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   5372篇
  免费   286篇
  国内免费   85篇
耳鼻咽喉   88篇
儿科学   27篇
妇产科学   49篇
基础医学   331篇
口腔科学   149篇
临床医学   321篇
内科学   425篇
皮肤病学   43篇
神经病学   261篇
特种医学   182篇
外科学   1076篇
综合类   785篇
预防医学   335篇
眼科学   61篇
药学   466篇
  6篇
中国医学   475篇
肿瘤学   663篇
  2024年   19篇
  2023年   80篇
  2022年   170篇
  2021年   223篇
  2020年   168篇
  2019年   160篇
  2018年   150篇
  2017年   160篇
  2016年   160篇
  2015年   174篇
  2014年   386篇
  2013年   347篇
  2012年   288篇
  2011年   352篇
  2010年   320篇
  2009年   296篇
  2008年   277篇
  2007年   283篇
  2006年   218篇
  2005年   188篇
  2004年   156篇
  2003年   137篇
  2002年   109篇
  2001年   116篇
  2000年   80篇
  1999年   77篇
  1998年   69篇
  1997年   68篇
  1996年   54篇
  1995年   35篇
  1994年   43篇
  1993年   34篇
  1992年   35篇
  1991年   26篇
  1990年   26篇
  1989年   22篇
  1988年   14篇
  1987年   26篇
  1986年   23篇
  1985年   32篇
  1984年   27篇
  1983年   10篇
  1982年   17篇
  1981年   15篇
  1980年   17篇
  1979年   11篇
  1978年   7篇
  1977年   8篇
  1974年   6篇
  1973年   6篇
排序方式: 共有5743条查询结果,搜索用时 15 毫秒
1.
Retinal fundus photographs are employed as standard diagnostic tools in ophthalmology. Serial photographs of the flow of fluorescein and indocyanine green (ICG) dye are used to determine the areas of the retinal lesions. For objective measurements of features, the registration of the images is a necessity. In this paper, we employ optimization techniques for registration with the help of 2-parameter translational motion model of retinal angiograms, based on non-linear pre-processing (Wiener filtering and morphological gradient) and computation of the similarity criteria for the alignment of the two gradient images for any given rigid transformation. The optimization methods are effectively employed to minimize the similarity criterion.

The presence of noise, the variations in the background and the temporal variation of the fluorescence level pose serious problems in obtaining a robust registration of the retinal images. Moreover, local search strategies are not robust in the case of ICG angiograms, even if one uses a multiresolution approach.

The present work makes a systematic comparison of different optimization techniques, namely the minimization method derived from the optical flow formulation, the Nelder-Mead local search and the HCIAC ant colony metaheuristic, each optimizing a similarity criterion for the gradient images. The impact of the resolution and median filtering of gradient image is studied and the robustness of the approaches is tested through experimental studies, performed on macular fluorescein and ICG angiographies.

Our proposed optimization techniques have shown interesting results especially for high resolution difficult registration problems. Moreover, this approach seems promising for affine (6-parameter motion model) or elastical registrations.  相似文献   

2.
To compare pulmonary effects, postoperative pain and fatigue, morbidity, patient satisfaction, and cost of different anesthetic techniques for inguinal hernia repair, 50 patients were randomized to local and general anesthesia groups (LA and GA). All patients received the same premedications and the same postoperative analgesic regimen. The standardized postoperative analgesic, intramuscular pyroxicam 20 mg, was given to all patients in the recovery room and an additional 20 mg on the same day was given as requested by each patient. Pulmonary function studies and arterial blood gas analysis were performed 1 h prior to the operation and at the postoperative 8th and 24th hours. All patients underwent Lichtenstein's tension-free hernioplasty. Postoperative pain and fatigue were registered 8 h and 24 h after the operation. A questionnaire was filled out by the patients, and they were asked to give grades for the general comfort of the anesthesia and the surgical procedure (1=worst, 10=best). Postoperative pulmonary function tests were significantly poorer in the GA group both on 8th- and 24th-hour measurements (P<0.05). Patients who underwent LA had significantly lower PCO2 and higher PO2 at the postoperative 8th hour (P<0.05). Mean postoperative pain and fatigue scores revealed a significant difference in favor of local anesthesia at only the 8th hour (P<0.05). There were two complications, one in each group (a hematoma in LA and a urinary retention in GA). Patient satisfaction grades were not different in the two groups. We conclude that LA in inguinal hernia repair does not adversely affect pulmonary functions, patients feel less pain, and patient satisfaction is comparable to that with GA. Electronic Publication  相似文献   
3.
4.
Most of the papers published on spigelian hernia are either case reports or small retrospective series. In this prospective multicenter study, we aimed to outline the specific features of spigelian hernias and patients’ characteristics more clearly. Surgeons enrolled patients to be entered into the database as they diagnosed and treated the hernias at will. The baseline and surgical outcome parameters were noted in each patient. A painful mass was the main presenting complaint in half of 34 patients. Accurate preoperative diagnosis was possible in 31 patients. Open intraperitoneal mesh repair was the preferred technique. The mean hospital stay and time until return to normal daily activities were 4.1 and 15.6 days. Although a rare condition, diagnosis of a spigelian hernia is not difficult once remembered. Its surgical repair seems to cause few complications and is very well tolerated by the patient.  相似文献   
5.
In this study we consider the process of the clinical encounter, and present exemplars of how assumptions of both clinicians and their patients can shift or transform in the course of a diagnostic interview. We examine the process as it is recalled, and further elaborated, in post-diagnostic interviews as part of a collaborative inquiry during reflections with clinicians and patients in the northeastern United States. Rather than treating assumptions by patients and providers as a fixed attribute of an individual, we treat them as occurring between people within a particular social context, the diagnostic interview. We explore the diagnostic interview as a landscape in which assumptions occur (and can shift), navigate the features of this landscape, and suggest that our examination can best be achieved by the systematic comparison of views of the multiple actors in an experience-near manner. We describe what might be gained by this shift in assumptions and how it can make visible what is at stake for clinician and patient in their local moral worlds—for patients, acknowledgment of social suffering, for clinicians how assumptions are a barrier to engagement with minority patients. It is crucial for clinicians to develop this capacity for reflection when navigating the interactions with patients from different cultures, to recognize and transform assumptions, to notice ‘surprises’, and to elicit what really matters to patients in their care.  相似文献   
6.
Summary Thermoregulatory sweating [total body (m sw,b), chest (m sw,c) and thigh (m sw,t) sweating], body temperatures [oesophageal (T oes) and mean skin temperature (T sk)] and heart rate were investigated in five sleep-deprived subjects (kept awake for 27 h) while exercising on a cycle (45 min at approximately 50% maximal oxygen consumption) in moderate heat (T air andT wall at 35° C. Them sw,c andm sw,t were measured under local thermal clamp (T sk,1), set at 35.5° C. After sleep deprivation, neither the levels of body temperatures (T oes,T sk) nor the levels ofm sw, b,m sw, c orm sw, t differed from control at rest or during exercise steady state. During the transient phase of exercise (whenT sk andT sk,1 were unvarying), them sw, c andm sw, t changes were positively correlated with those ofT oes. The slopes of them sw, c versusT oes, orm sw, t versusT oes relationships remained unchanged between control and sleep-loss experiments. Thus the slopes of the local sweating versusT oes, relationships (m sw, c andm sw, t sweating data pooled which reached 1.05 (SEM 0.14) mg·cm–2·min–1°C–1 and 1.14 (SEM 0.18) mg·cm–2·min–1·°C–1 before and after sleep deprivation) respectively did not differ. However, in our experiment, sleep deprivation significantly increased theT oes threshold for the onset of bothm sw, c andm sw, t (+0.3° C,P<0.001). From our investigations it would seem that the delayed core temperature for sweating onset in sleep-deprived humans, while exercising moderately in the heat, is likely to have been due to alterations occurring at the central level.  相似文献   
7.
A retrospective analysis of treatment for endometrial carcinoma is reported here. From 1987 to 1989, 138 patients were referred to the oncology department following total abdominal hysterectomy and bilateral salpingo-oophorectomy for endometrial cancer. Forty-seven patients were not prescribed postoperative radiotherapy; 31 had Stage I well differentiated adenocarcinoma with minimal myometrial invasion, while the remaining 16 patients were considered unfit for postoperative radiotherapy. There were no instances of local relapse amongst the 31 patients with minimal myometrial invasion.The remaining 91 patients all received external beam irradiation to the pelvis and, according to the preference of the individual therapist, 51 were prescribed additional intracavitary vault caesium-137. Patients receiving postoperative radiotherapy were analysed according to whether or not they received additional intracavitary vault caesium. The two groups were also analysed for incidence of vaginal vault recurrence and treatment related morbidity.In the group receiving additional intracavitary treatment more patients had Stage II or III disease (P<0.05), and had greater depth of myometrial invasion (P<0.05). Vaginal vault recurrence was not observed in patients receiving intracavitary therapy in addition to external beam therapy. Four patients (10%) receiving external beam therapy alone developed vaginal vault recurrence.The incidence of Kottmeier-Perez grade 2 or 3 bowel toxicity following treatment was significantly higher in those patients receiving combined treatment (18% vs. 2.5%; P<0.03). There was also a higher incidence of vaginal stenosis in the group receiving both external beam and intracavitary therapy (21% vs. 3%; P<0.05). There was only one instance of grade 2 bladder toxicity in the external beam and intracavitary treatment group and none in the external beam therapy alone group.In conclusion, postoperative radiotherapy for Stages I-III endometrial carcinoma was carried out in a non-randomized manner by two regimens; either external beam therapy alone or external beam therapy with additional intracavitary vaginal caesium. The combined therapy gave significantly better local control but resulted in significantly more late bowel and vaginal morbidity.  相似文献   
8.
It has earlier been proposed by the author that the aetiology of schizophrenic symptomatology may be due to the presence of abnormally connected interhemispheric fibres which link specialised functions in the brains of schizophrenics that are not connected in normal subjects, and that the neuroleptic drugs may produce their action through a local anaesthetic-like effect in suppression of conduction in these fibres. This line of thought has been extended here to consider the possible mechanism of action of the neuroleptic drugs in more detail, as well as that of the tricyclic antidepressant drugs which are derivatives of the phenothiazine group. Pharmacological similarities with the local anaesthetics both structurally and functionally have been considered, as well as the effects that these drug groups may have in common with the lithium salts. It has been suggested that these drugs all produce their primary effect on cell membranes, though not necessarily at the synapse, that the time course of their clinical effect may correlate with their incorporation into various cell membranes within the CNS, and that they may thus bring about a fundamental alteration in cell membrane microstructure. The possible role of electroconvulsive therapy has also been considered. The corollary of this argument is that the affective disorders may be genetically determined diseases of cell membrane microstructure.  相似文献   
9.
局部浸润麻醉在隆乳术中的应用   总被引:1,自引:0,他引:1  
目的 探讨局部浸润麻醉方法在隆乳术中的应用效果。方法 将2%利多卡因20ml加0.5%布匹卡因5ml配制成120ml局部麻醉液,采用局部浸润麻醉方法为568例受术者行隆乳手术,根据胸部神经、肌肉的解剖特点,行合理的分布药量和准确有效的注射。结果 568例隆乳术者,局部浸润麻醉方法均有效,且麻醉效果良好。无一例受术者因分离腔穴时产生疼痛而影响手术操作或停止手术。结论 局部麻醉效果理想可靠,方法简单易行,适用于任何术式的隆乳术。而在分离腔穴时产生的疼痛主要是因注射层次不当和药量分布不均所致。与麻醉方法无关;其麻醉效果与假体置入层次或乳腺胸大肌是否发达无因果关系。  相似文献   
10.
Background: There is a growing interest in the use of local anaesthesia for inguinal hernia repair. It certainly seems to be an acceptable alternative for the elderly. Supporting intravenous sedation, however, still requires monitoring, anaesthetic personnel and some preparations for the patient. Therefore we set up a feasibility study of hernia repair under local anaesthesia without intravenous sedation or monitoring in elderly patients. Method: A total of 62 patients (aged 65 years or more) with unilateral inguinal hernia received a Mesh Plug Repair. Prospectively collected data included procedure-related complications and information on pain and quality of life as measured by Short Form 36. Results: No procedure-related complications were noted. Comparing the preoperative scores, the SF-36 on day 14 (n=61) did not differ significantly. After a median follow-up of ten months (n=54), significantly higher scores were found for scales of physical and emotional role and pain (all p<0.05). Twenty-two patients reported some form of pain (40.7%). 94.4% of the patients would recommend the procedure when asked. Conclusion: The results of this study indicated that Mesh Plug Repair performed under unmonitored local anaesthesia with no intravenous sedation is a feasible alternative for elderly patients. It has advantages for the medical organization without disadvantages for the patient.  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