全文获取类型
收费全文 | 72665篇 |
免费 | 5868篇 |
国内免费 | 3382篇 |
专业分类
耳鼻咽喉 | 199篇 |
儿科学 | 1355篇 |
妇产科学 | 842篇 |
基础医学 | 12951篇 |
口腔科学 | 743篇 |
临床医学 | 5713篇 |
内科学 | 17085篇 |
皮肤病学 | 1078篇 |
神经病学 | 2876篇 |
特种医学 | 1306篇 |
外国民族医学 | 9篇 |
外科学 | 3935篇 |
综合类 | 10743篇 |
现状与发展 | 19篇 |
预防医学 | 6086篇 |
眼科学 | 490篇 |
药学 | 8897篇 |
18篇 | |
中国医学 | 3591篇 |
肿瘤学 | 3979篇 |
出版年
2023年 | 803篇 |
2022年 | 1880篇 |
2021年 | 2311篇 |
2020年 | 2172篇 |
2019年 | 2433篇 |
2018年 | 2308篇 |
2017年 | 2265篇 |
2016年 | 2640篇 |
2015年 | 2897篇 |
2014年 | 4745篇 |
2013年 | 4924篇 |
2012年 | 4846篇 |
2011年 | 5166篇 |
2010年 | 4198篇 |
2009年 | 3963篇 |
2008年 | 3962篇 |
2007年 | 3831篇 |
2006年 | 3498篇 |
2005年 | 2986篇 |
2004年 | 2483篇 |
2003年 | 2172篇 |
2002年 | 1760篇 |
2001年 | 1558篇 |
2000年 | 1196篇 |
1999年 | 1061篇 |
1998年 | 976篇 |
1997年 | 801篇 |
1996年 | 680篇 |
1995年 | 689篇 |
1994年 | 583篇 |
1993年 | 478篇 |
1992年 | 458篇 |
1991年 | 355篇 |
1990年 | 324篇 |
1989年 | 289篇 |
1988年 | 244篇 |
1987年 | 208篇 |
1986年 | 176篇 |
1985年 | 445篇 |
1984年 | 463篇 |
1983年 | 371篇 |
1982年 | 379篇 |
1981年 | 316篇 |
1980年 | 292篇 |
1979年 | 262篇 |
1978年 | 207篇 |
1977年 | 159篇 |
1976年 | 176篇 |
1975年 | 153篇 |
1974年 | 126篇 |
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
101.
为了解先天性肾上腺皮质增生症患者的21-羟化酶CYP21B基因中Ile~(172)→Asn错义突变的发生率,根据放大受阻突变体系(Amplificationrefractorymutationsystem,ARMS)的要求,设计了3种引物:5'd(TTGGGAGACTACTCCCTGCTCT)3'(共同引物)、5'd(AGGTGAGGTAACAGA)3'(正常引物)、5'd(AGGTGAGGTAACAGT)3'(突变引物),在7例患儿中进行了检测,发现具有本突变者3例。对其中一例进行的家系分析,结果提示:这组引物有快速、简便的优点,不需使用同位素就能对具有Ile~(172)→Asn变异的高危家庭成员作产前诊断。 相似文献
102.
Successive infection of coxsackievirus B3 and encephalomyocarditis virus: an animal model of chronic myocarditis. 总被引:1,自引:0,他引:1
Successive infection of coxsackievirus B3 and encephalomyocarditis virus was investigated as a disease model of chronic myocarditis. Four-week-old C3H/He mice were inoculated with coxsackievirus B3 and then inoculated with encephalomyocarditis virus at 8 weeks old. The hearts were evaluated on histopathological changes compared with those of non-infected mice and mice infected with either virus alone. At 10 weeks old, the hearts of the mice infected successively with both viruses showed co-existence of fibrosis surrounding calcified lesions and marked cellular infiltration with myocardial necrosis. These findings resembled chronic active myocarditis in humans, unlike the lesions due to either virus alone. At 12 weeks old, the hearts of all the infected mice showed fibrosis with scarce cellular infiltration. The successively infected hearts also showed a significantly higher heart weight to body weight ratio than that of the non-infected control mice, and localized wall thinning in the damaged regions. Thus, we conclude that successive infection additively causes myocardial damage that resembles chronic myocarditis and may produce a heart condition similar to dilated cardiomyopathy. 相似文献
103.
Mary C. Kuhns Anne L. McNamara Robert P. Perrillo Carlos M. Cabal Carolyn R. Campbell 《Journal of medical virology》1989,27(4):274-281
Serological markers of hepatitis B virus (HBV) replication were assessed in a randomized, controlled trial of prednisone withdrawal followed by α -interferon in the treatment of chronic hepatitis B. HBV DNA levels in more than 700 serial serum samples from 41 patients were determined by a sensitive and quantitative solution hybridization assay. Results were compared with HBV DNA polymerase (DNAp) activity and hepatitis B e antigen (HBeAg) in 21 untreated controls and 20 treated patients. Among treated patients, the mean pretherapy HBV DNA values were higher in nonresponders than in responders. During prednisone treatment, DNA levels increased an average of 2.1-fold in responders and 1.4-fold in nonresponders. During the 2-week rest interval between prednisone and interferon, DNA values fell an average of 57% in responders. In contrast, the mean DNA values in nonresponders did not change during the same interval. This early distinction between responders and nonresponders was not apparent from DNAp or HBeAg results. During interferon treatment, HBV DNA became undetectable in responders and remained negative during a 1-year follow-up. DNA in nonresponders declined to 14% of baseline during interferon treatment but increased to pretherapy levels after treatment. DNAp values generally paralleled HBV DNA values, but DNAp activity showed more variability and lower sensitivity than did the hybridization assay results. HBeAg values varied independently of HBV DNA and DNAp with a much delayed decline in responders. These results indicate that HBV DNA, when measured quantitatively by a sensitive solution hybridization assay, is an early predictor of the effects of antiviral agents on replication. 相似文献
104.
M. Flesch A. Sachinidis Y. D. Ko K. Kraft H. Vetter 《Journal of molecular medicine (Berlin, Germany)》1994,72(12):944-950
In recent years there have been many studies demonstrating a correlation between increased arterial blood pressure and altered lipid profiles, and there has been an especially positive correlation between high cholesterol levels and blood pressure. There are differences between the various reports that are important. In our study the lipid distribution in 105 hypertensive patients with mild or moderate arterial hypertension according to WHO criteria without clinically or ultrasonographically apparent atherosclerosis was compared to the lipid distribution in 65 age-matched healthy persons. On the epidemiological level a significant, positive association was found between LDL serum levels (P 0.001), Apo B serum levels (P 0.001), serum triglyceride levels (P 0.05) and VLDL serum levels (P 0.01) and arterial hypertension. However, in contrast to recent reports, no significant difference was found between total serum cholesterol levels in normotensives and hypertensives, and there was no difference in HDL serum levels. No evidence could be found for a significant increase in lipoprotein (a) serum levels in hypertensives.Abbreviations LDL
low density lipoprotein
- VLDL
very low density lipoprotein
- HDL
high density lipoprotein
- Apo B 100
apolipoprotein B 100
- Apo A I
apolipoprotein A I
Correspondence to: H. Vetter 相似文献
105.
106.
Bi-directional modulation of T cell-dependent antibody production by prostaglandin E(2). 总被引:1,自引:0,他引:1
Xiaowen He Cornelia M Weyand J?rg J Goronzy Wanyun Zhong John M Stuart 《International immunology》2002,14(1):69-77
T cell-dependent Ig production involves interaction between T cells and B cells. This study evaluated the effects of prostaglandin (PG) E(2) on Ig production in a system in which B cells were co-cultured with autologous CD4(+) T cell clones non-specifically activated by anti-CD3. The effects of PGE(2) on T cell-dependent Ig production differed substantially, depending on the T cells employed. We selected six T cell clones that were able to enhance Ig production (resistant T cell clones) and six T cell clones that inhibited Ig production in the presence of PGE(2) (sensitive T cell clones) for comparison. The resistant T cells produced high levels (>1000 pg/ml) of IL-2 and/or IL-4, and expressed high CD40L, OX40 and CD45RA, and low CD45RO. In contrast, sensitive T cells secreted low IL-2 (<500 pg/ml) and IL-4 (<200 pg/ml), and expressed low CD40, OX40 and CD45RA, and high CD45RO. Adding supernatant derived from resistant T cell clones restored Ig production inhibited by PGE(2), while removing IL-2, IL-4 or IL-10 using specific antibodies inhibited Ig production. In addition, we demonstrated a direct effect of PGE(2) on B cells to enhance Ig production. Consistently, in the presence of resistant T cells, PGE(2) increased B cell proliferation and differentiation. In conclusion, the effects of PGE(2) on Ig production consist of its indirect effects through T cells and its direct effects on B cells. The outcome of the effects can be up-regulatory or down-regulatory, depending whether resistant or sensitive T cells are involved. 相似文献
107.
M Pistello L Ceccherini-Nelli N Cecconi M Bendinelli F Panicucci 《Journal of medical virology》1991,33(1):43-46
The overall prevalence of anti-HCV antibody in a group of 125 haemophiliacs was 62%. Four patients who had never received replacement therapy were anti-HCV negative. Of the 121 patients injected regularly with commercial concentrates, 76 were already anti-HCV seropositive in 1985 and remained so throughout the follow-up. Two patients seroconverted in 1987 without obvious signs or symptoms of hepatitis. Our patients were treated with dry heat-treated concentrates since 1985 and with wet heat- or solvent/detergent-treated concentrates since 1988. The absence of further seroconversions and of symptoms of acute post-transfusion non-A, non-B hepatitis since 1988 suggest that present virucidal treatments of concentrates are effective in preventing HCV transmission. Anti-HCV positivity appeared to be unrelated to the type and degree of haemophilia as well as to the presence of antibodies to hepatitis B virus, human immunodeficiency virus type 1, and human herpesvirus type 6. 相似文献
108.
Gertrud Dudin Denis Alexander Fayrouz Talj Mary Deeb Salim Musallam Vazken M. Der Kaloustian 《Clinical genetics》1984,25(5):455-458
A six-months-old girl is presented with psychomotor retardation and multiple congenital malformations. The karyotype done on peripheral blood lymphocytes and skin fibroblasts was found to be 46,XX del(5)(411q13). The parents are consanguineous. Their karyotypes were normal.
The genes for Arylsulphatase B and Hexosaminidase B are not located in band 5q12. 相似文献
The genes for Arylsulphatase B and Hexosaminidase B are not located in band 5q12. 相似文献
109.
Multiple sulphatase deficiency presenting at birth 总被引:1,自引:0,他引:1
M. Burch A. H. Fensom Marie Jackson T. Pitts-Tucker P. J. Congdon 《Clinical genetics》1986,30(5):409-415
A new case of multiple sulphatase deficiency with onset at birth is described. The patient had many dysmorphic features and hydrocephalus, similar to one other case with early onset described in the literature. The new patient differed from the other case in having chondrocalcificans congenita, heart abnormalities and an abnormal fold of tissue present between the laryngeal inlet and the oesophagus. Excessive mucopolysacchariduria was present and there was profound deficiency of all sulphatases examined in plasma, leucocytes and cultured skin fibroblasts. 相似文献
110.
Accumulating evidence indicates that tumor viruses represent a major etiological factor in a significant portion of human cancers. These cancers include human papillomavirus induced anogenital cancers, hepatitis B and C virus associated hepatocellular carcinomas, nasopharyngeal carcinomas and lymphomas linked to Epstein-Barr virus infection, and human T cell leukemia virus associated adult T cell leukemias. This review summarizes the recent progress made in understanding the molecular mechanisms of viral carcinogenesis, with a particular focus on the interaction of viral factors with cellular tumor suppressor proteins. The functional inactivation of tumor suppressor proteins may represent a common strategy by which several tumor viruses contribute to malignant cell transformation.Abbreviations
EBV
Epstein-Barr virus
-
E6AP
E6-associated protein
-
HBV
Hepatitis B virus
-
HCC
Hepatocellular carcinoma
-
HPV
Human papillomavirus
-
HTLV
Human T cell leukemia virus
-
pRb
Retinoblastoma protein
-
RB
Retinoblastoma
-
SV40
Simian virus 40 相似文献