全文获取类型
收费全文 | 26837篇 |
免费 | 2403篇 |
国内免费 | 52篇 |
专业分类
耳鼻咽喉 | 307篇 |
儿科学 | 687篇 |
妇产科学 | 692篇 |
基础医学 | 3257篇 |
口腔科学 | 722篇 |
临床医学 | 2949篇 |
内科学 | 5119篇 |
皮肤病学 | 291篇 |
神经病学 | 2474篇 |
特种医学 | 814篇 |
外科学 | 3757篇 |
综合类 | 845篇 |
一般理论 | 30篇 |
预防医学 | 2770篇 |
眼科学 | 576篇 |
药学 | 1911篇 |
中国医学 | 17篇 |
肿瘤学 | 2074篇 |
出版年
2022年 | 142篇 |
2021年 | 362篇 |
2020年 | 233篇 |
2019年 | 374篇 |
2018年 | 458篇 |
2017年 | 343篇 |
2016年 | 413篇 |
2015年 | 463篇 |
2014年 | 628篇 |
2013年 | 941篇 |
2012年 | 1416篇 |
2011年 | 1396篇 |
2010年 | 810篇 |
2009年 | 754篇 |
2008年 | 1332篇 |
2007年 | 1423篇 |
2006年 | 1341篇 |
2005年 | 1338篇 |
2004年 | 1270篇 |
2003年 | 1211篇 |
2002年 | 1183篇 |
2001年 | 768篇 |
2000年 | 744篇 |
1999年 | 664篇 |
1998年 | 382篇 |
1997年 | 279篇 |
1996年 | 283篇 |
1995年 | 266篇 |
1994年 | 248篇 |
1993年 | 233篇 |
1992年 | 488篇 |
1991年 | 465篇 |
1990年 | 485篇 |
1989年 | 435篇 |
1988年 | 431篇 |
1987年 | 417篇 |
1986年 | 419篇 |
1985年 | 362篇 |
1984年 | 300篇 |
1983年 | 255篇 |
1982年 | 182篇 |
1981年 | 149篇 |
1979年 | 268篇 |
1978年 | 209篇 |
1977年 | 171篇 |
1976年 | 169篇 |
1975年 | 180篇 |
1974年 | 200篇 |
1973年 | 159篇 |
1972年 | 146篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Antibodies to a synthetic peptide from the preS 120-145 region of the hepatitis B virus envelope are virus neutralizing 总被引:26,自引:0,他引:26
Studies with synthetic peptides have provided evidence for the presence of preS coded sequences in the envelope (env) proteins of hepatitis B virus (HBV) and indicated that these sequences are involved in the specific attachment of HBV to liver cells. Scanning of the preS sequence for immunodominant continuous epitopes identifies the sequence within residues preS (120-145) as the most immunogenic in eliciting antibodies recognizing HBV and as the most efficiently binding antibodies from sera of rabbits and humans immunized with HBV env proteins. To assess the potential of preS (120-145) as a synthetic vaccine against hepatitis B, in vitro neutralization of the virus by rabbit antiserum to the peptide was assayed in chimpanzees. The animals, subsequently proven to be susceptible to HBV infection, did not develop hepatitis B as judged by negative serological tests for HBV-associated antigens and antibodies and by normal serum alanine aminotransferase levels and normal liver biopsies. These results establish the role of preS domains in the process of virus neutralization and the potential of synthetic preS analogues for hepatitis B vaccination. 相似文献
102.
R J Harrison P T Klouda D L Easty M Manku J Charles C M Stewart 《The British journal of ophthalmology》1989,73(10):816-822
Sixty-seven patients with keratoconus were classified according to atopic status. Keratoconus patients with and without atopy did not differ significantly with regard to sex, age of onset, or rate of keratoplasty, but patients with very high IgE levels were more prone to graft rejection. Atopy was less common in patients with unilateral keratoconus, and keratoconus occurred more frequently on the side of the dominant hand. There was a significantly lower frequency of HLA B7 in the keratoconus group than in the controls. No abnormalities of essential fatty acid metabolism were found in keratoconus patients with or without atopy. There was no social class bias in the group. The study included a brother and sister with keratoconus and atopy, and a non-atopic patient whose identical twin did not have keratoconus. 相似文献
103.
R A Hawkins G White N J Bundred J M Dixon W R Miller H J Stewart A P Forrest 《The British journal of surgery》1987,74(11):1009-1013
The prognostic significance of the tumour activities of 2 steroid receptors, those for oestrogen (ER) and for progestogen (PgR), has been studied in 372 patients with breast cancer, in whom follow-up was available for 2-6 years (median 41 months). Of 252 patients with operable disease, 75.8 per cent had ER-positive tumours and 46.4 per cent had PgR-positive tumours, though a small additional fraction (6.3 per cent) had an equivocal PgR assay result. For the 236 patients with unequivocal receptor status, the relationships between disease-free interval or overall survival and receptor activity and other factors were evaluated by univariate and multivariate analyses. The latter revealed that only tumour size, node status, menstrual status and ER status related significantly to both disease-free interval and survival, though adjuvant therapy also related to disease-free interval, and tumour grade related to survival. It is concluded that measurements of PgR activity do not add to the prognostic significance of ER status. 相似文献
104.
The role of anal/genital warts in HIV infection 总被引:1,自引:0,他引:1
105.
C P Stewart 《Prosthetics and orthotics international》1987,11(3):113-116
A review of smoking habits of 77 vascular related amputees demonstrated a high incidence of smoking significantly greater for men than in the general population. Male smoking amputees with atherosclerosis related peripheral vascular disease were found to have a high risk of having an above-knee amputation. Those with diabetes mellitus whether male or female, smokers or not, had a significantly greater chance of having a below-knee amputation. Overall, non-smokers were found more likely to have a below-knee amputation than an above-knee (p less than 0.05). 相似文献
106.
The authors review the natural occurrence of tumour dormancy in man and animal models, which show the importance of cellular defence mechanisms in inducing and maintaining the state of tumour dormancy. Six cases of non-small-cell lung cancer are described. The patients exhibited moderate to very strong delayed hypersensitivity reactions to soluble lung-cancer antigen after specific immunotherapy. Three patients had nonregional metastases at 11, 12 and 14 years. Two had regional recurrence after 9 years, and in one patient a small hilar-node metastasis was found at autopsy after 7.6 years. In each case an immunodepressive event or drug treatment preceded resurgent growth. The effect of renal transplantation in patients with a history of surgery for cancer supports the conclusion that cellular defence mechanisms are crucial for the maintenance of tumour dormancy in man. 相似文献
107.
We have investigated the structural and histochemical features of the blood-brain barrier (b-bb) in both adults and embryos of chicken (Gallus domesticus, White Leghorn) and quail (Corturnix coturnix japonica). We found that brain endothelial cells of both species are characterized structurally by tight junctions, a low density of pinocytotic vesicles, and a moderately elevated density of mitochondria. Both alkaline phosphatase and butyryl cholinesterase were found in adult quail brain capillaries, but only alkaline phosphatase was found in adult chick brain capillaries. Aromatic amino acid decarboxylase was not found in brain capillaries of either species. In the chick embryo alkaline phsophatase appeared during the time when b-bb matures functionally; i.e., during the third week of development. However, an elevation in mitochondrial density was not apparent until after hatching. In the quail, alkaline phosphatase and butyrl cholinesterase appeared during the last week of embryonic development. By 2 days posthatching the structural characteristics of the brain capillaries were similar to those in the adult. 相似文献
108.
109.
E A Stewart K V Jackson A J Friedman M S Rein J H Fox M D Hornstein 《Fertility and sterility》1992,57(6):1274-1278
STUDY OBJECTIVE: To determine the effect of baseline complex ovarian cysts on controlled ovarian hyperstimulation and in vitro fertilization (IVF) outcome. DESIGN: Retrospective analysis with stratification by stimulation regimen and the presence or absence of surgically documented endometriosis. PATIENTS: Two hundred sixty-one women undergoing IVF from May 1, 1989 to December 31, 1990. MAIN OUTCOME MEASURES: The outcome measures assessed were the maximum estradiol (E2) concentration on day of human chorionic gonadotropin (hCG) administration, number of follicles with maximum diameter greater than or equal to 15 mm, number of follicles with maximum diameter greater than or equal to 12 mm, number of days to hCG administration, number of ampules of human menopausal gonadotropin (hMG) used, number of oocytes retrieved and fertilized, number of embryos transferred, and pregnancy and cycle cancellation rates. RESULTS: There were no statistical differences between cyst and noncyst groups in any of the above parameters of IVF performance. In a single subgroup, patients with endometriosis stimulated with hMG and patients with cysts had significantly lower E2 concentrations than patients without cysts. CONCLUSION: The presence of a complex cyst on a baseline ultrasound does not appear to adversely affect IVF cycle outcomes. 相似文献
110.
A case of mosaic trisomy 2 diagnosed at amniocentesis in an abnormal fetus and confirmed in multiple fetal tissues 总被引:2,自引:0,他引:2
Jacqueline Robinson Helen Stewart Lynette Moore Lorraine Gaunt 《Clinical genetics》1997,51(6):417-420
Pseudomosaicism for trisomy 2 is a relatively common finding at amniocentesis. However, genuine trisomy 2 mosaicism is extremely rare. As a result, very few cases have been described and little information is available with which to counsel the parents of an affected fetus. We describe a case of mosaic trisomy 2 diagnosed at amniocentesis in a fetus with multiple anomalies on ultrasound scan. Following termination of pregnancy, the fetus was found to have mild dysmorphic features, together with an absent gall bladder, cystic left kidney, a 13th left rib and mild unilateral talipes. The presence of trisomy 2 cells was confirmed by both standard cytogenetic analysis and fluorescent in-situ hybridisation techniques in multiple fetal tissues, as well as in the cord and placenta. 相似文献