全文获取类型
收费全文 | 1210篇 |
免费 | 57篇 |
国内免费 | 149篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 60篇 |
妇产科学 | 6篇 |
基础医学 | 96篇 |
口腔科学 | 20篇 |
临床医学 | 190篇 |
内科学 | 328篇 |
皮肤病学 | 30篇 |
神经病学 | 26篇 |
特种医学 | 315篇 |
外科学 | 61篇 |
综合类 | 28篇 |
预防医学 | 51篇 |
眼科学 | 31篇 |
药学 | 114篇 |
1篇 | |
肿瘤学 | 57篇 |
出版年
2021年 | 7篇 |
2019年 | 9篇 |
2018年 | 18篇 |
2017年 | 9篇 |
2016年 | 14篇 |
2015年 | 17篇 |
2014年 | 23篇 |
2013年 | 34篇 |
2012年 | 17篇 |
2011年 | 20篇 |
2010年 | 39篇 |
2009年 | 42篇 |
2008年 | 31篇 |
2007年 | 111篇 |
2006年 | 28篇 |
2005年 | 32篇 |
2004年 | 17篇 |
2003年 | 7篇 |
2002年 | 21篇 |
2001年 | 22篇 |
2000年 | 13篇 |
1999年 | 18篇 |
1998年 | 78篇 |
1997年 | 76篇 |
1996年 | 71篇 |
1995年 | 61篇 |
1994年 | 42篇 |
1993年 | 53篇 |
1992年 | 10篇 |
1991年 | 16篇 |
1990年 | 14篇 |
1989年 | 56篇 |
1988年 | 35篇 |
1987年 | 33篇 |
1986年 | 30篇 |
1985年 | 34篇 |
1984年 | 21篇 |
1983年 | 16篇 |
1982年 | 28篇 |
1981年 | 17篇 |
1980年 | 14篇 |
1979年 | 11篇 |
1978年 | 7篇 |
1977年 | 19篇 |
1976年 | 31篇 |
1975年 | 18篇 |
1974年 | 7篇 |
1973年 | 7篇 |
1972年 | 10篇 |
1971年 | 8篇 |
排序方式: 共有1416条查询结果,搜索用时 0 毫秒
71.
Diet and cancer prevention: the fiber first diet 总被引:3,自引:0,他引:3
Diet can play a major role in cancer prevention. The international
differences in cancer incidence are largely accounted for by lifestyle
practices that include nutrition, exercise, and alcohol and tobacco use.
About 50% of cancer incidence and 35% of cancer mortality in the U.S.,
represented by cancers of the breast, prostate, pancreas, ovary,
endometrium, and colon, are associated with Western dietary habits. Cancer
of the stomach, currently a major disease in the Far East, relates to
distinct, specific nutritional elements such as excessive salt intake. For
these cancers, information is available on possible initiating genotoxic
factors, promoting elements, and prophylactic agents. In general, the
typical diet in the United States contains low levels of the potent
carcinogenic agents, heterocyclic amines, formed during the cooking of
meats. It provides only about half the potent appropriate fiber intake and
is high in calories. About twice as many calories as would be desirable
come from fat, certain kinds of which enhance the development of cancers.
Other foods with functional properties, such as soy products and tea, can
be beneficial. To achieve reduction in risk of certain cancers, diet must
be optimized, primarily to reduce caloric intake and the fat component. The
latter should be 20% or less of total caloric intake and fiber should be
increased to 25- 35 g per day for adults. One approach to achieving these
goals is the Fiber First Diet, a diet designed around adequate fiber intake
from grains, especially cereals, vegetables, legumes, and fruits, which
thereby reduces both calorie and fat intake. Such dietary improvements will
not only reduce cancer and other chronic disease risks, but will contribute
to a healthy life to an advanced age. A corollary benefit is a lower cost
of medical care.
相似文献
72.
Blood coagulation of healthy premature newborns, since birth, was studied for 45 days by a method of capillary blood sampling in a plastic tube. The most often measured clotting factors allowed to establish control coagulation times for the tests performed in premature sick infants. In this study, the clotting factors were identical in at-term and premature children. Vitamin-K dependent factors showed the most important deficits; however, at birth their levels seemed higher in at-term newborns. They reached control values after one month, with a progressive evolution. The other blood-clotting factors were normal. 相似文献
73.
P. Perrier J. L. Thomas C. Bonaiti-Pellie G. Gay J. Leclere F. Streiff 《Tissue antigens》1987,29(1):13-17
In this study, linkage between HLA and a dominant gene determining multiple endocrine neoplasia type 2 (MEN 2) in a large pedigree was investigated. All lod scores for recombination fractions ranging from 0 to 0.45 were negative. If we pool data from our family and the families studied by Jackson et al. (1976) and Simpson & Falk (1982), a link between HLA and the locus for MEN 2 can be excluded. Linkage studies with various markers and pooled data should be pursued to permit detection of high risk individuals and to identify a genetic defect. 相似文献
74.
In the Orient there is a high frequency of residual intrahepatic stones after biliary tract surgery. Percutaneous removal of residual intrahepatic stones was attempted in a group of 74 patients. Stones were exclusively intrahepatic in 57 patients, whereas 17 patients also had stones in the common bile duct. Biliary strictures were present in 60 cases (81%). A combination of techniques was used, including preshaped angulated catheters, irrigation-suction, balloon dilation of strictures, and crushing of large stones. In 36 cases all stones were removed and in 14 cases most stones were removed, for a success rate of 67.6%. Biliary stricture was the factor most often responsible for failure. 相似文献
75.
Activation and complexation of protein C and cleavage and decrease of protein S in plasma of patients with intravascular coagulation 总被引:2,自引:0,他引:2
Activated protein C (APC) is inhibited by two major plasma inhibitors (PCIs). To find evidence for in vivo complexation of APC, immunoblotting studies were performed on plasmas of 85 patients with suspected disseminated intravascular coagulation (DIC). Samples from 62 of these patients contained 5% to 35% of protein C antigen in APC:inhibitor complexes, indicating that protein C activation and inhibition had occurred. In 24 normal plasmas, no detectable APC:PCI complexes were observed (less than 5%). Patients with higher levels of complexes had more abnormal coagulation test data for DIC. The major band of APC complexes detected by anti-protein C antibodies did not react with antibodies to the heparin-dependent protein C inhibitor (PCI- 1) previously described. Rather, APC was complexed with another recently described plasma protein C inhibitor, PCI-2. Immunoblotting studies for protein S, the cofactor for APC, revealed that the majority of the DIC patient plasmas contained a higher than normal proportion of protein S in cleaved form, suggesting that protein S may have been proteolytically inactivated. Protein S total antigen levels were also found to be low in DIC patients, excluding those with malignancy. These studies support the hypothesis that the protein C pathway is activated during DIC. 相似文献
76.
Lipohemarthrosis of the knee: a review of recent experiences 总被引:4,自引:0,他引:4
The radiographs of 268 patients with knee trauma were retrospectively reviewed. In 15 patients with intraarticular fracture, the images demonstrated fat-fluid levels. In 28 other patients with intraarticular fracture, only joint effusion without a fat-fluid level was depicted. The presence of a fat-fluid level in the knee indicated fracture in all patients in whom it was seen. The absence of such a level, however, did not exclude intraarticular fracture. 相似文献
77.
78.
79.
Todd C Rideout Scott V Harding Peter JH Jones Ming Z Fan 《Vascular health and risk management》2008,4(5):1023-1033
The hypocholesterolemic effects associated with soluble fiber consumption are clear from animal model and human clinical investigations. Moreover, the modulation of whole-body cholesterol metabolism in response to dietary fiber consumption, including intestinal cholesterol absorption and fecal sterol and bile acid loss, has been the subject of many published reports. However, our understanding of how dietary fibers regulate molecular events at the gene/protein level and alter cellular cholesterol metabolism is limited. The modern emphasis on molecular nutrition and rapid progress in ‘high-dimensional’ biological techniques will permit further explorations of the role of genetic polymorphisms in determining the variable interindividual responses to soluble fibers. Furthermore, with traditional molecular biology tools and the application of ‘omic’ technology, specific insight into how fibers modulate the expression of genes and proteins that regulate intestinal cholesterol absorption and alter hepatic sterol balance will be gained. Detailed knowledge of the molecular mechanisms by which soluble fibers reduce plasma cholesterol concentrations is paramount to developing novel fiber-based “cocktails” that target specific metabolic pathways to gain maximal cholesterol reductions. 相似文献
80.