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   5135篇
  免费   253篇
  国内免费   38篇
耳鼻咽喉   102篇
儿科学   174篇
妇产科学   140篇
基础医学   494篇
口腔科学   127篇
临床医学   428篇
内科学   1108篇
皮肤病学   123篇
神经病学   245篇
特种医学   331篇
外科学   879篇
综合类   143篇
一般理论   4篇
预防医学   338篇
眼科学   193篇
药学   325篇
中国医学   17篇
肿瘤学   255篇
  2023年   37篇
  2022年   81篇
  2021年   178篇
  2020年   84篇
  2019年   120篇
  2018年   138篇
  2017年   106篇
  2016年   143篇
  2015年   171篇
  2014年   200篇
  2013年   277篇
  2012年   334篇
  2011年   368篇
  2010年   204篇
  2009年   179篇
  2008年   308篇
  2007年   324篇
  2006年   312篇
  2005年   320篇
  2004年   254篇
  2003年   246篇
  2002年   197篇
  2001年   74篇
  2000年   77篇
  1999年   73篇
  1998年   40篇
  1997年   35篇
  1996年   29篇
  1995年   18篇
  1994年   18篇
  1993年   22篇
  1992年   30篇
  1991年   24篇
  1990年   27篇
  1989年   20篇
  1988年   27篇
  1987年   24篇
  1986年   33篇
  1985年   19篇
  1984年   19篇
  1983年   18篇
  1980年   10篇
  1979年   14篇
  1978年   18篇
  1977年   11篇
  1975年   14篇
  1974年   20篇
  1973年   20篇
  1972年   16篇
  1971年   12篇
排序方式: 共有5426条查询结果,搜索用时 0 毫秒
81.
82.
83.
The bipolar radiofrequency device (Habib®) has been recently introduced in order to reduce intraoperative bleeding for a safe hepatic resection as an alternative to the conventional tools. However, indications, perioperative findings, and outcome of the device for hepatic resections remain and deserve to be analyzed. The current study aims to analyze the feasibility of the bipolar radiofrequency device (Habib®) for hepatic resections. Information of the patients that underwent hepatic resection using with the Habib® device between 2007 and 2011 was abstracted. Patient, disease, and operation-related findings and perioperative data were investigated. A total of 71 cases (38 [53.5 %] males, mean age was 56.8 ± 11.9) were analyzed. Metastatic disease (n = 55; 77.5 %) was the leading indication followed by primary liver and biliary malignancies (n = 7; 9.9 %), hemangioma (n = 5; 7 %), hydatid disease (n = 3; 2.8 %), and hepatic gunshot trauma (n = 1; 1.4 %). Metastasectomy was the most commonly performed procedure (n = 31; 56.3 %), but in 24 (77.4 %) cases, it was performed in addition to extended resections. Other procedures in the study patients include segmentectomy in 17, bisegmentectomy in 19, trisegmentectomy in 17, right or left hepatectomy in 8, and extended right/left hepatectomy in 3. The mean (±SD) operation time was 241.7 ± 78.2 min. The median amount of bleeding was 300 cc (range 25–2500), and 23 (32.4 %) cases required perioperative transfusion. The median hospitalization period was 5 days (range 1–47). Lengthened drainage (n = 9, 12.7 %) and intraabdominal abscess (n = 8, 11.23 %) were the most common problems. Hepatic resections using the Habib® device seem to be feasible in cases with primary and metastatic hepatic lesions and benign liver masses and even those with hepatic trauma. It may lessen the amount of intraoperative hemorrhage, although lengthened drainage and intraabdominal abscess were the major postoperative problems in these cases.  相似文献   
84.
Pulmonary resections comprise most of the operations performed in thoracic surgery departments. Diseases like pulmonary cancers, bronchiectasis, pulmonary abscess, tuberculosis and fungal infections are treated surgically by pulmonary resections. One of the important steps of the pulmonary resection is to suture the bronchi through which the air is supplied to the resected pulmonary tissue. Bronchopleural fistula developed in the bronchial stump is encompassed as one of the most important factors affecting mortality and morbidity regarding postoperative complications.  相似文献   
85.
86.
Visceral basidiobolomycosis is an unusual fungal infection of viscera caused by saprophyte Basidiobolus ranarum. It is very rare in healthy children and poses a diagnostic challenge due to the non-specific clinical presentation and the absence of predisposing factors. We report a case of gastrointestinal basidiobolomycosis in a 4-year-old healthy girl who presented with a short history of abdominal pain, bleeding per rectum, fever, and weight loss. The diagnosis was based on high eosinophilic count, classical histopathology findings of fungal hyphae (the Splendore-Hoeppli phenomenon), and positive fungal culture from a tissue biopsy. Fungal infection was successfully eradicated with a combined approach of surgical resection of the infected tissue and a well-monitored course of antifungal therapy. The atypical clinical presentation, diagnostic techniques, and the role of surgery in the management of a rare and lethal fungal disease in an immunocompetent child are discussed.Key words: Basidiobolomycosis, child, fungal infection, gastrointestinal, immunocompetent  相似文献   
87.
88.

Objectives:

To compare the insertion time, ease of device insertion, ease of gastric tube insertion, airway leakage pressure, and complications between the laryngeal mask airway (LMA) ProSeal (P-LMA) and I-gel (I-gel) groups.

Methods:

Eighty patients with age range 18-65 years who underwent elective surgery were included in the study. The study took place in the operation rooms of Haydarpaşa Numune Hospital, Istanbul, Turkey from November 2013 to April 2014. Patients were equally randomized into 2 groups; the I-gel group, and the P-LMA group. In both groups, the same specialist inserted the supraglottic airway devices. The insertion time of the devices, difficulty during insertion, difficulty during gastric tube insertion, coverage of airway pressure, and complications were recorded.

Results:

The mean insertion time in the I-gel group was significantly lower than that of the P-LMA group (I-gel: 8±3; P-LMA: 13±5 s). The insertion success rate was higher in the I-gel group (100%, first attempt) than in the P-LMA group (82.5%, first attempt). The gastric tube placement success rate was higher in the I-gel group (92.5%, first attempt) than in the P-LMA group (72.5%, first attempt). The airway leakage pressures were similar.

Conclusion:

Insertion was easier, insertion time was lower, and nasogastric tube insertion success was higher with the I-gel application, and is, therefore, the preferred LMA.Laryngeal mask airways (LMA) represent a good alternative to endotracheal intubation in suitable cases. The LMAs are used to provide ventilation, or to ease the insertion of an endotracheal tube (TT) in difficult airways, but they are also becoming more frequently used to reduce TT associated complications.1 In particular, the recently developed models of LMAs, which include a gastric tube, have become more commonly preferred in anesthesia applications.2 The I-gel (I-gel) (Intersurgical Ltd, Workingham, UK) has a latex-free, non-inflatable, gel-like, thermoplastic elastomeric cuff that provides easy coverage by properly fitting the anatomy of the supraglottic region and also involves a gastric tube; therefore, it has become more frequently used in patients under general anesthesia and receiving positive pressure ventilation.3 It has been reported that the single-use, inflatable cuff-free I-gel can be inserted more easily and has a reduced morbidity rate.4,5 It is recommended in emergency cases requiring intubation, and particularly in airway management of cases experiencing cardiopulmonary arrest.6 Another supraglottic airway device that enables gastric aspiration is the LMA ProSeal (Laryngeal Mask Company Ltd, Berkshire, UK). Since it is a semi-rigid device with an inflatable cuff, it has been reported to cause mucosa and nerve damage in the supraglottic region, sore throat, and hoarseness due to the cuff pressure.7The present study aimed to compare the I-gel and the LMA ProSeal (P-LMA) with respect to the duration of insertion, ease of insertion, airway pressure leakage, gastric tube insertion success ratio, and complications.  相似文献   
89.
In two previous studies, we observed that recombinant human interleukin- 3 (IL-3) induced an increase in marrow burst-forming unit-erythroid- derived colonies in vitro in some patients with Diamond-Blackfan anemia (DBA). To determine whether a similar erythropoietic response could be induced in vivo, we treated 13 patients with DBA (aged 4 to 19 years) with two preparations of IL-3. All patients had absent absolute reticulocyte counts and markedly reduced to absent recognizable bone marrow erythroid elements; patients with circulating reticulocytes in the previous 12 months were excluded from study. All patients except 1 had failed steroid therapy and had been transfusion-dependent since infancy; 1 patient was maintained on high-dose prednisone at the time of enrollment. On the first arm of the study, IL-3 (Immunex Corp, Seattle, WA) was administered subcutaneously using a dose escalation regimen of 125 to 500 micrograms/m2/day in divided dosage at 12-hour intervals, coadministered with 1.5 mg/kg/d of oral ferrous sulphate. Of the 13 patients that entered the trial, 4 stopped prematurely because of adverse side effects. In the other 9 evaluable cases, reticulocytes increased transiently in 1 patient from 0 to 65 x 10(9)/L after 35 days of IL-3 therapy at 250 micrograms/m2, but transfusion dependency persisted. One transient peak in absolute reticulocyte count was noted in 6 other patients, but no erythroid response was observed after completion of a full course of IL-3. Oral prednisone at 0.5 mg/kg/d was then coadministered with IL-3 at 500 micrograms/m2 to 5 of the patients without effect, and treatment was stopped. In 2 patients, a second preparation of IL-3 (Sandoz Canada Inc, Dorval, Quebec, Canada) was initiated in a dose escalation regimen of 2.5 to 10 micrograms/kg and was coadministered with ferrous sulphate. No erythroid response was observed in either patient, and in one of the two, alternate-day subcutaneous recombinant erythropoietin at 300 U/kg was administered for 3 weeks in combination with daily IL-3 at 10 micrograms/kg, but no increased erythropoiesis was seen. Significant increases in white blood cell and eosinophil counts during administration of both preparations of IL-3 were observed in all patients. These data show that the response of DBA patients to IL-3 in vivo is heterogeneous and cannot be predicted from in vitro studies. The absence of a corrective effect of IL-3 in these patients with DBA indicates that a deficiency of the cytokine is not central in the pathogenesis of the disorder.  相似文献   
90.
Biological nitrogen fixation in aerobic organisms requires a mechanism for excluding oxygen from the site of nitrogenase activity. Oxygen exclusion in Frankia spp., members of an actinomycetal genus that forms nitrogen-fixing root-nodule symbioses in a wide range of woody Angiosperms, is accomplished within specialized structures termed vesicles, where nitrogen fixation is localized. The lipidic vesicle envelope is apparently a functional analogue of the cyanobacterial heterocyst envelope, forming an external gas-diffusion barrier around the nitrogen-fixing cells. We report here that purified vesicle envelopes consist primarily of two hopanoid lipids, rather than of glycolipids, as is the case in cyanobacteria. One envelope hopanoid, bacteriohopanetetrol phenylacetate monoester, is vesicle-specific. The Frankia vesicle envelope thus represents a layer specific to the locus of nitrogen fixation that is biosynthetically uniquely derived.  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