全文获取类型
收费全文 | 7386篇 |
免费 | 491篇 |
国内免费 | 28篇 |
专业分类
耳鼻咽喉 | 121篇 |
儿科学 | 420篇 |
妇产科学 | 175篇 |
基础医学 | 1060篇 |
口腔科学 | 58篇 |
临床医学 | 539篇 |
内科学 | 1535篇 |
皮肤病学 | 220篇 |
神经病学 | 283篇 |
特种医学 | 184篇 |
外科学 | 739篇 |
综合类 | 559篇 |
一般理论 | 1篇 |
预防医学 | 489篇 |
眼科学 | 181篇 |
药学 | 635篇 |
中国医学 | 36篇 |
肿瘤学 | 670篇 |
出版年
2023年 | 50篇 |
2022年 | 99篇 |
2021年 | 182篇 |
2020年 | 105篇 |
2019年 | 121篇 |
2018年 | 145篇 |
2017年 | 122篇 |
2016年 | 160篇 |
2015年 | 210篇 |
2014年 | 244篇 |
2013年 | 301篇 |
2012年 | 441篇 |
2011年 | 428篇 |
2010年 | 299篇 |
2009年 | 272篇 |
2008年 | 377篇 |
2007年 | 349篇 |
2006年 | 326篇 |
2005年 | 298篇 |
2004年 | 286篇 |
2003年 | 243篇 |
2002年 | 220篇 |
2001年 | 205篇 |
2000年 | 193篇 |
1999年 | 155篇 |
1998年 | 97篇 |
1997年 | 97篇 |
1996年 | 99篇 |
1995年 | 79篇 |
1994年 | 76篇 |
1993年 | 56篇 |
1992年 | 111篇 |
1991年 | 98篇 |
1990年 | 98篇 |
1989年 | 77篇 |
1988年 | 93篇 |
1987年 | 84篇 |
1986年 | 75篇 |
1985年 | 75篇 |
1984年 | 51篇 |
1983年 | 47篇 |
1979年 | 54篇 |
1978年 | 44篇 |
1976年 | 42篇 |
1975年 | 40篇 |
1974年 | 45篇 |
1973年 | 37篇 |
1972年 | 52篇 |
1971年 | 37篇 |
1970年 | 37篇 |
排序方式: 共有7905条查询结果,搜索用时 15 毫秒
41.
Chakraborty S Garg P Ramamurthy T Thungapathra M Gautam JK Kumar C Maiti S Yamasaki S Shimada T Takeda Y Ghosh A Nair GB 《Journal of medical microbiology》2001,50(10):879-888
This study identified 17 matching serogroups of Vibrio cholerae belonging to serogroups other than O1 and O139 isolated from human cases and from the environment during a concurrent clinical and environmental study conducted in Calcutta, a cholera endemic area. Isolates within these matching serogroups were compared by various phenotypic and genotypic traits to determine if the environment was the source of the organisms associated with the disease. Clinical strains of V. cholerae were resistant to a greater number of drugs and exhibited multi-drug resistance compared with their environmental counterparts. Except for the presence of the genes for the El Tor haemolysin and the regulatory element ToxR in most of the strains of V. cholerae examined, non-O1, non-O139 V. cholerae strains lacked most of the other known virulence traits associated with toxigenic V. cholerae O1 or O139. Restriction fragment-length polymorphism of virulence-associated genes, ribotypes and DNA fingerprints of strains of matched serogroups showed considerable diversity, although some gene polymorphisms and ribotypes of a few strains of different serogroups were similar. It is concluded that despite sharing the same serogroup, environmental and clinical isolates were genetically heterogeneous and were of different lineages. 相似文献
42.
Acute myelomonocytic leukaemia with pseudo-Chediak-Higashi inclusions in leukaemic blasts report of an unusual case 总被引:1,自引:0,他引:1
Giant inclusions in the blast cells resembling that of Chediak-Higashi syndrome have been reported only in a handful of cases with acute leukaemia. There is a paucity of data on the ultrastructural appearance of such unique light microscopic findings. As many of such patients were reported in late seventies and early eighties [1-4] the outcome of treatment using present day multiple induction/consolidation regimens in such patients has also been rarely reported due to the rarity of such patients. We report here on a patient with acute myeloid leukaemia showing pseudo-Chediak-Higashi inclusions in leukaemic blasts with unusual ultrastructural morphology. 相似文献
43.
Pyramidal neurons in the mammalian cerebral cortex can be described by a fractal dimension (Mandelbrot, 1982), which is an objective, quantitative measure of the complexity of their soma/dendritic borders. In the cat, the fractal dimensions of lamina V cells, which include pyramidal tract neurons (PTN), indicate that these cells are more complex than other pyramidal neurons (PN) in the same region of motor cortex. The lamina V cells of the cat are also more complex than those in motor cortex of the monkey. Moreover, lamina III neurons in the monkey are more complex than monkey lamina V neurons. The fractal dimension of the intracortical axon collateral arborizations of the same pyramidal neurons indicated, in all cases, that the branching of these terminals is less complex than the branching of the dendrites of the same cells. In line with the observation that the fractal dimensions of some homologous cellular populations are different in different species, it is suggested that the fractal dimension and the degree of morphological complexity may relate to the requirement for the number of separable functions to be accommodated within one neuron. For example, as the size of the cortex and the number of neurons in a region increase, the opportunity exists within a given cortical zone, for individual functions to be segregated and for functional specialization to be accommodated with less morphological complexity of the individual neurons performing each of these functions. 相似文献
44.
45.
S K Ghosh C De Vos I McIlroy K R Patel 《The Journal of allergy and clinical immunology》1991,87(5):1010-1013
Cetirizine, a derivative of hydroxyzine, is a new compound with potent antihistaminic property without antiserotonin and anticholinergic activities. The effect of both a single dose (15 mg) and 7 days of treatment (15 mg twice daily) with cetirizine, a potent H1 antagonist on bronchoconstriction induced by histamine and leukotriene D4 (LTD4) has been examined in 10 patients with mild atopic asthma in a placebo-controlled, double-blind, crossover study. Cetirizine, after a single dose and 7 days of treatment with placebo, the geometric mean values of the provocative concentration of histamine causing a 20% fall in FEV1 (millimolars) were 1.60 (95% confidence interval, 0.82 to 3.11) and 1.67 (0.77 to 3.65), compared with 118.07 (77.22 to 180.54) (p less than 0.0001) and 53.16 (20.50 to 137.84) after cetirizine administration (p less than 0.0002). The mean inhibition after a single dose was twofold higher than after 1 week of treatment (p less than 0.05). After a single dose and 7 days of treatment with placebo, the geometric mean values of the provocative concentration of LTD4 causing a 20% fall in FEV1 (micromolars) were 2.26 (1.74 to 2.94) and 2.37 (1.77 to 3.17), compared with 3.90 (2.60 to 5.86) (p less than 0.05) and 3.21 (2.28 to 4.52) after cetirizine administration. This result suggests that cetirizine is a potent H1 antagonist in the human airways. Diminished activity after 1 week of treatment suggests subsensitivity of H1 receptors developing in human airways. The small protective effect after a single dose against LTD4-induced bronchoconstriction indicates a nonspecific rather than a specific receptor antagonism. 相似文献
46.
Summary. A Burkholderia cepacia DR11 strain was isolated during the survey of microorganisms from coastal water of deltaic Sunderbans. This strain always
released temperate phage BcP15 into culture supernatant. UV irradiation of the strain also induced phage induction. The phage
titer was 2.3 × 108. New temperate phage BcP15 has unusual structure. It has a hexagonal head, 65 nm in diameter and a tail 200 nm long, attached
with single thick wavy tail fiber (424–705 nm). Phage DNA is double stranded 11.9 kb long. Southern hybridization result indicated
that the phage DNA was in lysogenic state into the B. cepacia DR11 genome. SDS-PAGE of phage protein showed two major bands of molecular weight 20 kDa and 40 kDa. 相似文献
47.
The ability of currently available anti-arthritic gold preparations to inhibit lysosomal glycosidases from rheumatoid synovial fluid and normal human serum was studied in vitro.It was shown that these preparations differ markedly in their ability to inhibit the enzymes. Gold thioglucose (Solganal) did not inhibit -glucuronidase (-GLUC), -N-acetylglucosaminidase (-NAG) or hyaluronidase (HASE). Chloro(triethylphosphine)gold (SK&F 36914) was a potent inhibitor of -NAG only. Sodium aurothiomalate (Myochrysine and sodium 3-aurothio-2-propanol-1-sulphonate (Allyochrisine) were inhibitors of all three enzymes, notably -GLUC.Kinetic analysis of inhibition by aurothiomalate demonstrated apparent competitive inhibition with -GLUC, but non-competitive inhibition with HASE and -NAG -GLUC was also strongly inhibited by silver and copper thiomalates.The concentrations of these drugs required for effective inhibition of lysosomal glycosidases probably exceed those attained in serum and therefore preclude this action extracellularly. It is suggested that durg sequestration and retention within phagocytic cells facilitates inhibition of glycosaminoglycan catabolism that mediates cleavage of glucuronidic linkages of hyaluronic acid and chondroitin sulphates.The hypothesis that gold dompounds act in vivo by attenuating the activity of lysosomal enzymes is discussed in relation to these and previous findings. 相似文献
48.
49.
Signaling to NF-kappaB 总被引:30,自引:0,他引:30
50.
Panja M Mazumdar A Ghosh S Mazumdar B Kar AK Mondal P 《The Journal of the Association of Physicians of India》2000,48(12):1193-1196
In recent years, the indications for permanent pacemakers have expanded. The interest has focussed on hypertrophic cardiomyopathy, dilated cardiomyopathy and a new entity called hypertensive hypertrophy with cavity obliteration (HHCO). Pacemaker therapy is establishing itself for the prevention of atrial fibrillation. Pacing for neurocardiogenic syncope with newer pacing mode has encouraging datas. Pacemaker for long QT syndrome, after cardiac transplant and for haemodynamic improvement in occasional cases of first degree atrio-ventricular block is getting attention. The AHA and ACC guidelines updated in 1998 for implantation of cardiac pacemakers, now include several of these newer indications. 相似文献