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   8047篇
  免费   439篇
  国内免费   57篇
耳鼻咽喉   89篇
儿科学   180篇
妇产科学   210篇
基础医学   1114篇
口腔科学   164篇
临床医学   714篇
内科学   2027篇
皮肤病学   98篇
神经病学   767篇
特种医学   209篇
外科学   1385篇
综合类   43篇
一般理论   2篇
预防医学   263篇
眼科学   112篇
药学   467篇
  1篇
中国医学   13篇
肿瘤学   685篇
  2024年   8篇
  2023年   75篇
  2022年   131篇
  2021年   256篇
  2020年   150篇
  2019年   204篇
  2018年   199篇
  2017年   128篇
  2016年   198篇
  2015年   250篇
  2014年   358篇
  2013年   377篇
  2012年   586篇
  2011年   622篇
  2010年   365篇
  2009年   299篇
  2008年   555篇
  2007年   617篇
  2006年   521篇
  2005年   496篇
  2004年   474篇
  2003年   423篇
  2002年   355篇
  2001年   55篇
  2000年   37篇
  1999年   68篇
  1998年   81篇
  1997年   65篇
  1996年   61篇
  1995年   62篇
  1994年   59篇
  1993年   46篇
  1992年   40篇
  1991年   35篇
  1990年   23篇
  1989年   24篇
  1988年   11篇
  1987年   18篇
  1986年   23篇
  1985年   23篇
  1984年   22篇
  1983年   18篇
  1982年   16篇
  1981年   12篇
  1980年   12篇
  1976年   5篇
  1975年   9篇
  1974年   5篇
  1966年   5篇
  1908年   5篇
排序方式: 共有8543条查询结果,搜索用时 0 毫秒
71.
OBJECTIVE: This prospective study quantified cytokine and chemokine levels in seminal plasma of patients with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) and benign prostatic hyperplasia (BPH), to evaluate inflammatory mediators as possible surrogate markers for diagnosis and treatment efficacy. METHODS: Seminal plasma levels of eight cytokines and nine chemokines were evaluated by multiplex arrays in 83 men: 20 healthy controls and 9 men with CP/CPPS IIIA, 31 with CP/CPPS IIIB, and 23 with BPH. Prostate samples obtained by transurethral resection of the prostate from 13 patients with BPH were analysed by immunohistochemistry to detect interleukin 8 (IL-8)-producing cells and characterise inflammatory infiltrates. RESULTS: Significantly increased levels of cytokines (IL-1alpha, IL-1beta, IL-6, IL-10, IL12p70) and chemokines (CCL1, CCL3, CCL4, CCL17, CCL22, CXCL8/IL-8) were observed in seminal plasmas from patients with CP/CPPS or BPH. However, only IL-8 was significantly elevated compared to controls (median [quartiles] 1984 [1164-2444] pg/ml), in patients with CP/CPPS IIIA (15,240 [10,630-19,501] pg/ml; p<0.0001), CP/CPPS IIIB (2983 [2033-5287] pg/ml; p=0.008), and BPH (5044 [3063-11,795] pg/ml, p<0.0001), discriminating CP/CPPS IIIA versus IIIB (accuracy=0.882+/-0.078; p=0.001). Inflammatory infiltrates were detected in prostate samples from 13 of 13 BPH patients, and IL-8-producing prostate cells in 11 of 13 samples. IL-8 concentration in seminal plasma was positively correlated with symptom score and prostate-specific antigen levels both in CP/CPPS and BPH patients. CONCLUSIONS: IL-8 is expressed in situ by epithelial and stromal prostate cells and is functional, as shown by recruitment of cells expressing cognate receptors in BPH prostate tissue, indicating its involvement in disease pathogenesis. Among all the cytokines and chemokines analysed, IL-8 appears to be the most reliable and predictive surrogate marker to diagnose prostate inflammatory conditions, such as CP/CPPS and BPH.  相似文献   
72.
The levels of the soluble (s) CD40:sCD40 ligand (L) dyad, which belongs to the tumor necrosis factor (TNF)-alpha:TNF-alpha-receptor superfamily, are significantly increased in the cerebrospinal fluid (CSF), but not the serum of cobalamin (Cbl)-deficient (Cbl-D) rats. They were normalized or significantly reduced after treatment with Cbl, transforming growth factor-beta1 or S-adenosyl-L-methionine, and the normal myelin ultrastructure of the spinal cord was concomitantly restored. The concomitance of the two beneficial effects of these treatments strongly suggests that the increases in CSF sCD40:sCD40L levels may participate in the pathogenesis of purely myelinolytic Cbl-D central neuropathy in the rat. In keeping with this, an anti-CD40 treatment prevented myelin lesions.  相似文献   
73.

Background  

Band erosion is reported with a highly variable incidence (0.3–14%) after laparoscopic adjustable gastric banding. Removal of the band is mandatory because the patient regains weight and may become symptomatic, but no consensus exists about the best method, surgical or endoscopic, for this purpose. This study aimed to evaluate the feasibility and effectiveness of endoscopic management of band erosion.  相似文献   
74.
The intra-aortic balloon pump (IABP) is used worldwide as an anti-ischemic strategy. However, little is known about the modifications of the graft blood flow during IABP. A retrospective study aimed at analyzing transit-time flow measurements during 1:1 IABP and during its cessation in 401 consecutive patients receiving IABP before coronary artery bypass grafting (n = 880 graft segments) was reported. All normally functioning grafts were considered. Mean diastolic and mean blood flow improved significantly during 1:1 IABP compared with during IABP cessation (P < 0.001), although mean and end-diastolic arterial pressures were significantly lower (P = 0.001). Arterial and sequential saphenous vein (SV) grafts showed greater improvements in mean diastolic and mean flow compared with single venous grafts. Higher flows were also observed in the grafts directed to the circumflex territory. Surplus graft flow (SGF, defined as mean flow during 1:1 IABP/mean flow with IABP off) was recruited (SGF >1) during 1:1 IABP, with higher values in single arterial or sequential SV grafts versus single venous grafts (both P < 0.001). Y-conduit radial artery (RA) grafts showed higher maximum diastolic flow, mean flow, and SGF compared to aortocoronary RA or SV grafts. In this retrospective analysis, IABP was associated with improved diastolic and mean blood flow in bypass grafts. Arterial, sequential, and Y-conduit grafts were associated with greater improvements in blood flow and SGF than aortocoronary SV grafts.  相似文献   
75.
Negative pressure wound therapy (NPWT) is becoming routine for the preparation of wounds prior to grafting for wound closure. We have been using both foam- and gauze-based NPWT to prepare wounds for closure prior to skin grafting and have obtained similar proportions of closed wounds; 7/7 for wounds treated with gauze-based NPWT and 11/11 for wounds treated with foam-based NPWT. In our follow-up consultations we observed that skin grafts on the foam-treated patients were less pliable than those on the gauze-treated patients. To assess what the mechanism of this effect might be, we compared the specific details of the treatments of both 11 foam and 7 gauze patients, including depth, location, patients' age and co-morbidity; biopsies of granulation and scar tissue were taken and stained with haematoxylin-eosin and by Masson's trichrome staining and conducted ultrasound analysis of the closed wounds, to see if there were features which explained those effects. All foam patients were treated at -125 mm Hg for an average of 25·9 days before skin grafts were applied. All gauze patients were treated at -80 mm Hg for an average of 24·7 days before skin grafts were applied. Biopsies of granulation tissue prior to skin grafting from five foam and four gauze-based NPWT patients did not reveal any obvious histological differences between the treatments. Ultrasound analysis of the skin-grafted wounds showed an average depth of scar tissue of 18 mm in the wound beds of the foam-treated wounds and 7 mm in the gauze-treated ones. Biopsies taken on the scar tissue after treatment with the gauze showed a minor tissue thickness and disorganisation and less sclerotic components. The findings of this preliminary analysis suggest that foam-based NPWT may induce a thicker layer of scar tissue beneath skin grafts than gauze-based NPWT which might explain a reduced pliability of the reconstructed bed. At present it is unclear which mechanism might be responsible for the difference in pressure (-125 versus -80 mm Hg), either the length of the time taken to reconstruct the wound bed or the intrinsic nature of the foam or gauze on the tissue surface. Prospective studies are necessary to investigate whether these preliminary observations are confirmed and to investigate what the mechanism might be.  相似文献   
76.
Pancreatic fistula: definition and current problems   总被引:1,自引:0,他引:1  
Postoperative pancreatic fistula (POPF) is the most common major complication after pancreatoduodenectomy (PD) and it can lead to prolonged hospital stay, increased costs, and mortality. The POPF rate is strictly correlated to the definition applied, but there are so many different definitions in the literature that comparison between published series of patients is difficult. The International Study Group of Pancreatic Fistula (IGSPF) has developed a new definition, with a grading system able to stratify complicated patients into three groups, based upon the clinical implications and costs of their postoperative course.The most important risk factors identified are a soft pancreatic texture and a main pancreatic duct diameter of 3 mm or less. Several surgical techniques have been studied in order to prevent anastomotic leakage, but none has been demonstrated to be superior to others. The use of somatostatin analogues is still matter of controversy. Conservative management of POPF is usually effective, but in patients with deteriorating clinical status with evidence of sepsis, surgical management is needed.  相似文献   
77.
Bile leak after hepatectomy: predictive factors of spontaneous healing   总被引:1,自引:0,他引:1  
BACKGROUND: Bile leakage after hepatectomy usually has spontaneous healing, but some patients require interventional procedures. To identify early predictive factors of conservative management failure. METHODS: This study focused on patients with bile leak after hepatectomy without extrahepatic biliary resection from 1996 through 2006. RESULTS: Bile leakage occurred in 34 of 593 patients (5.7%). Conservative management was successful in 26 patients (76.5%). At univariate analysis overall associated resections, vascular associated resections, and drainage output on days 1, 3, and 10 from leak onset were significant negative predictors of spontaneous healing. At multivariate analysis drainage output greater than 100 mL on day 10 was the only independent prognostic factor of conservative management failure (relative risk, 55.985; P = .008) with 80% sensitivity, 93.3% specificity, and 90% accuracy. CONCLUSIONS: Wait-and-see treatment is successful in most cases. Patients with drainage output greater than 100 mL 10 days after bile leakage diagnosis should be scheduled for interventional treatments.  相似文献   
78.
A 40-year-old woman in the twenty-fifth week of pregnancy presented with a gross retroperitoneal mass. At the end of the pregnancy, the patient was submitted to surgery, and the gross infiltration of the inferior vena cava wall required the resection of the vena cava with its prosthetic substitution. The histopathological examination demonstrated the presence of a leiomyosarcoma of the inferior vena cava. An electronic video supplement showing the most important intraoperative passages is available online at doi:10.1016/j.eururo.2008.06.074.  相似文献   
79.
Tracheal bronchus is a congenital abnormality rarely described in the literature. It is mostly completely asymptomatic. This condition may rarely be associated with inflammatory diseases. Exceptional are those cases in which the condition is associated with malignancy. We describe a case of a 45-year-old man in whom a 3-month history of non-productive cough and chest pain led to a diagnosis of a solitary pulmonary nodule associated with a tracheal bronchus. The histopathological examination after VATS enucleation showed the presence of a hamartochondroma. To the best of our knowledge this is the first case in which a hamartochondroma has been found to be associated with a tracheal bronchus.  相似文献   
80.
Introduction Laparoscopic repair of inguinal hernias is usually achieved by totally extraperitoneal (TEP) or transabdominal preperitoneal (TAPP) techniques. The intraperitoneal onlay mesh (IPOM) could be an interesting alternative as it is much easier to perform and faster to execute. This technique is subject to correct selection of indications and to demonstration of its safety. Materials and methods From January 2003 to January 2006 we performed 61 laparoscopic hernia procedures on 60 selected patients (60 males with a mean age of 60 and mean weight of 76 kg) with an IPOM technique combining the Parietex composite mesh (12 cm circular model) and a fibrin glue (Tissucol) for its fixation. The glue was diluted to increase fixation time and applied to the mesh prior to positioning on the hernia defect. Results Mean operative time was 10 minutes. Mean hernia diameter was 2.5 cm (± 0.8 cm). 10 hernias were direct, 51 were indirect and 10 out of 61 were recurrent. We did not convert any of the laparoscopic procedures. Mean hospital stay was one day; mean recovery time for working and general physical activities was five days. Patients were checked after one week, 1-3-6 months and 1-2 years. Average follow up time was 23.7 months. 1.6 % of patients showed short-term complications: one trocar site haematoma. No additional complications were reported; particularly, we had no recurrence, no seroma, no mesh migration, and no bowel obstruction or fistula. Conclusion Results of this study show intraperitoneal (IP) tolerance to this kind of mesh and the safety of its fixation with Tissucol. The absence of recurrence and complications could be a good reason to extend the indication of IPOM hernia repair. However, these preliminary results should be confirmed by longer follow-up.  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