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   10823篇
  免费   647篇
  国内免费   78篇
耳鼻咽喉   75篇
儿科学   301篇
妇产科学   383篇
基础医学   1679篇
口腔科学   333篇
临床医学   903篇
内科学   2349篇
皮肤病学   237篇
神经病学   1184篇
特种医学   392篇
外科学   971篇
综合类   48篇
一般理论   5篇
预防医学   826篇
眼科学   194篇
药学   758篇
  1篇
中国医学   54篇
肿瘤学   855篇
  2024年   33篇
  2023年   129篇
  2022年   252篇
  2021年   394篇
  2020年   261篇
  2019年   302篇
  2018年   345篇
  2017年   275篇
  2016年   309篇
  2015年   356篇
  2014年   447篇
  2013年   523篇
  2012年   877篇
  2011年   897篇
  2010年   455篇
  2009年   441篇
  2008年   643篇
  2007年   693篇
  2006年   637篇
  2005年   649篇
  2004年   562篇
  2003年   452篇
  2002年   420篇
  2001年   102篇
  2000年   102篇
  1999年   125篇
  1998年   99篇
  1997年   78篇
  1996年   57篇
  1995年   65篇
  1994年   35篇
  1993年   51篇
  1992年   39篇
  1991年   41篇
  1990年   41篇
  1989年   32篇
  1988年   29篇
  1987年   30篇
  1986年   31篇
  1985年   20篇
  1984年   16篇
  1983年   20篇
  1982年   18篇
  1981年   14篇
  1979年   16篇
  1976年   11篇
  1974年   10篇
  1972年   14篇
  1970年   11篇
  1969年   14篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
The present study was carried out at an institution for mentally retarded persons where the subjects (college students) were transported. Under the guise of being "normal," mentally ill, or mentally retarded, each of four confederates met three independent groups of subjects. The verbal reports of the subjects did not vary a great deal as a function of condition, but amount of pain inflicted in an experimental task was strikingly different. In the mentally retarded confederate condition, shocks delivered were shorter and less intense than those given in the "normal" or mentally ill confederate conditions. Since subjects had to teach the confederate, they might have been kinder in the mentally retarded confederate condition because less was expected of the learner. Evidence was also found suggesting that the social impact of stigmas depends on the personal characteristics of the stigmatized person.  相似文献   
42.
The issues of confidentiality and boundaries cause ethical dilemmas for psychotherapists. We investigated whether therapists have ethical attitudes to confidentiality and boundaries that are unique to their professional group compared with lay persons and whether gender or professional characteristics are associated with these attitudes. Clinical vignettes capturing ethical dilemmas regarding confidentiality and boundaries were presented to 93 psychotherapists of different professional backgrounds (professional group) and 55 staff and students from the fields of law and the humanities (lay group). In general, the lay group showed a greater tendency to maintain confidentiality than the professional group. Regarding boundaries, the majority of psychotherapists were against initiating any sexual relationship with current patients, former patients, students, or supervisees; the differences between the groups in this area were statistically significant. The vast majority of therapists (96.7%) disapproved of accepting money in advance compared with only 54.4% of the lay group. Analysis of the psychotherapists by professional background revealed that for the majority of the vignettes, there was no difference in attitude to confidentiality and boundaries between psychiatrists, psychologists, and social workers. The present study shows that therapists have different ethical codes from nontherapists regarding the issues of boundaries and the treatment contract. Therapists are stricter than nontherapists regarding issues of boundaries but less strict regarding issues of confidentiality, and there are some minor differences in the attitudes to these issues among different types of therapists.  相似文献   
43.
Microtia has been treated over the years with autogenous tissues, although the results continue to improve, it is technically a very demanding procedure, even in the hands of a well trained surgeon. Osseointegrated implant-supported ear prosthesis, is less demanding, more straightforward, and offers a better cosmetic result. Since 1996 we have treated 8 patients with microtia types III and IV, with titanium osseointegrated implant-supported ear prosthesis in the bone of the mastoid process. The surgical procedure consists in two stages. First stage: when the three titanium screws are drill in the mastoid process of the temporal bone, with a previous CT scan of the area, that is used to measured the bone thickness. Second stage is done 3 to 6 months later. Ear remnants are removed at the beginning of the procedure, three titanium couplings are then secured to the integrated fixtures, a plastic cap is attached to each of the abutments, until healing takes place; three to four weeks later the auricular prosthesis made out of silicone over a metallic structure, will we plug in the titanium screws. Cosmetic results and patients acceptability have been good in all 8 cases, with few postoperative complications. This procedure has become and option for the patients with ear malformations.  相似文献   
44.
PURPOSE: Imatinib (Glivec) is a potent inhibitor of bcr/abl, an oncogenic fusion protein that causes chronic myelogenous leukemia (CML). alpha1 acid glycoprotein (AGP) binds to imatinib with high affinity and inhibits imatinib activity in vitro and in vivo in an animal model. A pharmacokinetics analysis of imatinib was undertaken in CML patients. EXPERIMENTAL DESIGN: Imatinib plasma concentrations were measured in 19 CML patients treated with imatinib (400 or 600 mg/day). Five patients received a concomitant short-term course of clindamycin (CLI). RESULTS: A positive correlation between AGP and imatinib plasma levels was observed. CLI administration decreased imatinib plasma concentrations, evaluated as area under the curve (AUC) and peak concentrations (C(max)). The effects of a bolus of CLI was studied in three patients on imatinib 23 h after the last imatinib dose. Within 5-10 min in three of three cases, CLI caused a decrease in imatinib plasma concentrations of 2.6-, 2.7-, and 4.7-fold, respectively. In vitro experiments using fresh blasts from CML patients showed that AGP, at concentrations observed in the patients, decreased imatinib intracellular concentrations up to 10 times and blocked imatinib activity. The incubation with CLI restored imatinib intracellular concentrations and biological activity. CONCLUSION: AGP exerts significant effects of the pharmacokinetics, plasma concentrations, and intracellular distribution of imatinib in CML patients; these data indicate that plasma imatinib levels represent unreliable indicators of the cellular concentrations of this molecule.  相似文献   
45.
BACKGROUND: Only a part of patients suffering from Crohn's disease has enteric fistulae and a different behaviour of Crohn's disease with fistulae is reported in the literature. Aim of this paper is to evaluate if enteric fistulae are a factor conditioning mortality, morbidity and overall postoperative course, in patients with Crohn's disease. METHODS: Data on the postoperative course of 126 laparotomies for Crohn's disease, performed between November 1993 and July 1998, have been prospectively examined. Moreover, the presence of enteric fistula has been evaluated during surgery. RESULTS: Out of 126 interventions, in 58 (46%) enteric fistulae were present. Mortality (5.2% vs 0), morbidity (14.5% vs 7.3%), necessity for a temporary ostomy (20.4% vs 3.5%) were greater in those patients with fistula, as compared as those without fistula. CONCLUSIONS: In conclusion, it is suggested that Crohn's disease with fistulae is a different type of disease, with higher mortality and morbidity rates.  相似文献   
46.
47.
Over the past years, research attention has been focusing more on waste-derived, naturally derived, and renewable materials, in the view of a more sustainable economy. In this work, different topical formulations were obtained from the valorization of marine and agro-industrial by-products and the use of Carbopol 940 as gelling agent. In particular, the combination of extracts obtained from the marine snail, Rapanosa venosa, with Cladophora vagabunda and grape pomace extracts, was investigated for wound healing purposes. Rapana venosa has demonstrated wound healing properties and antioxidant activity. Similarly, grape pomace extracts have been shown to accelerate the healing process. However, their synergic use has not been explored yet. To this aim, four different formulations were produced. Three formulations differed for the presence of a different extract of Rapana venosa: marine collagen, marine gelatin, and collagen hydrolysate, while another formulation used mammalian gelatin as further control. Physico-chemical properties of the extracts as well as of the formulations were analyzed. Furthermore, thermal stability was evaluated by thermogravimetric analysis. Antioxidant capacity and biological behavior, in terms of cytocompatibility, wound healing, and antimicrobial potential, were assessed. The results highlighted for all the formulations (i) a good conservation and thermal stability in time, (ii) a neutralizing activity against free radicals, (iii) and high degree of cytocompatibility and tissue regeneration potential. In particular, collagen, gelatin, and collagen hydrolysate obtained from the Rapana venosa marine snail represent an important, valuable alternative to mammalian products.  相似文献   
48.
IntroductionThe detection in mild cognitive impairment (MCI) of metabolic alterations suggestive of depression and/or of evolution to dementia.MethodsSixty-nine MCI patients underwent clinical and imaging evaluation including position emission tomography/computed tomography with fluorodeoxy-glucose (FDG-PET/CT).ResultsThe metabolism mean values in parietal, temporal and pre-cuneus areas were lower in subjects who evolved to dementia, and in frontal and in anterior cingulate areas in depressed subjects. Abnormal metabolism values were higher in the frontal and parietal lobes, and in the precuneus in subjects who evolved to dementia independently from depression.ConclusionsIn MCI FDG-PET/CT abnormality patterns suggest the presence of depression or the evolution to dementia.  相似文献   
49.
OBJECTIVES: To estimate the combined screening performance of first and early second trimester prenatal serum markers for Down syndrome, in screening for the development of preeclampsia, and analyze the correlation among marker levels, week of onset, and severity of the disease. METHODS: A retrospective cohort study was carried out on 32 women with preeclampsia and 3044 controls. Serum samples from these pregnancies were assayed for pregnancy-associated plasma protein-A (PAPP-A), alpha-fetoprotein (AFP), unconjugated estriol (uE3), human chorionic gonadotrophin (hCG), and inhibin-A. A likelihood ratio and the odds of being affected given a positive result (OAPR) of various combinations of markers were calculated and receiver operating characteristic (ROC) curves analysis was performed. RESULTS: In the pregnancies that subsequently developed preeclampsia, first trimester PAPP-A concentration was significantly lower and concentrations of early second trimester inhibin-A and hCG significantly elevated. Levels of early second trimester uE3 and AFP were not significantly altered. We also found that inhibin-A correlates with both onset of the disease and the severity. CONCLUSION: Down syndrome biochemical markers levels are altered in those patients who subsequently developed preeclampsia and may be a useful screening test for preeclampsia. Inhibin-A is the most predictive marker and correlates with the severity of subsequent preeclampsia and inversely with the week of occurrence of preeclampsia.  相似文献   
50.
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