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   1515篇
  免费   133篇
  国内免费   8篇
耳鼻咽喉   2篇
儿科学   54篇
妇产科学   20篇
基础医学   157篇
口腔科学   38篇
临床医学   197篇
内科学   305篇
皮肤病学   28篇
神经病学   115篇
特种医学   148篇
外科学   162篇
综合类   93篇
一般理论   2篇
预防医学   84篇
眼科学   94篇
药学   91篇
  1篇
中国医学   1篇
肿瘤学   64篇
  2020年   12篇
  2019年   15篇
  2018年   26篇
  2017年   17篇
  2016年   26篇
  2015年   30篇
  2014年   43篇
  2013年   66篇
  2012年   49篇
  2011年   54篇
  2010年   38篇
  2009年   58篇
  2008年   54篇
  2007年   39篇
  2006年   70篇
  2005年   26篇
  2004年   44篇
  2003年   48篇
  2002年   44篇
  2001年   22篇
  2000年   20篇
  1999年   20篇
  1998年   40篇
  1997年   56篇
  1996年   52篇
  1995年   37篇
  1994年   39篇
  1993年   45篇
  1992年   39篇
  1991年   25篇
  1990年   23篇
  1989年   28篇
  1988年   32篇
  1987年   30篇
  1986年   25篇
  1985年   20篇
  1984年   30篇
  1983年   15篇
  1982年   27篇
  1981年   18篇
  1980年   16篇
  1979年   29篇
  1978年   21篇
  1977年   16篇
  1976年   21篇
  1975年   19篇
  1974年   12篇
  1973年   13篇
  1971年   14篇
  1967年   15篇
排序方式: 共有1656条查询结果,搜索用时 15 毫秒
1.
2.
3.
We report the results of administration of danazol after suspension of gonadotrophin-releasing hormone analogue (GnRHa) therapy for uterine myomas. A total of 21 women with uterine myomas was treated with 100 mg danazol for 6 months after GnRHa therapy. Uterine volume and endocrine status were monitored monthly by ultrasound and assay of plasma gonadotrophins, oestradiol and progesterone. The results show a rebound of uterine volume about 30% less than in controls at the end of danazol therapy. Menstrual cyclicity returned after 65 +/- 3 days in 16 subjects and five patients remained amenorrhoeic. Hormone assays confirmed renewed ovarian function in the women whose menstrual periods returned. Bone mineral content was substantially reduced during GnRHa treatment but improved significantly during danazol therapy even in the women who remained amenorrhoeic. These results show the utility of danazol in prolonging the therapeutic effects of GnRHa. The mechanism by which danazol inhibits rebound of uterine volume may be due to its antiprogesterone effects on uterine myomas.   相似文献   
4.
5.
Eighty-two women with complaints of moderate to severe premenstrual symptoms were recruited for a double-blind, controlled trial of a triphasic oral contraceptive (o.c.). Subjects made daily ratings of symptoms for at least one baseline cycle and were then randomly assigned to receive either placebo or o.c. for three months. Twenty-three women dropped out of the study (18 o.c., 5 placebo), 13 failed to show prospective confirmation of moderate to severe premenstrual symptoms, and one placebo subject had an anovulatory cycle. Forty-five women with prospectively-confirmed premenstrual changes (20 o.c., 25 placebo) completed the study. Premenstrual breast pain and bloating were significantly reduced with active treatment compared to placebo (p less than 0.03) but there were no beneficial effects of the o.c. over placebo for any of the mood symptoms. Women who received o.c.s reported decreased sexual interest after starting treatment and this effect was independent of any adverse influence on mood.  相似文献   
6.
7.
Prior studies have shown that pneumothorax is one of the more difficult entities to diagnose with digitized radiography. This study was designed to test whether increasing resolution from 1.25 to 2.5 line pairs per millimeter (lp/mm) and image processing (edge enhancement from unsharp masking) would increase accuracy and confidence in the diagnosis of pneumothorax, as well as normal cases and other forms of lung disease. Conventional radiographs were digitized with use of a laser reader and then reformatted as film hard copy. Eleven observers read 35 cases reformatted in three different ways (1.25 lp/mm, 2.5 lp/mm, 1.25 lp/mm unsharp mask). The images with finer resolution (2.5 lp/mm) and unsharp mask images were superior to those with coarser resolution (1.25 lp/mm) for the diagnosis of pneumothorax. There was no difference in diagnostic accuracy for normal patients. For abnormalities other than pneumothorax, the unsharp mask images were significantly worse. Confidence in the diagnosis of pneumothorax and other abnormalities was highest with the finest resolution (2.5 lp/mm).  相似文献   
8.
The authors review the detrimental effects of cigarette smoke and its constituents to normal physiology. Nicotine and carbon monoxide, principle components of cigarette smoke appear to exert an influence on wound repair by inhibiting epithelization, damaging blood cellular components, and creating a cellular hypoxia. Recommendations for perioperative cessation of smoking by the patient are made.  相似文献   
9.
The authors report the clinical and laboratory findings of a patient who had severe immune hemolytic anemia due to hydrochlorothiazide (HCTZ). In this case, the HCTZ antibody reacted not only with other thiazide and thiazide-like drugs, but also with a chemically unrelated diuretic, ethacrynic acid. These results indicate that HCTZ antibody activity is not restricted solely to the thiazides and imply that therapy with any of the reactive drugs would be contraindicated for this patient. The serologic screening for drug reactivity may be useful for selecting alternative therapy for patients with drug-induced immune hemolytic anemia.  相似文献   
10.
Fiala  ES; Sohn  OS; Li  H; El-Bayoumy  K; Sodum  RS 《Carcinogenesis》1997,18(9):1809-1815
We observed that pretreatment of male F344 rats with benzyl selenocyanate, a versatile organoselenium chemopreventive agent in several animal model systems, decreases the levels of DNA and RNA modifications produced in the liver by the hepatocarcinogen 2- nitropropane. To clarify the mechanisms involved, we pretreated male F344 rats with either benzyl selenocyanate, its sulfur analog benzyl thiocyanate, phenobarbital or cobalt protoporphyrin IX; the latter is a depletor of P450. We then determined (1) the ability of liver microsomes to denitrify 2-nitropropane, (2) effects on 2-nitropropane- induced liver DNA and RNA modifications and (3) amount of nitrate excreted in rat urine following administration of the carcinogen. Pretreatment with benzyl selenocyanate or phenobarbital increased the denitrification activity of liver microsomes by 217 and 765%, respectively, increased liver P4502B1 by 31- and 435-fold, respectively, decreased the levels of 2-nitropropane-induced modifications in liver DNA (29-70% and 17-30%, respectively) and RNA (67-85% and 30-50%, respectively), and increased the 24-h urinary excretion of nitrate by 157 and 209%, respectively. Pretreatment with benzyl thiocyanate had no significant effect on any of these parameters. Pretreatment with cobalt protoporphyrin IX decreased liver P4502B 1 by 87%, decreased the denitrification activity of liver microsomes by 76%, decreased the 24 h urinary excretion of nitrate by 88.5%, but increased the extent of 2-nitropropane-induced liver nucleic acid modifications by 17-67%. These results indicate that the metabolic sequence from 2-nitropropane to the reactive species causing DNA and RNA modifications does not involve the removal of the nitro group. Moreover, they suggest that benzyl selenocyanate inhibits 2-NP-induced liver nucleic acid modifications in part by increasing its detoxication through induction of denitrification, although it is evident that other mechanisms must also be involved.   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