全文获取类型
收费全文 | 2723篇 |
免费 | 199篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 23篇 |
儿科学 | 100篇 |
妇产科学 | 34篇 |
基础医学 | 296篇 |
口腔科学 | 58篇 |
临床医学 | 227篇 |
内科学 | 764篇 |
皮肤病学 | 67篇 |
神经病学 | 144篇 |
特种医学 | 102篇 |
外科学 | 415篇 |
综合类 | 97篇 |
一般理论 | 1篇 |
预防医学 | 139篇 |
眼科学 | 62篇 |
药学 | 217篇 |
中国医学 | 12篇 |
肿瘤学 | 170篇 |
出版年
2023年 | 24篇 |
2022年 | 36篇 |
2021年 | 78篇 |
2020年 | 40篇 |
2019年 | 57篇 |
2018年 | 57篇 |
2017年 | 46篇 |
2016年 | 54篇 |
2015年 | 61篇 |
2014年 | 67篇 |
2013年 | 84篇 |
2012年 | 142篇 |
2011年 | 169篇 |
2010年 | 83篇 |
2009年 | 85篇 |
2008年 | 107篇 |
2007年 | 113篇 |
2006年 | 115篇 |
2005年 | 99篇 |
2004年 | 95篇 |
2003年 | 69篇 |
2002年 | 57篇 |
2001年 | 56篇 |
2000年 | 78篇 |
1999年 | 51篇 |
1998年 | 27篇 |
1997年 | 20篇 |
1996年 | 18篇 |
1995年 | 15篇 |
1992年 | 77篇 |
1991年 | 38篇 |
1990年 | 51篇 |
1989年 | 35篇 |
1988年 | 39篇 |
1987年 | 42篇 |
1986年 | 35篇 |
1985年 | 33篇 |
1984年 | 23篇 |
1979年 | 41篇 |
1978年 | 24篇 |
1977年 | 25篇 |
1975年 | 23篇 |
1974年 | 26篇 |
1973年 | 37篇 |
1972年 | 32篇 |
1971年 | 22篇 |
1970年 | 20篇 |
1969年 | 15篇 |
1935年 | 16篇 |
1934年 | 13篇 |
排序方式: 共有2928条查询结果,搜索用时 31 毫秒
1.
2.
Lungiswa L Nkonki Tanya M Doherty Zelee Hill Mickey Chopra Nikki Schaay Carl Kendall 《AIDS research and therapy》2007,4(1):27
Background
The objective of this study was to examine missed opportunities for participation in a prevention of mother-to-child transmission (PMTCT) programme in three sites in South Africa. A rapid anthropological assessment was used to collect in-depth data from 58 HIV-positive women who were enrolled in a larger cohort study to assess mother-to-child HIV transmission. Semi-structured interviews were conducted with the women in order to gain an understanding of their experiences of antenatal care and to identify missed opportunities for participation in PMTCT. 相似文献3.
Immunodiagnosis of Entamoeba histolytica and Ascaris lumbricoides infections in Caucasian and aboriginal Australians 总被引:1,自引:0,他引:1
J S Welch C Dobson S Chopra 《Transactions of the Royal Society of Tropical Medicine and Hygiene》1986,80(2):240-247
The immunodiagnostic efficiency of an indirect immunofluorescence test (IFAT) and in vitro lymphocyte proliferative responsiveness (cell mediated immunity test, CMIT) used to measure the immunological responses of individuals with known natural Entamoeba histolytica and Ascaris lumbricoides infections, was studied under survey conditions. E. histolytica was common among Aborigines from Cherbourg, Kowanyama and Central Australia, but it was not found in Brisbane Caucasians. The protozoan was selected for the study because it was prevalent and purified antigen was commercially available. Immunodiagnosis for A. lumbricoides was made using an antigen prepared by affinity chromatography. Diagnosis based on frequency distribution of immunological data gave valid assessment of the number of infected individuals in each population studied. 相似文献
4.
Sheetal Chopra Anna S Lev-Toaff Fatih Ors Diane Bergin 《Journal of ultrasound in medicine》2006,25(5):617-27; quiz 629
OBJECTIVE: The purpose of this presentation is to show the imaging findings of the common and uncommon variants of adenomyosis as seen on sonography and magnetic resonance imaging (MRI). METHODS: A 3-year database search was performed to identify women who had pelvic sonography and pelvic MRI within a 6-month interval. Images of these cases were retrospectively reviewed. RESULTS: Eighty women were identified. Adenomyosis was diagnosed on MRI, which was used as the reference standard, in 45 of these women. The correct diagnosis was made on sonography in 73% of the cases. CONCLUSIONS: Awareness of the spectrum of imaging features of adenomyosis is important to use sonography effectively for diagnosing this entity and to help avoid misdiagnosis. 相似文献
5.
A total of 168 strains of Salmonella were isolated in the Command Pathology Laboratory (WC) Delhi Cantt during the year 1990. Out of this, 143 were Salmonella typhi, 17 Salmonella paratyphi A, 7 Salmonella typhimurium and 1 Salmonella manhattan. The commonest phage type and biotype of Salmonella typhi was type E1 and type 1 respectively. The dominant biotype of Salmonella paratyphi A was type I. There was a very high degree of multidrug resistance of most of the strains. But all the strains were sensitive to ciprofloxacin and norfloxacin. 相似文献
6.
Comparison of survival in cardiac surgery at a Veterans Administration hospital and its affiliated university hospital 总被引:5,自引:0,他引:5
D C Kress G M Kroncke P S Chopra D J Cohen P W Rasmussen R D Nichols E S Beatty H A Berkoff 《Archives of surgery (Chicago, Ill. : 1960)》1988,123(4):439-443
Survival data were reviewed for 3330 open cardiac procedures from 1975 through 1984 at the William S. Middleton Memorial Veterans Hospital, Madison, Wis, and the University of Wisconsin Hospitals and Clinics, Madison. Respective operative survivals were 98.6% and 98.7% for myocardial revascularizations with vein graft or internal mammary artery (CABG), 96.2% and 96.8% for CABG reoperation, 97.8% and 95.9% for aortic valve replacement, 96.3% and 90.3% for aortic valve replacement plus CABG, 100.0% and 94.9% for mitral valve replacement, and 100.0% and 82.9% for mitral valve replacement plus CABG. There were no significant differences in six-year survival curves between hospitals despite threefold differences in average annual caseload (88 vs 294). This suggest that residency-directed cardiac surgery programs can function equally as well at a Veterans Administration hospital as at an affiliated university hospital. 相似文献
7.
Since the initial report of coarctation balloon angioplasty in 1982, several groups have used this technique for native coarctations in neonates, infants, and children and for postoperative recoarctations. However, recommendations for use of balloon angioplasty as a treatment procedure of choice are clouded by reports of aneurysm development at the site of coarctation. Here we review our experience as well as that published in the literature, including Valvuloplasty and Angioplasty of Congenital Anomalies Registry data, and present evidence in support of balloon angioplasty as a therapeutic procedure of choice for treating native and recurrent postoperative aortic coarctations. Balloon angioplasty of native aortic coarctations in 20 neonates and infants 1 year old or less reduced peak systolic pressure gradient across the coarctation from 40 +/- 12 mm Hg (mean +/- standard deviation) to 11 +/- 8 mm Hg (p less than 0.001); no patient required immediate surgical intervention. The residual gradient at follow-up (mean follow-up, 12 months) in 16 infants was 18 +/- 16 mm Hg, a significant improvement (p less than 0.01) compared with preangioplasty values. In none of the patients did an aneurysm develop. Recoarctation developed in 5 (31%) of the 16 infants and was successfully treated either by surgical resection (in 2) or by repeat balloon angioplasty (in 3). A comparison of mortality and recurrence rates between the balloon angioplasty and surgical groups was made with the help of data pooled from the literature published since 1980. The initial (7% versus 23%) and late (2% versus 25%) mortality and recoarctation (11% versus 18%) rates were higher (p less than 0.025) after surgical intervention than after balloon therapy. When only reports in which patients were operated on after 1979 were included in this type of analysis, the initial and late mortality rates remained higher (p less than 0.01) after operation than after angioplasty, and the recoarctation rates became similar (p greater than 0.1). Thirty-two children (greater than 1 year old) underwent balloon angioplasty of native coarctation with a resultant reduction in peak systolic pressure gradient from 48 +/- 19 mm Hg to 10 +/- 9 mm Hg (p less than 0.001), which continued to remain low (14 +/- 11 mm Hg; p less than 0.001) at follow-up catheterization in 24 children 13 months (mean) later. There were no immediate or late deaths. A small aneurysm developed in 1 patient (4%) but did not require intervention. Recoarctation developed in 2 patients (8%), and in both, repeat balloon angioplasty was performed with good results.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
8.
P W Collins C N Gutteridge A O'Driscoll S Blair L Jones R Aitchison S M Kelsey R Chopra A Goldstone A C Newland 《Bone marrow transplantation》1992,10(6):499-506
Endothelial cell activation may play a role in thrombotic complications of BMT such as hepatic veno-occlusive disease (VOD), right atrial line thrombosis and microangiopathic haemolysis. To assess this, von Willebrand factor antigen (vWF:ag) was measured in 72 patients (25 allografts, 46 autografts and one syngeneic) during the first 6 weeks post-transplant. There was a significant rise in vWF:ag in both allografts and autografts but a greater increase was seen in the allografts. The changes in vWF:ag did not correlate with changes in C reactive protein showing that this was not merely an acute phase response. vWF multimers were normal in a subgroup of uncomplicated transplants showing that there was no large scale endothelial cell disruption. Patients with VOD did not have changes in vWF:ag that were consistently different from uncomplicated controls. Three of four patients who developed line thrombosis had higher levels of vWF:ag compared with control groups; multimeric structure of the vWF was again normal. These results show that there is endothelial cell activation post-BMT and that this is greater in allografts compared with autografts, thus suggesting a possible mechanism for the higher incidence of VOD in this group. There were no useful predictive markers of VOD or thrombosis in individual patients. 相似文献
9.
J M Dawson B O'Riordan S Chopra 《The Australian and New Zealand journal of surgery》1992,62(2):161-163
A patient with acute peritonitis due to ovarian actinomycosis and the association of this disease with the intrauterine contraceptive device is discussed. Because adequate treatment requires prolonged antibiotics the diagnosis should be sure. Unfortunately if antibiotics are given pre-operatively culture is usually unsuccessful and thus careful examination of all removed material is essential. As many of these women are of child bearing age surgical intervention should aim to preserve fertility wherever possible. 相似文献
10.
The tracheal mucosa of the Syrian golden hamster has been extensively employed as a model system for respiratory tract cell renewal, injury, and carcinogenesis. However, baseline cell kinetic data are not available for normal juvenile and adolescent animals in which the mucosa and cartilage are rapidly enlarging. The objective of this research was to elucidate alterations in cell kinetics, epithelial morphology, and gene expression in the trachea of hamsters at different ages. Cell kinetics were examined by 3H-thymidine labeling indices, morphology by light and electron microscopic examination, and gene expression by slot blot analysis. Results showed that mucosal epithelium of the young and adolescent hamster undergoes cyclic necrosis and cell shedding, exposing portions of the elastic basal lamina. Epithelial shedding was associated with hyperplasia and squamous metaplasia. Additionally, the labeling indices of mucosal epithelial cells and chondroblasts also exhibited variable patterns which were associated with a cyclic pattern of expression of c-fos and c-erbB2 proto-oncogenes and epidermal growth factor receptor. 相似文献