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   15472篇
  免费   828篇
  国内免费   111篇
耳鼻咽喉   143篇
儿科学   401篇
妇产科学   231篇
基础医学   1937篇
口腔科学   524篇
临床医学   982篇
内科学   3855篇
皮肤病学   346篇
神经病学   1196篇
特种医学   719篇
外科学   2754篇
综合类   64篇
一般理论   1篇
预防医学   336篇
眼科学   178篇
药学   1009篇
中国医学   48篇
肿瘤学   1687篇
  2023年   79篇
  2022年   153篇
  2021年   316篇
  2020年   189篇
  2019年   262篇
  2018年   325篇
  2017年   249篇
  2016年   323篇
  2015年   308篇
  2014年   403篇
  2013年   448篇
  2012年   688篇
  2011年   784篇
  2010年   464篇
  2009年   392篇
  2008年   689篇
  2007年   788篇
  2006年   788篇
  2005年   795篇
  2004年   804篇
  2003年   842篇
  2002年   868篇
  2001年   481篇
  2000年   483篇
  1999年   407篇
  1998年   231篇
  1997年   169篇
  1996年   158篇
  1995年   145篇
  1994年   121篇
  1993年   109篇
  1992年   363篇
  1991年   305篇
  1990年   270篇
  1989年   300篇
  1988年   238篇
  1987年   212篇
  1986年   184篇
  1985年   206篇
  1984年   164篇
  1983年   107篇
  1979年   73篇
  1978年   48篇
  1977年   59篇
  1974年   50篇
  1973年   53篇
  1971年   45篇
  1970年   43篇
  1969年   50篇
  1968年   49篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
BACKGROUND: In patients on long-term continuous ambulatory peritoneal dialysis (CAPD), peritoneal dysfunction may occur due to loss of peritoneal mesothelial cells, peritoneal fibrosis and neovascularization. Lactate, long used as a buffer in peritoneal dialysates, has been substituted by bicarbonate in recent years. However, their effects on the peritoneum of CAPD patients are unknown. This study investigated the influence of lactate and bicarbonate on peritoneal dysfunction in CAPD patients. METHODS: The mitochondrial activity of human peritoneal mesothelial cells (HPMCs) and their expression of basic fibroblast growth factor (bFGF) were studied after culture under various conditions. We also assessed the mitochondrial-activating effect of the supernatant of those cultures on human peritoneal fibroblasts (HPFBs) and human umbilical vein endothelial cells (HUVECs) and the effect of recombinant human bFGF on the mitochondrial activity of HPFBs and HUVECs. We used the WST-1 assay to determine mitochondrial activity in HPMC. RESULTS: At pH 7.4, the mitochondrial activity of HPMCs was lowest in a medium containing 40 mM (Lac), intermediate in a lactate (15 mM) plus bicarbonate (25 mM) medium (Lac/Bic), and highest in a 40 mM bicarbonate medium (Bic). In culture supernatant, the increase of bFGF was: Lac > Lac/Bic > Bic. Mitochondrial activation of HPFBs and HUVECs was stimulated by HPMC culture supernatants in the following decreasing order: Lac > Lac/Bic > Bic. The effects of these supernatants were suppressed by a bFGF-neutralizing antibody, while recombinant bFGF caused concentration-dependent mitochondrial activation in HPFBs and HUVECs. CONCLUSIONS: The role of bFGF in peritoneal fibrosis and neovascularization may be important. A bicarbonate-containing medium is better than a lactate-containing medium for preserving cell viability in HPMCs and preventing bFGF expression by these cells.  相似文献   
62.
We operated on a patient who had been paraplegic since sustaining a spinal cord injury 11 years ago. We made a reversed L-shaped sternum incision and cannulated all tubes for the cardiopulmonary bypass through a wound window. This provided an excellent surgical view without restricting the patient's upper limbs (needed for wheel chair operation), and recovery was good. Just after surgery, however, it was difficult to control blood pressure and the loss of serum albumin. We believe this is the first report of open-heart surgery undertaken in a paraplegic patient and that the reversed L-shaped incision and careful monitoring of hemodynamics each played an important role in the successful outcome. We hope that this report will help in the treatment of other paraplegic patients who need open-heart surgery.  相似文献   
63.
This paper presents a case of intercostal hemangioma, in which a complete surgical resection was accomplished based upon a tentative diagnosis provided by magnetic resonance imaging (MRI). A 27-year-old man visited our hospital for the evaluation of chest pain and shortness of breath after exertion. Computed tomography showed a soft tissue mass, 5.5×3.5 cm in size, arising from the right lateral 7th intercostal space. Dynamic MRI showed that the mass was enhanced rapidly in the early phase and that this early enhancement was maintained during the delayed phase, which was compatible with a diagnosis of intercostal hemangioma. The patient underwent surgery, and a complete resection of the tumor with the right 7th and 8th ribs and their intercostal muscles was accomplished. Histopathological examination confirmed the diagnosis of intramuscular hemangioma of the large-vessel type. Presently, 6 months after the operation, the patient is doing well, without any evidence of local recurrence.  相似文献   
64.
OBJECTIVE: Many phase II trials have shown that preoperative chemotherapy for lung cancer is feasible but associated with postoperative morbidity and mortality. However, little is known about the effect of preoperative chemotherapy on surgical stress and postoperative complications associated with surgical intervention. We evaluated the effect of preoperative chemotherapy on perioperative inflammatory cytokine production as a surgical stress marker. METHODS: The study group comprised 38 patients undergoing anatomical lung resection and mediastinal nodal dissection for clinical stage IB/II non-small cell lung cancer during the period October 2001-December 2003. Nineteen patients received a single cycle of cisplatin (80 mg/m(2)) and docetaxel (60 mg/m(2)) chemotherapy prior to surgery (neoadjuvant group), and 19 patients underwent surgery without any previous chemotherapy (control group). White blood cell and neutrophil counts and serum concentrations of C-reactive protein (CRP), interleukin-6 (IL-6), and granulocyte colony-stimulating factor (GCSF) were determined before surgery and on postoperative days 1 and 3. Postoperative complications were reviewed. Differences were assessed by repeated analysis of variance. RESULTS: Serum concentrations of IL-6 and GCSF rose significantly on postoperative days 1 and 3 in the neoadjuvant group in comparison to concentrations in the control group, but white blood cell count, neutrophil count, and CRP did not differ between the groups. No major complication occurred in either group. CONCLUSIONS: A single cycle of cisplatin and docetaxel chemotherapy followed by surgery can exacerbate overproduction of inflammatory cytokines during the perioperative period in lung cancer patients.  相似文献   
65.
Endosonography‐guided celiac plexus neurolysis (EUS‐CPN) safely and effectively relieves pain associated with intra‐abdominal malignancies when the neurolytic is accurately injected. We applied contrast medium to evaluate the ethanol injection sites in patients who received EUS‐CPN due to abdominal pain caused by malignancies. We injected, under the guidance of endoscopic ultrasonography (EUS), ethanol containing 10% contrast medium into the celiac plexus of patients with intra‐abdominal pain due to malignancies. Immediately after the endoscopic therapy, patients underwent computed tomography (CT) to confirm the injection site. Images of distribution of injected solutions were classified into three groups. Injected solution dispersed in unilateral and bilateral anterocrural space was defined as ‘unilateral injection’ or ‘bilateral injection’, respectively. Injected solution located out of the anterocrural space was defined as ‘inappropriate injection’. Pre‐ and postprocedure pain was assessed using a standard analog scale. Before and 2, 4, 8, 12, and 16 weeks after the procedure, pain scores were evaluated. From April 2003 to May 2005, 13 patients were enrolled in this study. Improvement of pain score in the ‘bilateral injection’ and ‘unilateral injection’ groups was significantly superior to the change in the ‘inappropriate injection’ group. Although EUS‐CPN was effective in eight of 13 patients (61.5%), additional EUS‐CPN to the ‘inappropriate injection group’ increased the response rate to 84.6%. Injection of ethanol to the anterocrural space by EUS‐CPN produced adequate pain relief. Immediate examination by CT for confirmation of injection sites after EUS‐CPN would increase the likelihood of induction of pain relief.  相似文献   
66.
OBJECTIVES: To evaluate the accuracy of sonographic identification of the site of umbilical cord insertion (CI) at 18-20 weeks of gestation, to compare the sensitivities for detection of a velamentous cord insertion (VCI) secondary to a CI into the anterior, posterior or fundal wall, and to compare the intrapartum complications secondary to VCI into the upper, middle or lower third of the uterus. METHODS: As part of the routine ultrasound scan at 18-20 weeks' gestation we evaluated abnormal CI (VCI and marginal CI) and the location of the CI in the uterus in 3446 pregnancies. In cases of abnormal CI, the location of the CI was further classified as being in the upper, middle or lower third of the uterus. After delivery, the placenta and the umbilical cord were examined and intrapartum complications were compared with the location of the CI. RESULTS: The values for antenatal detection of VCI were: sensitivity, 25 of 40 (62.5%); positive predictive value, 25 of 25 (100%); and negative predictive value, 3406 of 3421 (99.6%). The sensitivity for cases in which the CI was located on the anterior wall was 12 of 13 (92.3%); when it was located on the posterior wall, the sensitivity was 11 of 22 (50.0%); and when it was fundal the sensitivity was 2 of 5 (40.0%). Variable decelerations were frequently observed with a VCI. In lower VCI cases, non-reassuring fetal heart rate patterns and emergency Cesarean sections occurred with a higher frequency than in cases with upper or middle VCI (P < 0.01). After delivery, the length of the aberrant vessels in cases of VCI by pathologic examination was 3.9 +/- 3.3 cm in the upper third, 4.7 +/- 4.6 cm in the middle third, and 10.6 +/- 6.8 cm in the lower third; thus, the aberrant vessel length was significantly greater when the CI was in the lower third of the uterus (P = 0.024). CONCLUSION: We have demonstrated that VCI with a lower CI site and with longer aberrant vessels is associated with various intrapartum complications. This finding has the potential for improving perinatal outcome.  相似文献   
67.
Recently, a self‐expandable metallic stent has been recognized for treatment of malignant duodenal stenosis. But the complications by stenting are important problems even now. In the present study, we report our new method of duodenal stenting by using of double‐balloon enteroscopy considered safe and effective.  相似文献   
68.
The patient was a one-year-old boy, who underwent surgery with a diagnosis of atrial septal defect (ASD). During operation, aorto-pulmonary window (A-P window) which had not been detected by the preoperative examinations, was found. Therefore, the A-P window was divided prior to closing ASD. The patient is in good condition six months after the operation. The causes of the inaccurate preoperative diagnosis were discussed.  相似文献   
69.
Almost one tenth of more than 370 hepatectomies, mostly for tumors, involved resection of major parts of the caudate lobe, subsegment 1. Five of them were for tumors or hemangiomas here, compressing or invading the vena cava; two were for metastases of colorectal cancer located very close to the junctions of the right and middle hepatic veins with the vena cava. We would previously have deemed these tumors unresectable. In these patients the vein was banded above and below the liver, an internal shunt tube placed in preparation for shunting of blood, and the afferent liver blood flow controlled. Control of the vena cava by tightening of the bands was needed in two cases. Tumor-invaded parts of the vein wall were resected in two other cases, in whom the presence of the tube facilitated the resection but the bands did not have to be tightened. The procedure did not cause morbidity and we conclude that tumors close to the vena cava can often be resected without complex vascular exclusion techniques, even when they invade the vein.  相似文献   
70.
We performed Raz procedure and Gittes procedure for female stress incontinence since October 1986. Raz procedure was performed on 19 patients between October 1986 and February 1990, and Gittes procedure was performed on 18 patients between June 1990 and May 1991. We followed up 17 patients who underwent Raz procedure and all the patients who underwent Gittes procedure at the time August 1991. Disappearance or marked improvement of incontinence was confirmed in 12 patients by Raz procedure, and 16 patients by Gittes Procedure. No serious complications were recognized. The reason why the result of Raz procedure was not sufficient was due to our immature operative technique and incorrect patient selection in our early experience. From this experience, we believe that both procedures can be very useful and minimal invasive operation for female stress incontinence.  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