全文获取类型
收费全文 | 715404篇 |
免费 | 49873篇 |
国内免费 | 1319篇 |
专业分类
耳鼻咽喉 | 9242篇 |
儿科学 | 23648篇 |
妇产科学 | 17790篇 |
基础医学 | 111578篇 |
口腔科学 | 20255篇 |
临床医学 | 64874篇 |
内科学 | 136005篇 |
皮肤病学 | 16260篇 |
神经病学 | 50359篇 |
特种医学 | 26024篇 |
外国民族医学 | 76篇 |
外科学 | 106020篇 |
综合类 | 15154篇 |
现状与发展 | 2篇 |
一般理论 | 189篇 |
预防医学 | 52247篇 |
眼科学 | 16470篇 |
药学 | 54742篇 |
3篇 | |
中国医学 | 2363篇 |
肿瘤学 | 43295篇 |
出版年
2019年 | 5560篇 |
2018年 | 8006篇 |
2017年 | 6204篇 |
2016年 | 6921篇 |
2015年 | 7669篇 |
2014年 | 10484篇 |
2013年 | 15690篇 |
2012年 | 20872篇 |
2011年 | 21878篇 |
2010年 | 12943篇 |
2009年 | 12168篇 |
2008年 | 20374篇 |
2007年 | 21953篇 |
2006年 | 22300篇 |
2005年 | 20888篇 |
2004年 | 20392篇 |
2003年 | 19317篇 |
2002年 | 18799篇 |
2001年 | 36671篇 |
2000年 | 37201篇 |
1999年 | 30682篇 |
1998年 | 7999篇 |
1997年 | 6752篇 |
1996年 | 7070篇 |
1995年 | 6725篇 |
1994年 | 6188篇 |
1993年 | 5681篇 |
1992年 | 23227篇 |
1991年 | 23166篇 |
1990年 | 22550篇 |
1989年 | 22304篇 |
1988年 | 20258篇 |
1987年 | 19636篇 |
1986年 | 18672篇 |
1985年 | 17515篇 |
1984年 | 12851篇 |
1983年 | 10876篇 |
1982年 | 6035篇 |
1979年 | 11622篇 |
1978年 | 8201篇 |
1977年 | 6898篇 |
1976年 | 6684篇 |
1975年 | 7346篇 |
1974年 | 8588篇 |
1973年 | 8243篇 |
1972年 | 7743篇 |
1971年 | 7198篇 |
1970年 | 6924篇 |
1969年 | 6365篇 |
1968年 | 5844篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
61.
H Murakami M Togawa S Takahashi N Kasahara J Yamamoto N Matsuura Y Koshiyama Y Ino M Oda 《Arzneimittel-Forschung》1990,40(12):1352-1358
The effects of FUT-187 (6-amidino-2-naphthyl 4-[(4,5-dihydro-1H-imidazol-2-yl)amino]benzoate dimethanesulfonate, CAS 103926-82-5), a novel synthetic protease inhibitor, were examined in experimental rat and canine models of pancreatitis. 1. FUT-187 significantly increased the survival of rats with trypsin- and phospholipase A2-induced pancreatitis in a dose-dependent manner (10-100 mg/kg, p.o.). 2. FUT-187 decreased plasma enzymatic activity reflecting the degree of pancreatitis in rats with ethionine-induced pancreatitis, and showed a tendency to ameliorate histopathological changes in the pancreas (10-100 mg/kg p.o.). 3. FUT-187 (10 mg/kg) produced an obvious improvement of various biochemical parameters of pancreatitis and also reduced histopathological changes in the pancreas in animals with experimental pancreatitis produced by the closed duodenal loop method. In addition, FUT-187 significantly increased the survival of dogs when given by direct administration into the lumen of the closed duodenal loop. The therapeutic effects of FUT-187 in experimental pancreatitis were nearly equal in most instances to those of camostat mesilate. Thus, FUT-187 would appear to be an effective new agent for the treatment of pancreatitis. 相似文献
62.
Multicentricity of hepatocellular carcinoma (HCC) is considered, especially in patients with liver cirrhosis. This paper describes an operative case of a male patient with probable multicentric development of HCC in precirrhotic fibrosis. The main tumors inside the capsule were completely necrotic due to transarterial embolization (TAE). Histologic examination disclosed discrete tiny nodules of HCC that were not detected grossly. They showed highly differentiated trabecular arrangements: Edmondson I. A scirrhous type was noted in the center of the tumors. At the borders of the tumors the carcinoma cells exhibited replacing growth patterns and it was thought that they developed multicentrically. Partial resection must be performed as extensively as possible in a case such as the present one. 相似文献
63.
64.
65.
Sixty-three mallards were fed one of ten poly(methyl methacrylate) based synthetic grit formulations containing varying concentrations of a proposed wildlife contraceptive (nicarbazin), plasticizer (acetyl tributylcitrate) and/or cross-linking agent (1,4-butanediol diacrylate). Release characteristics of the contraceptive agent were monitored for the purpose of developing a contraceptive formulation for control of pest waterfowl in urban settings. The addition of plasticizer increased the erosion rate (t(1/2)=0.97-2.85 days), cross-linking the polymer matrix slightly decreased the erosion rate (t(1/2)=4.45-5.05 days) and increasing the concentration of the contraceptive agent increased the erosion rate (t(1/2)=3.3 and 9.9 days at 60% and 7.5% active ingredient, respectively). The larger and smaller grit pieces had longer half lives at 11.0 and 11.6 days, respectively while the mid sized grit had a half life of 4.95 days. Control grit had a half life of 12.7 days based on weight loss. Analysis of blood and feces for monitoring release from the grit and approximate indirect plasma levels of the active ingredient proved feasible. 相似文献
66.
67.
OBJECTIVE: To assess the effect of the residual stresses due to cement curing on the load transfer of cemented hip implants. DESIGN: The load transfer at the stem-cement interface of an idealized hip stem surrounded by cortical bone was investigated using a three-dimensional finite element analysis. A debonded stem-cement interface was considered to simulate a highly polished stem in contact with cement; Coulomb friction at the stem-cement interface was considered. BACKGROUND: Numerical analyses on the load transfer of cemented hip implants do not include residual stresses due to cement curing at the stem-cement interface. METHODS: The magnitude of the residual stresses was determined experimentally. In the finite element model, non-linear contact elements modelled the debonded stem-cement interface. In particular, the compressive radial residual stresses that are generated at the interface, due to the cement expansion during curing, were treated similar to a press-fit problem. RESULTS: The cement stress distributions were affected by the magnitude of the residual stresses. Failing to include residual stresses underestimated the cement stresses at the interface, mainly affecting the radial and hoop stresses. The load was transferred from the stem to the cement more uniformly along the interface once residual stresses were included. CONCLUSIONS: Because there is no chemical bond at the interface between the stem and cement, the interface resistance depends on friction thus radial residual compressive stresses developed by the cement curing play a direct role. RELEVANCE: Implant loosening of cemented hip implants is one of the major causes of late failure of the arthroplasty. The load is transferred from the stem to the bone primarily across the interfaces, consequently modelling accurately the interface is essential in predicting the load transfer. 相似文献
68.
B. Tutluolu S. At A. N. Anakkaya E. Altu G. A. Tosun M. Yaman 《Clinical and experimental allergy》2002,32(8):1170-1173
OBJECTIVE: This study aimed to investigate the rate of occupational sensitization to horse hair in grooms and whether occupational exposure to horse hair increases respiratory and allergic symptoms and affects lung function in grooms or not. METHODS: This is a cross-sectional study. Two hundred grooms were randomly selected among 1000 grooms working in Veliefendi Hippodrome of Istanbul. One hundred and twenty-five subjects agreed to enter the study. Ninety-two workers who worked in the different parts of this hippodrome enrolled as the control group. A detailed questionnaire including respiratory and allergic symptoms was filled in, physical examination, skin prick tests and pulmonary function tests were performed. RESULTS: Sensitization to horse hair was 12.8% in grooms and 4.3% in controls. The difference was statistically significant (P = 0.0035). Asthma was found in 14.4% of the grooms and 5.4% of the controls, allergic rhinitis in 42.4% of the grooms and 18.4% of the controls, allergic conjunctivitis in 35.2% of the grooms and 15.2% of the controls, and allergic skin diseases in 32.8% of the grooms and 13% of the controls. The differences were statistically significant (P = 0.043, P = 0.0002, P = 0.001 and P = 0.0008, respectively). The means of FEV1, FEV1/FVC and FVC parameters were significantly lower in the groom group (P = 0.006, P = 0.001 and P = 0.003, respectively). In the multivariate analysis, being in the groom group and working years were found to be predictive factors for impairments of lung function (P < 0.001 and P = 0.002, respectively). CONCLUSION: Occupational exposure to horse increases the sensitization to horse hair, induces asthma and allergic symptoms and also impairs lung functions. 相似文献
69.
The T-cell receptor (TCR) repertoire plays an important role in shaping specific immune responses. Genetic polymorphisms at the TCR locus, in both constant and variable regions, seem to represent an important mechanism for generating inter-individual and inter-population differences. Considering the scarcity of immune parameters characterized for normal human populations, we decided to determine the frequency of two TCRBV polymorphisms (located in the TCRBV3S1 and TCRBV18 gene segments) in two ethnically distinct groups of the general Brazilian population. Both polymorphisms are related to the expression of these segments at the T-cell surface and can consequently modulate the T-cell repertoire, potentially modifying the capacity of a given individual to develop an immune response. These DNA polymorphisms were analysed in material obtained from adult, normal South-American Caucasoid and Black individuals. A total of 139 individuals were analysed for the TCRBV3S1 and 141 for the TCRBV18 gene segment polymorphisms. The data indicated statistically significant differences in allelic frequencies for the two ethnic groups analysed, suggesting that any correlation between TCR usage or T-cell repertoire and development of a given disease should take in account the ethnic origin of the population studied. 相似文献
70.
HLA-DR typing in identical twins with insulin-dependent diabetes: difference between concordant and discordant pairs 总被引:3,自引:0,他引:3
C Johnston D A Pyke A G Cudworth E Wolf 《British medical journal (Clinical research ed.)》1983,286(6361):253-255
A total of 106 pairs of identical twins, of whom 56 were concordant and 50 discordant for insulin-dependent diabetes, were typed for HLA-DR. In both the concordant and discordant groups there was a high prevalence of the antigens DR3 and DR4, a low prevalence of DR5 and DR7, and a virtual absence of DR2. The heterozygous phenotype DR3,DR4 was more prevalent in concordant than discordant pairs. This was therefore the first demonstration of a genetic difference between concordant and discordant identical twin pairs. These findings suggest that possession of both DR3 and DR4 antigens confers a greater genetic predisposition to insulin-dependent diabetes than does the possession of either antigen alone. 相似文献