全文获取类型
收费全文 | 7547篇 |
免费 | 323篇 |
国内免费 | 50篇 |
专业分类
耳鼻咽喉 | 60篇 |
儿科学 | 84篇 |
妇产科学 | 100篇 |
基础医学 | 849篇 |
口腔科学 | 318篇 |
临床医学 | 441篇 |
内科学 | 2059篇 |
皮肤病学 | 79篇 |
神经病学 | 425篇 |
特种医学 | 134篇 |
外科学 | 1468篇 |
综合类 | 47篇 |
预防医学 | 182篇 |
眼科学 | 129篇 |
药学 | 753篇 |
中国医学 | 26篇 |
肿瘤学 | 766篇 |
出版年
2022年 | 66篇 |
2021年 | 142篇 |
2020年 | 71篇 |
2019年 | 101篇 |
2018年 | 130篇 |
2017年 | 108篇 |
2016年 | 114篇 |
2015年 | 106篇 |
2014年 | 160篇 |
2013年 | 197篇 |
2012年 | 316篇 |
2011年 | 293篇 |
2010年 | 164篇 |
2009年 | 138篇 |
2008年 | 284篇 |
2007年 | 352篇 |
2006年 | 324篇 |
2005年 | 323篇 |
2004年 | 289篇 |
2003年 | 269篇 |
2002年 | 316篇 |
2001年 | 247篇 |
2000年 | 265篇 |
1999年 | 256篇 |
1998年 | 91篇 |
1997年 | 76篇 |
1996年 | 77篇 |
1995年 | 80篇 |
1994年 | 51篇 |
1993年 | 50篇 |
1992年 | 205篇 |
1991年 | 169篇 |
1990年 | 159篇 |
1989年 | 190篇 |
1988年 | 163篇 |
1987年 | 155篇 |
1986年 | 150篇 |
1985年 | 145篇 |
1984年 | 105篇 |
1983年 | 94篇 |
1982年 | 59篇 |
1979年 | 76篇 |
1978年 | 62篇 |
1977年 | 55篇 |
1976年 | 57篇 |
1974年 | 57篇 |
1973年 | 48篇 |
1972年 | 51篇 |
1970年 | 48篇 |
1969年 | 66篇 |
排序方式: 共有7920条查询结果,搜索用时 15 毫秒
61.
Yoshida R; Nagira M; Imai T; Baba M; Takagi S; Tabira Y; Akagi J; Nomiyama H; Yoshie O 《International immunology》1998,10(7):901-910
EBI1-ligand chemokine (ELC) is a CC chemokine constitutively expressed in
various lymphoid tissues and a high-affinity functional ligand for
EBI1/CCR7, a seven transmembrane G-protein-coupled receptor originally
identified as an Epstein-Barr virus (EBV)-inducible gene. Here we examined
chemotactic activity of ELC on peripheral blood leukocytes. ELC attracted
both CD4+ and CD8+ T cells, particularly efficiently after activation with
IL-2 or with phytohemagglutinin (PHA) plus IL-2, as well as CD19+ B cells,
but not CD16+ NK cells, CD14+ monocytes or neutrophils. Among CD3+ T cells,
ELC attracted both CD45RO- naive and CD45RO+ memory subsets. ELC also
induced vigorous calcium mobilization in T cells stimulated with IL-2 with
an ED50 of 3 nM. ELC fused with the secreted form of alkaline phosphatase
(ELC-SEAP) specifically bound to lymphocytes and this binding was blocked
only by ELC among 10 CC chemokines so far tested. Notably, lymphocytes
stimulated with IL-2 or T cells expanded by PHA plus IL-2 showed much
higher levels of binding than fresh lymphocytes. Consistently, CCR7 mRNA
was detected in CD4+ and CD8+ T cells as well as B cells, but not in NK
cells, monocytes or neutrophils, and was dramatically increased in T cells
upon treatment with IL-2 or with PHA plus IL-2. Like ELC mRNA, CCR7 mRNA
was expressed in various lymphoid tissues. By in situ hybridization, ELC
and CCR7 mRNA were detected in the parafollicular and inner cortical
regions of a lymph node, and in the parafollicular regions of an appendix.
Collectively, ELC and CCR7 may be involved in the trafficking of a broad
spectrum of lymphocytes, especially activated T cells, into and within
various lymphoid tissues.
相似文献
62.
Saiki O Uda H Nishimoto N Miwa T Mima T Ogawara T Azuma N Katada Y Sawaki J Tsutsui H Matsui K Maeda A Nakanishi K 《Clinical immunology (Orlando, Fla.)》2004,112(1):120-125
Adult Still's disease (ASD) is a chronic multisystemic disease. Extraordinarily high serum levels of IL-18 in ASD patients have been described, whereas the mechanism remains to be clarified. This study aimed to evaluate proinflammatory cytokines and to consider their pathological roles. In patients with rheumatic diseases (n = 151), blood samples were taken at the active phase and the serum levels of IL-18 and other proinflammatory cytokines were measured by ELISA. The extra-high levels of IL-18 were confirmed selectively in ASD patients (n = 10). In the active phase of ASD patients, the levels of IL-6 were elevated accordingly, but IL-1beta and TNF-alpha were undetectable. As to Th1-Th2 cytokines, the levels of IL-4 and IL-13, but not INF-gamma, IL-12, or IL-2, were elevated in all ASD patients examined. Moreover, the serum levels of IL-18 showed a good correlation with those of IL-4, suggesting that ASD reflects a Th2 rather than a Th1 cytokine profile. 相似文献
63.
Tanabe A Tsuiki M Watanabe D Takagi S Takano K Naruse M 《Rinsho byori. The Japanese journal of clinical pathology》2004,52(8):704-710
Aldosterone is one the representative cardiovascular hormones involved in the blood pressure and body-fluid homeostasis. Elevation of aldosterone leads to systemic hypertension through its action on the mineralocorticoid receptor (MR) in the kidney. More recent studies demonstrated that aldosterone may produce target organ damage through its direct actions on the non-epithelial MR of the heart in addition to its systemic effects. Clinical experience in primary aldosteronism supports the concept that aldosterone is a risk factor of cardiovascular complications, since concentric type of cardiac hypertrophy is most common in primary aldosteronism among various types of endocrine hypertension. Clinical mega-trial in congestive heart failure (RALES study, EPHESUS study) demonstrated blocking angiotensin II action is not sufficient for cardioprotection unless aldosterone action is equally blocked. An important phenomenon related to this issue is the aldosterone breakthrough which implies a reelevation of plasma aldosterone during chronic administration of ACE inhibitors and Angiotensin receptor antagonists. Normal level of aldosterone could still be a risk factor. Combination of ACE inhibitor or ARB with aldosterone antagonist could result in a better cardioprotection in cardiovascular diseases. Although spironolactone has been the only one aldosterone antagonist, a new antagonist eplerenone has been developed. Eplerenone is specific to MR and is practically devoid of the major side effect gynecomastia of spironolactone. Another topic of aldosterone is its very quick cardiovascular effect presumably via a non-genomic action. All these recent findings support that this adrenocortical steroid hormone is as important as angiotensin II. Determining aldosterone levels is therefore much morel important than before in the diagnosis and treatment of cardiovascular diseases. 相似文献
64.
Shinichiro Ushigome Toshifumi Takakuwa Masayuki Takagi Hirotaka Koizumi Masamichi Morikubo 《Pathology international》1986,36(7):963-971
Cases of proliferative myositis and fasciitis were studied immunohisto-chemically and ultra structurally for further understanding of the nature of ganglion cell-like giant cells. Blood coagulation factor XIIIa, fibronectin, myoglobin, myosin, CPK MM, and alpha-1-antichymotrypsin were detected in three cases of proliferative myositis and two cases of proliferative fasciitis by the avid in-biotin-peroxidase complex method. Factor XIIIa (a fibrin-stabilizing factor) and flbronectin were strongly positive in the giant cells, but not in striated muscle fibers. A small quantity of myosin was demonstrated in the giant cells, but myoglobin and CPK MM were never demonstrated in these cells. No alpha-1-antichymotrypsin was demonstrated in the giant cells. One case of proliferative myositis showed ultrastructural features suggestive of fibroblast rather than muscle cell or histiocytic origin. Strongly positive factor XIIIa in the giant cells is suggestive of the fact that they are active fibroblasts. 相似文献
65.
The alar plate of the prosencephalon differentiates into a tectum-like structure when transplanted into the mesencephalon around the 10-somite stage. Here, we report on the projection pattern of the retinal ganglion cells to the transplants. Optic nerve fibers were labeled with horseradish peroxidase (HRP) and 3H-proline, and the innervation of the optic nerve fibers to the chimeric tectum was analyzed by HRP histochemistry on whole-mounted specimens, by autoradiography and by electron microscopy on embryonic day 16. In the chimeric tectum, the transplant was distinguished from the host by difference in nuclear structure between the quail and the chick cells. It was shown that the transplant had the laminar pattern of the optic tectum when the transplant was integrated into the host mesencephalon. The whole-mount HRP histochemistry showed that the optic nerve fibers extend to the transplants. Autoradiography showed that the distribution pattern of silver grains was similar in both the host and the transplant. These results may indicate that the optic nerve fibers turn to the transplant and terminate on the transplant. Electron microscopy further confirmed that optic nerve fibers ended by making synaptic contacts with the dendrites in the transplant region of the tectum. These results indicate that the transplant with the laminar pattern of the optic tectum is a true tectum receiving input from the eye. 相似文献
66.
The morphological features of substance P-immunoreactive (SP-IR) structures in the nucleus of the tractus solitarius (NTS) were examined by immunoelectron microscopy combined with an anterograde degeneration study. Vagal afferents were allowed to degenerate by resecting the nodose ganglion two days prior to the examination. SP-IR axon terminals in the ipsilateral NTS were often found to make a synaptic contact with non-reactive dendrites in contact with degenerated terminals. SP-IR terminals also made contact with degenerated terminals, or SP-IR cells in contact with degenerated terminals. These findings suggest a close relationship between SP neuronal structures and vagal afferents in the NTS. 相似文献
67.
68.
Herpes simplex virus type 1 restriction fragment polymorphism determined using southern hybridization 总被引:2,自引:0,他引:2
Summary Regions of herpes simplex virus type 1 (HSV-1) DNA with variation in the size of restriction endonuclease fragments were identified by comparison of theBam HI,KpnI orSalI restriction endonuclease digestion patterns among 15 HSV-1 isolates after hybridization with specific32P-labeled cloned HSV-1 DNA fragments. Of the types of restriction fragment polymorphism identified, one was a strain with a distinctly different restriction fragment than the prototype (loss or gain of restriction sites). Another type, the specific fragment varied only in size among strains. Thirteen distinct variations were identified. Ten were mapped to the unique sequence of the L component; two to the inverted repeat of the L component and one to the inverted repeat of the S component. The presence of a common ancestor from which some isolates of HSV-1 might derive was deduced from an analysis of the distribution of the thirteen variations among the 15 HSV-1 isolates.With 8 FiguresOn leave from the Chemo-Sero-Therapeutic Institute, Kumamoto, Japan. 相似文献
69.
Thalamo-parietal fibers originating from the ventroanterior-ventrolateral (VA-VL) complex in the cat were labeled with Phaseolus vulgaris leucoagglutinin (PHA-L) and examined by light and electron microscopy. PHA-L (2.5% aqueous solution) was injected iontophoretically through micropipets with anodal current pulses into the VA-VL complex. PHA-L-labeled terminals were distributed in the lateral and the suprasylvian gyri in the superficial and deep cortical layers. In layer I, horizontal varicose fibers and terminals were conspicuous in the upper one-third and were widely distributed. In the deeper cortical layers (layers III-V), varicose fibers and terminals were detected in moderate numbers. Electron microscopic examination revealed that the labeled terminals formed asymmetrical synapses on the dendritic spines of spiny neurons. These morphological findings appeared to be consistent with our previous intracellular recordings in this cortex. 相似文献
70.
The cells from 5 cases of non-lymphocytic leukemia were investigated by immunoelectron microscopy using an anti-granulocyte antibody, clone 1G10 (New England Nuclear), to clarify the nature of immature leukemic cells. Reaction products on the surface of the leukemic cells were composed of two layers, an inner translucent and an outer dense granular zone. Although non-leukemic cells of the granulocytic series in various stages of maturation between promyelocytes and neutrophils were all positive for the antigen-antibody reaction, non-neoplastic monocytes and lymphocytes were all negative. Using this method, it was possible to diagnose the undifferentiated leukemic cells that were negative for myeloperoxidase. Furthermore, the results of our present study suggest the possibility that the antibody 1G10 may be useful for distinguishing granulocytic cells from cells of monocytic lineage. 相似文献