全文获取类型
收费全文 | 6565篇 |
免费 | 376篇 |
国内免费 | 28篇 |
专业分类
耳鼻咽喉 | 43篇 |
儿科学 | 169篇 |
妇产科学 | 92篇 |
基础医学 | 929篇 |
口腔科学 | 222篇 |
临床医学 | 415篇 |
内科学 | 1458篇 |
皮肤病学 | 215篇 |
神经病学 | 814篇 |
特种医学 | 180篇 |
外科学 | 591篇 |
综合类 | 29篇 |
现状与发展 | 1篇 |
预防医学 | 358篇 |
眼科学 | 272篇 |
药学 | 553篇 |
中国医学 | 16篇 |
肿瘤学 | 612篇 |
出版年
2024年 | 8篇 |
2023年 | 53篇 |
2022年 | 116篇 |
2021年 | 172篇 |
2020年 | 104篇 |
2019年 | 142篇 |
2018年 | 149篇 |
2017年 | 127篇 |
2016年 | 171篇 |
2015年 | 176篇 |
2014年 | 219篇 |
2013年 | 257篇 |
2012年 | 465篇 |
2011年 | 544篇 |
2010年 | 301篇 |
2009年 | 221篇 |
2008年 | 432篇 |
2007年 | 460篇 |
2006年 | 442篇 |
2005年 | 456篇 |
2004年 | 446篇 |
2003年 | 413篇 |
2002年 | 399篇 |
2001年 | 38篇 |
2000年 | 35篇 |
1999年 | 53篇 |
1998年 | 69篇 |
1997年 | 43篇 |
1996年 | 57篇 |
1995年 | 41篇 |
1994年 | 34篇 |
1993年 | 31篇 |
1992年 | 28篇 |
1991年 | 32篇 |
1990年 | 33篇 |
1989年 | 23篇 |
1988年 | 22篇 |
1987年 | 22篇 |
1986年 | 13篇 |
1985年 | 19篇 |
1984年 | 16篇 |
1983年 | 8篇 |
1982年 | 18篇 |
1981年 | 12篇 |
1980年 | 18篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1975年 | 3篇 |
1974年 | 5篇 |
排序方式: 共有6969条查询结果,搜索用时 375 毫秒
91.
92.
93.
Ken Fukunaga Yoshio Ohda Nobuyuki Hida Masaki Iimuro Yoko Yokoyama Koji Kamikozuru Kazuko Nagase Shiro Nakamura Hiroto Miwa Takayuki Matsumoto 《Journal of gastroenterology and hepatology》2012,27(12):1808-1815
Background and Aim: Topical mesalamine or corticosteroid has shown efficacy in patients with ulcerative proctitis, but patients often become refractory to these interventions. Xilei San is a herbal preparation with evidence of anti‐inflammatory effects. We evaluated the efficacy of topical Xilei San in ulcerative proctitis patients. Methods: In a double blind setting, 30 patients with intractable ulcerative proctitis despite ≥ 4 weeks of topical mesalamine or corticosteroid were randomly assigned to True (n = 15) and placebo (n = 15). Patients in True received suppository Xilei San (0.1 g/dose per day of Xilei San), the other 15 received placebo suppository. The initial efficacy was evaluated on day 14. Primary endpoint of the trial was avoiding relapse during 180 days, relapse meant recurrence of active disease. Riley's index was applied for endoscopic and histological evaluations, while patients' quality of life was evaluated by an inflammatory bowel disease questionnaire. Results: On day 14, the number of patients who achieved remission, clinical activity index ≤ 4 in True was significantly higher versus placebo (P < 0.04). Likewise, at day 180, an 81.8% of patients in True were without relapse versus 16.7% in placebo (P < 0.001). Further, significant endoscopic (P < 0.01), histological (P < 0.02) and inflammatory bowel disease questionnaire (P < 0.04) improvements were observed in True, but not in placebo. Conclusions: This is the first controlled investigation showing significant clinical and endoscopic efficacy for Xilei San in patients with intractable ulcerative proctitis. Topical Xilei San was well tolerated, and was without safety concerns. 相似文献
94.
Megumi Fujita Chiaki Tohji Yoko Honda Yasuhiro Yamamoto Tsutomu Nakamura Tatsurou Yagami Motohiro Yamamori Noboru Okamura 《International journal of medical sciences》2012,9(7):555-566
Introduction: Agonists of peroxisome proliferator-activated receptor gamma (PPARγ) have been examined as chemopreventive and chemotherapeutic agents. The aim was to investigate the cytotoxicity and action mechanisms of 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), one of endogenous ligands for PPARγ, in terms of PPARγ-dependency and the mitogen-activated protein kinase (MAPK) and Akt pathway in three human renal cell carcinoma (RCC)-derived cell lines.Methods: 786-O, Caki-2 and ACHN cells were used as human RCC-derived cell lines. Cell viability and caspase-3 activity was detected by fluorescent reagents, and chromatin-condensation was observed with a brightfield fluorescent microscope after staining cells with Hoechst33342. The expression levels of proteins were detected by Western blot analysis.Results: 15d-PGJ2 showed cytotoxicity in dose-dependent manner. 15d-PGJ2 induced chromatin-condensation and elevated caspase-3 activity, and the cell viability was restored by co-treatment with a pan-caspase inhibitor, Z-VAD-FMK, indicating the involvement of caspase-dependent apoptosis. The cytotoxicity was not impaired by a PPARγ inhibitor, GW9662, suggesting that 15d-PGJ2 exerted the cytotoxicity in a PPARγ-independent manner. Some antioxidants rescued cells from cell death induced by 15d-PGJ2, but some did not, suggesting that reactive oxygen species (ROS) did not contribute to the apoptosis. 15d-PGJ2 also increased the expression levels of phospho-c-Jun N terminal kinase (JNK) in Caki-2 cells, and decreased those of phospho-Akt in 786-O cells, indicating that the JNK MAPK and the Akt pathways participated in the anticancer effects of 15d-PGJ2 in some cell lines.Conclusion: 15d-PGJ2 exerted cytotoxic effects accompanying caspase-dependent apoptosis, and this effect was elicited in a PPARγ-independent manner in three cell lines. In addition, the JNK MAPK and Akt pathway was involved in the cytotoxicity of 15d-PGJ2 to some extent in some cell line. Therefore, our study showed the 15d-PGJ2 to potentially be an interesting approach for RCC treatment. 相似文献
95.
Ryoma Tsuchiya Aino Kaneshima Masakazu Kobayashi Maki Yamazaki Yoko Takasu Hideki Sezutsu Yoshiaki Tanaka Akira Mizoguchi Kunihiro Shiomi 《Proceedings of the National Academy of Sciences of the United States of America》2021,118(1)
Diapause represents a major developmental switch in insects and is a seasonal adaptation that evolved as a specific subtype of dormancy in most insect species to ensure survival under unfavorable environmental conditions and synchronize populations. However, the hierarchical relationship of the molecular mechanisms involved in the perception of environmental signals to integration in morphological, physiological, behavioral, and reproductive responses remains unclear. In the bivoltine strain of the silkworm Bombyx mori, embryonic diapause is induced transgenerationally as a maternal effect. Progeny diapause is determined by the environmental temperature during embryonic development of the mother. Here, we show that the hierarchical pathway consists of a γ-aminobutyric acid (GABA)ergic and corazonin signaling system modulating progeny diapause induction via diapause hormone release, which may be finely tuned by the temperature-dependent expression of plasma membrane GABA transporter. Furthermore, this signaling pathway possesses similar features to the gonadotropin-releasing hormone (GnRH) signaling system for seasonal reproductive plasticity in vertebrates.To ensure survival under unfavorable environmental conditions and synchronize populations, most insect species enter diapause, which is a seasonal adaptation that evolved as a specific subtype of dormancy (1, 2). Diapause is not a passive response to changing conditions but rather an actively induced state that precedes adverse natural situations. Therefore, this diapause phenotype is accompanied by changes in energy metabolism or storage to improve cold/stress tolerance in later life stages, or progeny via reproductive switch (3). Although it has been generally suggested that brain/neuroendocrine systems are associated with this seasonal reproductive plasticity in both vertebrates and invertebrates (3, 4), the hierarchical relationship of the molecular mechanisms involved in the perception of environmental signals to integration into morphological, physiological, behavioral, and reproductive responses, known as the diapause syndrome, remains unclear (3).The silkworm Bombyx mori is a typical insect that arrests normal development during early embryogenesis, which is accompanied by metabolic changes in diapause (5, 6). The development of diapause-destined embryos is arrested during the G2 cell cycle stage immediately after the formation of the cephalic lobe and telson and sequential segmentation of the mesoderm (7). The bivoltine strain of B. mori has two generations per year, and progeny diapause is transgenerationally induced as a maternal effect and is determined by the environmental temperature, photoperiod, and nutrient conditions during embryonic and larval development of the mother (5, 6). The temperature signal during the mother’s embryonic development predominantly affects diapause determination, even if silkworms of the bivoltine Kosetsu strain are exposed to all cases of photoperiods during embryonic and larval development. In the Kosetsu strain, when eggs are incubated at 25 °C under continuous darkness, the resultant female moths (25DD) lay diapause eggs in almost all cases. In contrast, incubation of eggs at 15 °C in dark condition results in moths (15DD) that lay nondiapause eggs in almost all cases (6).Embryonic diapause is induced by the diapause hormone (DH) signaling pathway, which consists of highly sensitive and specific interactions between a neuropeptide, DH, and DH receptor (DHR) (6, 8). DH is exclusively synthesized in seven pairs of neurosecretory cells (DH-PBAN–producing neurosecretory cells [DHPCs]) located within the subesophageal ganglion (SG) in the mother’s generation (6). DH is released into the hemolymph during pupal–adult development and acts on the DHR, which belongs to the G protein-coupled receptors (GPCRs) (9). DH levels in the hemolymph are higher in the 25DD than 15DD pupae in the middle of pupal–adult development when the developing ovaries are sensitive to DH (6). Furthermore, the embryonic Bombyx TRPA1 ortholog (BmTRPA1) acts as a thermosensitive channel that is activated at temperatures above ∼21 °C and affects diapause induction through DH release (10). However, there remain questions about the thermal information that is received by BmTRPA1 and linked to DH signaling to induce diapause.From the 1950s, it has been suggested that the DH release was controlled by signals derived from certain region(s) in the brain based on surgical experiments, such as midsagittal bisection or transection (11–13). Especially, the operation in nondiapause producers changed them to diapause producers while transection of the protocerebrum had no effect on the diapause producers. These surgical results suggested the involvement of the protocerebrum in the inhibitory control of DH secretion (12, 14). Furthermore, the accumulation of the ovarian 3-hydroxykynurenine (3-OHK) pigment that accompanies the diapause syndrome was affected by injection with γ-aminobutyric acid (GABA) and the plant alkaloid picrotoxin (PTX), which is a widely used ionotropic GABA and glycine receptor antagonist (15, 16), and the selective ionotropic GABA receptor (GABAR) antagonist bicuculline. This suggests that a GABAergic neurotransmission via ionotropic GABAR is involved in DH secretion, which may be active in nondiapause producers but inactive in diapause producers throughout the pupal–adult development (14, 17). In general, ionotropic GABAR is composed of homo- or hetero-pentameric subunits. All known GABAR subunits display a similar structural scheme, with a large N-terminal extracellular domain involved in the formation of a ligand-binding pocket and a pore domain made of four transmembrane alpha-helices (TM1–TM4) (16, 18). Four homologous sequences of the ionotropic GABAR subunit genes were identified as RDL, LCCH3, GRD, and a GRD-like sequence named 8916 in various insects (19). However, the in vivo physiological roles of both signals derived from the brain and the GABAergic pathway in diapause induction have not been previously investigated.Corazonin (Crz) is an undecapeptide neurohormone sharing a highly conserved amino acid (a.a.) sequence across insect lineages and is involved in different physiological functions, such as heart contraction (20), stress response (21, 22), various metabolic activities (23–25), female fecundity (26), melanization of locust cuticles (27), regulation of ecdysis (28, 29), and control of caste identity (30). Moreover, Crz belongs to the gonadotropin-releasing hormone (GnRH) superfamily alongside adipokinetic hormone (AKH) and AKH/Crz-related peptide (ACP). Duplicates of an ancestral GnRH/Crz signaling system occurred in a common ancestor of protostomes and deuterostomes through coevolution of the ligand receptor (31, 32).Herein, we demonstrated that the hierarchical pathway consists of a GABAergic and Crz signaling system modulating progeny diapause induction by acting on DH release. We propose that the PTX-sensitive GABAergic signal may act to chronically suppress Crz release in dorsolateral Crz neurons (under nondiapause conditions) and that diapause conditions (or PTX injection) inhibits GABAergic signaling, resulting in accelerated Crz release, which in turn induces DH release. GABA signaling may be finely tuned by the temperature-dependent expression of the plasma membrane GABA transporter (GAT), which differs between the 25DD and 15DD conditions. Furthermore, this signaling pathway possesses similar features to the GnRH signaling system with respect to seasonal reproductive plasticity in vertebrates. 相似文献
96.
97.
98.
Kareem Morant Yoko Mikami Immaculate Nevis David McCarty John Stirrat David Scholl Martin Rajchl Peter Giannoccaro Louis Kolman Bobby Heydari Carmen Lydell Andrew Howarth Andrew Grant James A. White 《The international journal of cardiovascular imaging》2017,33(8):1201-1211
We sought to examine whether elongation of the mitral valve leaflets in patients with hypertrophic cardiomyopathy (HCM) is synergistic to septal wall thickness (SWT) in the development of left ventricular outflow tract obstruction (LVOTO). HCM is a common genetic cardiac disease characterized by asymmetric septal hypertrophy and predisposition towards LVOTO. It has been reported that elongation of the mitral valve leaflets may be a primary phenotypic feature and contribute to LVOTO. However, the relative contribution of this finding versus SWT has not been studied. 152 patients (76 with HCM and 76 non-diseased age, race and BSA-matched controls) and 18 young, healthy volunteers were studied. SWT and the anterior mitral valve leaflet length (AMVLL) were measured using cine MRI. The combined contribution of these variables (SWT × AMVLL) was described as the Septal Anterior Leaflet Product (SALP). Peak LVOT pressure gradient was determined by Doppler interrogation and defined as “obstructive” if?≥?30 mmHg. Patients with HCM were confirmed to have increased AMVLL compared with controls and volunteers (p?<?0.01). Among HCM patients, both SWT and SALP were significantly higher in patients with LVOTO (N?=?17) versus without. SALP showed modest improvement in predictive accuracy for LVOTO (AUC?=?0.81) among the HCM population versus SWT alone (AUC?=?0.77). However, in isolated patients this variable identified patients with LVOTO despite modest SWT. Elongation of the AMVLL is a primary phenotypic feature of HCM. While incremental contributions to LVOTO appear modest at a population level, specific patients may have dominant contribution to LVOTO. The combined marker of SALP allows for maintained identification of such patients despite modest increases in SWT. 相似文献
99.
Masatoshi Abe M.D. Ph.D. Chizuru Inoue M.D. Yoko Yokoyama M.H.S. Osamu Ishikawa M.D. Ph.D. 《Pediatric dermatology》2011,28(2):197-198
Abstract: We report a 12‐year‐old Japanese boy with a 3‐year history of skin lesions that had been unsuccessfully treated with topical steroids. We initiated two different topical treatments with adapalene gel 0.1% (Differin® Gel 0.1%) and high‐concentration vitamin D3 (tacalcitol) ointment; the lesions treated with adapalene gel improved dramatically in the first 2 months, whereas the high‐concentration vitamin D3 ointment resulted in little improvement. Topical adapalene gel 0.1% may be a promising choice as a topical treatment of Darier’s disease because of its high efficiency and lack of adverse effects. 相似文献
100.