首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1005503篇
  免费   76244篇
  国内免费   2647篇
耳鼻咽喉   13051篇
儿科学   34828篇
妇产科学   28596篇
基础医学   146067篇
口腔科学   27778篇
临床医学   92065篇
内科学   195500篇
皮肤病学   23014篇
神经病学   79845篇
特种医学   38484篇
外国民族医学   305篇
外科学   150142篇
综合类   23819篇
一般理论   390篇
预防医学   78939篇
眼科学   22716篇
药学   72260篇
  3篇
中国医学   2035篇
肿瘤学   54557篇
  2018年   10835篇
  2017年   8518篇
  2016年   9626篇
  2015年   10872篇
  2014年   14792篇
  2013年   22479篇
  2012年   29445篇
  2011年   31295篇
  2010年   18872篇
  2009年   17856篇
  2008年   29251篇
  2007年   30941篇
  2006年   31465篇
  2005年   30136篇
  2004年   29368篇
  2003年   28285篇
  2002年   27267篇
  2001年   47003篇
  2000年   48122篇
  1999年   40357篇
  1998年   11298篇
  1997年   10190篇
  1996年   10254篇
  1995年   9851篇
  1994年   9148篇
  1993年   8543篇
  1992年   32283篇
  1991年   31502篇
  1990年   31039篇
  1989年   29908篇
  1988年   27199篇
  1987年   27359篇
  1986年   25457篇
  1985年   24629篇
  1984年   18428篇
  1983年   15551篇
  1982年   9312篇
  1981年   8400篇
  1979年   16873篇
  1978年   12234篇
  1977年   10327篇
  1976年   9772篇
  1975年   10183篇
  1974年   12323篇
  1973年   11853篇
  1972年   10890篇
  1971年   10115篇
  1970年   9379篇
  1969年   8727篇
  1968年   8106篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
Recurrent erosion   总被引:1,自引:0,他引:1  
  相似文献   
102.
Chorioretinal folds have been reported as a result of many intraocular and extraocular inflammatory processes or tumors. Visual loss is usually secondary to a combination of the underlying process and chorioretinal folds involving the macula. We report a patient who developed decreased vision, metamorphopsia, chorioretinal folds, and a lamellar macular hole secondary to global compression by a bone fragment. The chorioretinal folds regressed and his vision stabilized following surgical decompression. Chorioretinal folds and lamellar macular hold formation are previously unrecognized complications of reconstructive craniofacial surgery.  相似文献   
103.
Summary We conducted a phase I clinical study of aziridinylbenzoquinone (Diaziquone, AZQ) given as a 4 hour infusion weekly × 4. Forty-five children with recurrent acute leukemia and 33 children with various advanced solid tumors participated. Severe myelosuppression was the dose limiting toxic effect, occurring in all patients at the upper dose levels. Gastrointestinal and hepatic toxicities were infrequent and not severe. No allergic reactions occurred. Objective tumor regression was noted in 3 of 25 patients with a CNS tumor and in 6 of 45 patients with acute leukemia. For phase II trials the recommended dosage of Diaziquone given by this schedule is 18 mg/M2×4 for patients with a solid tumor, and is 30 mg/M2/week × 4 for children with acute leukemia.  相似文献   
104.
N-3 fatty acid deficiency is described in a 7-year-old girl who had been fed solely by gastric tube from the age of 3 years. She had received the same nutrient during the last 22 months, supplying 16.2% of calories from linoleate and 0.07% from alpha-linolenate. She weighed 9.5 kg at the age of 3, and 10.3 kg at the start of the study, the weight being constant the last 15 months. She was now supplemented daily with 1.2 ml of a linseed- and cod liver-oil mixture (5:1, v/v), thereby increasing her alpha-linolenate intake to 0.71% and total N-3 fatty acids to 0.74% of total energy. Two months later, her rate of weight gain was 0.43 kg/month. After 5 months, the fatty acid supplement was changed to 7.5 ml of cod liver oil daily, thereby changing alpha-linolenate and total N-3 acid intake to 0.10% and 1.3% of total energy, respectively. Her rate of weight gain now increased to 0.64 kg/month, and her length increased from 117 to 122 cm in 5 months. The results indicate that the optimal dietary requirement for N-3 fatty acids in this child is higher than 0.74%, and extrapolation estimated the optimal requirement to be 1.1%-1.2% of total calories. The results suggest that N-3 fatty acids are required for normal growth in man.  相似文献   
105.
106.
107.
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   
108.
The composition of the clientele from an ophthalmological practitioner's office is described with special reference to the occurrence of glaucoma and disc haemorrhages (h in singular; hh in plural). This study could not be planned as an epidemiological survey and gives no clue to sensitivity or specificity of hh in glaucoma. During a period of about 10 years ending with 1986 there were 731 patients with h and/or glaucoma. When detected, 185 patients had h but no glaucoma, 33 had both h and glaucoma and 513 had glaucoma but no h. During the follow-up period hh were detected in 83 cases of glaucoma, and glaucoma developed in 27 cases with hh. The detection rate of hh among glaucoma was low but steady, indicating that hh may occur at any stage of the glaucoma process. This study shows no predilection for hh in cases with general hypertension or diabetes, nor is the frequency of hh among pseudoexfoliation cases significantly lower than among cases without this stigma.  相似文献   
109.
Isotretinoin (Accutane Capsules) is a synthetic vitamin A compound used for treatment of recalcitrant cystic acne. It has numerous ocular toxic side effects which include anterior segment inflammation, dry eye syndrome, contact lens intolerance, altered refraction, photosensitivity, and reduced night vision. Eye care practitioners should be aware of these potential side effects and be prepared to communicate with the prescribing physician if side effects present.  相似文献   
110.
Although extracellular matrix (ECM) glycoproteins play important roles in neural development, their levels are generally believed to decrease in the adult brain. Immunohistochemical analysis indicates that the anti-adhesive ECM glycoprotein SPARC/osteonectin, which contains a follistatin ‘module’, is expressed in the adult rabbit nervous system. In the cerebellum, SPARC is present in Bergmann glia, with a strong signal along their radial fibres. SPARC, while enriched in membrane fractions, is not a transmembrane protein. In the hippocampus, colocalization of SPARC is observed in cells which express the astrocytic marker GFAP. The expression of SPARC by a subset of astrocytes, particularly in synaptic enriched areas, suggests a continuing role for the ECM in the adult brain.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号