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   3418439篇
  免费   243408篇
  国内免费   10818篇
耳鼻咽喉   45586篇
儿科学   112188篇
妇产科学   94450篇
基础医学   484019篇
口腔科学   94324篇
临床医学   320045篇
内科学   665417篇
皮肤病学   78087篇
神经病学   283102篇
特种医学   129040篇
外国民族医学   1047篇
外科学   499401篇
综合类   71981篇
现状与发展   6篇
一般理论   1343篇
预防医学   272538篇
眼科学   76551篇
药学   250028篇
  12篇
中国医学   7483篇
肿瘤学   186017篇
  2019年   27656篇
  2018年   38865篇
  2017年   29649篇
  2016年   33900篇
  2015年   38284篇
  2014年   52761篇
  2013年   80408篇
  2012年   107494篇
  2011年   113798篇
  2010年   68254篇
  2009年   64665篇
  2008年   105753篇
  2007年   111973篇
  2006年   113636篇
  2005年   109073篇
  2004年   104643篇
  2003年   100891篇
  2002年   97525篇
  2001年   159176篇
  2000年   163390篇
  1999年   137946篇
  1998年   40256篇
  1997年   35759篇
  1996年   35757篇
  1995年   34507篇
  1994年   31854篇
  1993年   29960篇
  1992年   108307篇
  1991年   104732篇
  1990年   101553篇
  1989年   97726篇
  1988年   89771篇
  1987年   88039篇
  1986年   83025篇
  1985年   79331篇
  1984年   59330篇
  1983年   50647篇
  1982年   30173篇
  1981年   26903篇
  1979年   52948篇
  1978年   37600篇
  1977年   31532篇
  1976年   29783篇
  1975年   31365篇
  1974年   37424篇
  1973年   35830篇
  1972年   33481篇
  1971年   31152篇
  1970年   28837篇
  1969年   27302篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
During recent decades there has been a controversial discussion if comparable plasma level profiles which are rather constant or those which show a high peak are more efficient for the cure of gonorrhoea. So far, investigations in this field were not based on the Grasso apparatus. Although the findings with cefotiam and ceftizoxime do not allow to formulate a general hypothesis without any restriction, it can be stated that on the basis of an identical area under the antibiotic level time curve, 'peak concentration' profiles are more favourable.  相似文献   
992.
993.
Risedronate treatment reduces the risk of vertebral fracture in women with existing vertebral fractures, but its efficacy in prevention of the first vertebral fracture in women with osteoporosis but without vertebral fractures has not been determined. We examined the risk of first vertebral fracture in postmenopausal women who were enrolled in four placebo-controlled clinical trials of risedronate and who had low lumbar spine bone mineral density (BMD) (mean T-score =–3.3) and no vertebral fractures at baseline. Subjects received risedronate 5 mg (n= 328) or placebo (n= 312) daily for up to 3 years; all subjects were given calcium (1000 mg daily), as well as vitamin D supplementation (up to 500 IU daily) if baseline serum 25-hydroxyvitamin D levels were low. The incidence of first vertebral fracture was 9.4% in the women treated with placebo and 2.6% in those treated with risedronate 5 mg (risk reduction of 75%, 95% confidence interval 37% to 90%; P= 0.002). The number of patients who would need to be treated to prevent one new vertebral fracture is 15. When subjects were stratified by age, similar significant reductions were observed in patients with a mean age of 64 years (risk reduction of 70%, 95% CI 8% to 90%; P= 0.030) and in those with a mean age of 76 years (risk reduction of 80%, 95% CI 7% to 96%; P= 0.024). Risedronate treatment therefore significantly reduces the risk of first vertebral fracture in postmenopausal women with osteoporosis, with a similar magnitude of effect early and late after the menopause. Received: 12 September 2001 / Accepted: 11 December 2001  相似文献   
994.
This study examined the immunoregulatory role of recombinant interleukin 4 (IL-4), also known as B-cell stimulating factor 1, on the generation of cytotoxic effector cells from normal and leukaemic human blood mononuclear cells. When tested on cells from normal individuals, the addition of IL-4 to mixed lymphocyte cultures led to a dose-dependent proliferation of T-helper cells (CD3, 4 positive) with a concomitant decrease in phenotypic and functional cytotoxic T cells and natural killer (NK) cells. IL-4 also inhibited the interleukin-2 (IL-2)-induced generation of lymphokine-activated killer (LAK) activity when added at the beginning of mixed lymphocyte culture. When tested on mature leukaemic NK cells, IL-4 also inhibited the ability of IL-2 to induce LAK function using a short-term culture system. These results show that IL-4 acts on both normal and leukaemic cells and suggests that it acts at more than one level during the development of LAK function.  相似文献   
995.
996.
997.
998.
Nervensch?digungen als Begleitverletzungen bei Monteggia-Frakturen sind selten und betreffen meistens den N. radialis. üblicherweise kommt es bei frischen Frakturen zu einer spontanen neurologischen Remission, nachdem der Radiuskopf wieder reponiert wurde. Im vorliegenden Fall erlitt ein heute 33-j?hriger Mann eine Parese des N. interosseus posterior 27 Jahre nach einer Monteggia-Fraktur, wobei der Radiuskopf in luxierter Stellung verblieb. Nach einem Bagatelltrauma am Handgelenk beim Federballspielen kam es zu einer L?hmung der Handgelenk- und Fingerstreckmuskulatur. Eine konservative Behandlung mittels intensiver Physiotherapie blieb auch nach 4 Monaten erfolglos. Daraufhin wurde der Nerv exploriert. Der Profundusast zeigte sich dabei narbig adh?rent im Bereich einer beengenden und verdickten Frohse-Arkade. Anschlie?end erfolgte eine Narbenl?sung sowie Spaltung der Arkade, der Radiuskopf wurde im ursprünglichen verrenkten Zustand belassen. Eine v?llige Erholung des l?dierten Nerven war 9 Monate postoperativ erreicht.  相似文献   
999.
In der Behandlung von Frakturen spielt die Analgesie eine wesentliche Rolle. Es stellt sich daher die Frage, ob in der Klinik h?ufig eingesetzte Analgetika wie Tramadol oder Diclofenac negative Wirkungen auf die Knochenbruchheilung haben.  相似文献   
1000.
Stroke is a debilitating disease that affects millions each year.While in many cases cerebral ischemic in jury can be limited by effectivw resuscitation or thrombolytic treatment,the injured neurons wither in a process known as delayed neuronal death(DND).Mounting evidence indicates that DND is not simply necrosis played out in slow motion but apoptosis is triggered.Of particular interest are two groups of signal proteins that participate in apoptosis-cyclin dependent kinases(CDKs) and p53-among a myriad of signaling events after an ischemic insult.Recent investigations have shown that CDKs,a family of enzymes initially known for their role in cell cycle regulation,are activated in injured neurons in DND.As for p53,new reports suggest that its up-regulation may represent a failed attempt to rescue in jured neurons,although its up-regulation was previously considered an indication of apoptosis.These observations thus rekindle an old quest to identify new neuroprotective targets to minimize the stroke damage.In this review,the author will examine the evidence that indicates the participation of CDKs and p53 in DND and then introduce pre-clinical data to explore CDK inhibition as a potential neuroprotective target.Finally,using CDK inhibition as an example,this paper will discuss the pertinent criteria for a viable neuroprotective strategy for ischemic in jury.  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