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   2517176篇
  免费   176023篇
  国内免费   3315篇
耳鼻咽喉   33260篇
儿科学   82401篇
妇产科学   65824篇
基础医学   365249篇
口腔科学   65200篇
临床医学   222977篇
内科学   487084篇
皮肤病学   52496篇
神经病学   200776篇
特种医学   96693篇
外国民族医学   489篇
外科学   383302篇
综合类   50119篇
现状与发展   12篇
一般理论   857篇
预防医学   199321篇
眼科学   56922篇
药学   184078篇
  10篇
中国医学   5200篇
肿瘤学   144244篇
  2021年   19035篇
  2019年   19607篇
  2018年   47408篇
  2017年   36608篇
  2016年   41794篇
  2015年   26570篇
  2014年   36877篇
  2013年   54685篇
  2012年   81074篇
  2011年   98936篇
  2010年   64065篇
  2009年   55511篇
  2008年   93291篇
  2007年   101069篇
  2006年   80889篇
  2005年   80169篇
  2004年   78382篇
  2003年   77150篇
  2002年   72804篇
  2001年   109150篇
  2000年   112153篇
  1999年   93767篇
  1998年   27261篇
  1997年   24002篇
  1996年   24218篇
  1995年   22893篇
  1994年   21091篇
  1993年   19862篇
  1992年   72135篇
  1991年   70249篇
  1990年   68580篇
  1989年   65784篇
  1988年   60421篇
  1987年   59244篇
  1986年   55329篇
  1985年   53127篇
  1984年   39387篇
  1983年   33476篇
  1982年   19965篇
  1979年   35977篇
  1978年   25725篇
  1977年   21258篇
  1976年   20412篇
  1975年   21832篇
  1974年   26200篇
  1973年   24823篇
  1972年   23216篇
  1971年   22049篇
  1970年   20294篇
  1969年   19366篇
排序方式: 共有10000条查询结果,搜索用时 240 毫秒
991.
992.
Herpes zoster probably occurs more often than generally thought. Since it produces a radicular distribution of pain, it should be included in the differential diagnosis of radiculopathy. A case is presented in which evaluating the radicular low back pain before the characteristic rash appears was misleading. Careful history-taking concerning the exact nature of the pain and sensory changes is needed to differentiate between zoster and radiculopathy, if no rash is evident.  相似文献   
993.
994.
995.
Eledoisin has been tried as a possible treatment for dry eye based on the hypothesis that it pharmacologically stimulates tear secretion when topically applied to the eye. To determine if topically applied eledoisin pharmacologically stimulates orbital lacrimal secretion, the orbital lacrimal gland excretory duct of normal rabbits was cannulated, and eledoisin was applied topically with and without prior administration of proparacaine. To determine if topically applied eledoisin stimulated accessory lacrimal gland secretion, isotonic buffer with and without eledoisin was tested in a rabbit model with only accessory lacrimal tissue remaining after the administration of proparacaine. Topically applied eledoisin did not pharmacologically stimulate lacrimal secretion but rather increased lacrimal gland secretion only in non-anesthetized eyes through a sensory reflex mechanism that is blocked by proparacaine.  相似文献   
996.
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   
997.
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   
998.
Four hundred and twenty-three alcohol dependent subjects were enrolled into a 12-week randomized, double-blind, placebo-controlled study to determine the safety and efficacy of the 5-HT2 receptor antagonist, ritanserin (2.5 mg/day or 5 mg/day), in reducing alcohol intake and craving. All subjects received 1 week of single-blind placebo prior to randomization into the 11-week double-blind phase. Additionally, all subjects received weekly individual sessions of manual-guided cognitive-behavioral therapy. Comparing the single-blind period with endpoint, there was approximately a 23% reduction in drinks/day; 34% fall in the total number of drinking days/week; 22% decrease in drinks/drinking day; and a 37% diminution in alcohol craving for all treatment groups. All treatment groups experienced a beneficial clinical outcome as assessed by the Clinical Global Impression Scale. There was, however, no significant difference between treatment groups on any of these measures of alcohol drinking, craving, or clinical outcome. Subjects were of relatively high social functioning at baseline, and this did not change significantly during treatment. Treatment groups did not differ significantly on either medication compliance or reported adverse events. Ritanserin treatment was associated with a dose-related prolongation of subjects’ QTc interval recording on the electrocardiogram. These results suggest that alcohol dependent subjects can show marked clinical improvement within a structured alcohol treatment program. These findings do not support an important role for ritanserin in the treatment of alcohol dependence. Received: 30 April 1996/Final version: 3 July 1996  相似文献   
999.
OBJECTIVE. This article compares judgments about the treatment of Dukes' B2 and C colon cancer made by general surgeons to those of internists and family practitioners. Physician and practice variables were specialty, affiliation with a Community Clinical Oncology Program (CCOP) hospital, time in practice, professional centrality (level of participation in cancer information networks), solo practice, and number of colon cancer patients. DATA COLLECTION METHODS. Data are combined from national probability samples of CCOP- and non-CCOP-affiliated physicians. This study focused on 1,138 internists, family physicians, and general surgeons who participated in decision making for patients diagnosed with Dukes' B2 or C stage colon cancer. Judgments were elicited using brief vignettes. METHODS OF ANALYSIS. Judgments of adjuvant therapy are classified as (a) consistent with the National Institutes of Health Consensus Conference recommendations (experimental for Dukes' B2, accepted for Dukes' C); (b) accepted treatment for both stages; or (c) experimental for both stages. Multinomial logit analyses were used to examine the association of practice setting and physician characteristics to judgments of treatment. RESULTS. Surgeons and CCOP-affiliated physicians were more likely to endorse the NIH consensus conference position. Surgeons, younger physicians, and those in group practice were more likely to approve of chemotherapy for both cancer stages. The most common position (chemotherapy experimental) was more likely from nonsurgeons, solo practitioners, and non-CCOP physicians. CONCLUSION. Physician and practice setting characteristics, including organized structures such as the CCOP, are possible mediating structures that can facilitate dissemination of standards of treatment.  相似文献   
1000.
1. The effects of a novel and selective agonist at the endothelin ETB receptor, IRL 1620 (Suc-[Glu9, Ala11,15] endothelin-1 (8-21)), were examined in the isolated aorta of the rat. 2. IRL 1620 (1-300 nM) changed neither the resting tone nor the cytosolic Ca2+ level ([Ca2+]i) of the aorta without endothelium. In the presence of endothelium, however, IRL 1620 increased endothelial [Ca2+]i with little effect on the muscle tone. In the absence of external Ca2+, IRL 1620 still induced a transient increase in endothelial [Ca2+]i. 3. Noradrenaline (100 nM) increased both muscle [Ca2+]i and tension. IRL 1620 (1-300 nM) relaxed the muscle with an increase in endothelial [Ca2+]i only in the presence of endothelium. An inhibitor of nitric oxide synthase, 100 microM NG-monomethyl-L-arginine, inhibited the relaxant effect of IRL 1620 but not the increase in endothelial [Ca2+]i. 4. In resting and noradrenaline-stimulated aorta, the effects of IRL 1620 were inhibited by a selective antagonist of the ETB receptor, IRL 1038 (0.3-3 microM), although a selective antagonist of the ETA receptor, BQ-123 (3 microM), was ineffective. Verapamil (10 microM) did not alter the effects of IRL 1620. 5. A muscarinic receptor agonist, carbachol (1 microM), also induced endothelium-dependent relaxation with an increase in endothelial [Ca2+]i. However, the effects of carbachol were not inhibited by the ETB antagonist, IRL 1038 (3 microM).(ABSTRACT TRUNCATED AT 250 WORDS)  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