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   2458016篇
  免费   185052篇
  国内免费   7983篇
耳鼻咽喉   33804篇
儿科学   80981篇
妇产科学   69061篇
基础医学   347887篇
口腔科学   68947篇
临床医学   215439篇
内科学   487115篇
皮肤病学   56398篇
神经病学   199520篇
特种医学   99932篇
外国民族医学   639篇
外科学   382742篇
综合类   53224篇
现状与发展   3篇
一般理论   712篇
预防医学   188148篇
眼科学   55409篇
药学   179439篇
  6篇
中国医学   4505篇
肿瘤学   127140篇
  2018年   24681篇
  2016年   22876篇
  2015年   25808篇
  2014年   35101篇
  2013年   52863篇
  2012年   68926篇
  2011年   73118篇
  2010年   44720篇
  2009年   42596篇
  2008年   69726篇
  2007年   75177篇
  2006年   76587篇
  2005年   74997篇
  2004年   71855篇
  2003年   70121篇
  2002年   67712篇
  2001年   111413篇
  2000年   114573篇
  1999年   96593篇
  1998年   28778篇
  1997年   25750篇
  1996年   26409篇
  1995年   25789篇
  1994年   24321篇
  1993年   22665篇
  1992年   78665篇
  1991年   77166篇
  1990年   75166篇
  1989年   72003篇
  1988年   67018篇
  1987年   65737篇
  1986年   62493篇
  1985年   60011篇
  1984年   45436篇
  1983年   38794篇
  1982年   23989篇
  1981年   21413篇
  1980年   20109篇
  1979年   42240篇
  1978年   30245篇
  1977年   25802篇
  1976年   23990篇
  1975年   25982篇
  1974年   30496篇
  1973年   29216篇
  1972年   27420篇
  1971年   25437篇
  1970年   23427篇
  1969年   22337篇
  1968年   21050篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Although the evidence is not conclusive, overall many sexual changes seem to occur in the climacteric years. It would be easy to propagate and perpetuate longstanding beliefs and myths that would do a great disservice to all of the women to whom our care is dedicated. In the coming years it is hoped that we shall learn more about how to understand these changes. In recent years the International Menopause Society has actively encouraged work in this area. An entire issue of its journal Maturitas is devoted to a series of scientific papers on sexuality in the climacteric years. For those who desire further reading that issue is strongly recommended. All medical professionals who come into contact with women during the climacteric years should be prepared to ask about sexuality and to deal with any concerns that arise. Taking a good sexual history along with a good general medical history and full social background is the best starting point for coping with these concerns. How to take a comprehensive sexual history is well described by Munjack and Oziel. Of course, it is not usual to take this full history on every woman with menopause symptoms. A few key questions should identify the woman who has sexual problems and facilitate selection of appropriate questioning for each patient (Table 2). Often, taking such a history allows the physician to identify a problem area that may be helped by medication or, more often, by education and simple office counseling. When it is clear that these simple approaches will not be adequate, the physician should have good resources for referral to the appropriate specialist, whether it be gynecologist, menopause center, psychologist, family therapist, or sex therapist.  相似文献   
992.
993.
New parametric and non parametric statistical methods have been compared in the evaluation of experimental data of CEA and CA 19.9 using a brief program in BASIC. We have found that the distribution of the two markers is the same of that described in literature except for both the means that we have found being slightly higher than that ones described by other authors.  相似文献   
994.
Previous studies having shown that chloroquine and hydroxychloroquine could reduce interleukin 1 (IL-1)-induced cartilage degradation in-vitro, the effects of a range of antimalarial drugs on the cartilage proteoglycan degrading actions of porcine leucocyte (pI 4.8) alpha-interleukin 1 (syn. catabolin) have been examined using the standard bovine nasal cartilage culture system. The anti-IL-1 effects in this system were specific to several aminoquinoline and aminoacridine analogues having a side chain with a tertiary amino group similar to that of chloroquine. Aminoquinoline compounds devoid of this side chain and the tertiary amino, as well as pyrimidines or biguanides with antimalarial activity were without effect. Mefloquine, the most potent of the compounds active against porcine alpha-IL-1, was only equipotent with chloroquine and its hydroxyanalogue against human recombinant alpha-IL-1. This suggests that there may be subtle differences in the receptors for these drugs and interleukins in bovine cartilage. The results provide further evidence for the specificity and utility of antimalarial drugs in the treatment of chronic inflammatory conditions, especially in relation to actions on IL-1.  相似文献   
995.
Perbendazole was given orally and subcutaneously to mice infected with Angiostrongylus cantonensis at different stages of infection. The subcutaneous route of administration was more effective than the oral one. On the 5th day after infection, the perbendazole had a higher efficacy than on the 10th day postinfection. This finding shows that perbendazole had complete larvicidal effect at early stages of infection.  相似文献   
996.
Peripheral arterial thromboembolism and thrombosis of arterial grafts continue to threaten viability of extremities. Percutaneous intra-arterial thrombolysis (IAT) and angiodilatation have afforded limb salvage in some of these patients. Proper patient selection appears to be the hallmark of success with IAT. During a recent three-year period, we used IAT in 32 extremities in 28 patients who had acute arterial insufficiency. Before IAT, 16 extremities were painful at rest, and 16 had incapacitating claudication. The overall success rate was 38%, but some degree of thrombolysis occurred in 88%. Limb salvage was achieved in 27 of 32 extremities (84%). Only five of 17 limbs (29%) with arterial graft thrombosis required no operation or an operation of lesser magnitude than predicted before IAT. Of six extremities with native arterial embolism, four (67%) were completely cleared with IAT. Major complications occurred in eight cases (25%), with two IAT-related deaths (6%). This study suggests that IAT is best reserved for individuals with acute limb ischemia caused by arterial embolus, those whose degree of ischemia would tolerate a 24-hour trial of IAT, and those whose femoral or tibial runoff is not likely to require remedial operation.  相似文献   
997.
Several types of neurons were differentiated on the basis of a study of neuronal activity in various parts of the cortex near the sulcus principalis during the execution of spatial delayed reactions by monkeys. It was established that the different types of neurons are represented in different numbers in. different parts of the cortex near the sulcus principalis. The determination of several factors influencing the activity of these neurons and the comparison of data on their quantitative representation in the anterior, middle, and posterior parts of the cortex near the sulcus principalis with the existing behavioral data obtained after local ablations of identical regions of the brain made it possible to postulate that neurons belonging to the different types are involved in the analysis of different processes and represent different functional units.Translated from Fiziologicheskii. Zhurnal SSSR imeni I. M. Sechenova, Vol. 71, No. 12, pp. 1488–1494, December, 1985.  相似文献   
998.
999.
This paper outlines the impact of granulocyte‐colony stimulating factor (G‐CSF) used as a single modality therapy in 17 patients with secondary autoimmune neutropenia (S‐AIN) who had been treated a multiple number of times previously. Fifteen of these patients had demonstrable antineutrophil antibodies and two had cellular S‐AIN with haemopoietic inhibitory T‐cells present in the marrow. Prior to treatment, all had had problems with infection. All patients responded within 7 days of commencement of treatment. Provided G‐CSF neutrophil counts were maintained above 1 × 109/l, no further infections occurred. This was achievable by using G‐CSF administered as infrequently as once every 8 days. Eight of the 17 patients remained on G‐CSF, although five switched to the glycosylated form because of side‐effects. None have developed osteoporosis despite 47.29 patient years of total experience with G‐CSF. In conclusion both glycosylated and nonglycosylated G‐CSF can be used effectively in treating AIN on a long‐term basis.  相似文献   
1000.
Background: Both pain and the pharmacologic management of pain can cause the undesirable effect of sleep disruption. One goal of basic and clinical neuroscience is to facilitate rational drug development by identifying the brain regions and neurochemical modulators of sleep and pain. Adenosine is thought to be an endogenous sleep promoting substance and adenosinergic compounds can contribute to pain management. In the pontine brain stem adenosine promotes sleep but the effects of pontine adenosine on pain have not been studied. This study tested the hypothesis that an adenosine agonist would cause antinociception when microinjected into pontine reticular formation regions that regulate sleep.

Methods: The tail flick latency (TFL) test quantified the time in seconds for an animal to move its tail away from a thermal stimulus created by a beam of light. TFL measures were used to evaluate the antinociceptive effects of the adenosine A1 receptor agonist N6-p-sulfophenyladenosine (SPA). Pontine microinjection of SPA (0.1 [mu]g/0.25 [mu]l, 0.88 mm) was followed by TFL measures as a function of time after drug delivery and across the sleep-wake cycle.

Results: Compared with saline (control), pontine administration of the adenosine agonist significantly increased latency to tail withdrawal (P < 0.0001). The increase in antinociceptive behavior evoked by the adenosine agonist SPA was blocked by pretreatment with the adenosine A1 receptor antagonist 8-cyclopentyl-1, 3-dipropylxanthine (DPCPX, 0.75 ng/0.25 [mu]l, 10 [mu]m).  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