全文获取类型
收费全文 | 9148篇 |
免费 | 414篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 66篇 |
儿科学 | 146篇 |
妇产科学 | 247篇 |
基础医学 | 1239篇 |
口腔科学 | 204篇 |
临床医学 | 589篇 |
内科学 | 1987篇 |
皮肤病学 | 226篇 |
神经病学 | 783篇 |
特种医学 | 536篇 |
外科学 | 1600篇 |
综合类 | 28篇 |
一般理论 | 1篇 |
预防医学 | 250篇 |
眼科学 | 133篇 |
药学 | 592篇 |
中国医学 | 14篇 |
肿瘤学 | 954篇 |
出版年
2022年 | 99篇 |
2021年 | 169篇 |
2020年 | 90篇 |
2019年 | 116篇 |
2018年 | 135篇 |
2017年 | 111篇 |
2016年 | 120篇 |
2015年 | 150篇 |
2014年 | 200篇 |
2013年 | 252篇 |
2012年 | 406篇 |
2011年 | 425篇 |
2010年 | 221篇 |
2009年 | 172篇 |
2008年 | 399篇 |
2007年 | 393篇 |
2006年 | 365篇 |
2005年 | 392篇 |
2004年 | 366篇 |
2003年 | 403篇 |
2002年 | 423篇 |
2001年 | 329篇 |
2000年 | 394篇 |
1999年 | 264篇 |
1998年 | 93篇 |
1997年 | 81篇 |
1996年 | 85篇 |
1995年 | 75篇 |
1994年 | 82篇 |
1993年 | 66篇 |
1992年 | 223篇 |
1991年 | 232篇 |
1990年 | 202篇 |
1989年 | 243篇 |
1988年 | 208篇 |
1987年 | 212篇 |
1986年 | 186篇 |
1985年 | 152篇 |
1984年 | 98篇 |
1983年 | 84篇 |
1982年 | 47篇 |
1979年 | 76篇 |
1978年 | 71篇 |
1977年 | 50篇 |
1975年 | 49篇 |
1974年 | 52篇 |
1972年 | 59篇 |
1971年 | 55篇 |
1969年 | 45篇 |
1968年 | 49篇 |
排序方式: 共有9595条查询结果,搜索用时 0 毫秒
101.
Haruo Hagiwara Nobuo Ohwada Takeo Aoki Takeshi Suzuki Kuniaki Takata 《Medical molecular morphology》2008,41(4):221-226
Stromal cells in the lamina propria of the human oviduct mucosa are unique cells that can differentiate into decidual cells
during ectopic pregnancy in the oviduct. The nature of stromal cells is still unknown. In the present study, we investigated
human oviductal stromal cells with transmission electron microscopy and immunohistochemistry and revealed that they had ultrastructural
features similar to myofibroblasts and expressed alpha-smooth muscle actin, a marker used to identify myofibroblasts. Primary
cilia were also one of the characteristic profiles of the stromal cells. These findings showed that the connective tissue-stromal
cells in the human oviduct mucosa are myofibroblasts. They are considered to play an important role in the transport of oocytes
by bringing about contraction of the mucosal folds. 相似文献
102.
Ishii K Kurita-Taniguchi M Aoki M Kimura T Kashiwazaki Y Matsumoto M Seya T 《Immunology letters》2005,98(2):280-290
Adjuvants induce the expression of a number of genes in dendritic cells (DCs), which facilitate effective antigen-presentation and cytokine/chemokine liberation. It has been accepted that the toll-like receptor (TLR) family governs the adjuvant activity in DCs. An adjuvant with a long history is mycobacteria in an oil-in-water emulsion, namely Freund's complete adjuvant. Since the active center for the adjuvancy in mycobacteria is the cell-wall skeleton (CWS), we used the bacillus Calmette-Guerin cell-wall skeleton (BCG-CWS) to test DC maturation by GeneChip analysis. We identified the genes supporting an efficient DC response and output. Approximately 2000 genes were up-regulated by BCG-CWS stimulation. BCG-CWS-, peptidoglycan (PGN)- and lipopolysaccharide (LPS)-stimulation generally up-regulated some gene clusters including genes for inflammatory cytokines (TNF, IL1alpha, IL1beta, IL6, IL12 p40, IL23 p19, etc.), chemokines (CCL20, IL8, etc.), cell adhesion molecules (ICAM-1, etc.), apoptosis-related proteins (GADD45B, BCL2A1, etc.), metabolic enzymes (PTGS2, SOD2, etc.) and miscellaneous proteins (EHD1, TNFAIP6, etc.). LPS-stimulation, but not BCG-CWS- or PGN-stimulation, up-regulated the interferon-inducible antiviral proteins, including IFIT1, IFIT2, IFIT4, CXCL10, ISG15, OASL, IFITM1 and MX1. We also found that the BCG-CWS- or PGN-stimulation up-regulated CXCL5, MMP1, etc. We discussed their properties in association with TLRs and recently discovered TLR adapters. 相似文献
103.
104.
105.
The development of the rat meninx from the viewpoint of cell proliferation was studied microscopically and immunohistochemically using bromodeoxyuridine (BUdR). A compact cell layer around the neural tube, the meninx primitiva, was observed in 12- and 13-day fetuses. A reticular structure resembling the subarachnoid space appeared in the 14-day fetus. The ectomeninx, consisting of a collagen fiber layer, part of which became the dura mater, appeared in 15-day fetuses, allowing discrimination of the endomeninx, the arachnoid cell layer. The primordium of the choroid plexus also appeared in the lateral ventricle on the same day. Bone appeared in the primitive dura mater, and stratification of the meninx was almost complete in 21-day fetuses. BUdR-positive cells were confirmed in the meninx from day 12 of gestation to day 15 postpartum. The number of BUdR-positive cells was greatest in fetuses aged about 12 or 13 days, reaching nearly 50%, but decreased gradually toward the neonatal period. The findings of this study suggest that, after the migration of neural crest cells, marked cell proliferation in the meninx begins. Differentiation into various layers then follows and is almost complete before birth, whereas the proliferation of arachnoid cells continues even in the early neonatal period. 相似文献
106.
Hata T; Aoki S; Manabe A; Hata K; Miyazaki K 《Human reproduction (Oxford, England)》1997,12(8):1800-1804
Our purpose was to visualize normal embryonal and fetal surface anatomical
structures in the first trimester of human pregnancy by use of
three-dimensional ultrasonography with a specially developed abdominal
three-dimensional transducer. Four embryos and 31 fetuses of 8-13 weeks
gestation were studied with a specially-developed abdominal
three-dimensional transducer (3.5 MHz). This imaging system can provide
conventional two-dimensional ultrasonography images and can also generate,
within seconds, high-quality three-dimensional images in the surface and
transparent mode with no need for an external workstation. The percentage
of surface anatomical structures visualized at each gestational age
interval using two-dimensional and three-dimensional ultrasonography is
presented. Head and trunk were depicted in all cases. The number and the
clarity of visualization of face, upper and lower extremities, hand, and
foot increased with advancing gestation. The free loop of the umbilical
cord was depicted in most cases. The number of depictions of abdominal cord
insertion, midgut herniation, and yolk sac decreased with the increase of
gestation. Genitals could not be identified in the first trimester. The
ability to view some surface anatomical structures (face, hand, and foot)
was better with three-dimensional ultrasonography than with two-dimensional
ultrasonography. Three-dimensional ultrasonography provides a novel means
for visualization of surface anatomical structures of the embryo and early
fetus. These results suggest that three-dimensional ultrasonography can
become an important modality in future embryological and early fetal
research and in detection of embryonic and fetal developmental disorders in
the first trimester of pregnancy.
相似文献
107.
In the isolated lamprey spinal cord, a very slow rhythm (0.03-0.11 Hz), superimposed on fast N-methyl-D-aspartate (NMDA)-induced locomotor activity (0.26-2.98 Hz), could be induced by a blockade of GABA(A) or glycine receptors or by administration of (1 s, 3 s)-l-aminocyclopentane-1,3-dicarboxylic acid a metabotropic glutamate receptor agonist. Ventral root branches supplying dorsal and ventral myotomes were exposed bilaterally to study the motor pattern in detail. The slow rhythm was expressed in two main forms: 1) a dorsal-ventral reciprocal pattern was the most common (18 of 24 preparations), in which bilateral dorsal branches were synchronous and alternated with the ventral branches, in two additional cases a diagonal dorsal-ventral reciprocal pattern with alternation between the left (or right) dorsal and the right (or left) ventral branches was observed; 2) synchronous bursting in all branches was encountered in four cases. In contrast, the fast locomotor rhythm occurred always in a left-right reciprocal pattern. Thus when the slow rhythm appeared in a dorsal-ventral reciprocal pattern, fast rhythms would simultaneously display left-right alternation. A longitudinal midline section of the spinal cord during ongoing slow bursting abolished the reciprocal pattern between ipsilateral dorsal and ventral branches but a synchronous burst activity could still remain. The fast swimming rhythm did not recover after the midline section. These results suggest that in addition to the network generating the swimming rhythm in the lamprey spinal cord, there is also a network providing slow reciprocal alternation between dorsal and ventral parts of the myotome. During steering, a selective activation of dorsal and ventral myotomes is required and the neural network generating the slow rhythm may represent activity in the spinal machinery used for steering. 相似文献
108.
A rare case of intracranial metastatic amelanotic melanoma with cyst is presented. The patient was a 51 year old woman with a malignant melanoma arising on her right chest. Two years after a wide excision, skin and brain metastasis occurred. Brain magnetic resonance images demonstrated a tumour with a cyst in the left occipital lobe. Because the tumour showed low intensity on T1 weighted images and high intensity on T2 weighted images, the metastatic melanoma was identified as an amelanotic melanoma. Intracranial amelanotic melanoma is very rare, and there have been few reports of melanoma with cyst. 相似文献
109.
110.