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   23979篇
  免费   1891篇
  国内免费   77篇
耳鼻咽喉   410篇
儿科学   841篇
妇产科学   377篇
基础医学   2438篇
口腔科学   533篇
临床医学   2166篇
内科学   5284篇
皮肤病学   552篇
神经病学   1319篇
特种医学   1108篇
外国民族医学   1篇
外科学   4639篇
综合类   334篇
一般理论   15篇
预防医学   1157篇
眼科学   864篇
药学   2076篇
中国医学   38篇
肿瘤学   1795篇
  2023年   204篇
  2022年   347篇
  2021年   1039篇
  2020年   492篇
  2019年   831篇
  2018年   975篇
  2017年   638篇
  2016年   675篇
  2015年   693篇
  2014年   1041篇
  2013年   1219篇
  2012年   1803篇
  2011年   1772篇
  2010年   893篇
  2009年   836篇
  2008年   1302篇
  2007年   1225篇
  2006年   1144篇
  2005年   985篇
  2004年   885篇
  2003年   751篇
  2002年   646篇
  2001年   587篇
  2000年   550篇
  1999年   488篇
  1998年   160篇
  1997年   135篇
  1996年   138篇
  1995年   142篇
  1994年   113篇
  1993年   97篇
  1992年   267篇
  1991年   284篇
  1990年   248篇
  1989年   212篇
  1988年   208篇
  1987年   219篇
  1986年   192篇
  1985年   177篇
  1984年   111篇
  1983年   126篇
  1982年   85篇
  1981年   70篇
  1979年   129篇
  1978年   77篇
  1977年   69篇
  1975年   58篇
  1974年   65篇
  1973年   88篇
  1970年   58篇
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
21.
Primary mesenteric venous thrombosis: a study from western India.   总被引:1,自引:0,他引:1  
INTRODUCTION: The prevalence and clinical spectrum of mesenteric venous thrombosis (MVT) in India is largely unknown. METHODS: We retrospectively re-viewed the case records of patients with primary mesenteric venous thrombosis seen over a 10-year period and retrieved information on clinical picture, underlying hypercoagulable states and outcome. RESULTS: The 28 cases (mean age 41.2 [SD 10.2] years; 19 male) included 13 with acute MVT, 10 with subacute MVT and 5 with chronic MVT. Ten patients had past thromboembolic events (multiple events in five); four patients had isolated superior mesenteric vein involvement and 14 had multiple vessel involvement. Hypercoagulable state was identified in 17 patients, with multiple etiologies in 7 patients. Pre-operative diagnosis was made in all patients. Ten patients needed surgical management; the rest were managed medically initially, but 2 required surgery on follow up. Seven patients died during a follow up of up to 10 years, with in-hospital mortality during index admission in six. CONCLUSIONS: Most of the patients with MVT have multiple intra-abdominal vessel involvement and underlying hypercoagulable state. The policy of early treatment with anticoagulation in all and surgical treatment as per need, achieves low mortality.  相似文献   
22.
23.
24.
25.
BackgroundMesenteric internal hernia (MIH) is the most common cause of small bowel obstruction (SBO) after laparoscopic Roux-en-Y gastric bypass. Because MIH is a potentially life-threatening complication, we hypothesized that elective repair of MIH before developing acute SBO could decrease morbidity in this population.MethodsThe records of 702 consecutive patients undergoing primary laparoscopic Roux-en-Y gastric bypass from January 2002 and August 2007 were retrospectively reviewed to determine the incidence and etiology of SBO. During the last 9 months of the study, we offered elective laparoscopy to any patient who presented to us with symptoms of intermittent SBO.ResultsOf the 702 patients, 27 (3.8%) developed acute SBO. Of these 27 patients, 15 (55%) had obstruction related to an MIH. Nearly all patients had a typical history of intermittent abdominal pain, nausea, and bloating before developing acute SBO. Elective laparoscopy was offered to 11 patients with symptoms of intermittent SBO. Two patients who refused subsequently underwent operations for acute SBO. MIH was found at elective laparoscopic exploration in all cases. Of the 9 patients undergoing elective surgery, 3 (33%) had small bowel volvulus.ConclusionSBO due to MIH after laparoscopic Roux-en-Y gastric bypass is typically preceded by symptoms of intermittent obstruction. Patients who have these herald symptoms should promptly be offered elective laparoscopic exploration. Elective repair of MIH can be performed safely and expeditiously.  相似文献   
26.
The clinical significance of pre-transplant donor-specific antibodies (DSA), despite negative cytotoxicity and flow cytometry crossmatches (FCXMs), is unknown. We performed a retrospective cohort study of 60 living donor renal transplant recipients, all with pre-transplant cytotoxicity and T-cell and B-cell FCXMs that were negative. Twenty recipients had pre-transplant DSA detected by enzyme-linked immunosorbent assays (ELISA) and/or microbead methods. Forty contemporaneous DSA-negative controls were selected. In the DSA-positive group, after a median follow-up of 8.2 months (25-75% range, 5.4-22.8 months), patient survival was 100% and allograft survival was 95.0%. Acute humoral rejection (AHR) developed in four patients (20.0%). Three of the AHR episodes occurred within the first month post-transplant. Median serum creatinine at last follow-up was 1.3 mg/dL (25-75% range, 1.0-1.6 mg/dL), versus 1.1 mg/dL (25-75% range, 0.9-1.4 mg/dL) in the DSA-negative controls (p = 0.29). Only one of the 40 controls developed AHR (2.5%). Pre-transplant DSA was associated with a significantly increased incidence of AHR (p = 0.02 by log-rank test). In conclusion, despite negative pre-transplant cytotoxicity and FCXMs, renal transplant recipients with pre-transplant DSA detected by solid-phase methods may have an increased incidence of AHR and require close monitoring post-transplant.  相似文献   
27.
BACKGROUND: Simple surgical excision is one of the most common treatment methods in the dermatologist's armamentarium. We describe a precise postsurgical dressing technique that can be used for wound care of those patients whose treatment involves removal of lesions via cutaneous surgery. OBJECTIVE: To devise a novel, precise, and effective dressing technique for postsurgical wound care. MATERIALS AND METHODS: We describe the technique using common in-office instruments. RESULTS AND CONCLUSION: Wound dressings for lesions located on curved areas such as the ears, nose, cheeks, and chin often exhibit less than adequate adherence and stability. The kerf-cut dressing technique optimizes pliability of dressing tape, and this maximizes efficient and stable application of postsurgical wound dressings to curved areas of the body.  相似文献   
28.
Using fura-2 loaded neural tumour cells, SK-N-SH, we demonstrate that receptor-mediated activation of phosphoinositide hydrolysis not only causes the release of Ca2+ from intracellular stores but also causes a concomitant influx of extracellular Ca2+. Thapsigargin (TG), a sesquiterpene lactone, causes a sustained elevation of intracellular Ca2+ and depletion of the inositol 1, 4, 5-trisphosphate-sensitive intracellular Ca2+ stores. In the absence of extracellular Ca2+, the increase in intracellular Ca2+ concentration ([Ca2+]i) was transient, suggesting that thapsigargin activates both intracellular mobilization and the influx of Ca2+ from extracellular space. These results are consistent with the proposal that the depletion of the inositol 1, 4, 5-trisphosphate-sensitive intracellular Ca2+ pool serves as a signal for Ca2+ influx.  相似文献   
29.
Brain metastasis is the most common intracranial malignancy in adults. Improvements in modern imaging techniques are detecting previously occult brain metastases, and more effective therapies are extending the survival of patients with invasive cancer who have historically died from extracranial disease before developing brain metastasis. This combination of factors along with increased life expectancy has led to the increased diagnosis of brain metastases. Conventional treatment has been whole brain radiotherapy, which can improve symptoms, but potentially results in neurocognitive deficits. Several strategies to improve the therapeutic ratio are currently under investigation to either enhance the radiation effect, thereby preventing tumor recurrence or progression as well as reducing collateral treatment-related brain injury. In this review article, we discuss new directions in the management of brain metastases, including the role of chemical modifiers, novel systemic agents, and the management and prevention of neurocognitive deficits.  相似文献   
30.
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