AChE inhibitionOther cholinesterasesPhysical propertiesLatency and toxicityPharmacological propertiesClinical manifestationsTreatmentPyridostigmineAtropinePralidoxime
  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   1341268篇
  免费   100667篇
  国内免费   4600篇
耳鼻咽喉   16839篇
儿科学   43718篇
妇产科学   36444篇
基础医学   198227篇
口腔科学   36110篇
临床医学   130495篇
内科学   258671篇
皮肤病学   26458篇
神经病学   112010篇
特种医学   48387篇
外国民族医学   366篇
外科学   184480篇
综合类   30166篇
现状与发展   1篇
一般理论   460篇
预防医学   114960篇
眼科学   29063篇
药学   99466篇
  6篇
中国医学   3882篇
肿瘤学   76326篇
  2021年   11034篇
  2019年   11742篇
  2018年   16441篇
  2017年   12440篇
  2016年   13366篇
  2015年   15435篇
  2014年   21054篇
  2013年   32392篇
  2012年   44809篇
  2011年   47612篇
  2010年   27636篇
  2009年   25372篇
  2008年   43262篇
  2007年   45577篇
  2006年   45649篇
  2005年   44013篇
  2004年   41787篇
  2003年   39680篇
  2002年   38461篇
  2001年   60928篇
  2000年   62607篇
  1999年   52308篇
  1998年   14585篇
  1997年   13279篇
  1996年   13117篇
  1995年   12459篇
  1994年   11632篇
  1993年   10925篇
  1992年   41569篇
  1991年   40762篇
  1990年   39446篇
  1989年   37340篇
  1988年   34581篇
  1987年   33693篇
  1986年   32150篇
  1985年   30638篇
  1984年   23034篇
  1983年   19590篇
  1982年   11752篇
  1979年   20804篇
  1978年   14814篇
  1977年   12065篇
  1976年   11876篇
  1975年   12110篇
  1974年   14801篇
  1973年   14472篇
  1972年   13357篇
  1971年   12418篇
  1970年   11485篇
  1969年   10410篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
A topographic CEEG investigation was carried out in 20 drug-free, DSM-IIIR diagnosed schizophrenics and in a group of matched healthy controls. The effects of acute and chronic haloperidol treatment were then assessed in the patient group. On the baseline recording, schizophrenics showed a widespread increase in delta, theta 1 and beta 3 amplitude. Acute haloperidol administration produced a decrease in delta and an increase in slow beta amplitude. After 28 days of treatment, delta and fast beta were reduced while theta 2 and alpha 1 were increased. CEEG abnormalities in schizophrenic subjects appear, therefore, to be reduced by chronic neuroleptic treatment.  相似文献   
992.
The glomerular layer of the olfactory bulb contains a substantial population of dopaminergic neurons. We determined the quantity and location of D1 and D2 dopamine receptors which are the presumed targets of these neurons. Binding of the D1 selective ligand [3H]SCH23390 was slightly above background and was distributed through all layers of the bulb except the olfactory nerve layer. In contrast there were relatively high levels of [3H]spiperone binding to D2 DA receptors in the glomerular and olfactory nerve layers. The presence of relatively high concentrations of D2 DA receptors in both the nerve layer and glomerular layer suggests the novel hypothesis that these receptors may be localized on terminals of the olfactory nerve.  相似文献   
993.
Stereoisomers of remacemide (racemate form) were compared for anticonvulsant efficacy and safety in mice. In the maximal electroshock seizure (MES) test for oral efficacy, the (-) stereoisomer, FPL 14145, was more potent than the racemate or the (+) stereoisomer, FPL 14144. Respective ED50 values (expressed as mg/kg) were: remacemide, 58; FPL 14145, 45; FPL 14144, 79. In 2 of 3 tests for neural impairment, FPL 14145 yielded significantly better therapeutic indices (toxic dose 50/ED50) than the racemate. The margin of safety (estimated median lethal dose ED50) was more favorable for FPL 14144: remacemide, 15.1; FPL 14144, 18.9; FPL 14145, 15.7. The duration of protection against MES indicated the stereoisomers were longer acting than the racemate. After intravenous administration the order of potency against MES was similar: FPL 14145 greater than remacemide greater than FPL 14144. Following daily administration of the oral ED98 for 4 days, with a dose response curve run on day 5, the MES ED50 values for all compounds were increased. The test indicates tolerance. In the pentylenetetrazol infusion test the racemate and FPL 14144 demonstrated more proconvulsant properties than FPL 14145. Intraperitoneal administration of 50 mg/kg or more produced changes in behavior with all compounds. At higher doses the racemate and FPL 14145 elicited more severe symptoms with death at 200 mg/kg.  相似文献   
994.
The long term recovery of a series of 27 patients who had undergone rupture and repair of an aneurysm of the anterior communicating artery was assessed using a number of neuropsychological measures. Testing took place 12 to 84 months post surgery. On the basis of the results from tests of intellect, memory, and conceptual learning, three subgroups of patients were identified: those with persuasive cognitive defects, those with evidence of residual frontal lobe damage and those who showed no evidence of dysfunction. The occurrence of cerebral vasospasm was the most consistent predictor of long term cognitive deficit.  相似文献   
995.
BACKGROUND. A health risk appraisal (HRA) is a tool for health promotion. Conversational microcomputer-based HRAs may be more cost effective than other HRA formats. The acceptability of conversational HRAs, however, has not been demonstrated for older adults. METHODS. We studied the acceptability of a conversational microcomputer-based HRA in a sample of 247 adults at the Minnesota State Fair and the Senior Options Exposition. All users were offered the appraisal via mouse or keyboard interface. Acceptability was measured in terms of user-reported helpfulness, intent to change, time of use, and willingness to view HRA health recommendations. Data on completion time and willingness to view HRA recommendations were collected for Senior Exposition users only. Regression analyses were used to examine the combined impact of interface (mouse or keyboard), location (State Fair or Senior Exposition), age, and sex on user acceptability. Results. Interface and location had no effect on helpfulness or change ratings. Older users rated the appraisal more helpful (P less than .007). Both older and female users reported more intent to change behavior (P = .016, both). Time to use the appraisal was related to interface, age, and sex. Mouse users (P less than .0001), older users (P less than .0001) and female users (P less than .05) took significantly longer to use the appraisal. Significantly more mouse users declined to see recommendations (P less than .02). CONCLUSIONS. Older users can derive as much or more value from conversational health risk appraisals as younger users; however, a mouse interface may be less effective for this age group.  相似文献   
996.
997.
An improved method for determining 89Sr and 90Sr in urine   总被引:1,自引:0,他引:1  
A method has been developed for the rapid isolation and quantitation of 89Sr and 90Sr in urine samples. The radiostrontium is concentrated from the bulk urine sample by coprecipitation with calcium phosphate. The precipitate is then wet ashed with nitric acid, and a solution of the resulting residue in 2 M HNO3-0.5 M Al(NO3)3 is passed through an extraction chromatographic column containing a supported crown ether that preferentially retains strontium. Sorbed strontium may then be eluted from the column with either dilute HNO3 or water and counted via liquid scintillation. A new counting scheme that permits quantitation of both 89Sr and 90Sr on the same day the separation is performed is described.  相似文献   
998.
There is limited information regarding oral health status and other predictors of oral health‐related quality of life. An association between oral health status and perceived oral health‐related quality of life (OHQOL) might help clinicians motivate patients to prevent oral diseases and improve the outcome of some dental public health programs. This study evaluated the relationship between older persons' OHQOL and their functional dentition, caries, periodontal status, chronic diseases, and some demographic characteristics. A group of 733 low‐income elders (mean age 72.7 ISD=4.71, 55.6% women, 55.1% members of ethnic minority groups in the U.S. and Canada) enrolled in the TEETH clinical trial were interviewed and examined as part of their fifth annual visit for the trial. OHQOL was measured by the Geriatric Oral Health Assessment Index (GOHAI); oral health and occlusal status by clinical exams and the Eichner Index; and demographics via interviews. Elders who completed the four‐year assessment had an average of 21.5 teeth (SD=6.9). with 8.5 occluding pairs (SD=4.6), and 32% with occlusal contacts in all four occluding zones. Stepwise multiple regressions were conducted to predict total GOHAI and its subscores (Physical, Social, and Worry). Functional dentition was a less significant predictor than ethnicity and being foreign‐bom. These variables, together with gender, years since immigrating, number of carious roots, and periodontal status, could predict 32% of the variance in total GOHAI, 24% in Physical, 27% in Social, and 21 % in the Worry subscales. These findings suggest that functional dentition and caries influence older adults' OHQOL, but that ethnicity and immigrant status play a larger role.  相似文献   
999.
1000.
Geoghegan  James; Tong  Jeffrey L 《CEACCP》2006,6(6):230-234
The first 150 words of the full text of this article appear below. Key points
  • Chemical personal protective equipment must be wornwhen in contact with contaminated casualties.
  • Recognizing theclinical features of chemical warfare agent poisoning allowssupportive treatment and appropriate antidotes to be promptlyadministered.
  • The mnemonic DUMBELS describes the muscarinicfeatures of the nerve agent poisoning toxidrome.
  • There areeffective antidotes for poisoning with nerve agents, blood agents(metabolic poisons), botulinum toxin and kolokol-1.
  • There areno specific antidotes for blistering agents (vesicants) andchoking agents.
  Chemical warfare (CW) agents are chemical substances that havea direct toxic effect on plants, animals and humans. Classifiedaccording to their physiological effects, agents effective againsthumans include nerve agents, blistering agents (vesicants),blood agents, choking agents and toxins. Incapacitating, vomiting,psychoactive and riot control agents (e.g. CS gas) also exist.1 All personnel in contact with contaminated casualties must wearthe appropriate level of chemical personal protective equipment(CPPE) until adequate decontamination is . . . [Full Text of this Article]
   Nerve agents