全文获取类型
收费全文 | 18828篇 |
免费 | 2191篇 |
国内免费 | 357篇 |
专业分类
耳鼻咽喉 | 392篇 |
儿科学 | 939篇 |
妇产科学 | 1093篇 |
基础医学 | 1793篇 |
口腔科学 | 185篇 |
临床医学 | 1966篇 |
内科学 | 2678篇 |
皮肤病学 | 161篇 |
神经病学 | 868篇 |
特种医学 | 473篇 |
外国民族医学 | 3篇 |
外科学 | 1234篇 |
综合类 | 1309篇 |
现状与发展 | 2篇 |
预防医学 | 2780篇 |
眼科学 | 501篇 |
药学 | 1914篇 |
12篇 | |
中国医学 | 365篇 |
肿瘤学 | 2708篇 |
出版年
2024年 | 72篇 |
2023年 | 444篇 |
2022年 | 727篇 |
2021年 | 959篇 |
2020年 | 941篇 |
2019年 | 939篇 |
2018年 | 853篇 |
2017年 | 860篇 |
2016年 | 916篇 |
2015年 | 867篇 |
2014年 | 1324篇 |
2013年 | 1849篇 |
2012年 | 1056篇 |
2011年 | 1115篇 |
2010年 | 900篇 |
2009年 | 856篇 |
2008年 | 873篇 |
2007年 | 815篇 |
2006年 | 699篇 |
2005年 | 595篇 |
2004年 | 498篇 |
2003年 | 491篇 |
2002年 | 343篇 |
2001年 | 314篇 |
2000年 | 231篇 |
1999年 | 236篇 |
1998年 | 204篇 |
1997年 | 187篇 |
1996年 | 140篇 |
1995年 | 134篇 |
1994年 | 121篇 |
1993年 | 100篇 |
1992年 | 108篇 |
1991年 | 76篇 |
1990年 | 81篇 |
1989年 | 53篇 |
1988年 | 57篇 |
1987年 | 50篇 |
1986年 | 41篇 |
1985年 | 55篇 |
1984年 | 36篇 |
1983年 | 30篇 |
1982年 | 29篇 |
1981年 | 27篇 |
1980年 | 16篇 |
1979年 | 11篇 |
1978年 | 11篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1973年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
With the advent of array-based comparative genomic hybridization technology, the analog cytogenetic analysis that has been used for the past 100 years could be replaced by the quantitative, microarray-based molecular analysis. Major advantages of the new array-based cytogenetic technologies are the high resolution and the high throughput. This technology is the first to offer an autonomous whole-chromosome analysis in one hybridization reaction for the detection of submicroscopic gains/losses. However, as with any new technology, it needs to be validated with regard to its performance in various applications (e.g. clinical genetic testing and cancer applications), comparative cost, and the data interpretation. 相似文献
62.
A. Spiliopoulou V. Lakiotis A. Vittoraki D. Zavou D. Mauri 《Clinical microbiology and infection》2005,11(9):687-689
Genital Chlamydia trachomatis infection is the leading cause of bacterial sexually transmitted disease in industrialised countries, particularly among young people. The consequences of chlamydial infection may involve urethritis, cervicitis, pelvic inflammatory disease, ectopic pregnancy, tubal factor infertility, epididymitis and prostatitis. In addition, chlamydial infection increases the risk of acquisition of human immunodeficiency virus and has been associated with cervical cancer. Although screening programmes exist in a number of countries, the continuously increasing prevalence of chlamydial infections demonstrates the necessity for health authorities to establish effective screening policies, and the importance of defining a comprehensive European screening policy is emerging. 相似文献
63.
Gennarelli G Holte J Berglund L Berne C Massobrio M Lithell H 《Human reproduction (Oxford, England)》2000,15(10):2098-2102
Women with the polycystic ovary syndrome (PCOS) have a high prevalence of insulin resistance, with consequent increased risk of metabolic diseases later in life. An early metabolic screening would therefore be of clinical relevance. By using stepwise regression analysis on several variables obtained in 72 women with PCOS, we constructed simple and reliable mathematical models predicting insulin sensitivity, as measured by the euglycaemic hyperinsulinaemic clamp. The normal ranges of insulin sensitivity were calculated from 81 non-hirsute, normally menstruating women with normal ovaries, and similar body mass index (BMI) and age as the women with PCOS. Measured variables included BMI, waist and hip circumferences, truncal-abdominal skin folds, circulating concentrations of gonadotrophins, androgens, sex hormone-binding globulin (SHBG), triglycerides, total cholesterol and cholesterol subfractions, fasting insulin, C-peptide and free fatty acids. The three best prediction models included waist circumference, together with insulin (model I: R(2) = 0.77), serum triglycerides (model II: R(2) = 0.65), and the subscapularis skin fold (model III: R(2) = 0. 64). Using reference limits for insulin sensitivity obtained in the 81 normal pre-menopausal women, the models identify insulin resistant women with PCOS. These simple and inexpensive models are potentially useful in clinical practice as an early screening in women with PCOS. 相似文献
64.
Winnepenninckx B Errijgers V Hayez-Delatte F Reyniers E Frank Kooy R 《Human mutation》2002,20(4):249-252
Mutations in the methyl-CpG-binding protein 2 (MECP2) cause Rett syndrome, a severe neurodevelopmental disorder occurring predominantly in females. Male patients with Rett syndrome are extremely rare, as the Rett-causing mutations in the MECP2 gene are usually lethal in hemizygous males. However, different mutations in the same gene were reported to cause mental retardation, both in sporadic non-syndromic males as well as in syndromic families with disease manifestation in carrier females. The majority of the reported MECP2 mutations in mentally retarded patients cause amino acid substitutions and, especially in isolated cases, discrimination between a disease-causing mutation and a rare polymorphism is not obvious and the significance of each individual variation should be verified. We mapped a new non-syndromic X-linked family (MRX79) to the chromosomal region Xq27.3-Xq28 and identified an A140V mutation in the MEPC2 gene in all patients with the disease haplotype. In addition to data published by others, this suggests that A140V is a recurrent mutation (and not a polymorphism) found in patients with X-linked mental retardation. 相似文献
65.
The objective was to evaluate a postal questionnaire screening procedure for selection of subjects with positive reactions to skin prick tests with common allergens. The project consisted of a screening, with subsequent skin prick test of two selected groups. The setting was the Glostrup Population Studies institute in Copenhagen, Denmark. Participants in the screening included 8000 subjects, aged 15–69 years. The subjects were randomly selected from the population of western Copenhagen County, Denmark. From the 6998 respondents (87.5%), 793 subjects were randomly selected (Random Group), and 788 subjects were chosen on the basis of their answers to the questionnaire (Symptom Group). Both groups were invited to take skin prick tests. Attendance rates were 75.5% (Random Group) and 80.6% (Symptom Group).
The main outcome measures were responses (yes or no) to the specific questions and the subjects' skin reaction (positive or negative). The association between symptoms and skin reactivity, adjusted for the effects of sex and age, was summarized by odds ratios. Symptoms on exposure to allergens were highly associated with positive skin reactivity. In the Symptom Group the percentage of subjects with at least one positive skin reaction was 57.7%, which was twice as much (28.4%) as in the Random Group. The results show that it was possible to select a group with high skin reactivity on the basis of the symptoms reported in the screening. Questions about exposure to allergens were the most appropriate for selection of this group. 相似文献
The main outcome measures were responses (yes or no) to the specific questions and the subjects' skin reaction (positive or negative). The association between symptoms and skin reactivity, adjusted for the effects of sex and age, was summarized by odds ratios. Symptoms on exposure to allergens were highly associated with positive skin reactivity. In the Symptom Group the percentage of subjects with at least one positive skin reaction was 57.7%, which was twice as much (28.4%) as in the Random Group. The results show that it was possible to select a group with high skin reactivity on the basis of the symptoms reported in the screening. Questions about exposure to allergens were the most appropriate for selection of this group. 相似文献
66.
Elizabeth Dormandy Martin C Gulliford Erin P Reid Katrina Brown Theresa M Marteau 《The British journal of general practice》2008,58(548):154-159
BACKGROUND: Antenatal sickle cell and thalassaemia screening sometimes occurs too late to allow couples a choice regarding termination of affected fetuses. The target gestational age for offering the test in the UK is 10 weeks. AIM: To describe the proportion of women screened before 70 days' (10 weeks') gestation and the delay between pregnancy confirmation in primary care and antenatal sickle cell and thalassaemia screening. DESIGN OF STUDY: Cohort study of reported pregnancies. SETTING: Twenty-five general practices in two UK inner-city primary care trusts offering universal screening. METHOD: Anonymised data on all pregnancies reported to participating general practices was collected for a minimum of 6 months. RESULTS: There were 1441 eligible women intending to proceed with their pregnancies, whose carrier status was not known. The median (interquartile range [IQR]) gestational age at pregnancy confirmation was 7.6 weeks (6.0-10.7 weeks) and 74% presented before 10 weeks. The median gestational age at screening was 15.3 weeks (IQR = 12.6-18.0 weeks), with only 4.4% being screened before 10 weeks. The median delay between pregnancy confirmation and screening was 6.9 weeks (4.7-9.3 weeks) After allowing for practice level variation, there was no association between delay times and maternal age, parity, and ethnic group. CONCLUSION: About 74% of women consulted for pregnancy before 10 weeks' gestation but fewer than 5% of women were screened before the target time of 10 weeks. Reducing the considerable delay between pregnancy confirmation in primary care and antenatal sickle cell and thalassaemia screening requires methods of organising and delivering antenatal care that facilitate earlier screening to be developed and evaluated. 相似文献
67.
Carrozzo R Bornstein B Lucioli S Campos Y de la Pena P Petit N Dionisi-Vici C Vilarinho L Rizza T Bertini E Garesse R Santorelli FM Arenas J 《Human mutation》2003,21(4):453-454
Sixteen unrelated Southern European patients with the mitochondrial depletion syndrome (MDS) were analyzed for mutations in the TK2 and DGUOK genes. Three novel mutations were identified in TK2 (R183G, R254X, and 142insG). When we analyzed additional genes involved in the dNTPs pool, such as SLC25A19 (DNC) and NT5M (d-NT2), we did not detect mutations. The current study suggest that scanning the TK2, DGUOK, SLC25A19, and NT5M genes is likely to help about 10% of MDS families in terms of genetic counseling. Also, our findings indicate that genotype-phenotype correlations are not straightforward in MDS. 相似文献
68.
Lei Li Christine Eng Robert J. Desnick James German Nathan A. Ellis 《Molecular genetics and metabolism》1998,64(4):286-290
Bloom syndrome is more common in individuals of Ashkenazi Jewish descent than in any other population, and one particular mutation in the Bloom syndrome gene,blmAsh,is homozygous in nearly all Ashkenazi Jewish persons with Bloom syndrome. We have determined the frequency ofblmAshin 1491 Ashkenazi Jewish persons with no known history of Bloom syndrome and found that 1 in 107 persons was heterozygous. Although not common, genetic screening for Bloom syndrome is feasible in this population. 相似文献
69.
抗SARS-CoV抗原的人源Fab段噬菌体抗体库的构建 总被引:6,自引:1,他引:6
目的 :利用抗SARS冠状病毒IgG抗体阳性的SARS康复患者外周血淋巴细胞 ,构建人源Fab段抗体文库。方法 :制备外周血淋巴细胞总RNA ,逆转录成cDNA。以其为模板 ,利用针对家族特异性Ig基因的引物扩增重链Fd段和轻链基因 ,并重组到噬菌粒载体pComb3中 ,将重组噬菌粒载体电转化大肠杆菌XL 1Blue,酶切鉴定抗体库的重组率 ,并测定噬菌体抗体库的库容量。结果 :构建了源于SARS康复患者血清中抗Fab段的抗体文库 ,轻链、重链Fd段基因的重组率分别为91%和 75 % ,库容量为 7.2 3× 10 7。结论 :成功地构建了抗SARS CoV抗原的人源Fab段噬菌体抗体库 相似文献
70.
Continuing hepatitis B virus (HBV) infection is normally associated with the presence of hepatitis B surface antigen (HBsAg) in the serum. In spite of sensitive screening assays for HBsAg, rare cases of post-transfusion HBV infection are still observed. Antibody to hepatitis B core antigen (anti-HBc) often indicates remote HBV infection but DNA hybridisation and more sensitive polymerase chain reaction (PCR) assays have demonstrated that some HBsAg negative individuals, positive for anti-HBc, have continuing HBV replication. To determine the incidence of ongoing HBV infection in a Canadian HBsAg negative, anti-HBc positive population we studied three groups with this combination of HBV markers: Group A, 36 patients referred for investigation of raised serum aminotransferases; Group B, 21 Canadian Red Cross blood donors; Group C, seven vaccinees in an Ottawa Health Care Student hepatitis B vaccination programme. The PCR was carried out using a nested PCR reaction with primers specific for the pre-core region of HBV. Seven of 36 (19%) patients in Group A had detectable HBV DNA whereas none of Group B or C were positive. This data indicates that in some HBsAg negative patients with ongoing hepatic inflammation, continuing HBV replication may persist. This was not observed in any healthy blood donors or health care students investigated. Larger studies are required, but this data would suggest that, in Canada, the addition of anti-HBc testing for all blood donors for detection of low level HBV replication would not be indicated. © 1994 Wiley-Liss, Inc. 相似文献