全文获取类型
收费全文 | 4135篇 |
免费 | 200篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 13篇 |
儿科学 | 37篇 |
妇产科学 | 61篇 |
基础医学 | 548篇 |
口腔科学 | 174篇 |
临床医学 | 249篇 |
内科学 | 1206篇 |
皮肤病学 | 54篇 |
神经病学 | 217篇 |
特种医学 | 157篇 |
外科学 | 598篇 |
综合类 | 22篇 |
一般理论 | 1篇 |
预防医学 | 101篇 |
眼科学 | 64篇 |
药学 | 428篇 |
中国医学 | 19篇 |
肿瘤学 | 409篇 |
出版年
2023年 | 28篇 |
2022年 | 41篇 |
2021年 | 66篇 |
2020年 | 47篇 |
2019年 | 63篇 |
2018年 | 74篇 |
2017年 | 50篇 |
2016年 | 82篇 |
2015年 | 70篇 |
2014年 | 97篇 |
2013年 | 107篇 |
2012年 | 222篇 |
2011年 | 248篇 |
2010年 | 135篇 |
2009年 | 99篇 |
2008年 | 203篇 |
2007年 | 242篇 |
2006年 | 220篇 |
2005年 | 233篇 |
2004年 | 221篇 |
2003年 | 199篇 |
2002年 | 254篇 |
2001年 | 110篇 |
2000年 | 123篇 |
1999年 | 123篇 |
1998年 | 54篇 |
1997年 | 49篇 |
1996年 | 41篇 |
1995年 | 31篇 |
1994年 | 28篇 |
1993年 | 27篇 |
1992年 | 77篇 |
1991年 | 71篇 |
1990年 | 86篇 |
1989年 | 47篇 |
1988年 | 51篇 |
1987年 | 60篇 |
1986年 | 35篇 |
1985年 | 45篇 |
1984年 | 45篇 |
1983年 | 25篇 |
1981年 | 14篇 |
1979年 | 31篇 |
1978年 | 16篇 |
1977年 | 15篇 |
1976年 | 14篇 |
1975年 | 22篇 |
1974年 | 19篇 |
1971年 | 11篇 |
1969年 | 13篇 |
排序方式: 共有4358条查询结果,搜索用时 31 毫秒
21.
Twelve autopsied cases with adult T-cell leukemia (ATL) were reviewed clinicopathologically. The prognosis of three cases who had suffered from severe cutaneous lesions was much better than that of the other nine cases with no or negligible cutaneous lesions. The surface marker of leukemic cells from six cases was ordinary inducer/helper phenotype (OKT4+ and 8-), but in one case leukemic cells showed OKT4+ and 8+. In another case, a significant amount of leukemic cell infiltration was found in the thymic cortex. Calcium content in the bone of ATL cases was lower than that of the patients without ATL (control group), and six cases with ATL (50%) were complicated by severe hypercalcemia. Neither adenoma nor hyperplasia of the parathyroid glands was found in any case. In most severely hypercalcemic patients, bone trabeculae were actively absorbed by numerous osteoclasts and partly replaced by fibrous tissues. In two normocalcemic patients, skeletal calcium content was also markedly reduced by osteoporosis, but the activation of osteoclasts was inconspicuous. It was speculated that the manner of bone resorption in ATL cases was diverse and there were some clinicopathological subtypes in ATL from the viewpoints of cutaneous lesions, hypercalcemia, and bone lesions. 相似文献
22.
Phosphorylcholine (PC) antibodies in serum from patients with pulmonary infection, and from normal individuals, were studied. Anti-PC antibodies were detectable in the serum from normal individuals at mean concentrations of 320 g/ ml for the IgG class and 110 g/ml for the IgM class. Concentrations of anti-PC antibodies which were higher than normal for both the IgG and IgM classes were observed in the serum in pulmonary infection (1,440 g/ml and 210 g/ml, respectively). Despite the significant difference in the concentration of anti-PC antibodies, the PC-specific B cell precursor frequency in the peripheral blood lymphocytes showed no difference between normal individuals and the patients with pulmonary infection, or between the acute phase and the chronic phase in a single patient with chronic pulmonary infection. Serologically, the purified IgG anti-PC antibody did not share the cross-reactive idiotype of TEPC 15, which is the most common idiotype of the murine anti-PC antibodies. However, the purified IgM anti-PC antibody expressed a very weak cross-reactive idiotype of TEPC 15. It appears from these studies that human anti-PC antibodies may play an important biological role in pulmonary infection by microorganisms which possess a PC determinant. 相似文献
23.
K. Ito T. Watanabe R. Horie M. Shiota S. Kawamura S. Mori 《The American journal of pathology》1994,145(2):276-280
CD30 is a receptor-type membrane protein that belongs to the nerve growth receptor superfamily. It is expressed on Hodgkin's cells and activated lymphocytes, as well as in some human malignancies including malignant lymphomas, embryonal carcinomas, and other mesenchymal tumors. However, whether it is expressed in normal tissues remains unclear. To study the expression and biological function of CD30, we first examined various human tissues by immunohistochemistry. The monoclonal antibody Ber-H2 intensely stained the membranes of decidual and endometrial cells with decidual change in frozen sections. Western blots of these tissues with Ber-H2 revealed bands of 120, 105, and 90 kd as found on CD30-expressing cells. Northern blots of these tissues using a CD30 cDNA probe detected mRNAs of the same molecular mass and variety as those in the positive control cell line HUT 102. These results indicated that CD30 is expressed in human endometrial tissue with decidual change and imply that CD30 expression in endometrial tissue is induced by hormonal control. 相似文献
24.
A case of melanocytic schwannoma, a rare form of schwannian neoplasm, in the thoracolumbar spinal canal of a 52-year-old man is presented. Histopathologically, the tumor was composed of irregularly interlacing spindle-shaped cells showing cystic degeneration, with occasional pigmented tumor cells. The tumor cells showed a low degree of nuclear pleomorphism without any mitotic figures. These histological features were considered to be consistent with a benign schwannian tumor showing pigmentation. Most of the pigments were considered to be melanin histochemically and immunohistochemically. According to the pathological features of the present tumor and those described previously in the literature, the neoplastic Schwann cells were assumed to have melanogenetic capacity, and the concept of the common neural crest origin of Schwann cells and melanocytes appeared to be demonstrated in the present tumor. 相似文献
25.
A 56-year-old Japanese man with a malignant lymphoma of the parotid gland was reported. The tumor was located in the superficial lobe of the parotid gland, and somewhat invaded the surrounding soft tissues, but the regional lymph nodes were not involved. Histologically, the tumor was composed of round cells with plasmacytoid configurations and small lymphocytes. The plasmacytoid cells showed eccentric nuclei with fairly marked irregularities and perinuclearr halos. In a large number of tumor cells, a monoclonal cytoplasmic immunoglobulin (CIg), IgG-Kappa type, was demonstrated by the PAP method. Ultrastructurally, some of the tumor cells showed well-developed endoplasmic reticulum. From these findings, this tumor was diagnosed as a diffuse B-cell lymphoma, mainly composed of lymphoplasmacytoid cells. And this tumor may bear a similar nature to an extramedullary plasmacytoma of the classical terminology. Malignant lymphoma of the parotid gland is rare but a case with the demonstration of monoclonal CIg is considered very rare. 相似文献
26.
Analysis of recombinant human tumour necrosis factor-alpha-induced CD4 expression on human eosinophils. 下载免费PDF全文
We examined the hypothesis that one of the pro-inflammatory cytokines, tumour necrosis factor-alpha (TNF-alpha), could induce expression of the adhesion molecule CD4 on human eosinophils. We further examined the effector function of CD4 and the mechanisms regulating CD4 expression. Human eosinophils were cultured with various concentrations of recombinant human TNF-alpha (rhTNF-alpha) with or without various drugs for 24 hr. After culture, eosinophils were stained for CD4 using a monoclonal antibody and then analysed by flow cytometry. Eosinophil-derived neurotoxin (EDN) release as eosinophil degranulation was examined by cross-linking of CD4 on eosinophils. The rhTNF-alpha induced CD4 expression on human eosinophils in a dose- and time-dependent fashion; rhTNF-alpha-induced CD4 expression was significantly inhibited by 10(-6) M cycloheximide, 10(-8) M dexamethasone, or 10(-6) M herbimycin A. Recombinant human interferon-gamma inhibited rhTNF-alpha-induced CD4 expression in a dose-dependent manner. However, cross-linking of CD4 on eosinophils did not evoke EDN release, suggesting that newly expressed CD4 molecules on human eosinophils do not play any role in triggering degranulation. Our data indicate that TNF-alpha-induced CD4 expression on human eosinophils is dependent on protein synthesis and may be dependent on tyrosine kinase activity. 相似文献
27.
Depolarization thresholds for hippocampal damage, ischemic preconditioning, and changes in gene expression after global ischemia in the rat 总被引:1,自引:0,他引:1
Induced ischemic tolerance in rat hippocampus was investigated in a forebrain ischemia model of repeated 4-vessel occlusion (4-VO). Ischemic insult variability was reduced by the use of dc potential measurements to determine the duration of ischemic depolarization in hippocampus. The results demonstrate a depolarization threshold for ischemic injury to CA1 neurons of 4-6 min and a window for optimal preconditioning of 2.5-3.5 min. Levels of induced mRNAs encoding hsp72 and several immediate-early genes were also shown to vary with depolarization interval. Immediate-early genes were maximally induced after depolarization periods inducing optimal preconditioning, while hsp72 expression increased with insult severity over the range leading to neuron loss. These results are similar to those obtained in gerbil studies indicating that preconditioning does not require large increases in hsp72 expression, and demonstrate the fundamental comparability of rodent global ischemia models when monitored by this approach. 相似文献
28.
29.
To investigate whether adenohypophysial hormone expression is heterogeneous within individual clinically nonfunctioning pituitary
adenomas, immunohistochemical examinations were performed on tissues obtained by multiple sampling of 11 adenomas. Stained
sections were assessed by morphometric image analysis as well as semiquantitative estimation under microscopy. All tumors
except one were immunopositive for one or more gonadotropins. Results were divided into five grades based on the proportion
of immunoreactive cells per section. Semiquantitative estimation showed only a one-grade difference among samples from the
same tumor in four cases for FSHβ and in two cases for LHβ. These qualitative similarities between multiple samples were confirmed
by morphometric image analysis.
From the practical standpoint of making a diagnosis of nonfunctioning pituitary adenoma, it is not necessary to take into
account immunohistochemical heterogeneity within an individual tumor, and immunohistochemical findings in a given sample obtained
at surgery can be regarded as representative of the entire adenoma. 相似文献
30.
Yamada S Suou T Kawasaki H Horie Y Nagami M Yashima S Sugihara C Tanaka H 《Research communications in molecular pathology and pharmacology》1999,104(3):253-263
Hepatic vitronectin expression was assessed in 27 patients with chronic hepatitis C before and after interferon alpha treatment and in 7 control patients. Before interferon therapy, vitronectin was localized in the hepatocytes and in the portal and central venous regions. A high correlation was found for the vitronectin expression level with the histological grading and staging scores in the hepatocytes as well as in the portal region. After interferon therapy, the hepatic vitronectin was significantly decreased in the sustained and transient responders, but it was not as markedly decreased in the nonresponders and the non-treated group. A good correlation was found for the vitronectin expression with the staging scores but not with the grading scores in the portal region. These findings suggest that hepatic vitronectin is influenced by interferon therapy and that it may play an important role as a hepatic adhesion molecule through the improvement of inflammation, necrosis and fibrogenesis. 相似文献