全文获取类型
收费全文 | 1200篇 |
免费 | 77篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 27篇 |
妇产科学 | 55篇 |
基础医学 | 169篇 |
口腔科学 | 17篇 |
临床医学 | 73篇 |
内科学 | 298篇 |
皮肤病学 | 25篇 |
神经病学 | 97篇 |
特种医学 | 26篇 |
外科学 | 262篇 |
综合类 | 4篇 |
一般理论 | 1篇 |
预防医学 | 68篇 |
眼科学 | 20篇 |
药学 | 55篇 |
中国医学 | 1篇 |
肿瘤学 | 78篇 |
出版年
2023年 | 7篇 |
2022年 | 8篇 |
2021年 | 44篇 |
2020年 | 28篇 |
2019年 | 38篇 |
2018年 | 34篇 |
2017年 | 24篇 |
2016年 | 35篇 |
2015年 | 29篇 |
2014年 | 53篇 |
2013年 | 62篇 |
2012年 | 91篇 |
2011年 | 82篇 |
2010年 | 43篇 |
2009年 | 59篇 |
2008年 | 72篇 |
2007年 | 75篇 |
2006年 | 84篇 |
2005年 | 62篇 |
2004年 | 54篇 |
2003年 | 54篇 |
2002年 | 66篇 |
2001年 | 7篇 |
2000年 | 11篇 |
1999年 | 11篇 |
1998年 | 9篇 |
1997年 | 11篇 |
1996年 | 11篇 |
1995年 | 8篇 |
1993年 | 7篇 |
1992年 | 7篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 9篇 |
1981年 | 9篇 |
1980年 | 10篇 |
1979年 | 4篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1970年 | 3篇 |
1961年 | 2篇 |
1931年 | 2篇 |
1928年 | 2篇 |
排序方式: 共有1287条查询结果,搜索用时 46 毫秒
1.
Journal of Neuro-Oncology - 相似文献
2.
David Jiménez Castro Gema Díaz David Martí Carlos Escobar Javier Ortega Sergio García-Rull Joaquin Picher Antonio Sueiro 《Blood coagulation & fibrinolysis》2007,18(2):173-177
This study aimed to determine whether a weight-adjusted dose of subcutaneous enoxaparin is as effective and safe as oral acenocoumarol for the secondary prophylaxis of pulmonary embolism. Three hundred and eighty consecutive noncancer outpatients hospitalized with an episode of symptomatic pulmonary embolism selected treatment with acenocoumarol or enoxaparin at a dose of 1 mg/kg once daily after being informed of the type of administration and expected frequency of laboratory monitoring for both medicinal products. Endpoints were symptomatic recurrent thromboembolic events evaluated by standard objective testing, and a composite endpoint of recurrent venous thromboembolism, major bleeding, and death from any cause. One hundred and ninety-nine patients (52%) chose acenocoumarol therapy and 181 chose enoxaparin monotherapy. Four patients in the enoxaparin group (2.2%) and six patients in the acenocoumarol group (3%) had an objective thromboembolic recurrence (hazard ratio, 1.35; 95% confidence interval, 0.38-4.79; P = 0.64). Nine patients in the enoxaparin group (5.0%) had a hemorrhagic complication compared with 11 in the acenocoumarol group (5.5%) (P = 0.81). The hospital length of stay was shorter with enoxaparin compared with acenocoumarol (11 versus 16 days, P = 0.0001). Enoxaparin is as effective and safe as acenocoumarol in the secondary prevention of recurrent thromboembolic disease and is associated with shorter hospitalization. 相似文献
3.
Meningitis due to mixed infection with penicillin-resistant and penicillin-susceptible strains of Streptococcus pneumoniae 下载免费PDF全文
Streptococcus pneumoniae is the major cause of bacterial meningitis. We report a case of meningitis due to a mixed infection with two distinct strains of S. pneumoniae: one penicillin-resistant strain of serotype 9V and one penicillin-susceptible strain of serotype 7. The two strains exhibited different pulsed-field gel electrophoresis profiles. 相似文献
4.
We constructed two-dimensional representations of profiles of gene conservation across different genomes using the genome of Escherichia coli as a model. These profiles permit both the visualization at the genome level of different traits in the organism studied and, at the same time, reveal features related to the genomes analyzed (such as defective genomes or genomes that lack a particular system). Conserved genes are not uniformly distributed along the E. coli genome but tend to cluster together. The study of gene distribution patterns across genomes is important for the understanding of how sets of genes seem to be dependent on each other, probably having some functional link. This provides additional evidence that can be used for the elucidation of the function of unannotated genes. Clustering these patterns produces families of genes which can be arranged in a hierarchy of closeness. In this way, functions can be defined at different levels of generality depending on the level of the hierarchy that is studied. The combined study of conservation and phenotypic traits opens up the possibility of defining phenotype/genotype associations, and ultimately inferring the gene or genes responsible for a particular trait. 相似文献
5.
Rueda J Cantos R Lim DJ 《The anatomical record. Part A, Discoveries in molecular, cellular, and evolutionary biology》2003,274(2):923-933
During development, different epithelial cells in the mouse cochlea express different cell surface glycoconjugates, which may reflect membrane specialization. Some of the lectins tested in this study (SBA, succ-WGA, and PSA) labeled the sensory cells of the cochlea around birth. Other lectins (WGA, Con A, RCA-II, and PHA-E) labeled surfaces of the sensory cells, particularly the stereocilia, from early stages of development (gestation day (GD) 16) through 21 days after birth. These may be adhesion molecules needed to attach the newly forming tectorial membrane (TM) to the stereocilia. Lectin staining of the developing TM revealed that the substructures of the TM are biochemically distinct. Lectin staining also showed the temporal sequence of the expression of cytoplasmic glycoconjugates of the cochlear epithelium during development. Biochemical changes during development are probably the result of different cells being involved in the production of glycoconjugates, and may have functional significance, specifically with regard to the expression of adhesion and/or signaling molecules. 相似文献
6.
Josep Clotet Francesc Posas Antonio Casamayor Ine Schaaff-Gerstenschläger Joaquin Arinõ 《Current genetics》1991,19(5):339-342
Summary
S. cerevisiae gene DIS2S1, which codes for a protein very similar to the catalytic subunit of mammalian protein phosphatase 1, was disrupted in vitro. Diploid yeast cells were transformed and sporulated. Tetrad analysis demonstrated that disruption of DIS2S1 is lethal for the cell. Glycogen phosphorylase a and glycogen synthase activity ratio were measured in diploids carrying a disrupted allele of the gene. Phosphorylase was dramatically activated in mutant cells but, under the same conditions, glycogen synthase activity was essentially identical in both mutant and wild-type cells. 相似文献
7.
8.
9.
Discrimination between clinically relevant and nonrelevant Acanthamoeba strains isolated from contact lens- wearing keratitis patients in Austria 总被引:3,自引:0,他引:3 下载免费PDF全文
Walochnik J Haller-Schober E Kölli H Picher O Obwaller A Aspöck H 《Journal of clinical microbiology》2000,38(11):3932-3936
Eighteen cases of Acanthamoeba-associated keratitis among contact lens wearers seen at the Department of Ophthalmology, Karl-Franzens-University, Graz, Austria, between 1996 and 1999 are reviewed. The amoebae were proven to be the causative agents in three patients. The aim of our study was to discriminate between clinically relevant and nonrelevant isolates and to assess the relatedness of the isolates to published strains. Altogether, 20 strains of free-living amoebae, including 15 Acanthamoeba strains, 3 Vahlkampfia strains, and 2 Hartmannella strains, were isolated from clinical specimens. The virulent Acanthamoeba strains were identified as A. polyphaga and two strains of A. hatchetti. To our knowledge this is the first determination of keratitis-causing Acanthamoeba strains in Austria. Clinically relevant isolates differed markedly from nonrelevant isolates with respect to their physiological properties. 18S ribosomal DNA sequence types were determined for the three physiologically most-divergent strains including one of the keratitis-causing strains. This highly virulent strain exhibited sequence type T6, a sequence type not previously associated with keratitis. Sequence data indicate that Acanthamoeba strains causing keratitis as well as nonpathogenic strains of Acanthamoeba in Austria are most closely related to published strains from other parts of the world. Moreover, the results of our study support the assumption that pathogenicity in Acanthamoeba is a distinct capability of certain strains and not dependent on appropriate conditions for the establishment of an infection. 相似文献
10.
When isolated from their dams and littermates, rat pups emit ultrasonic vocalizations to elicit attention and retrieval from their dams. This study examined the effects of perinatal alcohol exposure on ultrasonic vocalizations and maternal-infant interactions. Alcohol was administered throughout gestation to the dams and during the early postnatal period to the pups. Control groups consisted of a nontreated control and an intubated, pair-fed control. Ultrasonic vocalizations were measured on postnatal day (PD) 5 under varying conditions of isolation. Maternal behaviors were examined on PD2, 4, 6, 8, and 10. Maternal behaviors were not significantly affected by prior alcohol administration to either the dams or the pups. However, ethanol-exposed rat pups vocalized more on PD5 than controls regardless of condition. The heightened vocalization response of the ethanol-exposed pups might be an underlying factor in the persistent effects of perinatal ethanol exposure on social behavior. 相似文献