全文获取类型
收费全文 | 11584篇 |
免费 | 909篇 |
国内免费 | 53篇 |
专业分类
耳鼻咽喉 | 110篇 |
儿科学 | 615篇 |
妇产科学 | 305篇 |
基础医学 | 1745篇 |
口腔科学 | 240篇 |
临床医学 | 1060篇 |
内科学 | 2559篇 |
皮肤病学 | 130篇 |
神经病学 | 997篇 |
特种医学 | 488篇 |
外科学 | 1983篇 |
综合类 | 230篇 |
一般理论 | 3篇 |
预防医学 | 777篇 |
眼科学 | 221篇 |
药学 | 509篇 |
中国医学 | 11篇 |
肿瘤学 | 563篇 |
出版年
2021年 | 109篇 |
2019年 | 107篇 |
2018年 | 138篇 |
2017年 | 118篇 |
2016年 | 118篇 |
2015年 | 138篇 |
2014年 | 229篇 |
2013年 | 318篇 |
2012年 | 410篇 |
2011年 | 427篇 |
2010年 | 247篇 |
2009年 | 230篇 |
2008年 | 438篇 |
2007年 | 412篇 |
2006年 | 396篇 |
2005年 | 471篇 |
2004年 | 431篇 |
2003年 | 373篇 |
2002年 | 389篇 |
2001年 | 375篇 |
2000年 | 360篇 |
1999年 | 312篇 |
1998年 | 155篇 |
1997年 | 137篇 |
1996年 | 132篇 |
1995年 | 124篇 |
1992年 | 289篇 |
1991年 | 280篇 |
1990年 | 291篇 |
1989年 | 313篇 |
1988年 | 292篇 |
1987年 | 295篇 |
1986年 | 278篇 |
1985年 | 257篇 |
1984年 | 182篇 |
1983年 | 202篇 |
1982年 | 130篇 |
1981年 | 135篇 |
1980年 | 125篇 |
1979年 | 222篇 |
1978年 | 198篇 |
1977年 | 152篇 |
1976年 | 164篇 |
1975年 | 149篇 |
1974年 | 144篇 |
1973年 | 146篇 |
1972年 | 150篇 |
1971年 | 108篇 |
1970年 | 103篇 |
1969年 | 116篇 |
排序方式: 共有10000条查询结果,搜索用时 906 毫秒
81.
82.
Adam J. Kaplan Kenneth D. Chavin Li Hui Qin Hideo Yagita Jonathan S. Bromberg 《Immunologic research》1994,13(1):42-48
The baculovirus expression system was used to produce three different constructs of the murine cell surface adhesion receptor CD2. One construct coded for a single, N-terminal, Ig-fold domain. It was inefficiently secreted and therefore primarily intracellular. The second construct coded for both extracellular, N-terminal Ig-fold domains. This was efficiently secreted into culture supernatant. The third construct coded for the full-length transmembrane molecule which localized to the cell surface. All constructs were monomers of predicted MWr and were appropriately glycosylated. They retained epitopic specificity as demonstrated by binding to mAbs, and adhesion function as demonstrated by a rosetting assay. 相似文献
83.
F W Chandler J C Watts W Kaplan A T Hendry M R McGinnis L Ajello 《American journal of clinical pathology》1985,84(1):99-103
The authors describe spheric to ovoid chlamydoconidia and mucoraceous hyphae in tissues from four patients, two with cutaneous and two with pulmonary zygomycosis. The diagnosis in each case was confirmed by immunofluorescence staining and the presence of characteristic hyphae in tissue. It is important that these conidia be recognized, because they can easily be mistaken for other fungi, nematode ova, or other microorganisms in tissue sections, thereby resulting in the potential for misdiagnosis. 相似文献
84.
Coexpression of galanin and adrenocorticotropic hormone in human pituitary and pituitary adenomas.
下载免费PDF全文
![点击此处可从《The American journal of pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
D. W. Hsu S. C. Hooi E. T. Hedley-Whyte R. M. Strauss L. M. Kaplan 《The American journal of pathology》1991,138(4):897-909
Galanin is a neuropeptide that regulates the secretion of several pituitary hormones, including prolactin (PRL) and growth hormone (GH). Galaninlike immunoreactivity (Gal-IR) and galanin mRNA in the rat anterior pituitary is cell lineage specific, with predominant expression in lactotrophs and somatotrophs. The authors examined the cellular distribution of human Gal-IR in seven normal postmortem pituitaries and 62 pituitary tumors by immunoperoxidase staining. In contrast to the rat, Gal-IR in human anterior pituitaries was present in corticotrophs scattered throughout the gland, but not in lactotrophs, somatotrophs, thyrotrophs, or gonadotrophs. Distinct Gal-IR also was present in hyperplastic and neoplastic corticotrophs in 19 of 22 patients with Cushing's disease. In noncorticotroph cell tumors, unequivocal Gal-IR was present in 5 of 11 GH-secreting tumors associated with clinical acromegaly, 9 of 18 nonfunctioning pituitary adenomas, and 2 of 14 prolactinomas. Of these galanin-positive tumors, four of the five GH-secreting adenomas, six of the nine nonfunctioning adenomas, and both of the prolactinomas also contained adrenocorticotropic hormone immunoreactivity (ACTH-IR). Immunostaining and in situ hybridization on adjacent sections using an 35S-labeled probe complementary to human galanin mRNA demonstrated predominant galanin expression in normal corticotrophs. Immunoelectron microscopy confirmed the presence of Gal-IR in pituitary cells characteristic of corticotrophs in both normal and neoplastic pituitaries. Thus, as in the rat, galanin gene expression in the human pituitary is cell-type specific. Unlike the rat, however, human galanin gene expression is restricted to the corticotroph lineage. Studies of tumors confirmed the observed coexpression of galanin and adrenocorticotropic hormone. The divergent cell type specificity of galanin production in human and rat pituitaries reflects different patterns of gene activation in these two species. In addition, these results suggest that galanin in the human pituitary may participate locally in the regulation of the hypothalamic-pituitary-adrenal axis. 相似文献
85.
Nitric oxide participates in the intestinal pathology associated with murine syngeneic graft-versus-host disease 总被引:5,自引:0,他引:5
Flanagan DM Jennings CD Goes SW Caywood BE Gross R Kaplan AM Bryson JS 《Journal of leukocyte biology》2002,72(4):762-768
Syngeneic graft-versus-host disease (SGVHD) develops following lethal irradiation, reconstitution with syngeneic bone marrow, and treatment with a short course of cyclosporin A (CsA) therapy. The disease is characterized by the development of a T helper cell type 1-like cytokine response [interleukin (IL)-12, interferon-gamma (IFN-gamma), and tumor necrosis factor alpha], and macrophage activation is central to development of the syndrome. It has been shown that nitric oxide (NO) participates significantly in the development of allogeneic GVHD. Studies were initiated to determine if NO participates in the pathology associated with SGVHD. Significant increases in inducible NO synthase (iNOS) mRNA and circulating NO were found in the tissues of SGVHD versus control animals. Treatment of SGVHD animals with the iNOS inhibitor aminoguanidine (AG) reversed the pathology associated with this disease. Furthermore, AG treatment reduced the production of IL-12 and IFN-gamma mRNA in the colons of CsA-treated mice. These studies demonstrate that NO participates in the pathological processes that are associated with the development of murine SGVHD. 相似文献
86.
Androgen receptor YAC transgenic mice carrying CAG 45 alleles show trinucleotide repeat instability 总被引:1,自引:15,他引:1
La Spada AR; Peterson KR; Meadows SA; McClain ME; Jeng G; Chmelar RS; Haugen HA; Chen K; Singer MJ; Moore D; Trask BJ; Fischbeck KH; Clegg CH; McKnight GS 《Human molecular genetics》1998,7(6):959-967
X-linked spinal and bulbar muscular atrophy (SBMA) is caused by a CAG
repeat expansion in the first exon of the androgen receptor (AR) gene.
Disease-associated alleles (37-66 CAGs) change in length when transmitted
from parents to offspring, with a significantly greater tendency to shift
size when inherited paternally. As transgenic mice carrying human AR cDNAs
with 45 and 66 CAG repeats do not display repeat instability, we attempted
to model trinucleotide repeat instability by generating transgenic mice
with yeast artificial chromosomes (YACs) carrying AR CAG repeat expansions
in their genomic context. Studies of independent lines of AR YAC transgenic
mice with CAG 45 alleles reveal intergenerational instability at an overall
rate of approximately 10%. We also find that the 45 CAG repeat tracts are
significantly more unstable with maternal transmission and as the
transmitting mother ages. Of all the CAG/CTG repeat transgenic mice
produced to date the AR YAC CAG 45 mice are unstable with the smallest
trinucleotide repeat mutations, suggesting that the length threshold for
repeat instability in the mouse may be lowered by including the appropriate
flanking human DNA sequences. By sequence-tagged site content analysis and
long range mapping we determined that one unstable transgenic line has
integrated an approximately 70 kb segment of the AR locus due to
fragmentation of the AR YAC. Identification of the cis - acting elements
that permit CAG tract instability and the trans -acting factors that
modulate repeat instability in the AR YAC CAG 45 mice may provide insights
into the molecular basis of trinucleotide repeat instability in humans.
相似文献
87.
Positive alpha-fetoglobulin in a case of gastric carcinoma 总被引:1,自引:0,他引:1
M Kozower K A Fawaz H M Miller M M Kaplan 《The New England journal of medicine》1971,285(19):1059-1060
88.
Eakin EG Sassi-Dambron DE Ries AL Kaplan RM 《International journal of behavioral medicine》1995,2(2):118-134
Dyspnea, the clinical term for shortness of breath, is the primary symptom and an important outcome measure in evaluations of patients
with lung disease. It is a subjective symptom that has proved difficult to quantify. Many dyspnea measures are available,
yet it is difficult, based on the existing literature, to determine the most reliable and valid. In this study, we evaluated
6 measures of dyspnea for reliability and validity: (a) Baseline Dyspnea Index (BDI) and Transition Dyspnea Index, (b) UCSD Shortness of
Breath Questionnaire (SOBQ), (c) American Thoracic Society Dyspnea Scale, (d) Oxygen Cost Diagram, (e) Visual Analog Scale,
and (f) Borg Scale. Subjects were 143 patients (74 women and 69 men) with obstructive lung disease, ages 40 to 86, FEV., 0.36
to 3.53 L, FVC 1.07 to 5.74 L. Dyspnea measures were assessed for test-retest reliability, internal consistency, interrater
reliability, and construct validity (i.e.. correlations among dyspnea measures and correlations of dyspnea measures with exercise
tolerance, health-related quality of life, lung function, anxiety, and depression). Results suggest that the SOBQ and BDI
demonstrated the highest levels of reliability and validity among the dyspnea measures examined.
This research was supported by University of California Tobacco Related Disease Research Program Grant 2RT026S, National Heart.
Lung, and Blood Institute Grant HL 34732 to Robert M. Kaplan, and National Institutes of Health NHLBI Preventive Pulmonary
Academic Award No. HL02215 to Andrew L. Ries. 相似文献
89.
The burgeoning of consumer health informatics and virtual health care can help people improve their health. However, little is known about individuals' reactions to such systems. We conducted an evaluation of the telephone-linked care (TLC) system, a computer-based telecommunications system, that functions as an at home monitor, educator, and counselor for patients with chronic health conditions. Our multimethod assessment of individuals' reactions to using TLC included both quantitative and qualitative methods. Ethnographic in-depth open-ended interviews indicated more subtle and surprising reactions to TLC than the overall positive responses from surveys: individuals formed personal relationships with this technology. This relationship formation suggests that TLC designers may have been successful in their attempts to emulate a conversation with a human being. Our study adds to evidence that technology can serve as a projective device for peoples' values and psychological issues. Both designers and users project values and goals onto computer-based technologies and take on different identities through it. Different groups of users, therefore, may see the same technology differently. People also form relationships with technologies, as they did with TLC. These findings, as well as implications for system design and health outcomes, need to be explored in additional studies. 相似文献
90.
Role of adherence in the pathogenesis of Haemophilus influenzae type b infection in infant rats. 总被引:2,自引:11,他引:2
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)
We evaluated the role of pili in the pathogenesis of disease due to Haemophilus influenzae type b (HiTb), using the infant rat model. Piliated and nonpiliated HiTb strains were isolated from the nasopharynx and cerebrospinal fluid, respectively, of three children. Infant rats inoculated intranasally with nonadherent HiTb developed bacteremia and meningitis more frequently (P = 0.005) than animals inoculated with companion adherent HiTb strains. When analyzed separately, only one HiTb pair (884/880) demonstrated significant differences in the incidence of bacteremia and meningitis between the adherent and nonadherent strains. Blood or cerebrospinal isolates recovered from infant rats inoculated with piliated adherent HiTb strains were not piliated and were not adherent in vitro. Adherent and nonadherent HiTb colonized the nasopharynx of infant rats equally. The piliated strains of HiTb were not adherent in vivo or in vitro to rat nasal or buccal epithelial cells, respectively. Piliated strains of HiTb have no apparent advantage over nonpiliated HiTb strains for colonization or invasion of infant rats. Furthermore, the loss of piliation is noted for cerebrospinal fluid, blood, and nasal isolates of HiTb cultured from infant rats inoculated with an adherent piliated HiTb strain. Thus, the loss or suppression of pili may be an important prerequisite for the invasion of the host by HiTb strains that are highly piliated. 相似文献