全文获取类型
收费全文 | 225309篇 |
免费 | 5531篇 |
国内免费 | 83篇 |
专业分类
耳鼻咽喉 | 1645篇 |
儿科学 | 8162篇 |
妇产科学 | 4443篇 |
基础医学 | 23575篇 |
口腔科学 | 2621篇 |
临床医学 | 17833篇 |
内科学 | 40974篇 |
皮肤病学 | 1410篇 |
神经病学 | 20806篇 |
特种医学 | 10507篇 |
外国民族医学 | 9篇 |
外科学 | 34549篇 |
综合类 | 3205篇 |
现状与发展 | 1篇 |
一般理论 | 48篇 |
预防医学 | 23738篇 |
眼科学 | 3822篇 |
药学 | 13123篇 |
中国医学 | 715篇 |
肿瘤学 | 19737篇 |
出版年
2023年 | 381篇 |
2022年 | 584篇 |
2021年 | 1123篇 |
2020年 | 716篇 |
2019年 | 1192篇 |
2018年 | 22948篇 |
2017年 | 18224篇 |
2016年 | 20318篇 |
2015年 | 1925篇 |
2014年 | 2264篇 |
2013年 | 2831篇 |
2012年 | 10018篇 |
2011年 | 23954篇 |
2010年 | 20285篇 |
2009年 | 12913篇 |
2008年 | 21901篇 |
2007年 | 24262篇 |
2006年 | 2967篇 |
2005年 | 4542篇 |
2004年 | 5465篇 |
2003年 | 6289篇 |
2002年 | 4430篇 |
2001年 | 1497篇 |
2000年 | 1626篇 |
1999年 | 1231篇 |
1998年 | 659篇 |
1997年 | 633篇 |
1996年 | 501篇 |
1995年 | 470篇 |
1994年 | 462篇 |
1993年 | 399篇 |
1992年 | 990篇 |
1991年 | 1019篇 |
1990年 | 977篇 |
1989年 | 862篇 |
1988年 | 754篇 |
1987年 | 762篇 |
1986年 | 744篇 |
1985年 | 721篇 |
1984年 | 582篇 |
1983年 | 456篇 |
1982年 | 379篇 |
1981年 | 302篇 |
1980年 | 301篇 |
1979年 | 543篇 |
1978年 | 338篇 |
1976年 | 291篇 |
1975年 | 328篇 |
1974年 | 376篇 |
1973年 | 299篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Immune rabbit sera do not recognize antigenic variants of caprine arthritis-encephalitis virus isolated during persistent infection. 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Isolates of caprine arthritis-encephalitis virus recovered 12 to 18 months after infection of goats were tested for neutralization by using rabbit antisera directed to the original inoculum virus. Only slight differences in neutralization kinetics between the long-term isolates and the original virus were detected, indicating that heterologous rabbit antisera do not detect antigenic variation of the neutralizing epitopes of caprine arthritis-encephalitis virus. 相似文献
992.
Physiological and behavioral effects of prior aversive stimulation (preshock) in the rat 总被引:2,自引:0,他引:2
Physiological and behavioral measures were assessed in rats that had been previously exposed to unsignaled inescapable intense shock (preshock). Animals subjected to such prior aversive stimulation exhibited greater adrenocortical steroid response compared to nonpreshocked controls when subsequently tested in the open field. An increment in defecation was also observed, with ambulation and rearing behavior being markedly inhibited in the preshocked rat during these sessions. 相似文献
993.
Anderson LV Davison K Moss JA Young C Cullen MJ Walsh J Johnson MA Bashir R Britton S Keers S Argov Z Mahjneh I Fougerousse F Beckmann JS Bushby KM 《Human molecular genetics》1999,8(5):855-861
Recently, a single gene, DYSF, has been identified which is mutated in patients with limb-girdle muscular dystrophy type 2B (LGMD2B) and with Miyoshi myopathy (MM). This is of interest because these diseases have been considered as two distinct clinical conditions since different muscle groups are the initial targets. Dysferlin, the protein product of the gene, is a novel molecule without homology to any known mammalian protein. We have now raised a monoclonal antibody to dysferlin and report on the expression of this new protein: immunolabelling with the antibody (designated NCL-hamlet) demonstrated a polypeptide of approximately 230 kDa on western blots of skeletal muscle, with localization to the muscle fibre membrane by microscopy at both the light and electron microscopic level. A specific loss of dysferlin labelling was observed in patients with mutations in the LGMD2B/MM gene. Furthermore, patients with two different frameshifting mutations demonstrated very low levels of immunoreactive protein in a manner reminiscent of the dystrophin expressed in many Duchenne patients. Analysis of human fetal tissue showed that dysferlin was expressed at the earliest stages of development examined, at Carnegie stage 15 or 16 (embryonic age 5-6 weeks). Dysferlin is present, therefore, at a time when the limbs start to show regional differentiation. Lack of dysferlin at this critical time may contribute to the pattern of muscle involvement that develops later, with the onset of a muscular dystrophy primarily affecting proximal or distal muscles. 相似文献
994.
Florence Jobard Caroline Lefèvre Aysen Karaduman Claudine Blanchet-Bardon Serap Emre Jean Weissenbach Meral Ozgüc Mark Lathrop Jean-Fran?ois Prud'homme Judith Fischer 《Human molecular genetics》2002,11(1):107-113
We report the identification of mutations in lipoxygenase-3 (ALOXE3) and 12(R)-lipoxygenase (ALOX12B) genes in non-bullous congenital ichthyosiform erythroderma (NCIE) linked to chromosome 17. Linkage disequilibrium analysis of six families affected by NCIE permitted us to reduce a recently reported interval of 8.4 cM on chromosome 17p13.1 to a 600 kb region around the marker D17S1796, which contains LOX genes. LOX products have long been implicated in skin disorders. Two point mutations and one deletion were found in ALOXE3 and three point mutations were found in ALOX12B in these consanguineous families from the Mediterranean basin. ALOXE3 and ALOX12B are two genes which are physically linked and functionally related. They are separated by 38 kb, have one more exon than the other LOX genes and are mainly expressed in epithelial cells including keratinocytes. Although the main substrate(s) of the two enzymes is (are) still unknown, the products of ALOX12B obtained in experimental systems have been demonstrated to be of R-chirality. It seems likely that the product of one of these enzymes may be the substrate of the other, and that they belong to the same metabolic pathway. 相似文献
995.
Effects of Beta-Adrenergic Activity on T-Wave Amplitude 总被引:1,自引:0,他引:1
Richard J. Contrada David S. Krantz Lynn A. Durel Linda Levy Patrick J. LaRiccia Judith R. Anderson Theodore Weiss 《Psychophysiology》1989,26(4):488-492
This study addresses the hypothesis that electrocardiographic T-wave amplitude is influenced by beta-adrenergic stimulation of the heart. Beta-adrenergic activity was manipulated both pharmacologically and through behavioral challenge. Under resting conditions, 12 healthy men underwent infusion of placebo and then the beta-agonist, isoproterenol, and the beta-blocker, propranolol, in a counterbalanced, crossover design. During infusion of placebo, subjects also underwent two behavioral challenges, a structured interview and mental arithmetic. Analysis of the resting data indicated that propranolol produced a significant increase in T-wave amplitude, and isoproterenol produced significant T-wave amplitude attenuation. As previously reported, drug effects were also in evidence for heart rate. Behaviorally-induced reduction of T-wave amplitude was observed for mental arithmetic but not structured interview, which again paralleled heart rate data. Both pharmacological and behavioral data reported in this study support the hypothesis that the T-wave is significantly affected by beta-sympathetic influence on the heart. However, a nonspecific effect of heart rate change on T-wave amplitude would also account for these results. The findings are discussed in terms of their implications for the utility of T-wave amplitude in psychophysiological research. 相似文献
996.
Prenatal diagnosis of hemoglobinopathies may be obtained during the first trimester of pregnancy by a combination of chorion biopsy and DNA mapping. This study illustrates 2 DNA approaches which are available for identification of abnormal globin genes. These include restriction fragment length polymorphisms (RFLPs) and direct gene mapping. 相似文献
997.
998.
Human immunodeficiency virus generates the accessory proteins Nef, viral infectivity factor (Vif), viral protein R, and viral
protein U or viral protein X during viral replication in host cells. Although the significance of these accessory proteins
is often lost in vitro, they are essential for viral pathogenesis in vivo. Therefore, these proteins have much potential as
antiviral targets. Recent data reveal Vif perturbs an ill-defined antiviral pathway in host cells allowing HIV replication.
These data highlight a common feature among HIV accessory proteins in manipulating the host to aid viral pathogenesis. Therefore,
these new insights into Vif and other HIV accessory proteins are reviewed, emphasizing host cell interactions and new targets
for therapeutic intervention. 相似文献
999.
Terry?O?Herndon Salvador?Gonzalez TR?Gowrishankar R?Rox?Anderson James?C?WeaverEmail author 《BMC medicine》2004,2(1):12
Background
Painless, rapid, controlled, minimally invasive molecular transport across human skin for drug delivery and analyte acquisition is of widespread interest. Creation of microconduits through the stratum corneum and epidermis is achieved by stochastic scissioning events localized to typically 250 μm diameter areas of human skin in vivo. 相似文献1000.