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   716篇
  免费   39篇
耳鼻咽喉   3篇
儿科学   18篇
妇产科学   11篇
基础医学   71篇
口腔科学   7篇
临床医学   55篇
内科学   72篇
皮肤病学   23篇
神经病学   38篇
特种医学   18篇
外科学   187篇
综合类   7篇
预防医学   77篇
眼科学   12篇
药学   39篇
中国医学   2篇
肿瘤学   115篇
  2019年   8篇
  2018年   10篇
  2017年   6篇
  2015年   8篇
  2014年   7篇
  2013年   15篇
  2012年   25篇
  2011年   21篇
  2010年   11篇
  2009年   9篇
  2008年   20篇
  2007年   14篇
  2006年   14篇
  2005年   20篇
  2004年   25篇
  2003年   18篇
  2002年   13篇
  2001年   18篇
  2000年   18篇
  1999年   17篇
  1998年   7篇
  1996年   6篇
  1995年   7篇
  1994年   6篇
  1992年   9篇
  1991年   11篇
  1990年   18篇
  1989年   25篇
  1988年   22篇
  1987年   30篇
  1986年   27篇
  1985年   26篇
  1984年   26篇
  1983年   24篇
  1982年   25篇
  1981年   18篇
  1980年   13篇
  1979年   20篇
  1978年   10篇
  1977年   13篇
  1976年   9篇
  1975年   8篇
  1974年   5篇
  1973年   10篇
  1972年   10篇
  1971年   8篇
  1970年   8篇
  1969年   12篇
  1967年   9篇
  1966年   4篇
排序方式: 共有755条查询结果,搜索用时 15 毫秒
1.
Rupture of the corpus cavernosum is a rare but probably under-reported entity. It truly represents a urological emergency and current recommendations are for early surgical intervention. We review 5 cases with evaluation, treatment and followup. Delays in treatment lead to long-term complications, such as erectile dysfunction and penile curvature.  相似文献   
2.
In the mature rat, reflex sympathetic stimulation by insulin-induced hypoglycemia resulted in profound depletion of adrenal epinephrine, and to a lesser extent, norepinephrine. In the developing rat, insulin evoked little or no secretory response from the adrenals prior to 1 week of age. By 7 days, a moderate depletion of epinephrine was seen and the magnitude of the response increased with age. In contrast, during the first 3 weeks of postnatal life, insulin failed to deplete norepinephrine from the adrenal medulla and in fact, produced an increase. This chiefly resulted from de novo biosynthesis of the amine, as the rise was blocked by alpha-methyl-p-tyrosine. These results suggest that the ontogeny of the two chromaffin cell types (norepinephrine and epinephrine-containing) in the adrenals and the maturation of their secretory responses are under differential regulation. Because descending supraspinal catecholaminergic and serotonergic systems have been implicated to play key roles in regulating adrenomedullary function, the ontogeny of the sympatho-adrenomedullary axis was evaluated after neonatal central lesioning with 6-hydroxydopamine or 5,7-dihydroxytryptamine. 6-Hydroxydopamine resulted in a preferential elevation of epinephrine in the developing adrenals as well as an increase in the responsiveness of the adrenals to reflex stimulation by insulin; the mature secretory pattern was obtained as early as at 4 days postnatally for epinephrine and 9 days for norepinephrine. In contrast, 5,7-dihydroxytryptamine led to a preferential reduction of basal adrenal norepinephrine content.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
3.
Clinical trials have utilized intermittent diethylstilbestrol diphosphate (DES) therapy in advanced symptomatic prostatic carcinoma to diminish the morbidity of standard endocrine therapy. To determine the effect of intermittent DES administration on the Dunning R3327 rat prostatic adenocarcinoma 60 days following tumor implant, 6 groups were randomly assigned: control (N = 8), castrate (N = 10), high dose DES (N = 8, 1.6 micrograms/ml DES continuously in drinking water), low dose DES (N = 10, 0.4 microgram/ml continuously in drinking water), intermittent high dose DES (N = 10, 1.6 micrograms/ml DES in drinking water for 1 week, then off for 3 weeks), and intermittent low dose DES (N = 10, 0.4 microgram/ml DES for 1 week, then off for 3 weeks). Results indicate that low or high dose DES, and intermittent low or intermittent high dose DES during the week of administration were able to reduce serum testosterone to castrate levels (0.1 ng/ml). After withdrawal of intermittent DES, serum testosterone returned toward control levels (1.0 ng/ml). Initial mean tumor burden between control and treatment groups was not significantly different. All DES exposed rats had a tumor volume at death (range, 15.6-18.3 cm3) smaller than control (mean, 25.4 cm3) or castrate (mean, 40.8 cm3) rats. Despite this significant survival advantage from the time of randomization was achieved only in castrate (median survival, 331 days) or high dose DES (median survival, 359 days) groups compared to control (median survival, 225 days). Similarly, significant prolongation in tumor doubling time was achieved only by rats receiving castration or high dose DES. Intermittent DES administration controls tumor volume but does not provide a survival advantage. In this respect, intermittent DES is inferior to castration.  相似文献   
4.
We treated 13 patients with a second 125iodine implant for local recurrence of prostatic carcinoma. All patients had biopsy proved palpable recurrence without evidence of distant metastases. Full doses of irradiation were used (median matched peripheral dose 170 Gy.). Six patients had complete regression of palpable recurrence, 2 had partial regression, 2 had no apparent response and 3 were unevaluable for local response. Actuarial freedom from local disease progression at 5 years was 51%. Despite a relatively high rate of local disease control the actuarial rate of distant metastases reached 100% at 6 years after reimplantation. There were 2 severe rectal complications and 4 instances of mild to moderate urinary incontinence among the 13 patients. Local regression of recurrent prostatic carcinoma may be achieved with 125iodine reimplantation but most patients still had distant metastases.  相似文献   
5.
An expanding and increasingly older population, a rising incidence of prostate cancer, and uncertainties regarding treatment effectiveness have made this disease a target of special concern. The natural history of the cancer must be a consequence of host-tumor interactions, but little is known for sure about this subject. The growth rate of the tumor is determined by many factors, including genetic instability. At present, tumor grade, volume, and ploidy are the most useful techniques for judging the growth rate and metastatic potential. Stage A1 tumors generally are indolent, whereas stage A2 tumors are more aggressive. The natural history of stage B lesions is not well documented. The author asks two questions (Is cure necessary in those in whom it may be possible? Is cure possible in those in whom it may be necessary?) and reviews the problems inherent in screening for prostate cancer at this time.  相似文献   
6.
A pilot study was performed to test for melanoma-associated antigens (MAAgs) in the sera of patients with localized uveal melanoma, using monoclonal antibodies (MoAbs). Both whole sera and polyethylene glycol (PEG) 2.5% serum precipitates from 18 patients with clinically localized uveal melanoma and two patients with localized invasive conjuctival melanoma were analyzed for two human cutaneous MAAgs by an enzyme-linked immunosorbent assay (ELISA). These antigens could not be identified when whole sera were used. However, after PEG precipitation, a MoAb specific for the p210 MAAg reacted with four of 20 patient samples and none of 17 controls. A second MoAb specific for the p97a MAAg reacted with one of 20 patients and none of 17 controls. These findings indicate the existence of antigens common to both uveal and cutaneous melanoma and suggest that the refinement of assays to screen sera with a battey of MoAbs may be of value in diagnosing and/or monitoring patients with uveal melanoma. Circulating immune complexes were detected in the sera of six patients but did not correlate with any clinical features or with the presence or absence of detectable MAAgs.  相似文献   
7.
Each urologist can best form his or her own set of indications for and techniques of urodynamic evaluation or referral. Thus, what constitutes "office urodynamics" in one practice does not in another. The practicing urologist should at least have access to filling cystometry, flowmetry, residual urine determination, and voiding cystourethrography. All but the last named are certainly compatible with any office practice.  相似文献   
8.
Capillarity, fibre types, fibre cross-sectional areas and perimeters were studied along and across the rat tibialis anterior muscle. The muscle was sectioned at three different levels (proximal, equatorial and distal) choosing five sampling fields for measurements at each level (from anterior to posterior and lateral to medial zones). Significant differences were found in the percentage of fibre types and capillarity between different fields of the same muscle section. Slow oxidative fibres were confined to the posterior muscle zone with a maximum of 3.7%. The posterior fields also had a greater percentage of fast oxidative glycolytic fibres at proximal (72.3%) and equatorial (61.3%) levels, but a lower value at the distal level (44.8%) and lower capillary density counts in total cross-section means (758 vs. 1,069 capillaries/mm(2) in equatorial and 1,035 capillaries/mm(2) at proximal levels). The uneven distribution of both fast fibre types and the different degrees of capillarisation along the muscle are statistically significant and may be due to different biomechanical performances along the rat tibialis anterior. Fibre size was significantly larger at the distal level, but no morphometric differences were found across the section of the same level. At the distal level, the mean total fibre area of fast glycolytic fibres (5,130 microm(2)) and fast oxidative glycolytic fibres (2,493 microm(2)) contrasted with values at the proximal (fast glycolytic: 4,070 microm(2), fast oxidative glycolytic: 1,970 microm(2)) and equatorial (fast glycolytic: 3,535 microm(2), fast oxidative glycolytic: 1,714 microm(2)) levels. The differences along and across the muscle show the need to design a standardised procedure for sample location when performing comparative studies of morphofunctional adaptive changes in skeletal muscle. A significant difference between individuals (animals) in all parameters was evident and should be taken into consideration when analysing the variability: the factor 'animal' should be considered in multiway ANOVAs, especially when low sample sizes are used.  相似文献   
9.
10.
Hypothyroidism induced by perinatal administration of propylthiouracil (PTU) had profound effects on growth of the heart, with major organ weight deficits persisting well beyond the termination of drug treatment. These effects were preceded by disruption of the developmental patterns of cardiac ornithine decarboxylase (ODC) and the polyamines, which are thought to be intracellular modulators of cellular maturation. Activity of cardiac ODC was depressed in the PTU-treated group and putrescine and spermidine levels were markedly subnormal. PTU administration also affected brain growth, but much less so than in the heart. The disruption of the brain ODC/polyamine system was also less pronounced, with relatively small degrees of spermidine depletion and a slight elevation of ODC. For both tissues, the biochemical effects of perinatal hypothyroidism were opposite to those found previously for administration of exogenous thyroid hormones. These results support the views that:
1. (1) endogenous thyroid hormones contribute to the maintenance of normal developmental patterns of ODC and the polyamines, and
2. (2) the ODC/polyamine system participates in events modulating subsequent tissue growth.
Keywords: Hypothyroidism; Polyamines; Ornithine decarboxylase; Propylthiouracil  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