全文获取类型
收费全文 | 10006篇 |
免费 | 614篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 86篇 |
儿科学 | 340篇 |
妇产科学 | 219篇 |
基础医学 | 1264篇 |
口腔科学 | 120篇 |
临床医学 | 1201篇 |
内科学 | 1912篇 |
皮肤病学 | 218篇 |
神经病学 | 1070篇 |
特种医学 | 386篇 |
外科学 | 1103篇 |
综合类 | 61篇 |
一般理论 | 5篇 |
预防医学 | 1012篇 |
眼科学 | 285篇 |
药学 | 550篇 |
中国医学 | 13篇 |
肿瘤学 | 789篇 |
出版年
2023年 | 69篇 |
2022年 | 112篇 |
2021年 | 226篇 |
2020年 | 187篇 |
2019年 | 250篇 |
2018年 | 306篇 |
2017年 | 253篇 |
2016年 | 224篇 |
2015年 | 254篇 |
2014年 | 332篇 |
2013年 | 492篇 |
2012年 | 756篇 |
2011年 | 762篇 |
2010年 | 388篇 |
2009年 | 384篇 |
2008年 | 633篇 |
2007年 | 585篇 |
2006年 | 592篇 |
2005年 | 536篇 |
2004年 | 476篇 |
2003年 | 451篇 |
2002年 | 427篇 |
2001年 | 147篇 |
2000年 | 123篇 |
1999年 | 118篇 |
1998年 | 105篇 |
1997年 | 91篇 |
1996年 | 62篇 |
1995年 | 38篇 |
1994年 | 45篇 |
1993年 | 48篇 |
1992年 | 61篇 |
1991年 | 71篇 |
1990年 | 65篇 |
1989年 | 70篇 |
1988年 | 48篇 |
1987年 | 48篇 |
1986年 | 61篇 |
1985年 | 49篇 |
1984年 | 40篇 |
1983年 | 29篇 |
1982年 | 36篇 |
1976年 | 25篇 |
1975年 | 27篇 |
1973年 | 37篇 |
1972年 | 29篇 |
1971年 | 27篇 |
1970年 | 32篇 |
1968年 | 26篇 |
1967年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
51.
52.
Steffen Dietzel Anna Jauch Dirk Kienle Guoquiong Qu Heidi Holtgreve-Grez Roland Eils Christian Munkel Michael Bittner Paul S. Meltzer Jeffrey M. Trent Thomas Cremer 《Chromosome research》1998,6(1):25-33
Fluorescence in situ hybridization (FISH) with microdissection probes from human chromosomes 3 and 6 was applied to visualize arm and subregional band domains in human amniotic fluid cell nuclei. Confocal laser scanning microscopy and quantitative three-dimensional image analysis showed a pronounced variability of p- and q-arm domain arrangements and shapes. Apparent intermingling of neighbouring arm domains was limited to the domain surface. Three-dimensional distance measurements with pter and qter probes supported a high variability of chromosome territory folding. 相似文献
53.
The ultrastructure of the skin of four cetacean species, bottlenose dolphin (Tursiops truncatus) long-finned pilot whale (Globicephala melaena), humpback whale (Megaptera novaeangliae), and fin whale (Balaenoptera physalus) was investigated with particular reference to epidermal lipid. It has already been established that massive lipid reservoirs exist in whales, that the biochemical structures of cetacean lipids are unique, and that unusual intracellular lipid droplets appear in the epidermis. We report here some novel findings on scanning electron microscopic morphology of epidermal lipid, and on its ultrastructural morphology in general and specialized integumentary sites, including species not previously investigated. The intracellular epidermal lipid droplets were more extensive than lamellar body-derived intercellular lipid which is within the interstices of stratum externum cells. The intracellular droplets were spherical, highly variable in size ranging from 0.24 m to 3.0 m in diameter, appeared singly or were aggregated in cytoplasmic cavitations, and often were closely associated with epidermal cell nuclei. Evidence for exocytosis of the intracellular droplets was not observed. Significant numbers of intracellular lipid droplets are not observed in the epidermis of terrestrial mammals, so their presence is one of several aquatic specializations of the cetacean integument. Its full significance remains obscure, but it is more probably associated with epidermal cell metabolism than with secretion of lipid. 相似文献
54.
Flow Perfusion Culture of Marrow Stromal Cells Seeded on Porous Biphasic Calcium Phosphate Ceramics 总被引:2,自引:0,他引:2
Holtorf HL Sheffield TL Ambrose CG Jansen JA Mikos AG 《Annals of biomedical engineering》2005,33(9):1238-1248
Calcium phosphate ceramics have been widely used for filling bone defects to aid in the regeneration of new bone tissue. Addition of osteogenic cells to porous ceramic scaffolds may accelerate the bone repair process. This study demonstrates the feasibility of culturing marrow stromal cells (MSCs) on porous biphasic calcium phosphate ceramic scaffolds in a flow perfusion bioreactor. The flow of medium through the scaffold porosity benefits cell differentiation by enhancing nutrient transport to the scaffold interior and by providing mechanical stimulation to cells in the form of fluid shear. Primary rat MSCs were seeded onto porous ceramic (60% hydroxyapatite, 40% β-tricalcium phosphate) scaffolds, cultured for up to 16 days in static or flow perfusion conditions, and assessed for osteoblastic differentiation. Cells were distributed throughout the entire scaffold by 16 days of flow perfusion culture whereas they were located only along the scaffold perimeter in static culture. At all culture times, flow perfused constructs demonstrated greater osteoblastic differentiation than statically cultured constructs as evidenced by alkaline phosphatase activity, osteopontin secretion into the culture medium, and histological evaluation. These results demonstrate the feasibility and benefit of culturing cell/ceramic constructs in a flow perfusion bioreactor for bone tissue engineering applications. 相似文献
55.
David W. Barbara William D. Edwards Heidi M. Connolly Joseph A. Dearani 《Cardiovascular pathology》2008,17(3):166-171
BACKGROUND: Ebstein's anomaly has been described extensively in autopsy material. However, there have been no large surgical pathology series of this malformation. OBJECTIVE: To review clinical and surgical pathologic features of a large number of cases of Ebstein's anomaly from a single institution. METHODS: Review of medical histories, surgical reports, and surgical pathology reports at the Mayo Clinic (2000-2005). RESULTS: Among 104 patients, the mean age was 31 years (2 months-79 years), and 57% were female. Common ECG abnormalities included right bundle branch block (58%), first-degree heart block (31%), preexcitation (18%), and nonspecific intraventricular conduction delay/block (15%). Moreover, 74% had inter-atrial communication, 13% mitral valve prolapse, and 5% bicuspid aortic valve. Clinically, all had tricuspid regurgitation (severe in 74%), and 17% of anterior leaflets were fenestrated. No tricuspid valve was calcified. Surgically, tricuspid tissue was removed during replacement in 99% and repair in 1%. The anterior tricuspid leaflet was resected in 98%, and its length was 0.81-9.3 cm/m2 body surface area (mean, 3.3). Characteristically, leaflets were large and had irregular shapes and numerous short cordal or direct myocardial insertions. One tricuspid valve had two papillary fibroelastomas. None had clinical or pathologic evidence of active or healed endocarditis. CONCLUSIONS: Among patients with Ebstein's malformation, tricuspid valve tissue almost exclusively was removed during valve replacement and represented the anterior leaflet. Valve tissue was generally large, irregularly shaped, and associated with insertion of short cords or myocardial stumps. Interestingly, although appreciably deformed, Ebstein valves were not associated with infective endocarditis. 相似文献
56.
Werahera PN Miller GJ Torkko K Crawford ED Stewart JS Deantoni EP Miller HL Lucia MS 《Human pathology》2004,35(7):798-807
Advances in the detection of carcinoma of the prostate during the last 15 years have accounted for a sharp increase and then an abrupt decrease in the incidence of the disease. A more recent decline in its mortality rates has been variously interpreted as either the success of early detection and improved treatment or lead-time bias. The recently reported Prostate Cancer Prevention Trial had an overall detection rate that approached the 30%-40% prevalence rates reported in autopsy series in which men died of other causes. However, the prognostic information that can be obtained from prostate cancer found on biopsy is limited. Three-dimensional computer modeling is one technique that allows multiple studies on "immortal" prostates to test methods of biopsy sampling accuracy and to assist in the determination of the disease's severity. Computer modeling can assess detection rates and assesses tumor multifocality and heterogeneity. It can provide a more accurate representation of tumor volume, aiding in therapeutic decision making, and can assess sampling errors of various biopsy methods. It has been shown to be superior to wire-frame technique by immortalizing the original shape and dimensions of the surgically excised prostate gland. Moreover, our 3-dimensional computer modeling system improves upon other systems: It is more than a simple extension of the planimetric technique, and it is able to demarcate clearly the boundaries of Gleason grades just 1 grade apart. 相似文献
57.
R A Pfeiffer H St?ss H J Voight G F Wündisch 《American journal of medical genetics》1988,29(4):901-908
Absence of fibulae, and unilateral absence of ulna, associated with lateral oligodactyly, and rectangular bowing of the femora are the prominent features of a lethal syndrome studied in two children of related parents. Other malformations are cleft lip and palate and posterior midline abnormalities of the brain. One similar though not identical MCA-syndrome was reported. The literature is reviewed with respect to ulno-fibular malformations. 相似文献
58.
Irene Boo Alexandra E Fischer Doug Johnson Ruth Chin Maxine Giourouki Mandvi Bharadwaj Scott Bowden Joseph Torresi Heidi Drummer 《Journal of clinical virology》2007,39(4):288-294
BACKGROUND: The role of neutralizing antibody (NAb) in determining response to antiviral therapy has not been established. OBJECTIVE: In this study we have analysed the kinetic's of the NAb response in patients with chronic hepatitis C who received antiviral therapy. STUDY DESIGN: Seventeen patients infected with genotype 1, 2a/c or 3a hepatitis C virus (HCV) were enrolled, eight with a sustained virological response (SVR), five non-responders and four relapsers. RESULTS: The mean NAb titre required to neutralize 50% of the E1E2-pp in patients who achieved an SVR (294+/-S.D. 51), in relapsers (246+/-S.D. 61.7) and non-responders (286+/-S.D. 80.95) did not differ significantly between the patient groups and did not alter during the course of treatment (P>0.01). Genetic variation present before antiviral therapy was analysed by single strand conformation polymorphism (SSCP) and failed to demonstrate a significant difference in the mean number of amplified E1E2 DNA fragments from the serum of patients who achieved an SVR (3.15+/-S.D. 1.53), relapsers (2.8+/-S.D. 1.32) or non-responders (3.69+/-S.D. 1.75). The baseline serum HCV viral loads were also not significantly different between patients who achieved an SVR (1.4 x 10(6) copies/ml; +/-S.D. 2.4 x 10(6)), relapsers (1.3 x 10(7) copies/ml; +/-S.D. 2.4 x 10(7)) and non-responders (1.5 x 10(6) copies/ml; +/-S.D. 1.1 x 10(6)). CONCLUSION: We have shown that neutralizing anti-HCVpp antibody is not associated with response to antiviral therapy. In addition, there was no correlation between baseline virological load, circulating viral quasi-species, NAb titres and final response to treatment. 相似文献
59.
60.
Lugli A Forster Y Haas P Nocito A Bucher C Bissig H Mirlacher M Storz M Mihatsch MJ Sauter G 《Human pathology》2003,34(10):994-1000
Calretinin is a calcium-binding protein expressed in different normal and neoplastic tissues. Early studies suggested that calretinin is a useful marker to differentiate adenocarcinomas from malignant mesotheliomas of the lung, but subsequent work has shown that calretinin can be expressed in several other tumor types. To systematically investigate the epidemiology of calretinin expression in normal and neoplastic tissues, we used tissue microarrays (TMAs) to analyze the immunohistochemically detectable expression of calretinin in 5233 tissue samples from 128 different tumor categories and 76 different normal tissue types. At least 1 case with weak expression could be found in 74 of 128 (58%) different tumor types and 46 entities (36%) had at least 1 tumor with strong positivity. In normal tissues, a particularly strong expression was found in Leydig cells of the testis, neurons of the brain, theca-lutein and theca interna cells of the ovary, and mesothelium. In tumors, strong calretinin expression was most frequently found in malignant mesotheliomas (6 of 7), Leydig cell tumors of the testis (5 of 5), adenomas of adrenal gland (5 of 9), and adenomatoid tumors (4 of 9). In summary, calretinin is frequently expressed in many different tumor types. Metastases of various different origins must be included in the differential diagnosis of calretinin-positive pleura tumors. 相似文献