全文获取类型
收费全文 | 19273篇 |
免费 | 1618篇 |
国内免费 | 43篇 |
专业分类
耳鼻咽喉 | 177篇 |
儿科学 | 717篇 |
妇产科学 | 456篇 |
基础医学 | 2888篇 |
口腔科学 | 468篇 |
临床医学 | 1796篇 |
内科学 | 4260篇 |
皮肤病学 | 547篇 |
神经病学 | 1609篇 |
特种医学 | 795篇 |
外国民族医学 | 1篇 |
外科学 | 2329篇 |
综合类 | 268篇 |
一般理论 | 20篇 |
预防医学 | 1659篇 |
眼科学 | 472篇 |
药学 | 1059篇 |
中国医学 | 11篇 |
肿瘤学 | 1402篇 |
出版年
2021年 | 217篇 |
2019年 | 213篇 |
2018年 | 265篇 |
2017年 | 185篇 |
2016年 | 218篇 |
2015年 | 247篇 |
2014年 | 362篇 |
2013年 | 545篇 |
2012年 | 744篇 |
2011年 | 769篇 |
2010年 | 427篇 |
2009年 | 455篇 |
2008年 | 756篇 |
2007年 | 781篇 |
2006年 | 747篇 |
2005年 | 779篇 |
2004年 | 681篇 |
2003年 | 674篇 |
2002年 | 684篇 |
2001年 | 647篇 |
2000年 | 733篇 |
1999年 | 585篇 |
1998年 | 305篇 |
1997年 | 243篇 |
1996年 | 230篇 |
1995年 | 227篇 |
1994年 | 211篇 |
1993年 | 207篇 |
1992年 | 505篇 |
1991年 | 499篇 |
1990年 | 449篇 |
1989年 | 483篇 |
1988年 | 438篇 |
1987年 | 454篇 |
1986年 | 423篇 |
1985年 | 398篇 |
1984年 | 372篇 |
1983年 | 256篇 |
1982年 | 175篇 |
1981年 | 181篇 |
1980年 | 206篇 |
1979年 | 274篇 |
1978年 | 225篇 |
1977年 | 185篇 |
1976年 | 186篇 |
1975年 | 183篇 |
1974年 | 216篇 |
1973年 | 204篇 |
1972年 | 170篇 |
1971年 | 166篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
High-specificity in-situ hybridization. Methods and application. 总被引:2,自引:0,他引:2
A A Long J Mueller J Andre-Schwartz K J Barrett R Schwartz H Wolfe 《Diagnostic molecular pathology》1992,1(1):45-57
We describe a technique of in-situ hybridization using oligonucleotide probes employing the expression of immunoglobulin VH genes as a model. Optimal conditions for hybridization with the 35S-labeled oligonucleotide probes were established with monoclonal B-cell lines that express VH genes of known nucleic acid sequence. The range of sensitivity and specificity achieved with this technique is documented. Under conditions of high stringency, this method can detect the expression of highly related VH hypervariable regions. 相似文献
92.
93.
郭永建 《福建医科大学学报》1994,(1)
采用间接ELISA检测23名肾移植受者血清巨细胞病毒(CMV)抗体,共检出18名(78%)活动性CMV感染,其中10名(44%)为原发性感染。结果证实CMV-IgE和-IgA具有较好的血清学诊断价值,优于CMV-IgM。 相似文献
94.
95.
96.
CA von Arnim R Spoelgen ID Peltan M Deng S Courchesne M Koker T Matsui H Kowa SF Lichtenthaler MC Irizarry BT Hyman 《The Journal of neuroscience》2006,26(39):9913-9922
The beta-amyloid (Abeta) precursor protein (APP) is cleaved sequentially by beta-site of APP-cleaving enzyme (BACE) and gamma-secretase to release the Abeta peptides that accumulate in plaques in Alzheimer's disease (AD). GGA1, a member of the Golgi-localized gamma-ear-containing ARF-binding (GGA) protein family, interacts with BACE and influences its subcellular distribution. We now report that overexpression of GGA1 in cells increased the APP C-terminal fragment resulting from beta-cleavage but surprisingly reduced Abeta. GGA1 confined APP to the Golgi, in which fluorescence resonance energy transfer analyses suggest that the proteins come into close proximity. GGA1 blunted only APP but not notch intracellular domain release. These results suggest that GGA1 prevented APP beta-cleavage products from becoming substrates for gamma-secretase. Direct binding of GGA1 to BACE was not required for these effects, but the integrity of the GAT (GGA1 and TOM) domain of GGA1 was. GGA1 may act as a specific spatial switch influencing APP trafficking and processing, so that APP-GGA1 interactions may have pathophysiological relevance in AD. 相似文献
97.
D A Schwartz R T Bryan K O Hewan-Lowe G S Visvesvara R Weber A Cali P Angritt 《Archives of pathology & laboratory medicine》1992,116(6):660-668
Microsporidia are obligate intracellular protozoal parasites that infect a variety of cell types in a broad range of invertebrates and vertebrates. They have recently come to medical attention due to the increased frequency with which members of two microsporidian genera, Enterocytozoon and Encephalitozoon, are being diagnosed in patients with the acquired immunodeficiency syndrome (AIDS). The majority of published reports of human microsporidiosis describe Enterocytozoon infection of small intestinal enterocytes. In addition, a growing number of AIDS patients have been identified with infection due to the two species of Encephalitozoon-Encephalitozoon cuniculi and Encephalitozoon hellem, observed in conjunctival, corneal, and, recently, sinonasal tissues. However, there are scant data regarding the systemic pathology and epidemiology of these infections. This article describes a patient with AIDS who died with systemic Encephalitozoon infection. The etiologic microsporidian was found to be E hellem by using antemortem biochemical and antigenic analyses. A complete autopsy, the first to be reported in a patient with this infection, revealed organisms in the eyes, urinary tract, and respiratory tract. A surprising observation was the occurrence of numerous organisms within the lining epithelium of almost the entire length of the tracheobronchial tree, suggestive of respiratory acquisition. Detailed light and electron microscopic findings and the biological and diagnostic features of microsporidiosis are discussed. 相似文献
98.
J M Larner C H Shackleton E Roitman P E Schwartz R B Hochberg 《The Journal of clinical endocrinology and metabolism》1992,75(1):195-200
We have developed a gas chromatographic/mass spectral method for the sensitive and reproducible measurement of estradiol-17-fatty acid esters in human tissues and blood. To provide an internal standard for quantification, a trideuterated analog of a representative estradiol ester is added to the tissues. Estradiol (E2) released from the nonpolar ester fraction by alkaline hydrolysis is derivatized to form the ditrimethylsilyl ether and then analyzed by gas chromatographic/mass spectral, monitoring the molecular ions mass per U charge of the ditrimethylsilyl derivative of E2 and [2H3]E2. There are low but detectable levels of E2 ester in the blood of cycling females; there are none in urine. While the E2 ester is present in breast cyst fluid, its concentration, 77-140 pmol/L, is considerably less than E2, 110-2,863 pmol/L. But there is a large amount of E2 ester in fat. In premenopausal women the average E2 ester in fat (sc and omental) is 957 +/- 283 38 fmol/g (SEM); in women who are menopausal less than 12 yr, the E2 ester in fat is 669 +/- 158 fmol/g; in women who are menopausal at least 15 yr, the fat level is 399 +/- 146 fmol/g. Muscle from the same women have lower concentrations of the ester; in 8 out of 12 muscle specimens it was not detectable. The E2 esters are extremely potent estrogens. Although they are hormonally active they require enzymatic hydrolysis to exert their hormonal action. These studies show that these long chain esters of E2 are sequestered in fatty tissues, wherein they represent a protected store of preformed hormone. Under the proper stimulation, adipose tissue can activate the estrogenic signal through the action of hormonally sensitive esterases. Thus, through signaling between estrogen sensitive tissues and neighboring fat cells, a local paracrine loop may exist. 相似文献
99.
100.
Cell flow cytometry offers the opportunity to analyze cytopathological samples with regards to DNA content and proliferative activity. To investigate whether this modality can quantitate certain aspects of ovarian carcinoma by analyzing ascites, 43 samples from patients with advanced papillary serous adenocarcinoma of the ovary were studied. In 28 samples (65%) ploidy and the percentage of cells in S phase (%S phase) could be analyzed. Fifteen samples could not be analyzed because of overlapping cell populations distorting distinct cell cycle phases. Of the 28 samples studied, 8 (29%) were diploid and 20 (71%) were aneuploid. The DNA in aneuploid samples ranged from 1.23 to 2.65. The %S phase for aneuploid was greater than that for diploid samples. Patients with diploid samples survived longer. Cytometric analysis of cells from ascites in 4 patients in whom disease progressed after they received chemotherapy showed that the percentage of cells in S phase increased. Cells from ascites established in vitro showed that ploidy and proliferative activity changed as cells were passed in culture. In conclusion, the analysis of ascites by cell flow cytometry may be a prognosticator in patients with advanced ovarian carcinoma. In addition, conclusions extrapolated from in vitro data to the in vivo situation should be done cautiously since late-passaged cells may not always be representative of the initial tumor sample. 相似文献