全文获取类型
收费全文 | 22757篇 |
免费 | 1665篇 |
国内免费 | 42篇 |
专业分类
耳鼻咽喉 | 226篇 |
儿科学 | 926篇 |
妇产科学 | 589篇 |
基础医学 | 3073篇 |
口腔科学 | 659篇 |
临床医学 | 2570篇 |
内科学 | 4395篇 |
皮肤病学 | 317篇 |
神经病学 | 1811篇 |
特种医学 | 929篇 |
外科学 | 3094篇 |
综合类 | 456篇 |
一般理论 | 43篇 |
预防医学 | 2144篇 |
眼科学 | 348篇 |
药学 | 1405篇 |
1篇 | |
中国医学 | 17篇 |
肿瘤学 | 1461篇 |
出版年
2022年 | 141篇 |
2021年 | 329篇 |
2020年 | 229篇 |
2019年 | 366篇 |
2018年 | 401篇 |
2017年 | 329篇 |
2016年 | 333篇 |
2015年 | 427篇 |
2014年 | 587篇 |
2013年 | 769篇 |
2012年 | 1118篇 |
2011年 | 1217篇 |
2010年 | 663篇 |
2009年 | 572篇 |
2008年 | 1091篇 |
2007年 | 1185篇 |
2006年 | 1101篇 |
2005年 | 1088篇 |
2004年 | 958篇 |
2003年 | 949篇 |
2002年 | 812篇 |
2001年 | 639篇 |
2000年 | 632篇 |
1999年 | 535篇 |
1998年 | 270篇 |
1997年 | 220篇 |
1996年 | 227篇 |
1995年 | 225篇 |
1994年 | 215篇 |
1993年 | 187篇 |
1992年 | 471篇 |
1991年 | 459篇 |
1990年 | 436篇 |
1989年 | 434篇 |
1988年 | 401篇 |
1987年 | 354篇 |
1986年 | 307篇 |
1985年 | 383篇 |
1984年 | 293篇 |
1983年 | 262篇 |
1982年 | 163篇 |
1979年 | 211篇 |
1978年 | 186篇 |
1977年 | 155篇 |
1976年 | 152篇 |
1975年 | 160篇 |
1974年 | 158篇 |
1973年 | 197篇 |
1972年 | 159篇 |
1971年 | 142篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
We compared results of comprehensive neuropsychological testing in 42 patients with clinically diagnosed Alzheimer's disease (AD) and in an equal number of patients with clinically definite chronic-progressive multiple sclerosis. Age, sex, and education were controlled using demographically corrected T scores based on a large normal sample. Both groups showed significant impairment on the test battery, but the degree of dementia was more severe in the patients with AD. A deviation score analysis, controlling for overall level of cognitive impairment, revealed significant differences between the groups. Alzheimer's disease was associated with relatively greater impairment of learning, memory, and verbal skills, whereas the MS group showed greater relative impairment of attention, incidental memory, and psychomotor functions. These data suggest that both the degree and pattern of mental impairement differ in patients with AD and patients with multiple sclerosis. Our results support a distinction between "gray matter" and "white matter" dementia, and may help clarify the issue of "cortical" vs "subcortical" dementia by demonstrating neuropsychological differences based on secure neuropathologic distinctions. 相似文献
92.
P V Nelson W F Carey C P Morris A C Pollard 《The Medical journal of Australia》1989,151(3):126-7, 130-1
The analysis of restriction fragment length polymorphism (RFLP)s was used to detect 11 polymorphisms that are linked to cystic fibrosis in 42 Australian families with at least one child with cystic fibrosis. The data from all the families were fully informative in regard to the gene for cystic fibrosis (CF). Prenatal assessment was performed for 24 of these families: seven fetuses were assessed to be homozygous for cystic fibrosis, 13 fetuses were heterozygous and three fetuses were free of the CF gene. Of the seven pregnancies in which it was predicted that the infant would be affected by cystic fibrosis, two were continued electively; both have come to term and the infants each were shown to have cystic fibrosis at birth. Of the 17 pregnancies in which it was predicted that the infant would not be affected by cystic fibrosis, 13 have come to term and all the infants but one (who has not yet been followed-up) have been shown to be unaffected by cystic fibrosis at birth. The polymerase chain reaction has been used to amplify the CS.7 and KM.19 loci close to the CF gene. This procedure allows a polymorphic site in each locus to be analysed in a much shorter time (one or two days rather than 10 days) and allows the use of very small test-samples, such as dried blood on filter paper ("Guthrie blood spots"). Our observations confirm the results of overseas studies and indicate that these techniques are eminently useful for prenatal diagnosis and the detection of carriers in the vast majority of Australian families with cystic fibrosis. 相似文献
93.
Second malignant tumors in patients with laryngeal carcinoma: diagnosis, treatment, and prevention 总被引:3,自引:0,他引:3
S McDonald C Haie P Rubin D Nelson L D Divers 《International journal of radiation oncology, biology, physics》1989,17(3):457-465
Although the survival rates reported for patients with larynx carcinoma are quite good, there is a risk of developing second malignant tumors (SMT) in this population. The prognosis for SMT is poor, particularly with tumors of the lung and esophagus. The Rochester series was analyzed for larynx stage and specific SMT sites, possible common etiologic factors, and survival of the population as a whole, as well as for the SMT group. From a total of 235 patients with larynx carcinoma and a median follow-up of 10 years, 50 patients with 61 SMT were identified. The overall incidence of developing a SMT was 21%, with 44% of the SMT in the lung. The median survival from SMT diagnosis was 8.74 months and the 2-year survival was only 26%. More than twice as many SMT were observed than would be expected in the population at risk, with an observed-to-expected ratio (OER) for lung SMT of 5.3, and 8 times as many head and neck SMT occurring in our population. These SMT are not treatment related but are most likely caused by a combination of exposure to a common carcinogen, that is, tobacco smoke and alcohol, and to inherent factors, notably "condemned mucosa syndrome." Follow-up procedures, from the perspective of SMT development in larynx cancer patients, are addressed in an attempt to improve survival. The focus of this study is the high incidence of lung primaries that could be mistaken for metastatic disease, which is relatively uncommon in early larynx cancer patients. 相似文献
94.
P N Nelson P R Carnegie J Martin H Davari Ejtehadi P Hooley D Roden S Rowland-Jones P Warren J Astley P G Murray 《Molecular pathology》2003,56(1):11-18
Human endogenous retroviruses (HERVs) are a family of viruses within our genome with similarities to present day exogenous retroviruses. HERVs have been inherited by successive generations and it is possible that some have conferred biological benefits. However, several HERVs have been implicated in certain cancers and autoimmune diseases. This article demystifies these retroviruses by providing an insight into HERVs, their means of classification, and a synopsis of HERVs implicated in cancer and autoimmunity. Furthermore, the biological roles of HERVs are explored. 相似文献
95.
Melanotic lesions in the internal organs of miniature swine 总被引:4,自引:0,他引:4
96.
The repopulation of lymph nodes of dogs after 1200 R whole-body x-irradiation and intravenous administration of mononuclear blood leukocytes. 下载免费PDF全文
B. Nelson W. Calvo T. M. Fliedner E. Herbst C. Bruch H. P. Schnappauf H. D. Flad 《The American journal of pathology》1976,84(2):259-282
Fresh and cryopreserved autologous or allogeneic mononuclear blood cells (MBCs) intravenously injected in 1200 R total-body x-irradiated dogs repopulated lymph nodes within 10 days after tranfusion. Several parameters of the lymphopoietic regeneration were correlated with the number of cells transfused and with the number of colony-forming units contained in the cell suspension when they were cultured in agar (CFUc). Values within the normal or close to normal range were reached in the mesenteric nodes of most of the animals transfused with 10 X 10(9) MBC or more. These values were obtained when 5 X 10(5) CFUc or more were transfused. Axillary nodes showed lower values than mesenteric nodes. They were mostly under the normal range but well over those of the irradiated controls. Frozen and thawed MBCs seem to be as effective as fresh cells for lymphopoietic restoration. The mesenteric nodes of dogs transfused with allogeneic MBCs showed higher cellularity and larger cortical-paracortical areas than those of dogs tranfused with approximately the same number of autologous cells. The repopulation of lymph nodes parallels that of the marrow. 相似文献
97.
98.
Marlene Duarte Giles Andrea L Nelson Felisa Shizgal Eva-Marie Stern Anne Fourt Pat Woods Judith I Langmuir Catherine C Classen 《Journal of trauma & dissociation》2007,8(4):7-24
This article describes the Women Recovering from Abuse Program (WRAP), an outpatient day-hospital program for women suffering from the sequelae of childhood abuse. WRAP was conceived in 1998 by clinicians who advocated for its development based on a growing need to provide women who had experienced childhood trauma an alternative to an inpatient program. WRAP draws from a Stage 1 treatment approach to address chronic interpersonal trauma and dissociation by incorporating psychopharmacology, individual and group psychotherapy. The program is structured into two phases: a preparatory Building Resources Group (BRG) and an intensive multimodal segment comprised of seven types of group therapy. Each group is described in terms of the treatment rationale and its structure and process. Two research studies to date support the effectiveness of WRAP. 相似文献
99.
Ellen L. Glickman-Weiss Arnold G. Nelson Christopher M. Hearon S. R. Vasanthakumar Byron T. Stringer Susan S. Shulman 《European journal of applied physiology》1993,67(1):30-34
Summary When the loss of body heat is accelerated by exposure to low environmental temperatures, additional substrates must be oxidized to provide energy to sustain temperature homeostasis. Therefore, the present investigation examined the relation between feeding regime [pre-experimental carbohydrate feeding (FED) vs a fast (FAST)], during 120 min of exposure to 8, 20, and 27° C in well-nourished men. The following were examined: tissue insulation (I; °C · m2 · W–1), rectal temperature (T
re; °C), and oxygen consumption (
O2; ml · kg–1 · min–1).
O2, T
re, and I revealed no significant differences between treatments (FED vs FAST) at any temperature. At 27° C, I was less (P < 0.05) than at 20 and 8° C, and decreased (P < 0.05) as exposure time increased. At 8° C,
O2was higher (P < 0.5) than at 20 or 27°C, and
O2increased as time increased (P < 0.05). T
re decreased (P < 0.05) as time increased for all conditions. Respiratory exchange ratio (R) differed (P < 0.05) between treatments (FED vs FAST), temperature (8 vs 20° C), and across time. Values for R suggests that carbohydrate accounted for 56% and 33% of caloric utilization during the FED vs FAST conditions, respectively. At 8 vs 20° C, R represented 54% vs 30% of cabohydrate utilization. Across time, R demonstrated that in both conditions (FED vs FAST) there was a decreased reliance on carbohydrate utilization for energy provision. From these data it appears that while substrate utilization differed between dietary treatment and across time this did not differentially affect
O2or T
re during protracted exposure to 8, 20, and 27° C. The higher R in the 8° C condition for both dietary treatments demonstrates that carbohydrate utilization is increased in shivering cold-exposed humans. However, the reduction in R across time suggests that fat oxidation is also involved in metabolic heat production and core temperature maintenance during shivering in the cold. 相似文献
100.