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   22496篇
  免费   1960篇
  国内免费   41篇
耳鼻咽喉   227篇
儿科学   772篇
妇产科学   538篇
基础医学   2898篇
口腔科学   404篇
临床医学   2631篇
内科学   4356篇
皮肤病学   292篇
神经病学   1842篇
特种医学   885篇
外国民族医学   1篇
外科学   2949篇
综合类   526篇
一般理论   11篇
预防医学   2331篇
眼科学   860篇
药学   1539篇
中国医学   19篇
肿瘤学   1416篇
  2021年   385篇
  2020年   218篇
  2019年   388篇
  2018年   450篇
  2017年   334篇
  2016年   354篇
  2015年   444篇
  2014年   587篇
  2013年   826篇
  2012年   1196篇
  2011年   1232篇
  2010年   683篇
  2009年   672篇
  2008年   1139篇
  2007年   1197篇
  2006年   1147篇
  2005年   1065篇
  2004年   1079篇
  2003年   1009篇
  2002年   982篇
  2001年   555篇
  2000年   584篇
  1999年   522篇
  1998年   240篇
  1997年   233篇
  1996年   190篇
  1995年   212篇
  1994年   195篇
  1993年   197篇
  1992年   413篇
  1991年   433篇
  1990年   403篇
  1989年   389篇
  1988年   348篇
  1987年   341篇
  1986年   344篇
  1985年   328篇
  1984年   250篇
  1983年   200篇
  1982年   164篇
  1981年   142篇
  1980年   139篇
  1979年   203篇
  1978年   152篇
  1977年   150篇
  1976年   123篇
  1974年   137篇
  1973年   142篇
  1972年   122篇
  1971年   125篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
A national survey was conducted to determine how occupational therapists and rehabilitation nurses conduct sexuality counseling in practice settings with spinal cord-injured patients. A review of the literature and results from the survey demonstrated a high priority concern for sexuality counseling in the total rehabilitation of the spinal cord-injured patient; however, many of the professionals surveyed did not conduct sexuality counseling as part of their job. This study provides data comparing the sexuality counseling approach taken by these two disciplines and identifies ways to eliminate the incongruities between recommendations made in the literature and actual clinical practice.  相似文献   
102.
A comprehensive anatomic and radiographic analysis of the peribursal fat plane in 12 cadavers confirmed that the fat plane seen on radiographs represents extrasynovial fat lining the subacromial bursa and documented the anatomic relations of the bursa. A three-part retrospective clinical evaluation of rotator cuff tears, calcific tendinitis, and rheumatoid arthritis was performed. Two osteoradiologists blindly graded the appearance of the peribursal fat plane with the shoulder in external versus internal rotation in 21 patients with arthrographically intact rotator cuffs and 21 patients with disrupted rotator cuffs. The peribursal fat plane was seen better with disrupted rotator cuffs. The peribursal fat plane was seen better with the shoulder in internal rotation and was seen in 60% of control subjects but only 21% of patients with rotator cuff tears. Partial or complete obliteration of this fat plane is a sensitive (79%) but less specific (60%) indicator of rotator cuff tears. Obliteration of the peribursal fat plane by inflammatory processes in adjacent tissues, including calcific tendinitis and rheumatoid arthritis, occurred with a high frequency.  相似文献   
103.
104.
A double blind placebo controlled study was carried out in 40 subjects newly referred for treatment for obesity to determine the effects of the new thermogenic beta adrenoceptor agonist BRL 26830A. The subjects were randomised to receive either BRL 26830A, 200 mg daily for two weeks then 400 mg daily, or placebo for 18 weeks, and all were instructed to follow a 3.35 MJ diet that was low in fat and high in fibre. Weight loss was 15.4 (SD 6.6) kg in subjects given BRL 26830A compared with 10.0 (5.9) kg in those given placebo (p = 0.02). The relative weight loss was 0.93 (0.39%) a week with BRL 26830A and 0.61 (0.38)% with placebo (p = 0.02). Urinary excretion of nitrogen was similar in both groups, whereas measurements of skinfold thickness indicated a 4.1 kg difference in the amount of fat lost, suggesting that weight loss with BRL 26830A was mainly from adipose and not lean tissue. BRL 26830A had no effect on resting pulse rate or pressor effects on either diastolic or systolic blood pressure. No significant differences were found between the two groups in serum cholesterol concentration, percentage of high density lipoprotein cholesterol, plasma concentrations of glucose and insulin, the ratio of glucose to insulin, serum concentrations of triiodothyronine and thyroxine, and creatinine clearance. Short term administration of BRL 26830A to six subjects who had taken the drug for 18 weeks showed that the expenditure of energy increased by 11.6% during the second hour after administration, which suggests that BRL 26830A may enhance weight loss thermogenically. BRL 26830A may be a useful drug in the treatment of obesity.  相似文献   
105.
106.
Canine Distemper Virus (CDV) produces an encephalitis in dogs that varies with viral strain. We have studied the cell tropisms of two virulent strains (CDV-SH and CDV A75-17) and an attenuated strain, Rockborn (CDV-RO), in cultured canine brain cells. Infected cell types were identified by double immunofluorescent labeling of specific cell markers and viral antigens. All viral strains studied produced infection in astrocytes, fibroblasts, and macrophages. Neurons were not infected by CDV A75-17 but were rapidly infected by CDV-SH and CDV-RO. Multipolar oligodendrocytes were very rarely infected by any of the virus strains. In contrast, a morphologically distinct subset of bipolar oligodendrocytes were commonly infected by CDV-SH and CDV-RO. The kinetics of infection in the astrocytes, oligodendrocytes, neurons, and macrophages varied between strains. Both CDV-SH and CDV-RO rapidly infected bipolar oligodendrocytes, astrocytes, neurons, and macrophages by 14 days post infection while infection by CDV A75-17 was delayed until after 28-35 days post infection. The differences in the growth kinetics and cell tropisms for some brain cells, exhibited by the three viral strains examined in this in vitro study, may relate to the different CNS symptoms that these strains produce in vivo.  相似文献   
107.
Diquat produces hepatic necrosis in the Fischer-344 rat, and although reactive oxygen species generated by redox cycling are thought to mediate the damage, the possibility that covalent binding of diquat or diquat metabolites to tissue macromolecules contributes to the observed hepatotoxicity of diquat needed to be examined experimentally. Intraperitoneal administration of [ethylene-14C]diquat (0.1 mmol/kg) results in distribution of radioactivity to all organs examined. Measurable radioactivity remains associated with hepatic and renal protein even after extensive solvent extraction, but the amount (12-16 pmol/mg protein) is 100-fold less than the extent of covalent binding observed with comparably hepatotoxic doses of other hepatotoxins such as acetaminophen and bromobenzene. Similarly, although small amounts of radioactivity remain in Folch lipid extracts of liver and kidney (56-179 pmol/mg lipid), this is virtually completely removed by transesterification of the lipid (less than 5 pmol/mg lipid), indicating that the radioactivity does not represent an alkylation of electroneutral alkyl residues of the lipid. The diquat-induced increase in biliary excretion of glutathione disulfide temporally parallels the biliary excretion of radioactivity. Although the present results do not prove the absence of a contribution by alkylation mechanisms to diquat hepatotoxicity, the extremely low upper limits placed on possible covalent interactions reinforce the confidence with which the diquat-treated Fischer-344 rat can be employed as an animal model for mechanisms of cell death mediated by reactive oxygen species.  相似文献   
108.
A group of 12 internists, members of a university-affiliated hospital, designed and implemented protocols for the general inpatient management of four medical problems (chest pain, stroke, pneumonia, and upper gastrointestinal hemorrhage). Hospital charges for the 63 cases were compared with charges generated by 64 controls who had been patients admitted to the same physicians with the same diagnoses during the same period of the preceding year, before the project was begun. A group of nonparticipating internists was similarly evaluated during the two time periods to control for changes in practice patterns extraneous to the intervention. Adjustment was made for inflation (6%) and differences in case mix. The program resulted in a 15% reduction in total average charge generated by the cases. Sizeable reductions were achieved in utilization of EKGs (34.8%), x-rays (15.4%), laboratory testing (20.4%), and drugs (11.4%). Given the prevailing attitude that health care costs are too high and that many services are unnecessary, the benefit of altering physician behavior by using standards established by them for themselves could be substantial, especially with the threat of more restrictive and less sympathetic modes of controlling costs.  相似文献   
109.
We report on 44 consecutive patients who underwent 1-stage hypospadias repair based on a urethral splent (silicone pleated stent). The severity of hypospadias ranged from subcoronal in 12 cases and distal in 23 to midshaft in 4 and penoscrotal in 5. In the first 15 patients of this series the splent was used with a suprapubic tube. All patients were able to void within the first 36 hours postoperatively. The next 29 patients underwent repairs without the use of a bladder catheter, including 15 who had outpatient procedures. None of the 44 patients has required subsequent catheterization or hospitalization. There have been 2 fistulas in this series. The urethral splent permits normal voiding through and drainage of the neourethra in a variety of hypospadias repairs. The splent expands and contracts with the degree of edema and permits catheterization should this be necessary. The advantages of hypospadias repair without bladder drainage, such as short hospital stay, total ambulation, and decreased potential for infection and bladder spasm, can be realized with the use of a urethral splent.  相似文献   
110.
Recent developments in the epidemiology of diabetes in the Americas.   总被引:3,自引:0,他引:3  
The prevalence of diabetes recorded in population surveys in the American region varies from < 1% (rural Mapuche Indians aged 20 years and over, Chile) to almost 50% (Pima Indians aged 20 years and over, United States of America). The prevalence of non-insulin-dependent diabetes mellitus (NIDDM) was approximately 2.5 times higher among Mexican Americans than in non-Hispanic white Americans. In the Mexican Americans, prevalence followed a sociocultural gradient: 16% in low-income barrios, about 10% in middle-income neighbourhoods and 5% in high-income suburbs in San Antonio, Texas. Data from the Hispanic Health and Nutrition Examination Survey indicate prevalence of diabetes in the age range 45-74 years of 24% for Mexican Americans, 26% for Puerto Ricans and 16% for Cuban Americans, compared to 12% for non-Hispanic whites. Figures for a low-income district of Mexico City show a 36% lower prevalence than for Mexican Americans in the USA. Prevalence in Brazil is approximately 7% in subjects aged 30-69 years. Black Americans have a relatively high prevalence of NIDDM, though not as high as the Mexican Americans. There is evidence that complications of diabetes may vary between populations, and that they may be particularly severe in Mexican Americans, and higher in black than in white Americans. The extent to which these differences relate to access to health care and treatment remains to be clarified.  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