全文获取类型
收费全文 | 10586篇 |
免费 | 853篇 |
国内免费 | 484篇 |
专业分类
耳鼻咽喉 | 55篇 |
儿科学 | 83篇 |
妇产科学 | 100篇 |
基础医学 | 2020篇 |
口腔科学 | 295篇 |
临床医学 | 718篇 |
内科学 | 1801篇 |
皮肤病学 | 336篇 |
神经病学 | 1201篇 |
特种医学 | 153篇 |
外国民族医学 | 1篇 |
外科学 | 898篇 |
综合类 | 951篇 |
现状与发展 | 2篇 |
预防医学 | 231篇 |
眼科学 | 211篇 |
药学 | 1690篇 |
1篇 | |
中国医学 | 312篇 |
肿瘤学 | 864篇 |
出版年
2024年 | 36篇 |
2023年 | 216篇 |
2022年 | 316篇 |
2021年 | 440篇 |
2020年 | 404篇 |
2019年 | 348篇 |
2018年 | 384篇 |
2017年 | 293篇 |
2016年 | 323篇 |
2015年 | 384篇 |
2014年 | 625篇 |
2013年 | 742篇 |
2012年 | 617篇 |
2011年 | 726篇 |
2010年 | 633篇 |
2009年 | 650篇 |
2008年 | 662篇 |
2007年 | 578篇 |
2006年 | 533篇 |
2005年 | 454篇 |
2004年 | 478篇 |
2003年 | 391篇 |
2002年 | 252篇 |
2001年 | 191篇 |
2000年 | 149篇 |
1999年 | 136篇 |
1998年 | 149篇 |
1997年 | 114篇 |
1996年 | 112篇 |
1995年 | 83篇 |
1994年 | 60篇 |
1993年 | 54篇 |
1992年 | 49篇 |
1991年 | 42篇 |
1990年 | 35篇 |
1989年 | 23篇 |
1988年 | 14篇 |
1987年 | 10篇 |
1986年 | 20篇 |
1985年 | 45篇 |
1984年 | 29篇 |
1983年 | 22篇 |
1982年 | 22篇 |
1981年 | 20篇 |
1980年 | 15篇 |
1979年 | 10篇 |
1978年 | 7篇 |
1977年 | 9篇 |
1976年 | 12篇 |
1970年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
This ultrastructural study is based on nine cases of adenoid cystic carcinoma arising from the salivary glands. Electron microscopically, the tumors consisted of five cell types: relatively differentiated intercalated duct cells, secretory cells, undifferentiated cells, cells of a squamous nature, and myoepithelial cells. Special attention was paid to the characteristic extracellular substances noted by light microscopic examination of these tumors. The hyaline material of the pseudocysts contained not only mucopolysaccharide granules but also fingerprintlike structures formed by replicated basement membrane. Some of these structures had a dense core, probably composed of mucopolysaccharide granules. Cell islands surrounded by elasticlike material also were found. The true lumina were usually filled with membranovesicular structures originating from fragments of the lining cells, mainly those with squamous differentiation. These membranovesicular structures included electron-dense rods, filamentous whorls, and structures displaying periodicity. 相似文献
72.
Martina Milanetto Natascia Tiso Paola Braghetta Dino Volpin Francesco Argenton Paolo Bonaldo 《Developmental dynamics》2008,237(1):222-232
Emilins are a family of extracellular matrix proteins with common structural organization and containing a characteristic N-terminal cysteine-rich domain. The prototype of this family, Emilin-1, is found in human and murine organs in association with elastic fibers, and other emilins were recently isolated in mammals. To gain insight into these proteins in lower vertebrates, we investigated the expression of emilins in the fish Danio rerio. Using sequence similarity tools, we identified eight members of this family in zebrafish. Each emilin gene has two paralogs in zebrafish, showing conserved structure with the human ortholog. In situ hybridization revealed that expression of zebrafish emilin genes is regulated in a spatiotemporal manner during embryonic development, with overlapping and site-specific patterns mostly including mesenchymal structures. Expression of certain emilin genes in peculiar areas, such as the central nervous system or the posterior notochord, suggests that they may play a role in key morphogenetic processes. 相似文献
73.
P. Ljungberg C. Holmberg H. Jalanko I. Virtanen 《Virchows Archiv : an international journal of pathology》1996,428(6):333-346
The aim of this study was to examine the distribution of 1 and v integrins (Ints) and some of their ligands in the kidneys of patients with congenital nephrotic syndrome of the Finnish type (CNF) and in controls using indirect immunofluorescence with monoclonal antibodies. The mesangial reactivity of Int 1 and Int 1 subunits was more variable and an increased glomerular reactivity with Int 3 and Int-6 antibodies was found in CNF kidneys than in controls. Int 2 subunit was either completely missing from or found in significantly lesser amounts in CNF kidney glomeruli. The immunoreactivity for Int v was more variable, fainter and also more granular in CNF samples than in control kidneys. The glomerular reactivity for Int 5 was more diffuse and weaker, and in sclerotic Bowman's capsules more intense in CNF kidneys than in controls. Immunoreactivity for Int 6 was restricted and was comparable in extent in CNF and control kidneys. Of the extracellular matrix components studied, the expression of EDAFn, EDBFn, OncFn, Ln 2 chain, Ln 1 chain and tenascin was increased. This is also seen in several glomerular diseases with inflammation and sclerosis. Immunoreactivity for vitronectin was decreased. Several differences were found in the intensity or location of the immunostaining for the 1 and v Ints and their ligands in CNF kidneys compared with controls, which have not been found in any other proteinuric disease. Disturbed Int expression pattern in CNF may specifically reflect the disturbance of glomerular function caused by the primary defect in this disease. 相似文献
74.
整合素血小板膜糖蛋白IIb、IIIa在系膜增殖性肾炎中的表达 总被引:2,自引:1,他引:1
目的 :观察整合素血小板膜糖蛋白Ⅱb、Ⅲa(GPⅡb、GPⅢa)在人类系膜增殖肾炎 (MsPGN)中肾内表达 ,探讨GPⅡb Ⅲa在MsPGN的作用。方法 :18例肾活检标本均行光镜HE、PAS、PASM Masson染色 ,电镜及免疫荧光检查 ,以SABC法测定肾组织中GPⅡb、GPⅢa、P 选择素 (P 140 )、纤维连接蛋白 (FN)、粘连蛋白 (LN)表达与正常对照组分别比较 ,并行计算机图像分析。结果 :PAS阳性物 (PAS+ )、PASM阳性物 (PASM+ )及FN、LN明显增生 ;GPⅡb、GPⅢa、P 140表达上调 ;肾小球细胞数 (n)、平均肾小球体积 (AVG)及肾小球硬化指数显著增加 ;肾小管、间质轻度受损。结论 :GPⅡb、GPⅢa在肾小球及肾小管间质表达上调与系膜细胞基质增生、细胞浸润、肾小球硬化相关 ;可能与肾小球疾病中凝血功能紊乱、血小板在肾脏的致病作用相关 相似文献
75.
12例垂体瘤做原代细胞培养 ,检测了表皮生长因子 ( EGF)及染料木黄酮 ( Genistein)对肿瘤细胞 3H- Td R掺入率及酪氨酸激酶产物表达的影响。研究表明 EGF使大部分功能性腺瘤及所有非功能性腺瘤细胞的 3H- Td R掺入率明显增加 ,酪氨酸激酶活性增强 ,而 Genistein能抑制 EGF的作用使所有瘤细胞的 3H- Td R掺入率下降。提示表皮生长因子对垂体瘤细胞有明显的增殖刺激作用 ;Genistein能消除表皮生长因子的细胞增殖刺激作用 ,抑制肿瘤细胞增生 ,对垂体瘤治疗有重大意义。 相似文献
76.
Daniela A. Haehn Essa M. Bajalia Katherine J. Cockerill Amanda E. Kahn Colleen T. Ball David D. Thiel 《Translational andrology and urology》2021,10(1):227
BackgroundAdherent perinephric fat (APF) contributes to surgical complexity and can be associated with adverse perioperative outcomes for partial nephrectomy (PN). The Mayo Adhesive Probability (MAP) score accurately predicts the presence of APF during robotic-assisted partial nephrectomy (RAPN). Our primary aim is to validate MAP score as a predictor of APF in open partial nephrectomy (OPNx).MethodsWe reviewed 105 consecutive OPNx (100 patients) performed by a single surgeon with intraoperative determination of APF. We evaluated the ability of the MAP score to discriminate between those with APF and those without APF by estimating the area under the receiver operating characteristic curve (AUROCC). The association of perioperative outcomes with APF was evaluated as well.ResultsForty-three patients [49%; 95% confidence interval (CI), 39–59%] had intraoperative identification of APF. The MAP score had excellent ability to predict APF in OPNx (AUROCC, 0.82; 95% CI, 0.74–0.92). APF was observed in 6% of patients with a MAP score of 0-1, 27% with score 2, 52% with score 3, 75% with score 4, and 90% with score 5. The presence of APF was associated with longer operative times (P=0.004) and higher estimated blood loss (EBL) (P=0.003). Although not statistically significant, our study did suggest that APF may be associated with postoperative complications and prolonged length of stay (LOS) (>3 days).ConclusionsMAP score accurately predicts the presence of APF in patients undergoing OPNx. APF is associated with longer operative time and higher blood loss in OPNx. 相似文献
77.
78.
Kentaro Ariyoshi Yota Hiroyama Naoya Fujiwara Tomisato Miura Kosuke Kasai Akifumi Nakata Yohei Fujishima Valerie Swee Ting Goh Mitsuaki A Yoshida 《Journal of radiation research》2021,62(1):73
Alopecia is one of the common symptoms after high-dose radiation exposure. In our experiments, neonatal mice that received 7 Gy X-ray exhibited defects in overall hair growth, except for their cheeks. This phenomenon might suggest that some substances were secreted and prevented hair follicle loss in the infant tissues around their cheeks after radiation damage. In this study, we focused on exosome-like vesicles (ELV) secreted from cheek skin tissues and back skin tissues, as control, and examined their radiation protective effects on mouse fibroblast cell lines. We observed that ELV from irradiated cheek skin showed protective effects from radiation. Our results suggest that ELV from radiation-exposed cheek skin tissue is one of the secreted factors that prevent hair follicle loss after high-dose radiation. 相似文献
79.
Type IV collagenases in invasive tumors 总被引:11,自引:0,他引:11
Karl Tryggvason M.D. Ph.D. Matti Höyhtyä Charles Pyke 《Breast cancer research and treatment》1993,24(3):209-218
Summary The matrix metalloproteinases appear to be elevated in tumors with metastatic potential, and may well be involved in penetration of the basement membrane and degradation of extracellular proteins including type IV collagen. An imbalance between the 72 kDa and 92 kDa type IV collagenases and the associated tissue inhibitors of these metalloproteinases (TIMPs) may therefore have a role in the invasive phenotype. Cultured tumor cells with invasive potential secrete both type IV collagenases, though in tumors there is some evidence that the 72 kDa form at least may be produced by stromal cells at the invading tumor front rather than primarily by the tumor cells themselves, while the 92 kDa form may be synthesized in macrophages near the front. These collagenases are elevated in invasive as compared within situ tumor components, but their specific roles and prognostic significance are not yet established. 相似文献
80.
G. E. McVeigh M. McMaster T. Linton E. Whitehead G. D. Johnston 《European journal of clinical pharmacology》1990,38(4):351-357
Summary In this study we compared low (125 g) and conventional (500 g) doses of cyclopenthiazide on the renin angiotensin system, plasma and extracellular fluid volumes and the pressor responsiveness to angiotensin II since we have previously shown that the two doses have the same antihypertensive effect but different effects on plasma renin activity.Following a two week placebo run-in period, 8 healthy male volunteers received 125 g or 500 g of cyclopenthiazide for 2 treatment periods of 4 weeks as part of a double blind, 2-part crossover study with treatment periods separated by a 4-week placebo washout phase. Measurements were made on two study days at the beginning and end of the active treatment periods. On the first day serum potassium, plasma renin activity and plasma angiotensin II levels were measured after a 1 h period of supine rest. Plasma and extracellular fluid volumes were also measured after appropriate equilibration times. The blood pressure responses to angiotensin II were assessed on day 2.The 500 g dose of cyclopenthiazide had a greater effect than the 125 g dose on plasma renin activity, serum potassium, angiotensin II levels and extracellular fluid volumes. Neither drug had any effect on plasma volume or the responsiveness to infused angiotensin II.Low dose cyclopenthiazide failed to increase angiotensin II levels, contract body fluid volumes or attenuate vascular reactivity in normotensive volunteers. 相似文献