全文获取类型
收费全文 | 3711篇 |
免费 | 244篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 151篇 |
妇产科学 | 84篇 |
基础医学 | 509篇 |
口腔科学 | 75篇 |
临床医学 | 344篇 |
内科学 | 852篇 |
皮肤病学 | 45篇 |
神经病学 | 238篇 |
特种医学 | 239篇 |
外科学 | 501篇 |
综合类 | 42篇 |
一般理论 | 3篇 |
预防医学 | 342篇 |
眼科学 | 10篇 |
药学 | 270篇 |
中国医学 | 5篇 |
肿瘤学 | 224篇 |
出版年
2023年 | 28篇 |
2022年 | 26篇 |
2021年 | 62篇 |
2020年 | 42篇 |
2019年 | 67篇 |
2018年 | 72篇 |
2017年 | 59篇 |
2016年 | 67篇 |
2015年 | 58篇 |
2014年 | 80篇 |
2013年 | 133篇 |
2012年 | 195篇 |
2011年 | 218篇 |
2010年 | 128篇 |
2009年 | 127篇 |
2008年 | 191篇 |
2007年 | 215篇 |
2006年 | 209篇 |
2005年 | 209篇 |
2004年 | 170篇 |
2003年 | 169篇 |
2002年 | 163篇 |
2001年 | 113篇 |
2000年 | 97篇 |
1999年 | 84篇 |
1998年 | 35篇 |
1997年 | 36篇 |
1996年 | 47篇 |
1995年 | 28篇 |
1994年 | 26篇 |
1993年 | 36篇 |
1992年 | 52篇 |
1991年 | 53篇 |
1990年 | 80篇 |
1989年 | 49篇 |
1988年 | 48篇 |
1987年 | 41篇 |
1986年 | 34篇 |
1985年 | 43篇 |
1984年 | 29篇 |
1983年 | 18篇 |
1982年 | 18篇 |
1981年 | 22篇 |
1980年 | 22篇 |
1979年 | 33篇 |
1978年 | 24篇 |
1977年 | 23篇 |
1975年 | 22篇 |
1974年 | 29篇 |
1970年 | 18篇 |
排序方式: 共有3959条查询结果,搜索用时 10 毫秒
11.
We have examined 6 construction workers who developed chronic skin diseases on their hands over a period of 15 years (1970–1985). 4 developed a Trichophyton rubrum infection, and the other 2 an irritant contact dermatitis. All of them carried out jobs which caused traumatization of the skin, due to the presence of ethylene glycol and mineral oils during operation of pneumatic hammers in winter. They also suffered other types of skin trauma during their work. Construction workers may be at risk of developing an occupational skin disease involving fungal infection. 相似文献
12.
PURPOSE: The purpose of this project was to retrospectively compare and correlate body mass index (BMI) and hemodynamics in hypertensive and normotensive patients undergoing intravenous sedation for dentoalveolar surgery. PATIENTS AND METHODS: A retrospective chart analysis of 263 consecutive male patients undergoing intravenous (IV) sedation for dentoalveolar surgery was divided into 5 BMI groups: underweight, normal weight, overweight, obese, extremely obese. Data recorded were noninvasive baseline and intraoperative hemodynamic measurements at 5-minute intervals for systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), pulse pressure (PP), and pulse (P). Statistical analysis of mean values between groups was carried out using multivariate linear regression analysis, Pearson's correlation coefficient, and Student's t test and found significant for P < .05. RESULTS: Average hemodynamic values for normotensive patients were significantly lower for all groups except for pulse in the normal group, pulse in the obese group, and DBP in the extremely obese group. For normotensive patients, there were statistically significant strong positive correlation for elevated BMI and increased baseline changes in SBP and PP. For the hypertensive group, there was a statistically significant moderate positive correlation for elevated BMI and increased baseline changes in PP and statistically significant strong positive correlation for baseline changes in MAP. Baseline changes were significant for greater increases in SBP and decreases in DBP and MAP in the underweight hypertensive group. Significant increases from baseline in the normotensive group were for PP in the normal BMI group and for pulse in the obese group. All baseline changes, with the exception of normotensive underweight SBP (+26.7%) and hypertensive PP (+23.9%), were within +/-20% of baseline (range, -12.2% to +17.4%). CONCLUSION: In general, normotensive patients in this study had lower average hemodynamic values than hypertensive patients in all BMI groups. Great variability was seen in baseline changes for all BMI groups, but a substantial majority of changes were within +/-20% of baseline. There were statistically significant moderate and positive correlations in BMI for changes from baseline for several hemodynamic measurements. Intravenous sedation for oral and maxillofacial surgery procedures maintains a stable hemodynamic state in hypertensive and normotensive patients regardless of BMI. 相似文献
13.
Prevention of ischemic injury in renal transplantation 总被引:1,自引:0,他引:1
W F Finn 《Kidney international》1990,37(1):171-182
14.
Finn Ursin Knudsen 《Brain & development》1996,18(6):312-449
Assessment of treatment strategies in febrile seizures should be based on short- and long-term outcomes, with and without acute, intermittent, or chronic medical intervention, as well as short- and long-term side effects. Febrile seizures are a benign condition with a normal neurological, motor, intellectual, and cognitive long-term outcome and have a low risk of later epilepsy in most cases. Even many complex febrile seizures have a benign outcome. Prophylaxis may or may not reduce the recurrence rate, but does not appear to improve the long-term outcome as compared to acute treatment of seizures in progress. All agree that chronic prophylaxis with anti-epileptic agents is justified only in highly selected cases, if at all. Treatment with benzodiazepines during febrile episodes appears to effectively reduce the recurrence rate, provided adequate doses are given and compliance problems minimized. A selective approach to intermittent diazepam prophylaxis seems rational, as the recurrence risk and response to treatment are highly variable. An attractive alternative is acute treatment at seizure onset with rectal diazepam in solution given by the parents at home in order to prevent prolonged recurrent seizures. This regimen has the potential of moving the first line of anti-convulsant defence close to the child. It appears to be effective, inexpensive, feasible even for non-professionals, has few side effects and is well accepted by the parents. A reasonable policy would be to treat simple febrile seizures solely with acute rectal diazepam in solution and reserve intermittent diazepam prophylaxis for selected cases including those with multiple or prolonged recurrences, several risk factors for recurrent febrile seizures and other special situations. 相似文献
15.
Background
January 1, 2002, copayment for outpatient female sterilization in Norwegian public hospitals increased from 33 euros to 750 euros after a revision of the health care system. The aim of the present study was to investigate the effect of the new copayment system on female sterilization epidemiology. 相似文献16.
The present study describes the distribution of neurons of origin of zinc-containing pathways in the amygdaloid complex of the rat, using the selenium method for simultaneous retrograde labeling of all zinc-containing neurons. With this method, vesicular ionic zinc is precipitated intravitally with selenium compounds and transported retrogradely to the parent neurons, where it can be visualized by silver amplification. Neurons labeled retrogradely with silver-amplified precipitate were observed in all amygdaloid nuclei except for the lateral olfactory tract nucleus, the accessory olfactory tract nucleus and the central nucleus. Very few labeled cell bodies were seen in the anterior amygdaloid area and the medial nucleus. The amygdalo-hippocampal area and the amygdalo-piriform transition area both showed a substantial number of labeled somata throughout their rostrocaudal extent. In the anterior cortical nucleus, very few labeled cell bodies were found in the rostral pole, whereas they were abundant in the caudal quarter of the nucleus. In the posterolateral cortical nucleus, the number of labeled cell bodies increased gradually; there were none in the rostral pole, but most of the neurons in the caudal part were labeled. The posteromedial cortical nucleus contained a great number of labeled somata, but with some variation in the rostrocaudal extent of the nucleus. Considerable numbers of labeled neurons were observed throughout the lateral nucleus. In the basolateral nucleus, a small number of labeled cell bodies was present in the rostral half, but a gradual increase was observed in the caudal direction. Finally, in the basomedial nucleus, very few labeled cell bodies were present in the rostral two-thirds, whilst a considerable number was encountered in the caudal one-third. Possible functional implications of neuronal zinc are considered. The distribution of neurons of origin of zinc-containing projections has been compared with previously described intrinsic connections of the rat amygdala, and tracts that may possibly be zinc-containing are outlined and discussed. It is concluded that in all probability a substantial proportion of the intrinsic connectivity of the rat amygdaloid complex is zinc-containing.The authors thank Ms. M. Sørensen, Mrs. A. Lyhr, Mr. A. Meier and Mrs. K. Wiedemann for excellent technical help. 相似文献
17.
A study of the degree of progesterone support required for the maintenance
of various stages of pregnancy was undertaken in mice. Mated females were
ovariectomized at various stages of pregnancy and progesterone and
oestradiol support provided by s.c. Silastic implants with known release
characteristics. In the earliest stages of pregnancy (days 1-5), very low
concentrations of progesterone (<25% of normal physiological values)
were sufficient to maintain pre-implantation stages and allow implantation.
In the immediate post-implantation period (days 5-9), the development of
implantation sites and decidualization required considerably higher
progesterone support. In mid-pregnancy (days 11-14), progesterone alone
could not maintain pregnancy unless present in very high amounts; however,
the presence of oestradiol during this period lowered the progesterone
requirements to well within the physiological range. This effect of
oestradiol started on day 11 but required the level of oestradiol support
to be kept within strictly defined limits, with high concentrations
inducing abortion. Progesterone alone was able to maintain pregnancy from
day 15. These results indicate that the minimal progesterone support
required for pregnancy in mice varies considerably at different stages of
pregnancy and is at least partly modulated by oestradiol.
相似文献
18.
G Niedobitek M L Hansmann H Herbst L S Young D Dienemann C A Hartmann T Finn S Pitteroff A Welt I Anagnostopoulos 《The Journal of pathology》1991,165(1):17-24
The Epstein-Barr virus (EBV) is consistently associated with undifferentiated nasopharyngeal carcinoma (NPC). There is, however, conflicting evidence as to whether squamous cell NPCs are also EBV-associated. Moreover, it has been proposed that other epithelial tumours, particularly thymomas and thymic carcinomas, should be included in the group of EBV-associated neoplasias. However, since the viral DNA in these studies was demonstrated only in extracted DNA, the cellular origin of the viral DNA is uncertain. We have therefore investigated 152 epithelial tumours from various sites for the presence of EBV-DNA by in situ hybridization with 35S-labelled probes. Sixty-eight of 77 undifferentiated NPCs showed an EBV-specific autoradiographic signal, thus confirming the strong association of this tumour type with EBV even in geographical areas where undifferentiated NPC is not endemic. None of eight squamous cell NPCs showed an EBV-specific signal. All of 15 carcinomas with a similar morphology to undifferentiated NPC but from different anatomic sites (thymus, tonsil, breast) were EBV-negative as were 9 thymomas, 26 squamous cell carcinomas of the palatine tonsil, and 14 cervical carcinomas. Our results therefore suggest a unique association of EBV with undifferentiated NPC and support concepts assigning different biological properties to undifferentiated NPC as compared with squamous cell NPC. 相似文献
19.
Detection of human papillomavirus type 16 DNA in carcinomas of the palatine tonsil. 总被引:1,自引:1,他引:1
下载免费PDF全文
![点击此处可从《Journal of clinical pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
G Niedobitek S Pitteroff H Herbst P Shepherd T Finn I Anagnostopoulos H Stein 《Journal of clinical pathology》1990,43(11):918-921
Twenty eight tonsillar carcinomas of various histological types were investigated for the presence of Epstein-Barr virus (EBV), cytomegalovirus (CMV), and human papillomavirus (HPV) types 6, 11, and 16 by in situ hybridisation using highly stringent procedures. In six cases an autoradiographic signal was obtained in the tumour cell nuclei with the HPV type 16 specific probe. No signal was obtained with any of the other probes. Immunohistochemical investigations with mouse monoclonal antibodies directed against the L1 protein of HPV type and a rabbit antiserum that detects common protein determinants of HPV gave negative results, thus indicating latent infection. Furthermore, a series of tonsils from controls with comparable age distribution was negative by both in situ hybridisation and immunohistology. These results indicate a possible role for HPV 16 in the aetiology of a proportion of tonsillar carcinomas. 相似文献
20.
Neutrophil adhesion molecules in term and premature infants: normal or enhanced leucocyte integrins but defective L-selectin expression and shedding. 总被引:3,自引:0,他引:3
下载免费PDF全文
![点击此处可从《Clinical and experimental immunology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The functional deficits of neonatal neutrophils are well documented and are thought to contribute to the increased susceptibility of newborn infants to infection. We measured the adhesion molecules L-selectin, CD11a/CD18 and CD11b/CD18 on neutrophils from the cord blood of term (n = 22) and premature (n = 32) infants using a whole blood method with flow cytometry and quantitative bead standards to enumerate cell surface receptors. We also assayed plasma for the shed form of L-selectin (sL-selectin). Our results suggested that L-selectin expression on term infant neutrophils is lower than that on adult neutrophils (unstimulated and stimulated, both P < 0.001), but that stimulated premature infant cell express higher L-selectin than term infants (P < 0.05); it is possible that this deficiency is caused by physiological changes occurring around the normal time of parturition. We observed reduced sL-selectin in term infants (P < 0.001) compared with adults, and even lower concentrations in premature infants (P < 0.001). The sL-selectin concentrations in plasma may be a reflection of granulopoiesis, which may be reduced in premature infants. Our results showed increased resting neonatal neutrophil expression of CD11b/CD18 compared with adults, and the absence of any neonatal deficit of the ability to up-regulate CD11b/CD18 expression on stimulation. These findings are contrary to previous reports. Further studies suggested that the isolation procedures used in previous reports reduces the capability of the cells to respond to a formyl methionine leucine phenylalanine (fMLP) stimulus. This effect is more marked in neonatal neutrophils, suggesting that the previously reported deficiency is in fact due to the isolation techniques used rather than the cells' innate ability to up-regulate CD11b/CD18 expression. The results of our study lead us to propose that the adhesive function of neonatal neutrophils may be less defective than previously thought. 相似文献