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   10617篇
  免费   874篇
  国内免费   19篇
耳鼻咽喉   106篇
儿科学   218篇
妇产科学   266篇
基础医学   1640篇
口腔科学   184篇
临床医学   1084篇
内科学   2231篇
皮肤病学   143篇
神经病学   1569篇
特种医学   299篇
外科学   1379篇
综合类   149篇
现状与发展   1篇
一般理论   7篇
预防医学   813篇
眼科学   161篇
药学   701篇
中国医学   10篇
肿瘤学   549篇
  2021年   159篇
  2020年   101篇
  2019年   136篇
  2018年   208篇
  2017年   147篇
  2016年   185篇
  2015年   202篇
  2014年   270篇
  2013年   433篇
  2012年   611篇
  2011年   630篇
  2010年   324篇
  2009年   316篇
  2008年   523篇
  2007年   555篇
  2006年   548篇
  2005年   533篇
  2004年   466篇
  2003年   468篇
  2002年   508篇
  2001年   206篇
  2000年   194篇
  1999年   176篇
  1998年   133篇
  1997年   109篇
  1996年   92篇
  1995年   90篇
  1994年   85篇
  1993年   95篇
  1992年   123篇
  1991年   134篇
  1990年   123篇
  1989年   107篇
  1988年   113篇
  1987年   98篇
  1986年   107篇
  1985年   101篇
  1984年   105篇
  1983年   117篇
  1982年   126篇
  1981年   122篇
  1980年   109篇
  1979年   112篇
  1978年   106篇
  1977年   105篇
  1976年   84篇
  1975年   66篇
  1974年   71篇
  1973年   77篇
  1972年   83篇
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
21.
We present a case of volar luxation of the scaphotrapezial bone, in which radiographs suggested luxation of the scaphoid, but unclear relations to the other carpal bones. Computer tomographic reconstruction showed an isolated scaphotrapezial luxation. This was treated by closed reduction and a plaster cast, after which the patient regained normal function of her wrist.  相似文献   
22.
23.
During the development of a silicone rubber implant for the delivery of estradiol 17-beta some batches of implants made from a certain lot of commercial estradiol inexplicably developed surface crystals of estradiol after several days of storage. An impurity profile was obtained for 28 lots of estradiol by a newly developed HPLC method. One or more impurities may have had a role in the spontaneous crystal growth on the surface of the implants, because the one lot of estradiol that initially had surface crystals on aging produced acceptable implants after multiple recrystallizations. Attempts to isolate suspected impurities for characterization were unsuccessful. During the manufacture of the implants, temperatures sufficient to melt the estradiol (mp, 173-179 degrees C) were used. It was expected that, upon implant cooling, melted impure estradiol would form a thermodynamically more active (i.e., noncrystalline) physical form. This metastable form could have migrated to the implant surface, where ambient conditions favored crystallization. Because melted estradiol of a higher purity tended to crystallize more readily, it was less likely to form a glass upon cooling. The phenomenon of surface crystallization was limited to one lot of estradiol with the highest level of impurities. Data from differential scanning calorimetry studies supported this conclusion.  相似文献   
24.
18 patients (20 knee joints) were operated for Osgood-Schlatter disease. 12 patients (14 knee joints) had a follow-up of 2.4 years (0.5-13.5) after operation. The informations of the other patients were taken from our clinical data. 1 month (0.5-24) after operation 13 patients (15 knee joints) were painfree. In 5 cases there were still complaints, but 3 of them were improved by operation. One patient, who was operated on both knees, had no change after operation. The failures are analysed and interpreted concerning their pathogenesis. With help of our results the different operation methods of the literature are discussed.  相似文献   
25.
26.
Summary A 3-year-old boy developed several subcutaneous nodular lesions on his right arm. Based on the histological examination of one of these nodules furunculosis was suspected and cefuroxime was tentatively given. However, acid-fast bacilli were then detected in the tissue specimen and a few colonies of acid fast, gram-positive rods grew on blood agar. Definitive species diagnosis (Mycobacterium marinum) was rapidly achieved by automated sequencing of amplified 16S-rDNA and antimicrobial therapy was adjusted according to the available literature. After 3 weeks of treatment with clarithromycin, rifampicin and protionamid regression of the nodular lesions was evident.
Infektion der oberen Extremität durchMycobacterium marinum — Diagnose mit Hilfe von 16S-rDNA Analyse
Zusammenfassung Wir berichten von einem 3-jährigen Jungen, der verschiedene subkutane Knoten im rechten Arm entwickelte. Nach histologischer Untersuchung wurde zunächst der Verdacht auf Furunkulose geäußert und eine vorläufige Therapie mit Cefuroxim begonnen. Es wurden dann jedoch säurefeste Stäbchen im entnommenen Gewebe nachgewiesen und eine Woche später auf Blutagar grampositive, säurefeste Stäbchen angezüchtet. Die definitive Speziesdiagnose (Mycobacterium marinum) wurde rasch mit automatischer 16S-rDNA Sequenzbestimmung erzielt und die Therapie entsprechend der verfügbaren Literatur korrigiert. Nach drei Wochen einer Behandlung mit Clarithromycin, Rifampicin und Protionamid war ein Rückgang der subkutanen Knoten erkennbar.
  相似文献   
27.
Forty-one recurrent tension headache sufferers were randomly assigned to either cognitive-behavioral therapy (administered in a primarily home-based treatment protocol) or to amitriptyline therapy (with dosage individualized at 25, 50, or 75 mg/day). Cognitive-behavioral therapy and amitriptyline each yielded clinically significant improvements in headache activity, both when improvement was assessed with patient daily recordings (56% and 27% reduction in headache index, respectively), and when improvement was assessed with neurologist ratings of clinical improvement (94% and 69% of patients rated at least moderately improved, respectively). In instances where differences in treatment effectiveness were observed (headache index, somatic complaints, perceptions of control of headache activity), cognitive-behavioral therapy yielded somewhat more positive outcomes than did amitriptyline. Neither treatment, however, eliminated headache problems.  相似文献   
28.
Agents for prevention or treatment of osteoporosis must now be tested in a large animal species that exhibits bone remodeling. Ovariectomized, nonhuman primates provide one such model, and they consistently develop osteopenia accompanied by high bone turnover rates. The goal of this study was to further characterize this model, and particularly to determine the effect of ovariectomy on bone strength in vertebrae and femoral necks. Longitudinal evaluations of spinal bone mass and serum markers of bone turnover were performed in 19 sham-ovariectomized (SHAM) and 18 ovariectomized (OVX), domestically reared cynomolgus monkeys, aged >9 years. OVX monkeys lost bone relative to both baseline values and SHAM controls. Serum markers of bone turnover were increased by OVX. After 72 weeks, both vertebral bone compressive strength and femoral neck breaking strength were significantly decreased in OVX animals compared with SHAM. Ovariectomized cynomolgus monkeys, like postmenopausal women, develop accelerated bone loss, increased bone turnover, and reduced bone strength, and provide a suitable large animal model for efficacy studies with agents for prevention or treatment of osteoporosis. Received: 24 June 1996 / Accepted: 3 September 1996  相似文献   
29.
Nine-month-old male C57BL/6J mice were subjected to three-hour cold stress tests (partial restraint at 6 degrees C) at 9:00 a.m. or at 1:00 p.m. Tests were repeated three times at two-week intervals at the same time of day. Body temperature was measured by colonic thermoprobe, and metabolic heat production was measured by indirect calorimetry during each test. All mice showed habituation to repeated cold exposures (an improvement of cold tolerance across tests) due to an increase in metabolic heat production. The levels of metabolic heat production were similar during morning and afternoon testing; however, mice tested in the afternoon had consistently poorer cold tolerance, which indicated increased heat loss. Increased heat loss in mice of similar body weight and presumably similar body composition, suggests that there is less effective cold-induced skin vasoconstriction during the afternoon. We hypothesize that the compromised skin vasomotor response during the afternoon cold exposure results from competing effects of vasodilation due to local autoregulation stimulated by a circadian reduction of cardiac output during the sleep phase, and vasoconstriction due to the cold stress.  相似文献   
30.
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