全文获取类型
收费全文 | 4780篇 |
免费 | 206篇 |
国内免费 | 34篇 |
专业分类
耳鼻咽喉 | 33篇 |
儿科学 | 78篇 |
妇产科学 | 60篇 |
基础医学 | 697篇 |
口腔科学 | 74篇 |
临床医学 | 312篇 |
内科学 | 1230篇 |
皮肤病学 | 69篇 |
神经病学 | 242篇 |
特种医学 | 214篇 |
外科学 | 1045篇 |
综合类 | 25篇 |
预防医学 | 83篇 |
眼科学 | 54篇 |
药学 | 273篇 |
中国医学 | 2篇 |
肿瘤学 | 529篇 |
出版年
2023年 | 17篇 |
2022年 | 47篇 |
2021年 | 68篇 |
2020年 | 42篇 |
2019年 | 50篇 |
2018年 | 79篇 |
2017年 | 64篇 |
2016年 | 96篇 |
2015年 | 98篇 |
2014年 | 149篇 |
2013年 | 175篇 |
2012年 | 276篇 |
2011年 | 275篇 |
2010年 | 162篇 |
2009年 | 169篇 |
2008年 | 254篇 |
2007年 | 303篇 |
2006年 | 331篇 |
2005年 | 363篇 |
2004年 | 334篇 |
2003年 | 359篇 |
2002年 | 345篇 |
2001年 | 60篇 |
2000年 | 49篇 |
1999年 | 69篇 |
1998年 | 67篇 |
1997年 | 71篇 |
1996年 | 47篇 |
1995年 | 54篇 |
1994年 | 48篇 |
1993年 | 55篇 |
1992年 | 33篇 |
1991年 | 39篇 |
1990年 | 36篇 |
1989年 | 34篇 |
1988年 | 18篇 |
1987年 | 28篇 |
1986年 | 34篇 |
1985年 | 31篇 |
1984年 | 36篇 |
1983年 | 18篇 |
1982年 | 27篇 |
1981年 | 18篇 |
1980年 | 16篇 |
1979年 | 11篇 |
1978年 | 12篇 |
1977年 | 8篇 |
1976年 | 7篇 |
1975年 | 8篇 |
1974年 | 7篇 |
排序方式: 共有5020条查询结果,搜索用时 15 毫秒
11.
12.
The distribution patterns of choline acetyltransferase (CAT), as a marker for cholinergic neurons, and Calbindin-D28k (CaBP) immunoreactivities in the forebrain basal ganglia of the Japanese monkeyMacaca fuscata were compared. Similar distribution patterns of CAT and CaBP immunoreactivities were found in the medial septal nucleus (MS) and the nucleus of the diagonal band of Broca (DBB). Double-labeling fluorescence immunocytochemistry revealed that most, but not all, cholinergic neurons were CaBP-immunoreactive in the MS and DBB. The results suggest that CaBP may play a role in the septohippocampal cholinergic neuron system of the monkey. 相似文献
13.
Flat adenoma and flat mucosal carcinoma (IIb type)— A new precursor of colorectal carcinoma? 总被引:12,自引:10,他引:2
Dr. Miki Adachi M.D. Tetsuichiro Muto M.D. Yasuhiko Morioka M.D. Tatsuo Ikenaga M.D. Mitsuru Hara M.D. 《Diseases of the colon and rectum》1988,31(3):236-243
Two flat adenomas and a flat mucosal carcinoma of the colon were reported in patients with synchronous and metachronous colonic carcinomas. These lesions were almost flat and were not detected by preoperative endoscopic examinations. Colonoscopists should be aware of the presence of flat adenomas, which can be easily missed, and recognize them as lesions that play an important role in the "adenoma-carcinoma sequence." 相似文献
14.
Ken SAITO Hideo SHIMIZU Takeshi YOKOYAMA Katsuya KAWATA Takanori MATSUMURA Yasuhiko MORIOKA 《Pathology international》1983,33(2):249-256
Four cases of Ischemic enterocolitis without arterio–occlusive lesion were described. Three cases were associated with sigmoid colon carcinomas. Ischemic lesions developed anal to the carcinomas in two cases, and oral to sigmoidostomy to relieve intestinal obstruction by carcinoma in one case. One other case was associated with inguinal hernia. Grossly, ischemic lesions involved relatively short intestinal segments, and the ischemic colonic lesions were not related to teniae coli. Extensive veno–occlusive lesions were discovered in a case of ischemic stricture of the ileum, which had been incarcerated in the right inguinal hernia. Reversible mechanical occlusion of the intestinal vessels caused by transient or recurrent intestinal strangulation is the most probable cause of these ischemic lesions., ACTA PATHOL. JPN. 33: 249–256, 1983. 相似文献
15.
Satoshi Mochida Itsuro Ogata Yasuhiko Ohta Teruaki Oka Kenji Fujiwara 《Pathology international》1991,41(3):217-220
In order to investigate superoxide production by pulmonary macrophages in the rat, a route was created by ligating both the inferior and superior venae cavae and resecting the aorta after cannulation through the inferior vena cava into the right atrium of the heart. Lung perfusion was performed via this route with nitro blue tetrazolium. Although there was no formazan deposition throughout the lung, it became detectable in both alveolar and interstitial macrophages when phorbol myristate acetate was added to the perfusate. This deposition was markedly enhanced by previous injection of Corynebacterium parvum. The deposition disappeared after further addition of Cu(Lys)2 , a scavenger of superoxide anions. This procedure may be useful for estimating in situ the ability of pulmonary macrophages to produce superoxide in the rat. 相似文献
16.
17.
Influence of culture method on the proliferation and osteogenic differentiation of human adipo-stromal cells in nonwoven fabrics 总被引:1,自引:0,他引:1
The initial attachment, proliferation, and osteogenic differentiation of stromal cells from human fat tissue were investigated in three-dimensional nonwoven fabrics prepared from polyethylene terephthalate (PET) fiber with different diameters. The largest number of cells initially attached was observed in the nonwoven fabrics prepared from PET fiber with a diameter of 22.0 microm, irrespective of fabric porosity. The number of cells attached was larger and the cells were distributed more homogeneously in the fabrics by the agitated seeding method than by the static seeding method. The culture method depended on the time profile of cell proliferation. Cell proliferation improved in the following order: stirred (spinner flask) culture method > agitated culture method > static culture method. In addition, cells proliferated homogeneously in fabrics by the stirred culture method. When evaluated as a measurement of cell osteogenic differentiation, the activity of alkaline phosphatase (ALP) was not influenced by the diameter of fabrics. The static culture method tended to enable cells to enhance ALP activity, in contrast with the stirred and agitated culture methods. It is concluded that fabric fiber diameter and culture method greatly affected the proliferation and differentiation of cells in nonwoven fabrics. 相似文献
18.
Mikio Watanabe Dr. Yoshinori Iwatani Tatsunari Kaneda Yoh Hidaka Nobuaki Mitsuda Yasuhiko Morimoto Nobuyuki Amino 《American journal of reproductive immunology (New York, N.Y. : 1989)》1997,37(5):368-377
PROBLEM: Pregnancy affects the maternal immune system and the clinical course of maternal diseases. Here we report the changes in the detailed lymphocyte subsets of helper T cells, suppressor T cells, CD5+ B cells, T cell receptor (TCR) αβ-positive T cells (Tαβ cells), TCRαβ-negative T cell (Tγδ cells), and others during and after pregnancy through to one year postpartum, and discuss the significance of the changes. METHOD: The absolute numbers of helper T cells, suppressor T cells, cytotoxic T cells, TCRαβ-negative T cells (Tγδ cells), CD5— B cells, CD5+ B cells, and NK cell subsets were examined by two-color flow cytometry in peripheral blood from 51 healthy non-pregnant women, 106 healthy pregnant women, and 148 healthy postpartum women. RESULTS: In early pregnancy, the numbers of suppressor T cells and NK cells with strong cytotoxicity (NK+++ cells) increased, and the number of cytotoxic T cells decreased. In late pregnancy, the helper T cell and NK+++ cell numbers decreased. Tαβ, CD5— B and CD5+ B cells decreased during pregnancy. After delivery, helper T cells and cytotoxic T cells increased from 1 to 4 months postpartum, and suppressor T cells increased at 7 months postpartum. TCRαβ-negative T cells increased at 4 to 10 months postpartum. Both CD5— and CD5+ B cells decreased further at 1 month postpartum, but CD5+ B cells increased markedly at 7 to 10 months postpartum. CONCLUSIONS: These data indicate that 1) early increases of suppressor T cells and NK+++ cells during pregnancy may be related to the mechanism to accept or reject the fetus in early pregnancy, respectively; 2) late decreases of helper T cells and NK+++ cells may be related to the maintenance of pregnancy: 3) postpartum increases of helper T cells, cytotoxic T cells, TCRαβ-negative T cells (Tγδ cells), and CD5+ B cells may be related to the postpartum aggravation of autoimmune diseases; and 4) the immunological effects of pregnancy remains until about 1 year after delivery. 相似文献
19.
Yasuhiko Hirata Hiromi Ishibashi Harumichi Kimura Kazuhiro Hayashida Masanori Nagano Hideo Okubo 《Inflammation》1985,9(2):201-209
Isolated rat Kupffer cells produced a factor which stimulated the synthesis of
2-macroglobulin (2M) in primary cultured rat hepatocytes. Although Kupffer cells placed in culture produced the factor without stimulation by lipopolysaccharide (LPS), the LPS-stimulated cells produced larger amounts of the factor. On the other hand, the production of the factor was inhibited by addition of actinomycin D. The induction of2M synthesis by cultured hepatocytes was enhanced in the presence of dexamethasone (Dex), in that hepatic synthesis of2M increased by addition of the factor alone and with Dex 1.5 and three- to four-fold, respectively. The factor was nondialyzable and stable at 60°C for 30 min. When the factor was fractionated using the molecular sieve method, the activity recovered in the fraction had a molecular weight of over 30,000. 相似文献
20.
K Terashima K Takahashi M Kojima Y Imai S Tsuchida S Migita S Ebina C Itoh 《Acta pathologica japonica》1978,28(1):111-138
An autopsy case of systemic histiocytosis with excessive deposition of kappa-type light chain crystals was reported in a 58 year-old man who had consistently showed kappa-type light chain paraproteinemia, Bence Jones proteinuria and hypogammaglobulinemia for about 10 years until his death. However, no bony destruction was found by repeated X-ray examinations. At autopsy, extensive hyperplasia of crystal-storing histiocytes was observed in the bone marrow, spleen, liver, lymph nodes, interstitial tissues of visceral organs and loose connective tissues. In the bone marrow and some other tissues, mild proliferation of plasmocytoid cells containing small crystals were found. Histochemically the crystals positively stained with various methods for amino acids and proteins, especially with Weigerts' method for fibrin. Ultrastructurally intralysosomal crystal deposition was confirmed in the storage histiocytes and derivation of the crystals from Golgi's sacculi in the plasmocytoid cells was suggested. Biochemically the crystals were regarded as mainly consisting of dimers of a variable half of light chain immunoglobulin and immunochemically and immunohistochemically reacted to anti-kappa type light chain serum. Such a generalized storage histiocytosis may be secondarily induced by immunoglobulin synthesized in plasmocytoid cells. 相似文献