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   7476篇
  免费   524篇
  国内免费   40篇
耳鼻咽喉   73篇
儿科学   206篇
妇产科学   171篇
基础医学   1075篇
口腔科学   216篇
临床医学   598篇
内科学   1779篇
皮肤病学   200篇
神经病学   989篇
特种医学   178篇
外科学   847篇
综合类   18篇
一般理论   1篇
预防医学   510篇
眼科学   80篇
药学   480篇
中国医学   22篇
肿瘤学   597篇
  2024年   10篇
  2023年   72篇
  2022年   208篇
  2021年   314篇
  2020年   181篇
  2019年   279篇
  2018年   284篇
  2017年   187篇
  2016年   250篇
  2015年   279篇
  2014年   341篇
  2013年   439篇
  2012年   663篇
  2011年   579篇
  2010年   333篇
  2009年   282篇
  2008年   411篇
  2007年   421篇
  2006年   432篇
  2005年   337篇
  2004年   373篇
  2003年   295篇
  2002年   246篇
  2001年   78篇
  2000年   70篇
  1999年   74篇
  1998年   55篇
  1997年   40篇
  1996年   37篇
  1995年   20篇
  1994年   27篇
  1993年   16篇
  1992年   51篇
  1991年   35篇
  1990年   35篇
  1989年   34篇
  1988年   41篇
  1987年   37篇
  1986年   18篇
  1985年   23篇
  1984年   22篇
  1983年   17篇
  1982年   12篇
  1981年   11篇
  1979年   12篇
  1978年   9篇
  1977年   6篇
  1976年   5篇
  1973年   5篇
  1969年   5篇
排序方式: 共有8040条查询结果,搜索用时 31 毫秒
1.
Prevention Science - This study aimed to evaluate the effectiveness of the drug and violence resistance educational program (PROERD) on short-term secondary outcomes, such as intentions to use...  相似文献   
2.
Harinakshi Sanikini  David C. Muller  Marisa Sophiea  Sabina Rinaldi  Antonio Agudo  Eric J. Duell  Elisabete Weiderpass  Kim Overvad  Anne Tjønneland  Jytte Halkjær  Marie-Christine Boutron-Ruault  Franck Carbonnel  Iris Cervenka  Heiner Boeing  Rudolf Kaaks  Tilman Kühn  Antonia Trichopoulou  Georgia Martimianaki  Anna Karakatsani  Valeria Pala  Domenico Palli  Amalia Mattiello  Rosario Tumino  Carlotta Sacerdote  Guri Skeie  Charlotta Rylander  María-Dolores Chirlaque López  Maria-Jose Sánchez  Eva Ardanaz  Sara Regnér  Tanja Stocks  Bas Bueno-de-Mesquita  Roel C.H. Vermeulen  Dagfinn Aune  Tammy Y.N. Tong  Nathalie Kliemann  Neil Murphy  Marc Chadeau-Hyam  Marc J. Gunter  Amanda J. Cross 《International journal of cancer. Journal international du cancer》2020,146(4):929-942
Obesity has been associated with upper gastrointestinal cancers; however, there are limited prospective data on associations by subtype/subsite. Obesity can impact hormonal factors, which have been hypothesized to play a role in these cancers. We investigated anthropometric and reproductive factors in relation to esophageal and gastric cancer by subtype and subsite for 476,160 participants from the European Prospective Investigation into Cancer and Nutrition cohort. Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox models. During a mean follow-up of 14 years, 220 esophageal adenocarcinomas (EA), 195 esophageal squamous cell carcinomas, 243 gastric cardia (GC) and 373 gastric noncardia (GNC) cancers were diagnosed. Body mass index (BMI) was associated with EA in men (BMI ≥30 vs. 18.5–25 kg/m2: HR = 1.94, 95% CI: 1.25–3.03) and women (HR = 2.66, 95% CI: 1.15–6.19); however, adjustment for waist-to-hip ratio (WHR) attenuated these associations. After mutual adjustment for BMI and HC, respectively, WHR and waist circumference (WC) were associated with EA in men (HR = 3.47, 95% CI: 1.99–6.06 for WHR >0.96 vs. <0.91; HR = 2.67, 95% CI: 1.52–4.72 for WC >98 vs. <90 cm) and women (HR = 4.40, 95% CI: 1.35–14.33 for WHR >0.82 vs. <0.76; HR = 5.67, 95% CI: 1.76–18.26 for WC >84 vs. <74 cm). WHR was also positively associated with GC in women, and WC was positively associated with GC in men. Inverse associations were observed between parity and EA (HR = 0.38, 95% CI: 0.14–0.99; >2 vs. 0) and age at first pregnancy and GNC (HR = 0.54, 95% CI: 0.32–0.91; >26 vs. <22 years); whereas bilateral ovariectomy was positively associated with GNC (HR = 1.87, 95% CI: 1.04–3.36). These findings support a role for hormonal pathways in upper gastrointestinal cancers.  相似文献   
3.
4.
5.
Preoperative screening for potential cardiac complications is crucial in making rational decisions about surgery. A number of classification schemes are available to aid the primary care physician in assessing a patient's perioperative cardiac risk. In general, these schemes enable the physician to place patients in low-risk, moderate-risk and high-risk categories. Patients at low risk can often be safely referred for surgery with minimal preoperative evaluation, while those at potentially high risk frequently need further assessment and medical or surgical treatment of cardiac disease prior to surgery. The classification schemes are most accurate in identifying patients at high risk for perioperative cardiac complications. However, patients with silent underlying cardiac disease are often underclassified with respect to potential risk. For those patients, accurate prediction of perioperative cardiac complications can be challenging.  相似文献   
6.

Background  

Liver transplantation in presence of diffuse portal vein thrombosis is possible by using caval blood as portal inflow, through cavo-portal transposition. However, clinical results are heterogeneous and experimental studies are needed, but similar hemodynamic conditions are difficult to obtain, especially in small animals. Herein we describe a new simple model of cavo-portal transposition in rat.  相似文献   
7.
Isolated pure dislocations of the fifth carpo-metacarpal joint are extremely rare injuries. The dorsal form was described in mere 12 cases. The diagnosis can be easily missed. The lesion is also often overlooked in the routine diagnostic X-ray. Lateral and oblique views are important for the recognition of the true extent of the lesion. Treatment of these injures is still controversial and both closed reduction with percutaneous pinning or open reduction with internal fixation are advocated. The goal of treatment is early reduction and fixation of the metacarpal. Early diagnosis is the key to success. The aim of this paper is to review literature and present two new cases.  相似文献   
8.
BACKGROUND AND OBJECTIVES: The purpose of this study was to determine patient recall and comprehension after laparoscopic appendectomy in an underserved population. Laparoscopic surgery can lead to diagnostic uncertainty secondary to poor recall and variable port placement. METHODS: After institutional review board approval, we identified a cohort of patients who underwent laparoscopic appendectomy from 2000 to 2004 at a single institution. We then attempted to contact the patients to conduct a 10-question telephone survey, which determined whether the patient spoke English or Spanish as a primary language, ethnicity, educational level, and questions about recall of perioperative events and diagnoses. If we could not reach the patient, we tried to call back on 2 different occasions. RESULTS: Between 2000 and 2004, 186 patients underwent laparoscopic appendectomy. Of these, 65% were Hispanic. We found that only 17% of these patients returned for a postoperative visit. Only 19.3% could be contacted by phone. Forty-seven percent of the patients contacted by phone spoke Spanish exclusively. Overall 92% of patients contacted knew what operation they had, and gave their correct diagnosis. CONCLUSIONS: The low percentage of patients available to follow-up makes this study statistically insignificant. However, we believe that fact in itself is important. In Southwestern states, we see a large migrant population. This highlights the need to communicate effectively with the patients at the time of surgery, which we speculate we did based on the percentage of patients that knew their diagnosis.  相似文献   
9.
The epsilon-sarcoglycan gene (SGCE) on human chromosome 7q21 has been reported to be a major locus for inherited myoclonus-dystonia. Linkage to the SGCE locus has been detected in the majority of families tested, and mutations in the coding region have been found recently in families with autosomal dominant myoclonus-dystonia. To evaluate the relevance of SGCE in myoclonus-dystonia, we sequenced the entire coding region of the epsilon-sarcoglycan gene in 16 patients with either sporadic or familial myoclonus-dystonia. No mutations were found. This study suggests that epsilon-sarcoglycan does not play an important role in sporadic myoclonus-dystonia and supports genetic heterogeneity in familial cases.  相似文献   
10.
Hepatitis B virus (HBV) recurrence after liver transplantation is significantly reduced by prophylaxis with hepatitis B immune globulins (HBIG) or antiviral drugs in nonreplicating patients and by the combination of both drugs in replicating patients. However, the load of HBV DNA, which defines replicating status in patients undergoing liver transplantation, remains unclear. This study analyzes the correlation between the viral load, tested with a single amplified assay, at the time of liver transplantation, and the risk of hepatitis B recurrence in 177 HBV carriers who underwent transplantation in a single center from 1990 to 2002. Overall, HBV relapsed after surgery in 15 patients (8.5%) with a 5- and 8-year actuarial rate of recurrence of 8% and 21%, respectively. After liver transplantation hepatitis B recurred in 9% of 98 selected subjects treated only with immune globulins and in 8% of 79 viremic patients who received immune globulins and lamivudine (P = NS). A linear correlation was observed between recurrence and viral load at the time of surgery. In transplant patients with HBV DNA higher than 100,000 copies/mL, 200-99,999 copies/mL, and DNA undetectable by amplified assay, hepatitis B recurred in 50%, 7.5%, and 0% of patients, respectively. Overall, a viral load higher than 100,000 copies/mL at the time of liver transplantation was significantly associated with hepatitis B recurrence (P = .0003). In conclusion, spontaneous or antiviral-induced HBV DNA viral load at the time of surgery classifies the risk of HBV recurrence after liver transplantation and indicates the best prophylaxis strategy.  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