全文获取类型
收费全文 | 8895篇 |
免费 | 495篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 113篇 |
儿科学 | 503篇 |
妇产科学 | 147篇 |
基础医学 | 957篇 |
口腔科学 | 218篇 |
临床医学 | 619篇 |
内科学 | 1917篇 |
皮肤病学 | 188篇 |
神经病学 | 478篇 |
特种医学 | 438篇 |
外国民族医学 | 1篇 |
外科学 | 1329篇 |
综合类 | 514篇 |
一般理论 | 7篇 |
预防医学 | 489篇 |
眼科学 | 191篇 |
药学 | 737篇 |
中国医学 | 36篇 |
肿瘤学 | 540篇 |
出版年
2023年 | 59篇 |
2022年 | 101篇 |
2021年 | 256篇 |
2020年 | 150篇 |
2019年 | 173篇 |
2018年 | 231篇 |
2017年 | 180篇 |
2016年 | 202篇 |
2015年 | 239篇 |
2014年 | 303篇 |
2013年 | 412篇 |
2012年 | 541篇 |
2011年 | 579篇 |
2010年 | 406篇 |
2009年 | 321篇 |
2008年 | 466篇 |
2007年 | 489篇 |
2006年 | 434篇 |
2005年 | 393篇 |
2004年 | 367篇 |
2003年 | 283篇 |
2002年 | 269篇 |
2001年 | 207篇 |
2000年 | 224篇 |
1999年 | 203篇 |
1998年 | 122篇 |
1997年 | 99篇 |
1996年 | 99篇 |
1995年 | 80篇 |
1994年 | 74篇 |
1993年 | 37篇 |
1992年 | 98篇 |
1991年 | 92篇 |
1990年 | 88篇 |
1989年 | 104篇 |
1988年 | 94篇 |
1987年 | 76篇 |
1986年 | 69篇 |
1985年 | 75篇 |
1984年 | 74篇 |
1983年 | 63篇 |
1982年 | 42篇 |
1981年 | 31篇 |
1979年 | 47篇 |
1978年 | 33篇 |
1977年 | 32篇 |
1976年 | 33篇 |
1974年 | 38篇 |
1973年 | 38篇 |
1969年 | 35篇 |
排序方式: 共有9422条查询结果,搜索用时 937 毫秒
91.
L1 knockout mice show dilated ventricles, vermis hypoplasia and impaired exploration patterns 总被引:8,自引:3,他引:8
Fransen E; D'Hooge R; Van Camp G; Verhoye M; Sijbers J; Reyniers E; Soriano P; Kamiguchi H; Willemsen R; Koekkoek SK; De Zeeuw CI; De Deyn PP; Van der Linden A; Lemmon V; Kooy RF; Willems PJ 《Human molecular genetics》1998,7(6):999-1009
L1 is a neural cell adhesion molecule mainly involved in axon guidance and
neuronal migration during brain development. Mutations in the human L1 gene
give rise to a complex clinical picture, with mental retardation,
neurologic abnormalities and a variable degree of hydrocephalus. Recently,
a transgenic mouse model with a targeted null mutation in the L1 gene was
generated. These knockout (KO) mice show hypoplasia of the corticospinal
tract. Here we have performed further studies of these KO mice including
magnetic resonance imaging of the brain, neuropathological analysis and
behavioral testing. The ventricular system was shown to be abnormal with
dilatation of the lateral ventricles and the 4th ventricle, and an altered
shape of the Sylvius aqueduct. Additionally, the cerebellar vermis of the
KO mice is hypoplastic. Their exploratory behavior is characterized by
stereotype peripheral circling reminiscent of that of rodents with induced
cerebellar lesions.
相似文献
92.
X-linked agammaglobulinemia (XLA) is an immunodeficiency caused by mutations in the Bruton tyrosine kinase (BTK) gene. Twenty Australian patients with an XLA phenotype, from 15 unrelated families, were found to have 14 mutations. Five of the mutations were previously described c.83G>A (p.R28H), c.862C>T (p.R288W), c.904G>A (p.R302G), c.1535T>C (p.L512P), c.700C>T (p.Q234X), while nine novel mutations were identified: four missense c.82C>A (p.R28S), c.494G>A (p.C165Y), c.464G>A (p.C155Y), c.1750G>A (p.G584E), one deletion c.142_144delAGAAGA (p.R48_G50del), and four splice site mutations c.241-2A>G, c.839+4A>G, c.1350-2A>G, c.1566+1G>A. Carrier analysis was performed in 10 mothers and 11 female relatives. The results of this study further support the notion that molecular genetic testing represents an important tool for definitive and early diagnosis of XLA and may allow accurate carrier status and prenatal diagnosis. 相似文献
93.
Immune regulation by novel costimulatory molecules 总被引:10,自引:0,他引:10
CD4 helper T (Th)-cells and the cytokines that they produce play essential regulatory roles in immune and autoimmune responses.
Th activation and differentiation is regulated by costimulatory receptors. CD28 and CTLA-4 are important in maintaining the
threshold of T-cell activation. ICOS and PD-1 are novel costimulatory receptors expressed on activated T-cells. B7-H3 recognizes
a putative costimulatory receptor on activated T-cells. Here we summarize the latest developments in the novel costimulatory
molecules and their roles in regulating Th activation, differentiation, and function. 相似文献
94.
The recent implication of Helicobacter pylori in the pathogenesis of gastritis-peptic ulcer syndrome and its relevance for the development of upper gastrointestinal malignancy warrant efficient methods for the detection and demonstration of the organism in biopsy specimens. We have compared 5 staining methods, namely, haematoxylin and eosin (H & E), immunohistochemistry (IHC), the silver staining HpSS, the alcian yellow-toluidine blue (Leung) method (A-Y) and Genta staining, for the demonstration of the organism in gastric biopsies taken from antrum, body and fundus of 118 patients who presented to our hospital with upper gastrointestinal symptoms. We found no significant differences in the efficacy of H & E, IHC, HpSS and A-Y in the demonstration of H. pylori in all 3 gastric sites. The least reproducible stain in our hands was the Genta stain. We conclude that H & E is adequate for the initial assessment of gastric biopsies in symptomatic upper gastrointestinal patients. This is because it is a well-tested, cheap and easy staining method, requiring a relatively short period of time to perform, with highly reproducible results. It has an added advantage of enabling simultaneous assessment of morphological changes accompanying H. pylori infection. When the density of the organism is expected to be low, we recommend addition of HpSS staining because of its high sensitivity and low cost. The disadvantages of the other staining methods (IHC, A-Y and Genta) are discussed. 相似文献
95.
Rat F2408 cells transformed by polyoma virus contain, in addition to integrated viral genomes, a small number (an average of 20–50 copies per cell) of nonintegrated viral DNA molecules. On the other hand, SV40-transformed rat cells contain only integrated viral genomes. SV40-transformed rat cells also differ from the polyoma transformants, in that they grow in soft agar medium at a much slower rate. Cells doubly transformed by polyoma and SV40 can be easily isolated following polyoma superinfection of SV40-transformed rat cells, as their rate of growth in agar is enhanced. These doubly transformed cells yield polyoma or SV40, respectively, after fusion with cells permissive for each virus. However, only polyoma-specific DNA sequences can be detected in these cells in a “free” state. 相似文献
96.
Bhattacharya SK Singh NK Prasad RC Sinha PR 《The Journal of the Association of Physicians of India》1998,46(8):675-677
Thirty four patients aged 14 to 65 years (18 males and 16 females) admitted to the University Hospital with various unusual and severe forms of adverse drug reactions were studied. It comprised of toxic epidermal necrolysis in 8 patients, systemic vasculitis in 7 of which 3 patients had gangrene of fingers and/or toes, severe erosive gastritis in 9 patients, Stevens-Johnson syndrome in 7 patients, thrombocytopenic purpura in 2 patients and generalised convulsions in 1 patient. Various drugs responsible for causing these adverse drug reactions included antibacterials, antimalarials, anticonvulsants, antituberculars and nonsteroidal anti-inflammatory drugs. Most of the patients recovered. However, 5 of the 8 patients having toxic epidermal necrolysis died of which 2 patients had developed tetanus as a preterminal event. In view of ongoing addition of newer drugs to the therapeutic armamentarium and an increasing incidence of various unusual and severe forms of adverse drug reactions, it is our contention that a separate adverse drug reaction monitoring cell should be established in every hospital setting. 相似文献
97.
Vascular tumors of the breast are uncommon. Perilobular hemangiomas, the commonest histologic subtype of breast hemangiomas, constitute majority of microscopic, vascular mammary tumors. Macroscopic hemangiomas and vascular hamartomas of the breast are distinctly rare. We describe a giant, vascular hamartoma of the right breast in a five year old girl and discuss pertinent literature. 相似文献
98.
Debelenko LV; Brambilla E; Agarwal SK; Swalwell JI; Kester MB; Lubensky IA; Zhuang Z; Guru SC; Manickam P; Olufemi SE; Chandrasekharappa SC; Crabtree JS; Kim YS; Heppner C; Burns AL; Spiegel AM; Marx SJ; Liotta LA; Collins FS; Travis WD; Emmert-Buck MR 《Human molecular genetics》1997,6(13):2285-2290
Lung carcinoids occur sporadically and rarely in association with multiple
endocrine neoplasia type 1 (MEN1). There are no well defined genetic
abnormalities known to occur in these tumors. We studied 11 sporadic lung
carcinoids for loss of heterozygosity (LOH) at the locus of the MEN1 gene
on chromosome 11q13, and for mutations of the MEN1 gene using dideoxy
fingerprinting. Additionally, a lung carcinoid from a MEN1 patient was
studied. In four of 11 (36%) sporadic tumors, both copies of the MEN1 gene
were inactivated. All four tumors showed the presence of a MEN1 gene
mutation and loss of the other allele. Observed mutations included a 1 bp
insertion, a 1 bp deletion, a 13 bp deletion and a single nucleotide
substitution affecting a donor splice site. Each mutation predicts
truncation or potentially complete loss of menin. The remaining seven
tumors showed neither the presence of a MEN1 gene mutation nor 11q13 LOH.
The tumor from the MEN1 patient showed LOH at chromosome 11q13 and a
complex germline MEN1 gene mutation. The data implicate the MEN1 gene in
the pathogenesis of sporadic lung carcinoids, representing the first
defined genetic alteration in these tumors.
相似文献
99.
Reported complications rates for the construction of intestinal stomas are high. Many of these complications result from improper construction, improper location, or other technical errors. In order to sample the techniques of stoma construction currently in use, a survey was conducted at the 69th Annual Clinical Congress of the American College of Surgeons in Atlanta in conjunction with our scientific exhibit "Complications of Intestinal Stomas." A total of 245 surgeons completed the questionnaire with a mean age of 47.8 years. The routine use of fascial-seromuscular tacking sutures and primary maturation of a loop colostomy in the presence of distal obstruction were among the most controversial technical points considered. Many other subtle but important principles of stoma construction were also discussed. In addition, the authors contend that many of the techniques currently in use result from an underemphasis on the importance of proper stoma construction in many surgical training programs. 相似文献
100.
Journal of Public Health - Few studies have been performed to investigate multiorgan failure occurring with extrapulmonary symptoms like diarrhea, anorexia, and vomiting. There has been no attempt... 相似文献