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   184188篇
  免费   10985篇
  国内免费   946篇
耳鼻咽喉   2285篇
儿科学   5735篇
妇产科学   3618篇
基础医学   23599篇
口腔科学   7844篇
临床医学   14363篇
内科学   39351篇
皮肤病学   4437篇
神经病学   14375篇
特种医学   5745篇
外国民族医学   26篇
外科学   22142篇
综合类   5025篇
现状与发展   6篇
一般理论   60篇
预防医学   19885篇
眼科学   3330篇
药学   11810篇
  19篇
中国医学   2138篇
肿瘤学   10326篇
  2023年   925篇
  2022年   2124篇
  2021年   3917篇
  2020年   2778篇
  2019年   3595篇
  2018年   5063篇
  2017年   3973篇
  2016年   3688篇
  2015年   4519篇
  2014年   6288篇
  2013年   7998篇
  2012年   12382篇
  2011年   13093篇
  2010年   7265篇
  2009年   6377篇
  2008年   9911篇
  2007年   10259篇
  2006年   9343篇
  2005年   9294篇
  2004年   8560篇
  2003年   7733篇
  2002年   5716篇
  2001年   4989篇
  2000年   4979篇
  1999年   4339篇
  1998年   1538篇
  1997年   1282篇
  1996年   1280篇
  1995年   1077篇
  1994年   1074篇
  1993年   980篇
  1992年   2647篇
  1991年   2562篇
  1990年   2333篇
  1989年   2333篇
  1988年   2106篇
  1987年   1954篇
  1986年   1828篇
  1985年   1755篇
  1984年   1255篇
  1983年   1009篇
  1982年   566篇
  1981年   514篇
  1980年   493篇
  1979年   919篇
  1978年   604篇
  1977年   476篇
  1975年   542篇
  1974年   539篇
  1973年   540篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
Adipose tissue fatty acid composition, serum lipid profile, and dietary intake of 37 patients on maintenance hemodialysis were studied. In August 1982, 1984, and 1986, analyses were carried out in 15 normotriglyceridemic (NTG) and 22 hypertriglyceridemic (HTG; type IV hyperlipidemia) patients. No correlations were found between dietary intake of polyunsaturated fatty acids (PUFAs), ratio of polyunsaturated to saturated fatty acids (P-S ratio), and carbohydrate content on the one hand and serum lipid concentrations on the other in the two groups. Adipose tissue linolenic acid correlated negatively with serum cholesterol in both groups. Strong correlations were found between dietary intake of PUFAs and adipose tissue linoleic acid content, between PUFAs and the double-bond index, between P-S ratio and adipose tissue linoleic acid content, and between P-S ratio and the double-bond index. No significant differences in dietary intake or adipose tissue fatty acid composition were observed between NTG and HTG patients. Thus, no evidence was found for exogenous dietary influences on serum lipid concentrations. The adipose tissue linoleic acid content did reflect the dietary intake of PUFAs.  相似文献   
103.
OBJECTIVE.--To determine behavioral and demographic risk factors for human immunodeficiency virus (HIV) infection in central Africa. DESIGN.--Cross-sectional survey. SETTING.--Kigali, Rwanda. PARTICIPANTS.--A representative sample of 1458 childbearing women aged 19 to 37 years who were recruited from outpatient prenatal and pediatric clinics at the only community hospital in the city. MAIN OUTCOME MEASURE.--Antibodies to HIV assessed by enzyme immunoassay and confirmed by Western blot or indirect immunofluorescence. RESULTS.--The HIV seroprevalence was 32% overall. Infection rates were higher in women who were single, in those in steady relationships that began after 1981, and in the 33% of women reporting more than one lifetime sexual partner. Women in legal marriages or monogamous partnerships had lower rates of infection, but even low-risk women had prevalences on the order of 20%. History of venereal disease in the past 5 years, although the strongest risk factor in a multiple logistic analysis (odds ratio, 2.7; 95% confidence interval, 2.0 to 3.7), was reported by only 30% of those infected. Having a male sexual partner who drank alcohol or who had higher income were significant risk factors for HIV infection in the multivariate analysis, but use of oral contraceptives and having an uncircumcised partner were not. CONCLUSIONS.--The epidemic of the acquired immunodeficiency syndrome in Rwanda has spread beyond high-risk groups to the general population of women without known risk factors. For most of these women, a steady male partner is the source of their HIV risk and therefore a vital target for intervention efforts.  相似文献   
104.
A percentage of human T lymphocytes forms rosettes with autologous erythrocytes and this property has been considered as a marker for post-thymic precursor suppressor cells capable of providing suppression under the influence of inducer cells. We quantitated autologous rosette-forming T cells (ARFC) in the peripheral blood of 37 patients with chronic HBV infection: 8 healthy carriers, 9 chronic persistent hepatitis (CPH-B) and 20 chronic active hepatitis (CAH-B). Two control groups were studied, one consisting of 26 healthy individuals and the other of 8 individuals with non-HBV-associated CAH. Patients with non-HBV-associated CAH had a significant reduction in the proportion of ARFC, whereas CAH-B patients fell into 2 distinct patterns, one with increased and the other with decreased proportions of ARFC. This was unrelated to the degree of biochemical activity of the disease or to degree of viral replication as defined by HBeAg status and HBV-DNA in the serum. Healthy carriers and CPH-B had no changes in ARFC. Simultaneous quantitation of OKT4 and OKT8+ cells was done and a positive correlation was found between the proportions of ARFC and the proportions of OKT8+ cells. The possible significance of this correlation and the relevance of the bimodal distribution of autologous rosette-forming cells in CAH-B are discussed.  相似文献   
105.
106.
107.
108.
Summary In 1981 generalized anaphylaxis was registered on 166 occasions in Dutch general and academic hospitals. Clinical details of 120 of those patients revealed that in 107 anaphylaxis was either probable (n=90) or possible (n=17), whereas in 13 cases some other reaction than anaphylaxis had occurred. The series of confirmed cases contained 46 men and 61 women, with mean ages of 47 y and 48 y, respectively.There was a complete recovery in 102 patients and two patients died. Hypotension was present in 79 cases (74%), dyspnoea in 34 cases (32%) and a skin reaction, mainly urticaria, erythema or angioedema, was mentioned in 62 cases (58%). Most cases of anaphylaxis were drug-induced (76%), the main causes being the analgesic glafenine and contrast media. Glafenine was mentioned as the cause in 36% of all admissions for drug-induced anaphylaxis. Only 3.7% of cases had been reported to the voluntary reporting scheme of the Netherlands Centre for Monitoring of Adverse Reactions to Drugs.On the basis of reimbursement data, the risk of developing severe anaphylaxis to glafenine was estimated at 11.7–19.3-fold relative to indomethacin, and 13.4–20.2-fold relative to oral penicillins.  相似文献   
109.
We report the clinical, neurophysiological (comprehending electromyography, nerve conduction velocities, and multimodal evoked potentials), histological study of the nerve and muscle and the effect of vitamin E supplement in a 32-year-old case with chronic vitamin E deficiency subsequent to acquired intestinal malabsorption. An early diagnosis for an early treatment is essential in preventing severe neurological deterioration.  相似文献   
110.
To standardize the maximal static force (Fo) of the arm flexors, the accuracy of an anthropometric method for estimating the mid-arm cross-sectional muscle and bone area (MBA) was investigated. This was done by comparing the anthropometrically determined area (MBA.A) with the area measured by means of computerized tomography (MBA.S). In the same way, the accuracy of Heymsfield's equations (Heymsfield et al., 1982) for predicting MBA (MBA.H) from anthropometric measures was tested. MBA.A was significantly larger than MBA.S, the relative difference increasing with the thickness of the subcutaneous fat layer. This difference was attributed to a 27% underestimation of the fat layer thickness as measured with the skinfold caliper. Women being fatter than men, this caused the standardized maximal static force (Fo/MBA) to be lower in women than in men. MBA.H was 12% smaller than MBA.S. This may have been due to a difference in the way of measuring the arm circumference between the present authors and Heymsfield et al.  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