in men and women, with an average age- and sex-adjusted incidence per 100 000 persons of 3.9 (95% CI, 3.0-4.8); the incidence of squamous cell carcinoma increased significantly over the study period among both women (P = .01) and men (P = .04). Conclusions  This population-based study demonstrated an increase in the incidence of nonmelanoma skin cancer among young women and men residing in Olmsted County, Minnesota. There was a disproportionate increase in basal cell carcinoma in young women. This increase may lead to an exponential increase in the overall occurrence of nonmelanoma skin cancers over time as this population ages, which emphasizes the need to focus on skin cancer prevention in young adults.   相似文献   
76.
A 2-year-old girl with recurrent severe varicella infections had a fatal outcome. Studies of cellular and humoral immunity were normal. No natural killer (NK) cells were detected, and NK activity was markedly decreased. The interleukin (IL)15/IL15R signaling pathway was intact. This case emphasizes the role of NK cells in controlling herpes viral infection.  相似文献   
77.
Emotional signals in spoken language can be conveyed by semantic as well as prosodic cues. We investigated the role of the fronto-parietal operculum, a somatosensory area where the lips, tongue and jaw are represented, in the right hemisphere to detection of emotion in prosody vs. semantics. A total of 14 healthy volunteers participated in the present experiment, which involved transcranial magnetic stimulation (TMS) in combination with frameless stereotaxy. As predicted, compared with sham stimulation, TMS over the right fronto-parietal operculum differentially affected the reaction times for detection of emotional prosody vs. emotional semantics, showing that there is a dissociation at a neuroanatomical level. Detection of withdrawal emotions (fear and sadness) in prosody was delayed significantly by TMS. No effects of TMS were observed for approach emotions (happiness and anger). We propose that the right fronto-parietal operculum is not globally involved in emotion evaluation, but sensitive to specific forms of emotional discrimination and emotion types.  相似文献   
78.
Tetraplegia developed abruptly in an 11-y-old with pneumococcal meningitis. Magnetic resonance imaging showed multiple hyperintensities at the brainstem–spinal cord junction. Serological tests were positive for Mycoplasma pneumoniae (microparticle agglutination and specific IgMs). Erythromycin and dexamethasone were started promptly, and 10 d later the patient was discharged with normal neurological function.
Conclusion: Tetraplegia during the course of pneumococcal meningitis in an 11-y-old girl disappeared after treatment with ceftriaxone, erythromycin and dexamethasone.  相似文献   
79.
The Profile of Female Sexual Function (PFSF) is a patient-based instrument for the measuring of loss of sexual function in menopausal women with low libido (hypoactive female sexual desire disorder). The instrument, which contains 37 items in seven domains (sexual desire, arousal, orgasm, sexual pleasure, sexual concerns, sexual responsiveness, and sexual self-image) and a single-item measure of overall satisfaction with sexuality, has been extensively developed and initially validated in over 500 oophorectomized women with low libido in North America, Europe, and Australia. Initial validation results showed the PFSF is capable of discriminating these patients from age-matched controls and produced consistent responses and sensitivity across geographies. The objective of this nonrandomized, parallel-group study was to examine the psychometric properties of the final PFSF in an independent group of surgically menopausal women with low libido and to extend validation to naturally menopausal women with low libido. Participants from 16 study centers in North America included surgically (n = 59) and naturally (n = 88) menopausal women with low libido and their age-matched control subjects, both premenopausal (n = 57) and naturally menopausal (n = 47), who reported no problems with libido. Subjects completed the PFSF at baseline and again 4 weeks later. Adjusted mean scores for each of the seven domains were statistically significantly lower (P < 0.0001) in surgically menopausal women with low libido compared with age-matched control women, and in naturally menopausal women with low libido compared with naturally menopausal control women, demonstrating excellent discriminant validity. Test-retest reliability ranged from 0.57 to 0.91 for the seven domain scores, whereas internal-consistency reliability ranged from 0.74 to 0.95. Results of this research support the conclusion that the PFSF is a valid and reliable instrument for measurement of loss of sexual function in both naturally and surgically menopausal women with low libido.  相似文献   
80.
Several studies have shown that PPARgamma agonists play a role in the regulation of lymphocytes function and apoptosis. However, the molecular mechanism(s) underlying the immunomodulatory effects of PPARgamma agonists are not defined yet. In this study, the effects of PPARgamma (15d PGJ2 and ciglitizone) ligands on proliferation, cytokine production and apoptosis of Jurkat and Raji cells (human T and B lymphocytes, respectively) were examined. Ciglitizone and 15d PGJ2 presented antiproliferative and cytotoxic effects on Jurkat and Raji cells as shown by [14C]-thymidine incorporation and cell viability assay. In addition, 15d PGJ2 inhibited cytokine production (IL-2 in Jurkat cells and IL-10 in Raji cells). The mechanism whereby PPARgamma agonists induced cytotoxicity is via apoptosis as shown by DNA fragmentation, nuclear condensation and phosphatidylserine externalization. The induction of apoptosis by ciglitizone and 15d PGJ2 on Jurkat and Raji cells may explain the suppression of cytokine production and the decrease in proliferation observed in both cell types. The apoptotic process was associated with a decrease in mitochondrial membrane potential and a marked down-regulation of the c-myc expression. These findings might play a key role in the apoptosis of T and B lymphocytes induced by PPARgamma agonists.  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