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   13688篇
  免费   774篇
  国内免费   126篇
耳鼻咽喉   284篇
儿科学   238篇
妇产科学   336篇
基础医学   2018篇
口腔科学   387篇
临床医学   1137篇
内科学   2745篇
皮肤病学   252篇
神经病学   1070篇
特种医学   638篇
外科学   1859篇
综合类   156篇
一般理论   1篇
预防医学   752篇
眼科学   430篇
药学   1174篇
中国医学   170篇
肿瘤学   941篇
  2023年   97篇
  2022年   245篇
  2021年   467篇
  2020年   202篇
  2019年   330篇
  2018年   432篇
  2017年   301篇
  2016年   392篇
  2015年   574篇
  2014年   642篇
  2013年   857篇
  2012年   1278篇
  2011年   1200篇
  2010年   669篇
  2009年   560篇
  2008年   801篇
  2007年   729篇
  2006年   714篇
  2005年   617篇
  2004年   552篇
  2003年   458篇
  2002年   407篇
  2001年   368篇
  2000年   320篇
  1999年   235篇
  1998年   86篇
  1997年   49篇
  1996年   37篇
  1995年   46篇
  1994年   41篇
  1993年   39篇
  1992年   114篇
  1991年   88篇
  1990年   84篇
  1989年   87篇
  1988年   71篇
  1987年   61篇
  1986年   51篇
  1985年   49篇
  1984年   29篇
  1983年   28篇
  1982年   20篇
  1980年   13篇
  1979年   13篇
  1978年   16篇
  1977年   13篇
  1976年   11篇
  1975年   14篇
  1974年   17篇
  1973年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
BACKGROUND: This study examined crash severity and injury patterns between helmeted and unhelmeted adolescent motorcycle riders. METHODS: Among an initial population of 4,721 junior college students, 1,284 students were involved in 1,889 motorcycle crashes during a 20-month follow-up period. Crash severity was measured by both the type of collision object and the repair cost of motorcycle damage. RESULTS: The incidence rates of crash, injury, hospitalization, and deaths per 1,000 person-years in the cohort were 358, 104, 14, and 1.3, respectively. Compared with helmeted riders, unhelmeted riders had more noncollisions and fewer collisions with a moving car but there was no significant difference in repair cost of motorcycle damage between these groups. More injuries to the external skin, face, and head and more severe injuries occurred in unhelmeted than in helmeted riders. Among crashes resulting in hospitalization/death, more injuries to the face and head occurred in unhelmeted riders than in helmeted riders. CONCLUSION: Crashes involving unhelmeted riders were not more severe but more frequently involved face and head injuries than crashes involving helmeted riders.  相似文献   
103.
104.
BACKGROUND: Tumour recurrence is common after hepatic resection of hepatocellular carcinomas (HCCs) greater than 10 cm in diameter. This study evaluated the outcome of patients with huge HCC after primary resection and treatment of recurrent lesions. METHODS: A retrospective review was undertaken of clinical data for 100 patients with huge HCC who underwent liver resection. RESULTS: Mean(s.d.) tumour diameter was 13.3(3.0) cm; 80 per cent were single lesions. Systematic and non-systematic resections were performed in 80 and 20 per cent of patients respectively, with R0 resection achieved in 86 per cent. Overall 1-, 3- and 5-year disease-free survival rates were 43, 26 and 20 per cent respectively. Risk factors for HCC recurrence were resection margin less than 1 cm and macrovascular invasion. Extensive tumour necrosis of 90 per cent or more after preoperative transarterial chemoembolization was not a prognostic factor. Some 85 per cent of patients with recurrence received various treatments, and these patients had a longer post-recurrence survival than those who were not treated. Overall 1-, 3- and 5-year survival rates were 66, 44 and 31 per cent respectively. CONCLUSION: In patients with huge HCC, hepatic resection combined with active treatment for recurrence resulted in longer-term survival. Frequent protocol-based follow-up appears to be beneficial for the early detection and timely treatment of recurrence.  相似文献   
105.
Salvage liver transplantation has been performed for recurrent hepatocellular carcinoma (HCC) or deterioration of liver function after primary liver resection. Because prior liver resection per se is an unfavorable condition for living donor liver transplantation (LDLT), we assessed the technical feasibility of LDLT after prior hepatectomy, and we compared the outcome of salvage LDLT with that of primary LDLT in HCC patients. Of 342 patients with HCC, 17 (5%) underwent salvage LDLT, with 5 having undergone prior major liver resection and 12 prior minor resection. During salvage LDLT, 12 patients received right lobe grafts, 3 received left lobe grafts, and 2 received dual grafts. There was 1 incident (5.9%) of perioperative mortality. Recipient operation time was not prolonged in patients undergoing salvage LDLT, but bleeding complications occurred more frequently than in patients undergoing primary LDLT. Overall survival rates after salvage LDLT were similar to those after primary LDLT, especially when the extent of recurrent tumor was within the Milan criteria. These results indicate that every combination of prior hepatectomy and living donor liver graft is feasible for patients undergoing salvage LDLT, and the acceptable extent of HCC for salvage LDLT is equivalent to that for primary LDLT.  相似文献   
106.
Early identification of CKD risk factors may allow risk factor modification and prevention of CKD progression. We investigated the hypothesis that risk factors are present ≥30 years before the diagnosis of CKD in a case-control study using data from the Framingham Offspring Study. Patients with incident CKD (eGFR≤60 ml/min per 1.73 m2) at examination cycles 6, 7, and 8 were age- and sex-matched 1:2 to patients without CKD at baseline (examination 5). CKD risk factors were measured at each examination cycle. Logistic regression models, adjusted for age, sex, and time period, were constructed to compare risk factor profiles at each time point between cases and controls. During follow-up, 441 new cases of CKD were identified and matched to 882 controls (mean age 69.2 years, 52.4% women). Those who ultimately developed CKD were more likely to have hypertension (odds ratio [OR], 1.76; 95% confidence interval [CI], 1.23 to 2.51), obesity (OR, 1.71; 95% CI, 1.14 to 2.59), and higher triglyceride levels (OR, 1.43; 95% CI, 1.12 to 1.83) 30 years before CKD diagnosis, and were more likely to have hypertension (OR, 1.38; 95% CI, 1.07 to 1.79), higher triglyceride levels (OR, 1.35; 95% CI, 1.11 to 1.64), lower HDLc (OR, 0.89; 95% CI, 0.81 to 0.97), and diabetes (OR, 2.90; 95% CI, 1.59 to 5.29) 20 years before CKD diagnosis. These findings demonstrate that risk factors for CKD are identifiable ≥30 years before diagnosis and suggest the importance of early risk factor identification in patients at risk for CKD.  相似文献   
107.

Introduction

In 2009 the Department of Health instructed McKinsey & Company to provide advice on how commissioners might achieve world class National Health Service productivity. Asymptomatic inguinal hernia repair was identified as a potentially cosmetic procedure, with limited clinical benefit. The Birmingham and Solihull primary care trust cluster introduced a policy of watchful waiting for asymptomatic inguinal hernia, which was implemented across the health economy in December 2010. This retrospective cohort study aimed to examine the effect of a change in clinical commissioning policy concerning elective surgical repair of asymptomatic inguinal hernias.

Methods

A total of 1,032 patients undergoing inguinal hernia repair in the 16 months after the policy change were compared with 978 patients in the 16 months before. The main outcome measure was relative proportion of emergency repair in groups before and after the policy change. Multivariate binary logistic regression was used to adjust the main outcome for age, sex and hernia type.

Results

The period after the policy change was associated with 59% higher odds of emergency repair (3.6% vs 5.5%, adjusted odds ratio [OR]: 1.59, 95% confidence interval [CI]: 1.03–2.47). In turn, emergency repair was associated with higher odds of adverse events (4.7% vs 18.5%, adjusted OR: 3.68, 95% CI: 2.04–6.63) and mortality (0.1% vs 5.4%, p<0.001, Fisher’s exact test).

Conclusions

Introduction of a watchful waiting policy for asymptomatic inguinal hernias was associated with a significant increase in need for emergency repair, which was in turn associated with an increased risk of adverse events. Current policies may be placing patients at risk.  相似文献   
108.
We investigated the effects of magnesium sulphate on blood coagulation profiles using rotational thromboelastometry in patients undergoing laparoscopic colorectal cancer surgery. Patients were randomly allocated to the magnesium group (n = 22) or control group (n = 22). The magnesium group received intravenous magnesium sulphate (50 mg.kg?1 followed by a continuous infusion of 15 mg.kg?1.h?1), whereas the control group received the same volume of isotonic saline. Mean (SD) postoperative serum magnesium levels were 1.60 (0.13) mmol.l?1 in the magnesium group compared with 0.98 (0.06) mmol.l?1 in the control group (p < 0.001). All maximum clot firmness values of ROTEM analysis were significantly lower on the third postoperative day in the magnesium group compared with the control group (p < 0.05). We conclude that ROTEM analysis demonstrated that intra‐operative administration of intravenous magnesium sulphate reduces blood hypercoagulability in patients undergoing laparoscopic colorectal cancer surgery.  相似文献   
109.
110.
Congenital anomalies of the kidney and urinary tract (CAKUT) cover a wide range of structural malformations that result from defects in the morphogenesis of the kidney and/or urinary tract. These anomalies account for about 40–50 % of children with chronic kidney disease worldwide. Knowledge from genetically modified mouse models suggests that single gene mutations in renal developmental genes may lead to CAKUT in humans. However, until recently, only a handful of CAKUT-causing genes were reported, most of them in familial syndromic cases. Recent findings suggest that CAKUT may arise from mutations in a multitude of different single gene causes. We focus here on single-gene causes of CAKUT and their developmental origin. Currently, more than 20 monogenic CAKUT-causing genes have been identified. High-throughput sequencing techniques make it likely that additional CAKUT-causing genes will be identified in the near future.  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