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   2717篇
  免费   171篇
  国内免费   4篇
耳鼻咽喉   56篇
儿科学   119篇
妇产科学   89篇
基础医学   413篇
口腔科学   43篇
临床医学   241篇
内科学   509篇
皮肤病学   52篇
神经病学   352篇
特种医学   64篇
外国民族医学   1篇
外科学   367篇
综合类   15篇
预防医学   164篇
眼科学   54篇
药学   188篇
中国医学   4篇
肿瘤学   161篇
  2023年   12篇
  2022年   32篇
  2021年   54篇
  2020年   31篇
  2019年   63篇
  2018年   75篇
  2017年   39篇
  2016年   38篇
  2015年   56篇
  2014年   83篇
  2013年   130篇
  2012年   159篇
  2011年   152篇
  2010年   76篇
  2009年   82篇
  2008年   152篇
  2007年   143篇
  2006年   167篇
  2005年   179篇
  2004年   143篇
  2003年   129篇
  2002年   105篇
  2001年   97篇
  2000年   106篇
  1999年   73篇
  1998年   18篇
  1997年   16篇
  1996年   30篇
  1995年   21篇
  1994年   13篇
  1993年   13篇
  1992年   44篇
  1991年   36篇
  1990年   36篇
  1989年   31篇
  1988年   36篇
  1987年   28篇
  1986年   31篇
  1985年   21篇
  1984年   20篇
  1983年   9篇
  1982年   8篇
  1981年   7篇
  1980年   7篇
  1979年   14篇
  1978年   8篇
  1975年   8篇
  1974年   9篇
  1971年   7篇
  1967年   6篇
排序方式: 共有2892条查询结果,搜索用时 15 毫秒
1.
The case of a 34-yr-old man with congenitally corrected transposition of the great vessels is described. Both first-pass and equilibrium radionuclide angiographic data were acquired and demonstrate the value of both studies in delineating the ventricular inversion and the transposed great vessels that are characteristic of this disorder. In addition to the anatomic information, the ejection fractions of the venous and systemic ventricles at rest and during exercise, the lack of any left to right shunt, and the presence of systemic A-V valve insufficiency can all be obtained from the scintigraphic data.  相似文献   
2.
Unfractionated wheat gliadin was used to produce murine monoclonal antibodies to gliadin. A dot immunobinding assay, using these antibodies, was developed to detect possible gliadin contamination of nominally gluten-free flour, using dilute ethanol extracts spotted onto nitrocellulose membranes. The sensitivity of the assay was less than 10 micrograms/ml of unfractionated gliadin which permitted the detection of trace amounts of gliadin present in certain wheat starch based 'gluten-free' products. The assay detected not only wheat gliadin, but also prolamine extracts of rye, barley and oats; maize, soya and potato extracts as well as the control proteins casein and ovalbumin, gave negative results. The assay is of value as a simple and rapid method of screening foods for their suitability for consumption by patients with coeliac disease.  相似文献   
3.
Cystic fibrosis (CF) and Crohn's disease may both present as failure to thrive and recurrent intestinal obstruction. Proper treatment and adequate nutrition may reverse these manifestations and improve the patient's quality of life. We describe a girl with CF who, despite appropriate management, failed to grow and had several episodes of bowel obstruction. After the additional diagnosis of Crohn's disease was reached, the patient improved on antiinflammatory and nutritional therapy. This patient illustrates the pitfall in the diagnosis of Crohn's disease in a CF patient due to the clinical overlap between the two conditions. We suggest that therapeutic failure in a chronic disease justifies additional diagnostic efforts resulting in a completion of diagnosis and significant changes in management.  相似文献   
4.
5.
The purpose of this study was to analyze the clinical aspects in 130 patients presenting periodic lateralized epileptiform discharges (PLEDs) in their EEG and to compare these results with those found in the literature. Etiology, neurologic deficit, seizure occurrence, and evolution were studied in each patient by historical review. The recordings were obtained on 8- or 16-channel EEGs with electrode placement according to the International 10-20 System. Recordings containing PLEDs were selected. PLEDs were defined as repetitive periodic, focal, or hemispheric epileptiform discharges (spikes, spike and waves, polyspikes, sharp waves) usually recurring every 1 to 2 seconds. The statistical study was carried out via the chi(2) test using the computer program SPSS. The main etiology found in this group of patients was stroke (61 of 130 patients). Other processes found were brain infections, tumors, hematomas, and several other entities grouped together as miscellaneous (anoxic encephalopathy, subarachnoid hemorrhage, craniocerebral trauma, Creutzfeldt-Jacob disease, migraine, multiple sclerosis, and aminophylline intoxication). Half of these patients (65 of 130) developed seizures, mostly partial motor seizures. No significant relation between etiology and seizures was found (chi(2) = 2.81, P = 0.4222). Seizures recurred in 14 of 130 patients during a follow-up of 14.5 months. PLEDs were not recorded in any EEG at the time of seizure recurrence. PLEDs constitute a distinctive but uncommon EEG phenomenon of repetitive, periodic, and stereotyped lateralized complexes. In agreement with the literature, PLEDs were associated with an acute process and occurred early during the course of the illness in all patients studied and were usually associated with structural lesions, with stroke being the main etiology. Traditionally, seizures occur with PLEDs but it is also accepted that they can exist in patients who never develop epileptic activity, either clinically or electrically, as demonstrated in 50% of the patients studied. No significant association between seizures and any etiology could be found. It was not demonstrated that the occurrence of seizures may influence the outcome in any way.  相似文献   
6.
7.
A 57-year-old Caucasian male presented with severe nephrotic syndrome and diffuse organomegaly; he subsequently developed renal failure and died. Intracellular, crystalloid material was identified by light and electron microscopy in bone marrow, liver, spleen, mesenteric lymph nodes, and kidneys. Tissue extraction analysis identified the material as glucocerebroside and its immediate precursor, ceramide lactoside. Although Gaucher's disease cannot be completely excluded, glycolipid profiles do not conform to those of known storage disorders. Additionally, electron-microscopic studies indicate that the structural features of the glycolipid deposits are different from those of previously described storage diseases. These findings suggest a unique crystalloid deposition as the probable cause of a multisystem process, which was associated with renal insufficiency and death.  相似文献   
8.
9.
Oguchi disease: suggestion of linkage to markers on chromosome 2q.   总被引:2,自引:0,他引:2       下载免费PDF全文
Oguchi disease is a rare autosomal recessive form of congenital stationary night blindness. The condition is associated with fundus discolouration and abnormally slow dark adaptation. Earlier studies suggested that the 48 kD protein S antigen may be involved in the recovery phase of light transduction. Previous cytogenetic and linkage studies have localised the S antigen gene (SAG) to chromosome 2q37.1. In the present study markers which map to distal chromosome 2q were typed in an inbred Oguchi pedigree. The segregation data obtained suggested that the affected subjects are homozygous by descent for a region between D2S172 and D2S345. An intragenic SAG polymorphism was homozygous in all affected people and a recombination event suggested that SAG maps proximal to D2S345. Collectively, these findings support the hypothesis that a defect in S antigen may be responsible for Oguchi disease.  相似文献   
10.
Methylprednisolone was recently reported to significantly improve motor and sensory function after acute spinal cord injury in patients. Our study was designed to determine whether methylprednisolone exerts a beneficial effect after head injury. Diethyl ether-anesthetized rats were assigned to receive surgery with no cranial impact and no methylprednisolone (group A, n = 13); surgery with no cranial impact and intraperitoneal methylprednisolone (greater than or equal to 60 mg/kg) (group B, n = 8); surgery with cranial impact and no methylprednisolone (group C, n = 8, and group E, n = 8); or surgery with cranial impact and methylprednisolone (greater than or equal to 60 mg/kg) (group D, n = 15, and group F, n = 13). Neurologic severity score was determined at 1, 2, 4, and 24 h (when appropriate) after injury, and brain tissue eicosanoid levels and cerebral edema were determined when the animals were killed (4 h after injury in groups C and D and 24 h after injury in groups E and F). Treatment with methylprednisolone did not improve neurologic severity score or edema formation and did not alter brain tissue levels of prostaglandin E2, thromboxane B2, or 6-keto-prostaglandin F1 alpha at any time period. The authors conclude that methylprednisolone does not exert a beneficial effect on brain tissue edema or functional activity after cranial impact in rats.  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