全文获取类型
收费全文 | 18257篇 |
免费 | 1400篇 |
国内免费 | 31篇 |
专业分类
耳鼻咽喉 | 119篇 |
儿科学 | 592篇 |
妇产科学 | 353篇 |
基础医学 | 2126篇 |
口腔科学 | 369篇 |
临床医学 | 2116篇 |
内科学 | 3406篇 |
皮肤病学 | 208篇 |
神经病学 | 2097篇 |
特种医学 | 731篇 |
外科学 | 2822篇 |
综合类 | 231篇 |
一般理论 | 38篇 |
预防医学 | 1933篇 |
眼科学 | 159篇 |
药学 | 1259篇 |
中国医学 | 26篇 |
肿瘤学 | 1103篇 |
出版年
2023年 | 83篇 |
2022年 | 135篇 |
2021年 | 355篇 |
2020年 | 230篇 |
2019年 | 379篇 |
2018年 | 433篇 |
2017年 | 290篇 |
2016年 | 338篇 |
2015年 | 333篇 |
2014年 | 583篇 |
2013年 | 812篇 |
2012年 | 1170篇 |
2011年 | 1254篇 |
2010年 | 696篇 |
2009年 | 632篇 |
2008年 | 1122篇 |
2007年 | 1080篇 |
2006年 | 995篇 |
2005年 | 1098篇 |
2004年 | 1027篇 |
2003年 | 966篇 |
2002年 | 898篇 |
2001年 | 337篇 |
2000年 | 287篇 |
1999年 | 297篇 |
1998年 | 220篇 |
1997年 | 177篇 |
1996年 | 174篇 |
1995年 | 156篇 |
1994年 | 134篇 |
1993年 | 100篇 |
1992年 | 242篇 |
1991年 | 231篇 |
1990年 | 207篇 |
1989年 | 202篇 |
1988年 | 211篇 |
1987年 | 189篇 |
1986年 | 160篇 |
1985年 | 154篇 |
1984年 | 135篇 |
1983年 | 134篇 |
1982年 | 108篇 |
1981年 | 94篇 |
1980年 | 101篇 |
1979年 | 96篇 |
1978年 | 90篇 |
1977年 | 58篇 |
1974年 | 41篇 |
1972年 | 53篇 |
1971年 | 42篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
A E Fresia J L Currie J E Farrington R Laxman C A Griffin 《Cancer Genetics and Cytogenetics》1992,60(1):60-66
Uterine sarcomas constitute approximately 3% of all malignant uterine corpus tumors. Of these, the tumors that originate solely in the stromal elements of the uterine wall are relatively infrequent and have not been well characterized cytogenetically. We report data from a low-grade endometrial stromal sarcoma both at the time of resection and after months in long-term tissue culture. Cytogenetic analysis showed a clonal population of cells with an abnormal karyotype of 46,XX,del(5)(q31.1),der(7)t(6;7)(p21;p22) which remained unchanged in long-term culture. Electron microscopy suggests that these cells are similar to other neoplastic cells in having immature-appearing nuclei surrounded by a relatively mature cytoplasm (with well-developed organelles). Determination of the specificity of these observations must await study of additional stromal sarcomas. 相似文献
82.
Autonomic nerves in jejunal mucosa of HIV-infected patients show severe structural damage on electron microscopic examination. The aim of this study was to quantify loss of autonomic axons from the lamina propria of HIV-infected patients in different clinical stages of disease. Jejunal biopsies were taken from 19 HIV-antibody-positive homosexual men and from 10 control patients. Autonomic fibres in the mucosa were stained with a neurone-specific polyclonal antibody, PGP 9.5. The density of axons was quantified by a point-counting technique using a Lennox eyepiece graticule under light microscopic examination. There was significant reduction in axonal density in the villi of HIV-infected patients [mean, 9.0; standard deviation (s.d.), 4.7] compared with controls (mean, 15.3; s.d., 5.2; P = 0.003), and in the pericryptal lamina propria of HIV-infected patients (mean, 17.8; s.d., 5.4) compared with controls (mean, 27.3; s.d., 6.2; P = 0.0002). Although autonomic denervation occurs throughout the jejunal mucosa of HIV-infected patients, there was no correlation between the clinical stage of HIV disease and the degree of denervation. The denervation was greatest in patients with the most severe diarrhoea, but this difference was not significant. This study provides the first quantitative morphological evidence for depletion of autonomic nerves in the jejunum of patients infected with HIV. Autonomic neuropathy may contribute to chronic diarrhoea in HIV disease. 相似文献
83.
The risk estimates for individual carriers of ten different familial reciprocal translocations detected among 500 couples with reproductive failures are presented. These were established by application of the empirical data analysed by Stengel-Rutkowski et al. (1988) and the guidelines given in Stene & Stengel-Rutkowski (1988). Different risks were estimated for unbalanced offspring at birth or at second trimester prenatal diagnosis for abortions, or stillbirths/early deaths. These risk estimates varied considerably from translocation to translocation. Carriers of five translocations had risks for offspring with single-segment imbalances. The birth risk figures ranged from 0.1% to 13.8%. Carriers of five other translocations had risks for double-segment imbalances with birth risks ranging from 0% to 3.2%. The estimated risk figures were independent of the method of ascertainment. Among the parents of the index cases we found nine maternal carriers and only one paternal carrier. This presentation illustrates the need for individual risk counselling of each carrier with reciprocal translocation regarding further family planning. 相似文献
84.
We report the use of the AngioJet F140 rheolytic catheter to recannalize an acutely thrombosed aortopulmonary shunt in a 21-year-old female with palliated, complex congenital heart disease. After extracting the thrombus that filled the entire length of the shunt, three stents were placed at sites where the lumen was compromised by distortion or thrombus. Unobstructed flow was restored to the left pulmonary artery that persisted at 1-year follow-up. 相似文献
85.
86.
Genotypic selection of mutated DNA sequences using mismatch cleavage analysis, a possible basis for novel mutation assays 总被引:1,自引:1,他引:0
A novel technique for the selection of mutated DNA sequences,termed mismatch cleavage-polymerase chain reaction (MC-PCR),is proposed. The method is based on hybridizing genomic DNAwith a suitable probe, several 100 bp long. Mutated DNA sequenceswill form mismatched heteroduplexes which are cleaved by usingresolvases. Cleaved heteroduplexes are detected by ligationto an oligonucleotide adaptor and then amplified by using PCR.If practical, this technique would have considerable advantagesover the restriction site mutation (RSM) method. Failure toachieve cleavage efficiencies of close to 100% will not compromisesuccess. This is because positive signals (PCR amplification)arise from cleaved mutated sites and not, as in RSM, from DNAsequences resistant to cleavage by restriction endonucleases.Furthermore, the mutational target is much larger than in RSM.It would be possible to screen stretches of DNA several 100bp in length for mutations. Any mutation, independent of itslocation, could be identified. The usefulness of MC-PCR forthe genotypic selection of mutants will depend on the effectivenesswith which a small number of mismatched heteroduplexes can berecognized, cleaved and ligated.
1To whom correspondence should be addressed 相似文献
87.
Argon laser stapedectomy using an endo-otoprobe system 总被引:3,自引:0,他引:3
In summary, we believe that the endo-otoprobe system offers several advantages to the otologist. The system is safe and relatively inexpensive. The probes are designed to provide tactile feedback similar to that of standard otologic instruments and avoid the use of a cumbersome micromanipulator. There are currently shapes that are similar to a Rosen needle, Shea pick, and bayonet. We hope most otologists will find that one of the endo-otoprobes fits their particular style of surgery. 相似文献
88.
G Griffin 《Minnesota medicine》1989,72(3):128, 171-128, 173
89.
Feng-Chun Tsai Daniel Marelli Jessica Bresson David Gjertson Reza Kermani Abbas Ardehali Fardad Esmailian Michele Hamilton Gregg C Fonarow Jaime Moriguchi Mark Plunkett Antoine Hage Julie Tran Jon A Kobashigawa Hillel Laks 《American journal of transplantation》2002,2(6):539-545
Older age, prior transplantation, pulmonary hypertension, and mechanical support are commonly seen in current potential cardiac transplant recipients. Transplants in 436 consecutive adult patients from 1994 to 1999 were reviewed. There were 251 using standard donors in 243 patients (age range 18-69 years). To emphasize recipient risk, 185 patients who received a nonstandard donor were excluded from analysis. The indications for transplant were ischemic heart disease (n = 123, 47%), dilated cardiomyopathy (n = 82, 32%), and others (n=56, 21%). One hundred and forty-nine (57%) recipients were listed as status I; 5 and 6% were supported with an intra-aortic balloon and an assist device, respectively. The 30-d survival and survival to discharge were 94.7 and 92.7%, respectively; 1-year survival was 89.1%. Causes of early death were graft failure (n = 6), infection (n = 4), stroke (n = 4), multiorgan failure (n = 3) and rejection (n = 2). Predictors were balloon pump use alone (OR= 11.4, p =0.002), pulmonary vascular resistance > 4 Wood units (OR = 5.7, p = 0.007), pretransplant creatinine > 2.0 mg/dL (OR = 6.9, p = 0.004) and female donor (OR = 8.3, p = 0.002). Recipient age and previous surgery did not affect short-term survival. Heart transplantation in the current era consistently offers excellent early and 1-year survival for well-selected recipients receiving standard donors. Early mortality tends to reflect graft failure while hospital mortality may be more indicative of recipient selection. 相似文献
90.
Pramod K Pal Joanne Leung Katya Hedrich Ali Samii Abraham Lieberman Paul A Nausieda Donald B Calne Xandra O Breakefield Christine Klein A Jon Stoessl 《Movement disorders》2002,17(4):789-794
There are few reports of positron emission tomography (PET) in juvenile parkinsonism (JP). We report on the results of (18)F-6-fluoro-L-dopa (FD) PET in a 14-year-old patient with JP of 5 years duration associated with atypical features. This is the youngest subject to be investigated to date. There was a severe asymmetric reduction in striatal FD uptake, with a rostrocaudal gradient in the putamen similar to that seen in adult-onset idiopathic parkinsonism. Extensive DNA analysis in this patient did not show mutations in the parkin gene. 相似文献