全文获取类型
收费全文 | 28996篇 |
免费 | 1421篇 |
国内免费 | 188篇 |
专业分类
耳鼻咽喉 | 245篇 |
儿科学 | 459篇 |
妇产科学 | 465篇 |
基础医学 | 3678篇 |
口腔科学 | 623篇 |
临床医学 | 1903篇 |
内科学 | 7635篇 |
皮肤病学 | 450篇 |
神经病学 | 2276篇 |
特种医学 | 1072篇 |
外科学 | 4973篇 |
综合类 | 149篇 |
一般理论 | 1篇 |
预防医学 | 789篇 |
眼科学 | 655篇 |
药学 | 2120篇 |
中国医学 | 97篇 |
肿瘤学 | 3015篇 |
出版年
2023年 | 185篇 |
2022年 | 360篇 |
2021年 | 588篇 |
2020年 | 389篇 |
2019年 | 476篇 |
2018年 | 624篇 |
2017年 | 422篇 |
2016年 | 605篇 |
2015年 | 618篇 |
2014年 | 793篇 |
2013年 | 955篇 |
2012年 | 1617篇 |
2011年 | 1683篇 |
2010年 | 914篇 |
2009年 | 747篇 |
2008年 | 1415篇 |
2007年 | 1500篇 |
2006年 | 1365篇 |
2005年 | 1431篇 |
2004年 | 1449篇 |
2003年 | 1278篇 |
2002年 | 1351篇 |
2001年 | 884篇 |
2000年 | 893篇 |
1999年 | 829篇 |
1998年 | 354篇 |
1997年 | 285篇 |
1996年 | 235篇 |
1995年 | 217篇 |
1994年 | 221篇 |
1993年 | 183篇 |
1992年 | 566篇 |
1991年 | 490篇 |
1990年 | 485篇 |
1989年 | 489篇 |
1988年 | 445篇 |
1987年 | 375篇 |
1986年 | 366篇 |
1985年 | 368篇 |
1984年 | 267篇 |
1983年 | 202篇 |
1982年 | 90篇 |
1979年 | 172篇 |
1978年 | 126篇 |
1977年 | 125篇 |
1974年 | 92篇 |
1972年 | 89篇 |
1971年 | 95篇 |
1968年 | 95篇 |
1967年 | 90篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
91.
M Tsujii S Kawano S Tsuji K Nagano T Ito N Hayashi H Fusamoto T Kamada K Tamura 《Cancer letters》1992,65(1):15-18
Helicobacter pylori (HP) has been shown to possibly be a pathogen of gastric carcinoma. HP has urease activity and produces ammonia in the stomach. In this study, the role of ammonia on gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) were investigated in rats. After 24 weeks pretreatment with MNNG (83 mg/l), 0.01% ammonia or tap water as a drinking water was administered for 24 weeks. The ammonia-treated rats showed a significantly higher incidence of gastric cancer (percent of animals with tumors and number of tumors per rat). Ammonia would thus appear to have an important role in HP-related human gastric carcinogenesis. 相似文献
92.
Limited vertical skin incision for median sternotomy. 总被引:4,自引:0,他引:4
S Tatebe S Eguchi H Miyamura S Nakazawa H Watanabe M Sugawara J Hayashi K Date S Nakagawa 《The Annals of thoracic surgery》1992,54(4):787-788
The cosmetic deformity of the vertical skin incision for median sternotomy was decreased by using a mechanical traction system to increase exposure at the superior margin of a shorter wound. The limited vertical skin incision did not impede technical surgical maneuvers and produced a scar that was more acceptable than submammary incision or right anterior thoracotomy. The limited skin incision is especially useful in young women with congenital heart disease. 相似文献
93.
Mucoadhesive Microspheres Containing Amoxicillin for Clearance of Helicobacter pylori 总被引:5,自引:0,他引:5 下载免费PDF全文
Naoki Nagahara Yohko Akiyama Masafumi Nakao Mayumi Tada Megumi Kitano Yasuyuki Ogawa 《Antimicrobial agents and chemotherapy》1998,42(10):2492-2494
In an effort to augment the anti-Helicobacter pylori effect of amoxicillin, mucoadhesive microspheres, which have the ability to reside in the gastrointestinal tract for an extended period, were prepared. The microspheres contained the antimicrobial agent and an adhesive polymer (carboxyvinyl polymer) powder dispersed in waxy hydrogenated castor oil. The percentage of amoxicillin remaining in the stomach both 2 and 4 h after oral administration of the mucoadhesive microspheres to Mongolian gerbils under fed conditions was about three times higher than that after administration in the form of a 0.5% methylcellulose suspension. The in vivo clearance of H. pylori following oral administration of the mucoadhesive microspheres and the 0.5% methylcellulose suspension to infected Mongolian gerbils was examined under fed conditions. The mucoadhesive microspheres and the 0.5% methylcellulose suspension both showed anti-H. pylori effects in this experimental model of infection, but the required dose of amoxicillin was effectively reduced by a factor of 10 when the mucoadhesive microspheres were used. In conclusion, the mucoadhesive microspheres more effectively cleared H. pylori from the gastrointestinal tract than the 0.5% methylcellulose suspension due to the prolonged gastrointestinal residence time resulting from mucoadhesion. A dosage form consisting of mucoadhesive microspheres containing an appropriate antimicrobial agent should be useful for the eradication of H. pylori. 相似文献
94.
Mariko Kobayashi Yukihiro Takahashi Makoto Ando Naoki Wada Masamitsu Murata Toshio Kikuchi 《The Japanese Journal of Thoracic and Cardiovascular Surgery》2005,53(12):635-637
A 6 month-old male infant (weight: 4.5 kg) with congenital aortic stenosis underwent aortic valve replacement with a pulmonary
autograft (Ross procedure). The right ventricular outflow tract (RVOT) was reconstructed with a polytetrafluoroethylene (PTFE)-valved
equine pericardial conduit. At the age of 5, re-RVOT reconstruction with an equine pericardial patch bearing a PTFE monocusp
was required because of severe pulmonary stenosis resistant to 2 attempts of percutaneous transluminal pulmonary valvotomy.
Currently, at the age of 8, the degree of aortic regurgitation is trivial and the pulmonary autograft is free of functional
deterioration despite somatic growth. 相似文献
95.
M Kageyama Y Matsumura K Hayashi T Hosokawa S Morimoto 《Japanese journal of pharmacology》1990,52(2):245-253
Inhibitory effects of the calcium channel blocker nisoldipine on angiotensin II-induced antidiuresis were investigated in anesthetized dogs, and the findings were compared with those of saralasin. Intrarenal arterial infusion of 10 ng/kg/min angiotensin II resulted in marked decreases in renal blood flow (RBF) and urine formation, with a relatively moderate decrease in glomerular filtration rate. There were marked reductions in the fractional excretion of lithium, which is used as an index of the fractional proximal excretion of sodium, and the fractional distal excretion of sodium. Nisoldipine (50 ng/kg/min) administered intrarenally produced a partial inhibition on the decreased response of RBF to angiotensin II. The peptide-induced decreases in urine flow, urinary excretion of electrolytes and fractional excretion of electrolytes were abolished by nisoldipine. In contrast, when saralasin was administered intrarenally at 10 ng/kg/min, a dose which could partially inhibit the angiotensin II-induced decrease in RBF to the same extent as seen with nisoldipine, the antagonist attenuated, but did not abolish, the antidiuretic action of angiotensin II. Significant decreases in urine formation by angiotensin II were observed, even in the presence of saralasin. These results suggest that nisoldipine, unlike saralasin, preferentially interferes with the stimulatory effect of angiotensin II, as related to the renal tubular reabsorption of sodium and water. 相似文献
96.
Naoki Hori Hakuo Takahashi‡ Takeshi Okanoue Yoshihiko Sawa Takashi Mori Shiro Takami Manabu Yoshimura† Kei Kashima 《Clinical and experimental pharmacology & physiology》1995,22(8):506-511
1. Endothelium-derived nitric oxide (NO) is a potent vasodilator. Because the body oxidizes it to nitrate ions, NO3-, measurement of the serum concentration and the urinary excretion of NO3- may be an index for endogenous NO. We investigated the role of NO on hyperdynamic circulation in cirrhotic and partial portal vein-ligated rats by measuring NO3. 2. Liver cirrhosis was induced by administration of thioacetamide. Systemic and splanchnic haemodynamics and splenic-systemic shunting were determined by tracer microspheres. The concentration of NO3- was measured by using high-performance liquid chromatography with an anion-column. 3. We found that systemic and splanchnic hyperdynamic circulation existed to almost the same extent in cirrhotic and in portal vein-ligated rats as compared to the controls and sham-operated rats, respectively. Splenic-systemic shunting was markedly greater in portal vein-ligated rats than in cirrhotic rats. 4. Serum NO3- levels and urinary excretion of NO3- in cirrhotic rats tended to increase as compared to the controls. On the other hand, the levels in portal vein-ligated rats were significantly increased as compared to those of the sham-operated rats, and were significantly and negatively correlated to the splanchnic arterial resistance and total vascular resistance. The amount of urinary excretion of NO3- significantly correlated to splenic-systemic shunting (r = 0.61, P<0.05) only in portal vein-ligated rats. 5. We suggest that these high levels of NO3- in portal vein-ligated rats relate to the extensive formation of porto-collateral vasculature or acute changes in systemic and splanchnic haemodynamics due to portal vein-ligation. 相似文献
97.
K. Kawabe K. Goto I. Nishino C. Angelini Y. K. Hayashi 《European journal of neurology》2004,11(10):657-661
Mutations in the dysferlin gene (DYSF) on chromosome 2p13 cause distinct phenotypes of muscular dystrophy: limb-girdle muscular dystrophy type 2B (LGMD2B), Miyoshi myopathy (MM), and distal anterior compartment myopathy, which are known by the term 'dysferlinopathy'. We performed mutation analyses of DYSF in 14 Italian patients from 10 unrelated families with a deficiency of dysferlin protein below 20% of the value in normal controls by immunoblotting analysis. We identified 11 different mutations, including eight missense and three deletion mutations. Nine of them were novel mutations. We also identified a unique 6-bp insertion polymorphism within the coding region of DYSF in 15% of Italian population, which was not observed in East Asian populations. The correlation between clinical phenotype and the gene mutations was unclear, which suggested the role of additional genetic and epigenetic factors in modifying clinical symptoms. 相似文献
98.
99.
100.
Both goldthioglucose (GTG)-treated and the genetically obese (C57BL/6J ob/ob) mice were fed semisynthetic diets containing either soy protein isolate (SPI) or casein as a protein source, or laboratory chow. In GTG-induced obese mice, the plasma cholesterol level correlated positively with their body weight. The level was highest in mice fed high-fat diet, and lowest in ones fed laboratory chow. No difference was observed between SPI and casein groups whether the diet was low-fat or high-fat. Thus, in the GTG-treated mice, SPI did not have a hypocholesterolemic effect while dietary fat had a hypercholesterolemic effect, and laboratory chow contained some component(s) which can lower the plasma cholesterol level. Both neutral and acidic steroid contents in feces of the SPI group were not different from those of the casein group, and both groups of mice excreted a smaller amount of steroids than mice fed laboratory chow. Results of essentially the same tendency were obtained with normal mice regarding the effects of SPI and casein, although the degree of hypercholesterolemia was lower in high-fat-fed normal mice than in similarly fed GTG-treated mice. These results strengthened the inverse correlation between the amount of fecal steroids and the plasma cholesterol level upon feeding various proteins, indicating that the former is one of the important factors that determine the latter. The ob/ob mice showed a marked hypercholesterolemia irrespective of the kind of diet. The amount of fecal steroids was highest in the laboratory chow group and lowest in the casein group. This indicates that some factor(s) other than fecal steroid excretion is dominantly responsible for their hypercholesterolemia. 相似文献