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   22433篇
  免费   1008篇
  国内免费   132篇
耳鼻咽喉   199篇
儿科学   274篇
妇产科学   200篇
基础医学   2630篇
口腔科学   426篇
临床医学   1374篇
内科学   5382篇
皮肤病学   1486篇
神经病学   1981篇
特种医学   947篇
外科学   4052篇
综合类   121篇
预防医学   582篇
眼科学   180篇
药学   1712篇
中国医学   45篇
肿瘤学   1982篇
  2023年   118篇
  2022年   215篇
  2021年   398篇
  2020年   237篇
  2019年   301篇
  2018年   429篇
  2017年   332篇
  2016年   418篇
  2015年   455篇
  2014年   588篇
  2013年   685篇
  2012年   1062篇
  2011年   1140篇
  2010年   629篇
  2009年   530篇
  2008年   1036篇
  2007年   1147篇
  2006年   1108篇
  2005年   1109篇
  2004年   1136篇
  2003年   1114篇
  2002年   1085篇
  2001年   650篇
  2000年   702篇
  1999年   678篇
  1998年   330篇
  1997年   228篇
  1996年   225篇
  1995年   212篇
  1994年   167篇
  1993年   135篇
  1992年   464篇
  1991年   420篇
  1990年   424篇
  1989年   461篇
  1988年   427篇
  1987年   392篇
  1986年   340篇
  1985年   299篇
  1984年   178篇
  1983年   162篇
  1982年   91篇
  1979年   170篇
  1978年   88篇
  1977年   86篇
  1975年   74篇
  1974年   73篇
  1973年   82篇
  1972年   85篇
  1970年   74篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Background: For management of bowel obstruction due to colorectal cancer, endoscopic trans‐anal decompression technique has been first reported by Lelcuk et al. in 1986 using balloon dilatation technique. Since then, various types of trans‐anal decompression tubes have been clinically used for patients suffering from left side obstructing colorectal cancer as an emergent decompressing device. At present, two types of trans‐anal ileus tube (trans‐anal decompression tube) have been available for clinical use, but they have two main problems that are late colon perforations caused by the tip of the tube and tube obstruction by stool. Methods: Analysis on three late colon perforations experienced with the use of conventional devices drew possible improvements to make a trans‐anal ileus tube less harmful. To overcome the pitfalls inherent to conventional tubes, the author has developed an improved trans‐anal ileus tube with a balloon installed at the very end of the tube (‘balloon‐tipped type’) made of silicone, measuring 1200 or 1700 mm in total length and 22 Fr in outer diameter. It has been used for 12 cases with obstructing colorectal cancer etc. and its outcomes were compared with those obtained by the use of conventional trans‐anal ileus tube. Results: No late perforations have been encountered, but tube obstruction did occur in one of 12 cases. Conclusion: The new trans‐anal ileus tube with a balloon installed at the tip of ileus tube is considered to be safer and especially effective in preventing late colon perforation and tube obstruction.  相似文献   
3.
A nationwide survey of transient hyperammonemia in newborns was carried out in Japan. A total of 18 patients, consisting of 12 male and 6 female infants, were reported from 11 facilities. These neonates exhibited hyperammonemia with plasma ammonia levels in the range from 124 to 6256 micrograms/dl. Four newborn infants of the 18 died in the neonatal period, and an additional one died in the early infancy. Among the 13 infants who were alive at the time of this survey, 6 had neurological sequelae, including mental retardation, spastic quadriplegia and epilepsy. The multivariate analysis revealed that the Apgar score at 1 minute, peak plasma ammonia concentration, birth weight and sex were significant factors affecting the prognosis of life.  相似文献   
4.
5.
St. Jude Medical valve replacement was performed in 1,039 patients; 320 had aortic (AVR), 543 mitral (MVR), and 176 had double valve replacement (DVR). There were 44(4.2%) early deaths. Follow-up extended in 995 patients from 10 to 130 months, with a cumulative period of 2,730 patients-years. The overall survival rates of AVR, MVR, and DVR patients at 10 years were 60.5%, 89.6%, 90.3% respectively. The linearized incidences of valve thrombosis, thromboembolism, anticoagulation-related hemorrhage, prosthetic valve endocarditis, and significant hemolysis were as follows: 0.11%/pt-yr, 1.33%/pt-yr, 0.04%/pt-yr, 0.18%/pt-yr, and 0.11%/pt-yr, respectively. There were no structural failure after 10 years follow-up. Reoperation (explant and re-replacement or suture repair) was required in 10 patients. Seven of them had periprosthetic leakage, 2 had valve thrombosis, and one underwent reoperation because of a technical error. Actuarially over 98% of patients were free of valve-related mortality at 10 years. St. Jude Medical valve is an excellent alternative for use in the surgical treatment of valvular heart disease.  相似文献   
6.
7.
The present study was undertaken to examine whether the second generation antibiotic drug minocycline attenuates behavioral changes (eg, acute hyperlocomotion and prepulse inhibition (PPI) deficits) in mice after the administration of the N-methyl-D-aspartate (NMDA) receptor antagonist (+)-MK-801 (dizocilpine). Dizocilpine (0.1 mg/kg)-induced hyperlocomotion was significantly attenuated by pretreatment with minocycline (40 mg/kg). Furthermore, the PPI deficits after a single administration of dizocilpine (0.1 mg/kg) were attenuated by pretreatment with minocycline (10, 20, or 40 mg/kg), in a dose-dependent manner. Moreover, in vivo microdialysis study in the free-moving mice revealed that pretreatment with minocycline (40 mg/kg, i.p.) significantly attenuated the increase of extracellular dopamine (DA) levels in the frontal cortex and striatum after administration of dizocilpine (0.1 mg/kg), suggesting that the inhibition of dizocilpine-induced DA release by minocycline may, at least in part, be implicated in the mechanism of action of minocycline with respect to dizocilpine-induced behavioral changes in mice. These findings suggest that minocycline could attenuate behavioral changes in mice after the administration of the NMDA receptor antagonist dizocilpine. Therefore, it is possible that minocycline would be a potential therapeutic drug for schizophrenia.  相似文献   
8.
Hyperlipidemia, hypertension, and diabetes mellitus (DM) are well-established risk factors for cardiovascular disease. We analyzed the cardiovascular events in hyperlipidemic patients with or without DM who were administered open-labeled simvastatin in groups stratified by blood pressure level using data from the Japan Lipid Intervention Trial (J-LIT). Hyperlipidemic patients with DM (n=6,288) had significantly more cardiovascular events than those without DM (n=33,933). The incidence rates of total cardiovascular events in the Non-DM and DM groups were 15.40 and 25.76 per 1,000 patients for the 6-year period, respectively. The relative risk of total cardiovascular events in the DM vs. the Non-DM group was 1.68, and the relative risk was significantly higher in the DM than in the Non-DM group. The relative risks of total cardiovascular events were significantly higher in DM and Non-DM patients whose systolic blood pressure (SBP) was greater than or equal to 130 mmHg compared to that of Non-DM patients whose SBP was less than 130 mmHg, and in DM and Non-DM patients whose diastolic blood pressure (DBP) was greater than or equal to 80 mmHg compared to that of Non-DM patients whose DBP was less than 80 mmHg. In all groups stratified by SBP and DBP, relative risks of total cardiovascular events were higher in DM patients than in Non-DM patients. For patients with hypercholesterolemia and DM, blood pressure should be strictly controlled in order to prevent both coronary events and stroke. These results are in good agreement with the JNC 7 and the ESH/ESC guidelines for DM patients, which recommended that the SBP and DBP be less than 130 and 80 mmHg, respectively.  相似文献   
9.
A 75-year-old man had been admitted to another hospital because of left abdominal pain, and was given a diagnosis of left hydronephrosis and acute pancreatitis. After a JJ stent insertion and medication, he was transferred to our hospital for further examinations. US and EUS revealed a chronic pancreatitis-like pattern and multicystic lesion in the pancreas head and body. At that time enhanced CT findings showed an extrapancreatic low density area to be inflammatory change, extending from the pancreas body to the left crus of the diaphragm and posteriorly the spreading from the left crus of the diaphragm via the left urinary duct into the left iliopsoas muscle, in which MRI revealed partial high intensity. ERCP and MRCP showed focal irregular narrowing of the pancreatic duct of unknown cause, and we decided that an internal pancreatic fistula due to pancreatitis had induced left ureteral obstruction, caused by a protein plug or alcohol. Follow-up 6 months later showed that extrapancreatic spreading of the low density area had markedly regressed without any change in the ureteral obstruction.  相似文献   
10.
Transrectal ultrasonotomography is useful in following patients with benign prostatic hypertrophy, because prostatic shape and weight are precisely assumed. We studied the effect of chlormadinone acetate (CMA) on benign prostatic hypertrophy. CMA (50 mg/day) was administered to 30 patients with benign prostatic hypertrophy. Weight reduction over 10% of the gland was noticed in 24 cases (80%). Mictional conditions were improved in 70% subjectively and in 71.4% objectively. However, the number of nocturia decreased in only 18.9%. Reduction rate of the weight was unrelated with the weight of prostate before administration of CMA. Duration of administration of CMA and the reduction rate were estimated. There was no definite difference in reduction rate for the first 15 months, but there was a slightly high reduction rate after administration of CMA for more than 24 months. In 3 cases, the shape and weight of prostate were studied after discontinuation of CMA. The size of prostate showed a tendency to increase gradually.  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