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   5327篇
  免费   398篇
  国内免费   47篇
耳鼻咽喉   57篇
儿科学   117篇
妇产科学   195篇
基础医学   663篇
口腔科学   156篇
临床医学   576篇
内科学   1291篇
皮肤病学   83篇
神经病学   327篇
特种医学   343篇
外科学   690篇
综合类   130篇
预防医学   189篇
眼科学   155篇
药学   365篇
中国医学   37篇
肿瘤学   398篇
  2023年   21篇
  2022年   63篇
  2021年   110篇
  2020年   72篇
  2019年   89篇
  2018年   142篇
  2017年   103篇
  2016年   123篇
  2015年   235篇
  2014年   204篇
  2013年   229篇
  2012年   379篇
  2011年   364篇
  2010年   227篇
  2009年   159篇
  2008年   279篇
  2007年   283篇
  2006年   265篇
  2005年   245篇
  2004年   235篇
  2003年   292篇
  2002年   256篇
  2001年   192篇
  2000年   167篇
  1999年   126篇
  1998年   56篇
  1997年   38篇
  1996年   39篇
  1995年   29篇
  1994年   26篇
  1993年   34篇
  1992年   93篇
  1991年   70篇
  1990年   63篇
  1989年   57篇
  1988年   55篇
  1987年   58篇
  1986年   49篇
  1985年   28篇
  1984年   19篇
  1983年   19篇
  1982年   15篇
  1981年   14篇
  1980年   9篇
  1979年   25篇
  1978年   14篇
  1977年   15篇
  1974年   9篇
  1973年   9篇
  1972年   10篇
排序方式: 共有5772条查询结果,搜索用时 15 毫秒
61.
62.
PurposeThis study aimed to compare the efficacy of decreasing leg-length discrepancy (LLD) and postoperative complications between tension band plates (TBP) and percutaneous transphyseal screws (PETS).MethodsThis retrospective study reviewed LLD patients who underwent temporary epiphysiodesis at the distal femur and/or proximal tibia from 2010 to 2017 (minimum two years follow-up). Efficacy of decreasing LLD was assessed one and two years postoperatively. Complications were classified with the modified Clavien-Dindo-Sink complication classification system. Knee deformities were assessed by percentile and zone of mechanical axis across the tibial plateau.ResultsIn total, 53 patients (25 boys, 28 girls) underwent temporary epiphysiodesis (mean age, 11.4 years). The efficacy of decreasing LLD at two years between the TBP (n = 38) and PETS (n = 15) groups was comparable. Seven grade III complications were recorded in six TBP patients and in one PETS patient who underwent revision surgeries for knee deformities and physis impingement. Four grade I and two grade II complications occurred in the TBP group. The mechanical axis of the leg shifted laterally in the PETS group and medially in the TBP groups (+7.1 percentile versus -4.2 percentile; p < 0.05). Shifting of the mechanical axis by two zones was noted medially in four TBP patients and laterally in two PETS patients.ConclusionMore implant-related complications and revision surgeries for angular deformities were associated with TBP. A tendency of varus and valgus deformity after epiphysiodesis using TBP and PETS was observed, respectively. Patients and families should be informed of the risks and regular postoperative follow-up is recommended.Level of evidenceLevel III  相似文献   
63.
台湾早期之教会医学   总被引:1,自引:1,他引:0  
台湾如同中国本土一样,其现代医学的开端系来自西方基督教传教士的医疗。虽然17世纪荷兰人曾带来了西方医学,但是当郑成功驱逐了荷兰人,西方医学也随之自台湾消失。1865年英国长老教会派遣马雅各医师来台从事医疗传教,才使西方医学在台湾生根。19世纪最后的30年是台湾近代医学史的关键时期。本文就台湾早期教会医学的三位重要人物:马雅各医师、马偕博士、兰大卫医师之主要事迹和他们对台湾近代医学的贡献加以整理叙述。  相似文献   
64.
Medical professionalism in society   总被引:11,自引:0,他引:11  
  相似文献   
65.
Extracranial magnetic resonance angiography (MRA) was performed in 20 children to evaluate for various arterial and venous conditions. Time-of-flight and phase-contrast angiograms were constructed using a maximal-intensity-projection algorithm. The accuracy of MRA was comparable to Doppler ultrasound (n = 12) and conventional angiography (n = 3). MRA could provide an excellent mapping of patent (including collaterals) versus thrombosed vessels at sites not evaluated or inaccessible by sonography. Limitations included assessment of small and/or tortuous vessels, severely stenotic lesions, and very slow flow.  相似文献   
66.
OBJECT: The purpose of this study was to analyze the change in carotid and middle cerebral artery (MCA) hemodynamics before and after endoscopic upper thoracic sympathectomy in patients with palmar hyperhidrosis (PH). METHODS: Sixty-eight patients with PH (35 males and 33 females) for whom the average age was 24.5+/-10.7 years (+/- standard deviation) were recruited into this study. These patients all underwent routine upper T-2 sympathectomy to treat their PH. Ultrasonography studies of the carotid arteries (CAs) and MCA were obtained in each patient before and after T-2 sympathectomy. The blood flow volume, flow velocity, and resistivity index (RI) in the bilateral common CAs (CCAs), internal CAs (ICAs), and external CAs (ECAs) were evaluated using duplex ultrasonography. The systolic peak velocity, mean velocity, diastolic peak velocity, pulsatility index, and RI of the bilateral MCAs were evaluated using transcranial Doppler ultrasonography. Blood pressure and heart rate were also recorded during this study. The Student paired t-test was used to analyze the differences between studies before and after bilateral T-2 sympathectomy. There was a significant reduction in diastolic pressure after T-2 sympathectomy (p = 0.003), but not in systolic pressure or heart rate. The vessel diameter was increased after sympathectomy in the left CAs and right CCA. The T-2 sympathectomy led to significant elevation of blood flow volume and RI in the left CCA, ICA, and ECA (p < 0.05). The authors found significant increases in maximum flow velocity and RI in the left MCA (p < 0.05). CONCLUSIONS: Patients who underwent T-2 sympathectomy demonstrated a significant increase in blood flow volume and flow velocities of the CAs and MCA, especially on the left side. Asymmetry of sympathetic influence on the hemodynamics of the CAs and MCA was noted. The usefulness of sympathectomy for the treatment of ischemic cardiovascular and cerebrovascular disease deserves further investigation.  相似文献   
67.
BACKGROUND: Controversies regarding how urgent bowel perforation should be diagnosed and treated exist in recent reports. The approach for early diagnosis is also debatable. The purposes of this study were to evaluate the relationship between treatment delay and outcome of small bowel perforation after blunt abdominal trauma and to determine the best assessment plan for the diagnosis of this injury. METHODS: One hundred eleven consecutive patients with small bowel perforations caused by blunt abdominal trauma were retrospectively reviewed. The patients were divided into four groups according to the time interval between injury and surgery. Hospital stay, time to resume oral intake, and mortality and morbidity rates were compared between groups. Physical signs, laboratory and computed tomographic findings, and the results of diagnostic peritoneal lavage were analyzed to find the most sensitive and specific test for early diagnosis of small bowel perforation. RESULTS: Delay in surgery for more than 24 hours did not significantly increase the mortality with modern method of treatment; however, complications increased dramatically. Hospital stay and time to resume oral intake increased significantly when surgery was delayed for more than 24 hours. Abdominal tenderness was a common finding, but it was not specific for bowel perforation. Only 40% of the computed tomographic scans were diagnostic for bowel perforations: 50% of them showed suggestive signs, and 10% were considered as negative. Persistence of abdominal signs indicated peritoneal lavage. By using cell count ratio in diagnostic peritoneal lavage and/or increased lavage amylase activity, presence of particulate matter and/or bacteria in the lavage fluid, all patients with intraperitoneal bowel perforation were diagnosed accurately before operation. CONCLUSION: Small bowel perforation has low mortality and complication rates if it is treated earlier than 24 hours after injury. The principle of "rushing to the operation suite" for a stable blunt abdominal trauma patients without detailed systemic examination is not justified. The priority of treatment for the small bowel perforation should be lower than the limb-threatening injuries. Diagnostic peritoneal lavage provides high sensitivity and specificity rates for the diagnosis of small bowel perforation if a specially designed positive criterion is applied.  相似文献   
68.
腹膜外结肠造口一期乳头成形术的临床效果   总被引:4,自引:1,他引:3  
目的探讨腹膜外结肠造口加一期乳头成形术的临床效果。②方法对51例肛管和直肠癌病人施行腹膜外结肠造口一期乳头成形术,并与施行传统Miles腹膜内结肠造口术40例病人的效果进行比较,观察造口并发症和排便功能改善情况。③结果51例腹膜外结肠造口术病人经1~5年的随访,仅有1例发生造口旁疝,并发症的发生率为1.9%,40例病人获排便感。对照组各种并发症的发生率为30.0%,无1例病人有排便感。两组比较差异有极显著性(χ2=13.80,P<0.001)。④结论腹膜外结肠造口一期乳头成形术具有并发症少,排便功能好,易于术后管理等优点。  相似文献   
69.
PURPOSE: The dysplastic corneal epithelium is characterized by the abnormal proliferation of epithelial cells. The phenotypes of these cells have not been elucidated. We investigated whether such epithelium expresses the phenotypes of corneal or conjunctival epithelial cells. METHODS: The corneas and conjunctivae from four normal subjects and from one patient with epithelial dysplasia of the central cornea were immunostained for IV and VII collagens and for cytokeratins. Monoclonal antibodies against collagen IV reacted to the [alpha1(IV)]2alpha2(IV) or alpha5(IV) molecule. Anti-cytokeratin antibodies were used to define epithelial cell types. The ultrastructure of the basement membrane (BM) of each specimen also was examined. RESULTS: Type VII collagen immunoreactivity was detected in all the specimens of epithelial BM. The anti-collagen IV [alpha1(IV)]2alpha2(IV) antibody labeled the conjunctival BMs, not the BMs of the corneal epithelia, of each subject. The normal corneal epithelial BM, not the BM of the conjunctival or dysplastic corneal epithelium, was immunolabeled with anti-alpha5(IV) antibody. The pattern of cytokeratin expression in the corneal epithelial dysplasia resembled that seen in the normal conjunctivae. Small breaks in the BM of dysplastic corneal epithelium were ultrastructurally revealed. The number of hemidesmosomes in the dysplastic corneal epithelium was decreased as compared with that in the normal BM. CONCLUSION: The composition of collagen types within the BM and the cellular phenotype of the dysplastic epithelium in the cornea resembled those of conjunctival epithelium, not of the cornea.  相似文献   
70.
The effects of 24-hr exposures to 5-fluorouracil (FUra) and paclitaxel in various sequences were studied in MCF-7 breast cancer cells to determine an optimal schedule for possible clinical use. In clonogenic assays, pre-exposure to FUra followed by paclitaxel resulted in marked antagonism, while sequential paclitaxel followed by FUra was optimal. Concurrent or pre-exposure to paclitaxel did not affect [3H]FUra metabolism, [3H]FUra-RNA incorporation, or the extent of FUra-mediated thymidylate synthase inhibition. Paclitaxel led to G2/M phase accumulation that persisted for up to 24 hr after drug exposure, while a 24-hr FUra exposure produced S-phase accumulation. FUra pre-exposure diminished paclitaxel-associated G2/M phase block, whereas subsequent exposure to FUra after paclitaxel did not. FUra exposure resulted in transient induction of p53 and p21, which returned to basal levels 24 hr after drug removal. p53 and p21 protein content also increased markedly during paclitaxel exposure, accompanied by phosphorylation of Bcl-2. Double-stranded DNA fragmentation (approximately 50 kb) was seen at 48 hr when cells were exposed to paclitaxel for an initial 24-hr period. Paclitaxel-associated DNA fragmentation was not prevented by concurrent or subsequent exposure to FUra. Thus, paclitaxel-mediated G2/M phase arrest appeared to be a crucial step in induction of DNA fragmentation. Since an initial 24-hr paclitaxel exposure did not interfere with subsequent FUra metabolism or thymidylate synthase inhibition, and delayed exposure to FUra did not impede either paclitaxel-mediated induction of mitotic blockade or DNA fragmentation, the sequence of paclitaxel followed by FUra is recommended for clinical trials.  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