全文获取类型
收费全文 | 717147篇 |
免费 | 50155篇 |
国内免费 | 1320篇 |
专业分类
耳鼻咽喉 | 9282篇 |
儿科学 | 23604篇 |
妇产科学 | 17831篇 |
基础医学 | 112238篇 |
口腔科学 | 20194篇 |
临床医学 | 65178篇 |
内科学 | 136424篇 |
皮肤病学 | 16377篇 |
神经病学 | 50365篇 |
特种医学 | 26105篇 |
外国民族医学 | 76篇 |
外科学 | 105963篇 |
综合类 | 15106篇 |
现状与发展 | 2篇 |
一般理论 | 176篇 |
预防医学 | 52761篇 |
眼科学 | 16456篇 |
药学 | 54875篇 |
3篇 | |
中国医学 | 2362篇 |
肿瘤学 | 43244篇 |
出版年
2021年 | 5618篇 |
2018年 | 8052篇 |
2017年 | 6249篇 |
2016年 | 7003篇 |
2015年 | 7738篇 |
2014年 | 10519篇 |
2013年 | 15766篇 |
2012年 | 21002篇 |
2011年 | 22029篇 |
2010年 | 13003篇 |
2009年 | 12224篇 |
2008年 | 20476篇 |
2007年 | 21991篇 |
2006年 | 22402篇 |
2005年 | 20924篇 |
2004年 | 20474篇 |
2003年 | 19372篇 |
2002年 | 18844篇 |
2001年 | 36652篇 |
2000年 | 37247篇 |
1999年 | 30687篇 |
1998年 | 8019篇 |
1997年 | 6778篇 |
1996年 | 7076篇 |
1995年 | 6723篇 |
1994年 | 6192篇 |
1993年 | 5688篇 |
1992年 | 23201篇 |
1991年 | 23185篇 |
1990年 | 22546篇 |
1989年 | 22308篇 |
1988年 | 20247篇 |
1987年 | 19618篇 |
1986年 | 18655篇 |
1985年 | 17493篇 |
1984年 | 12867篇 |
1983年 | 10880篇 |
1982年 | 6017篇 |
1979年 | 11668篇 |
1978年 | 8276篇 |
1977年 | 6949篇 |
1976年 | 6699篇 |
1975年 | 7364篇 |
1974年 | 8626篇 |
1973年 | 8261篇 |
1972年 | 7751篇 |
1971年 | 7220篇 |
1970年 | 6960篇 |
1969年 | 6393篇 |
1968年 | 5852篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
102.
103.
104.
105.
Mice killed shortly after receiving c. 2000 spores of a type E strain of Clostridium botulinum per os were incubated at one of five chosen temperatures together with bottles of cooked meat medium seeded with a similar inoculum. After incubation the rotting carcasses were homogenized. Sterile membrane filtrates of the homogenates (10%, w/v) and pure cultures were then titrated for toxicity. Some of the main findings were confirmed with two further type E strains. Toxicity produced at 37 degrees C was poor in both carcasses and cultures (200-20,000 mouse intraperitoneal LD/g or ml). It was good in both systems at 30 and 23 degrees C, usually reaching 20,000-200,000 LD/g or ml, and in carcasses occasionally more; at 30 degrees C maximal toxicity was reached more quickly in carcasses than in cultures. Prolonged incubation (36-118 days) at 30 or 23 degrees C resulted in complete loss of toxicity in virtually all carcasses but not in cultures. At 16 degrees C the development of toxicity in carcasses was strikingly greater than in cultures. At 9 degrees C neither system produced more than slight toxicity after prolonged incubation. Trypsinization increased the toxicity of cultures but not usually of carcasses. Unfiltered carcass homogenate (10%, w/v) with maximal intraperitoneal toxicity was harmless for mice by mouth in doses of 0.25 ml. These findings differed in important respects from those made earlier with a type C strain. 相似文献
106.
J. Kralovanszky N. Prajda S. Kerpel-Fronius T. Bagrij E. Kiss G. J. Peters 《Cancer chemotherapy and pharmacology》1993,32(3):243-248
Selective protection of the normal host tissues from the toxic effects of anticancer agents would allow the use of higher, probably more effective, doses of the drugs. It has been demonstrated that delayed high-dose uridine administration after 5-fluorouracil decreases the extent of myelosuppression and causes faster regeneration of the bone marrow. We studied the biochemical consequences of the gastrointestinal toxicity caused by 5-fluorouracil and the potential of high-dose uridine treatment to influence these adverse effects. 5-Fluorouracil caused dose-related decreases in the biochemical parameters (thymidine kinase, sucrase, maltase, alkaline phosphatase) selected as early markers of the impaired metabolic activity of the intestinal mucosa. The nadir of the biochemical changes was reached between 24 h and 72 h after 5-fluorouracil treatment, and complete regeneration of the mucosa took 6–7 days. Delayed high-dose uridine administration failed to mitigate the severity of the gastrointestinal damage that ensued after 5-fluorouracil treatment, but caused significantly earlier regeneration of the mucosa. 相似文献
107.
In 82 CHD male patients aged 35-54 years with well-preserved working capacity (threshold load, 600-750 kgm/min) who had underwent bicycle ergometer test, the time course of changes in the major hemodynamic parameters was found to be significantly similar to that of healthy individuals. The cases who stopped performing bicycle ergometer tests because of anginal attacks, and ST segment depression or either showed a more significant elevation in systolic and diastolic blood pressure at the maximum load rate and lower increase in heart rate than in healthy subjects, which may be regarded as a compensatory mechanism that prevents a further decrease in coronary flow. Diminished increase in stroke index and cardiac index suggests reduced myocardial contractility. 相似文献
108.
M D Silverstein D A Albert N M Hadler M W Ropes 《Journal of clinical epidemiology》1988,41(7):623-633
109.
SRIVASTAVA Z. I.; MATHUR N.; RASTOGI S. K.; GUPTA B. N. 《Occupational medicine (Oxford, England)》1988,38(4):134-136
Eighty-nine cases of chronic bronchitis were matched against167 asymptomatic controls from the glass bangle industry ofFirozabad. Factors of age, social status, smoking habit andduration of exposure were studied. Duration of exposure wasfound to be a factor contributing significantly to the causationof disease.
Requests for reprints should be addressed to: Dr B. N. Gupta, Division of Epidemilogy, Industrial Toxicology Research Centre, Mahatma Gandhi Marg, Lucknow P.O. Box 80, 226001, India 相似文献
110.