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   2638篇
  免费   126篇
  国内免费   15篇
耳鼻咽喉   19篇
儿科学   117篇
妇产科学   21篇
基础医学   289篇
口腔科学   37篇
临床医学   230篇
内科学   844篇
皮肤病学   30篇
神经病学   109篇
特种医学   102篇
外科学   289篇
综合类   139篇
预防医学   172篇
眼科学   48篇
药学   178篇
中国医学   14篇
肿瘤学   141篇
  2023年   14篇
  2022年   41篇
  2021年   81篇
  2020年   32篇
  2019年   42篇
  2018年   61篇
  2017年   49篇
  2016年   51篇
  2015年   55篇
  2014年   76篇
  2013年   97篇
  2012年   179篇
  2011年   172篇
  2010年   109篇
  2009年   103篇
  2008年   158篇
  2007年   180篇
  2006年   117篇
  2005年   97篇
  2004年   125篇
  2003年   96篇
  2002年   76篇
  2001年   59篇
  2000年   48篇
  1999年   56篇
  1998年   34篇
  1997年   33篇
  1996年   20篇
  1995年   16篇
  1994年   15篇
  1993年   14篇
  1992年   21篇
  1991年   25篇
  1990年   28篇
  1989年   29篇
  1988年   28篇
  1987年   29篇
  1986年   38篇
  1985年   24篇
  1984年   19篇
  1983年   25篇
  1982年   18篇
  1976年   11篇
  1975年   11篇
  1974年   11篇
  1973年   17篇
  1972年   14篇
  1971年   19篇
  1968年   12篇
  1958年   11篇
排序方式: 共有2779条查询结果,搜索用时 15 毫秒
1.
2.
3.
Low diastolic blood pressure is alleged to impose excess cardiovascular disease (CVD) risk in patients with treated hypertension, impeding aggressive reduction of blood pressure. Most investigations that assessed the potential J-shaped relations of diastolic blood pressure and adverse outcomes have not adequately considered systolic or pulse pressure in statistical analyses. An overview of hypertension trials indicates that lowering elevated blood pressure reduces the risk of CVD outcomes irrespective of the associated decrease in diastolic pressure, even if the achieved diastolic pressure averages less than 70 mm Hg. The Framingham study investigations have determined that the increased CVD incidence observed at low diastolic blood pressure levels is confined largely to persons with concomitantly increased systolic pressure. This finding of no true excess risk at low diastolic blood pressure agrees with the results of trials that have evaluated the J-curve phenomenon adjusting for systolic pressure. Aggressively treating systolic hypertension appears to produce no cause for alarm.  相似文献   
4.
Background: The fabrication of dental prosthesis requires the transfer of interocclusal records from patient's mouth to semiadjustable articulators using different kinds of recording media. Any inaccuracy in these interocclusal records leads to occlusal errors in the final prosthesis. This study was conducted to evaluate the dimensional changes occurring in the interocclusal recording material over a given period of time and the material's resistance to compression during the cast mounting on the articulator.  相似文献   
5.
de Vries Reilingh  TS  van Geldere  D  Langenhorst  BLAM  de Jong  D  van der Wilt  GJ  van Goor  H  Bleichrodt  RP 《Hernia》2004,8(1):56-59
Polypropylene mesh is widely used for the reconstruction of incisional hernias that cannot be closed primarily. Several techniques have been advocated to implant the mesh. The objective of this study was to evaluate, retrospectively, early and late results of three different techniques, onlay, inlay, and underlay. The records of 53 consecutive patients with a large midline incisional hernia — 25 women and 28 men, mean age 60.4 (range 28–94) — were reviewed. Polypropylene mesh was implanted using the onlay technique in 13 patients, inlay in 23 patients, and underlay in 17 patients. Either the greater omentum or a polyglactin mesh was interponated between the mesh and the viscera. The records of these 53 patients were reviewed with respect to: size and cause of the hernia, pre- and postoperative mortality and morbidity, with special attention to wound complications. Patients were invited to attend the outpatient clinic at least 12 months after implantation of the mesh for physical examination of the abdominal wall. Postoperative complications occurred in 14 (26.4%) patients. The onlay technique had significantly more complications, as compared to both other techniques. Reherniation occurred in 15 (28.3%) patients. The reherniation rate of the inlay technique was significantly higher than after the underlay technique (44% vs 12%, P=0.03) and tended to be higher than the onlay technique (44% vs 23%, P=0.22). Repair of large midline incisional hernias with the use of a polypropylene mesh carries a high risk of complications and has a high reherniation rate. The underlay technique seems to be the better technique.  相似文献   
6.
The antimutator phenotype, reportedly conferred by disruption of the Saccharomyces cerevisiae DDR48 gene, was suggested to affect only a specific spontaneous mutational pathway. We attempted to identify the types of mutation that are DDR48-dependent by determining the specificity of the ddr48 antimutator. However, disruption of DDR48 did not decrease the rates of spontaneous forward mutation in a plasmid-borne copy of the yeast SUP4-o gene, the reversion or suppression of the lys2–1 allele, or forward mutation at the CAN1 locus. Interestingly, the latter gene had been reported previously to be subject to the antimutator effect. DNA sequence analysis of spontaneous SUP4-o mutations arising in DDR48 and ddr48 backgrounds provided no evidence for a reduction in the rates of individual mutational classes. Thus, we were unable to verify that disruption of DDR48 causes an antimutator phenotype.  相似文献   
7.
During the first half of the 20th century, chronic energy undernutrition due to low dietary intake, repeated infections, and rapid succession of pregnancy were the factors most responsible for maternal undernutrition and consequent adverse outcomes of pregnancy. Efforts to improve dietary intake, treatment of infections, and provision of contraceptive care were the major focuses of intervention from 1950 to 1990. These interventions resulted in reduction in severe grades of undernutrition. However, there was no reduction in mild and moderate degrees of undernutrition and anemia during pregnancy and there was no significant improvement in the course and outcome of pregnancy, or in birth weight. During the 1990s, among the middle- and upper-income groups, there has been a progressive rise in obesity and consequent adverse effects. The advent of HIV infection in India in the 1980s will inevitably lead to increases in severe undernutrition associated with HIV infection in pregnancy and an adverse impact of maternal HIV infection on the fetus. Practicing physicians and nutritionists in the new millennium will therefore have to assess each person individually and provide appropriate advice regarding diet, exercise, fertility, and infection prevention and control in order to achieve optimum health and nutrition status during pregnancy and to prevent adverse pregnancy outcomes.  相似文献   
8.
The authors report the clinical and laboratory findings of a patient who had severe immune hemolytic anemia due to hydrochlorothiazide (HCTZ). In this case, the HCTZ antibody reacted not only with other thiazide and thiazide-like drugs, but also with a chemically unrelated diuretic, ethacrynic acid. These results indicate that HCTZ antibody activity is not restricted solely to the thiazides and imply that therapy with any of the reactive drugs would be contraindicated for this patient. The serologic screening for drug reactivity may be useful for selecting alternative therapy for patients with drug-induced immune hemolytic anemia.  相似文献   
9.
Since the clinical significance of CT abnormalities found in bipolar patients remains obscure, we studied 26 DSM-III bipolar patients who had specific CT abnormalities (third ventricle enlargement, and hyperdensity of the caudate, thalamus, anterior frontal white matter, and right temporal lobe) on numerous parameters such as EEG, the Halstead-Reitan Neuropsychological Battery, premorbid personality adjustment, family history of affective disorder, positive and negative symptoms, employment history, and response to lithium carbonate treatment. None of these measures could differentiate between the CT abnormal and CT normal subgroups. The implications of these findings are discussed.  相似文献   
10.
We report an unusual case of chronic subdural haematoma (CSH) associated with cerebrospinal fluid (CSF) rhinorrhoea emphasizing the importance of managing both conditions simultaneously. A 59- year-old man presented with watery discharge from the right nostril, of 2 months duration. MRI of the brain showed a CSH in the left fronto-parietal region with significant mass effect. There was an arachnoidocoele with a defect in the planum sphenoidale. He first underwent a burr hole evacuation of the CSH following which the CSF rhinorrhea did not subside, even with bed rest. Transnasal endoscopic closure of the CSF dural fistula was done. On the first post-operative day, he was disoriented and a CT scan showed a recollection of the subdural haematoma that required repeat evacuation. The patient was asymptomatic at discharge. To our knowledge this is the first reported case of CSF rhinorrhoea associated with CSH. Simultaneous closure of the CSF dural fistula at the time of evacuation of a coexisting CSH would be the optimal management.  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