全文获取类型
收费全文 | 750篇 |
免费 | 53篇 |
国内免费 | 55篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 10篇 |
妇产科学 | 3篇 |
基础医学 | 102篇 |
口腔科学 | 14篇 |
临床医学 | 80篇 |
内科学 | 218篇 |
皮肤病学 | 15篇 |
神经病学 | 32篇 |
特种医学 | 74篇 |
外科学 | 145篇 |
综合类 | 9篇 |
预防医学 | 36篇 |
眼科学 | 7篇 |
药学 | 79篇 |
肿瘤学 | 30篇 |
出版年
2023年 | 6篇 |
2022年 | 9篇 |
2021年 | 6篇 |
2020年 | 6篇 |
2019年 | 11篇 |
2018年 | 16篇 |
2017年 | 12篇 |
2016年 | 22篇 |
2015年 | 15篇 |
2014年 | 20篇 |
2013年 | 17篇 |
2012年 | 27篇 |
2011年 | 28篇 |
2010年 | 29篇 |
2009年 | 24篇 |
2008年 | 27篇 |
2007年 | 71篇 |
2006年 | 32篇 |
2005年 | 42篇 |
2004年 | 28篇 |
2003年 | 22篇 |
2002年 | 30篇 |
2001年 | 37篇 |
2000年 | 27篇 |
1999年 | 18篇 |
1998年 | 25篇 |
1997年 | 14篇 |
1996年 | 23篇 |
1995年 | 16篇 |
1994年 | 21篇 |
1993年 | 12篇 |
1992年 | 11篇 |
1991年 | 13篇 |
1990年 | 16篇 |
1989年 | 16篇 |
1988年 | 14篇 |
1987年 | 11篇 |
1986年 | 16篇 |
1985年 | 12篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 5篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1975年 | 5篇 |
1972年 | 2篇 |
排序方式: 共有858条查询结果,搜索用时 15 毫秒
1.
2.
Hepatocyte contribution to hepatic collagen production in vivo was estimated in rats, based on the fact that ornithine is used for protein synthesis in the liver as arginine after conversion by way of the urea cycle only by hepatocytes. From rats given a mixture of [14C] ornithine and [3H]arginine, hepatic collagen and serum albumin were obtained. The hepatocyte contribution was calculated from the 14C and 3H in arginine purified from collagen and albumin by high performance liquid chromatography. The contribution was less than 10% of total collagen production in normal and early fibrotic livers induced by a single dose of carbon tetrachloride or dimethylnitrosamine. We conclude that hepatocytes may play a minor role in collagen production in normal and early fibrotic rat livers. 相似文献
3.
Uroscopy in the 21st century: high-field NMR spectroscopy 总被引:1,自引:1,他引:0
Neild GH; Foxall PJ; Lindon JC; Holmes EC; Nicholson JK 《Nephrology, dialysis, transplantation》1997,12(3):404-417
From the experiments described, it can be seen that there are different
research approaches that can be taken and these are summarized in Table 1.
Whereas much scientific research is principally hypothesis led, there
remains, nevertheless, an important place for exploratory research. High
resolution NMR can measure, directly and simultaneously, a wide range of
endogenous metabolites in biological fluids and has the unique capability
of providing structural information on the metabolites detected. It has
proved to be a powerful research tool with which to study inherited
metabolic diseases, renal disease, drug metabolism, and toxicity, and can
be used to monitor the effects of drug therapy. For instance, by using a
library of experimental toxins one can map the metabolic profile of
site-specific nephron injury. With this approach in man one could
eventually take an unknown disease such as Balkan nephropathy and predict
the initial site of tubular injury, the mode of injury and therefore the
kind of toxin capable of producing that injury. NMR spectroscopic
techniques are still advancing rapidly, with ever increasing sensitivity
and sophistication of NMR pulse sequences to enhance structural elucidation
in complex mixtures. Given the advances in directly coupled HPLC-NMR and
even HPLC-NMR-mass spectroscopy it is likely that these technologies in
conjunction with pattern recognition will make major contribution to our
understanding of renal processes and provide new diagnostic insights in the
21st century.
相似文献
4.
Tamiya G Shinya M Imanishi T Ikuta T Makino S Okamoto K Furugaki K Matsumoto T Mano S Ando S Nozaki Y Yukawa W Nakashige R Yamaguchi D Ishibashi H Yonekura M Nakami Y Takayama S Endo T Saruwatari T Yagura M Yoshikawa Y Fujimoto K Oka A Chiku S Linsen SE Giphart MJ Kulski JK Fukazawa T Hashimoto H Kimura M Hoshina Y Suzuki Y Hotta T Mochida J Minezaki T Komai K Shiozawa S Taniguchi A Yamanaka H Kamatani N Gojobori T Bahram S Inoko H 《Human molecular genetics》2005,14(16):2305-2321
A major goal of current human genome-wide studies is to identify the genetic basis of complex disorders. However, the availability of an unbiased, reliable, cost efficient and comprehensive methodology to analyze the entire genome for complex disease association is still largely lacking or problematic. Therefore, we have developed a practical and efficient strategy for whole genome association studies of complex diseases by charting the human genome at 100 kb intervals using a collection of 27,039 microsatellites and the DNA pooling method in three successive genomic screens of independent case-control populations. The final step in our methodology consists of fine mapping of the candidate susceptible DNA regions by single nucleotide polymorphisms (SNPs) analysis. This approach was validated upon application to rheumatoid arthritis, a destructive joint disease affecting up to 1% of the population. A total of 47 candidate regions were identified. The top seven loci, withstanding the most stringent statistical tests, were dissected down to individual genes and/or SNPs on four chromosomes, including the previously known 6p21.3-encoded Major Histocompatibility Complex gene, HLA-DRB1. Hence, microsatellite-based genome-wide association analysis complemented by end stage SNP typing provides a new tool for genetic dissection of multifactorial pathologies including common diseases. 相似文献
5.
Satoshi Mochida Itsuro Ogata Yasuhiko Ohta Teruaki Oka Kenji Fujiwara 《Pathology international》1991,41(3):217-220
In order to investigate superoxide production by pulmonary macrophages in the rat, a route was created by ligating both the inferior and superior venae cavae and resecting the aorta after cannulation through the inferior vena cava into the right atrium of the heart. Lung perfusion was performed via this route with nitro blue tetrazolium. Although there was no formazan deposition throughout the lung, it became detectable in both alveolar and interstitial macrophages when phorbol myristate acetate was added to the perfusate. This deposition was markedly enhanced by previous injection of Corynebacterium parvum. The deposition disappeared after further addition of Cu(Lys)2 , a scavenger of superoxide anions. This procedure may be useful for estimating in situ the ability of pulmonary macrophages to produce superoxide in the rat. 相似文献
6.
Background
Correct diagnosis in psychiatry may be improved by novel diagnostic procedures. Computerized Decision Support Systems (CDSS) are suggested to be able to improve diagnostic procedures, but some studies indicate possible problems. Therefore, it could be important to investigate CDSS systems with regard to their feasibility to improve diagnostic procedures as well as to save time. 相似文献7.
Investigations of the Ia afferent discharge in clarifying problems in disused and malused skeletal muscles have been carried out mainly in muscles of the upper extremities. However, such problems actually occur more frequently in the antigravity muscles of the lower extremities, such as the triceps surae muscle. An analysis of microneurographically recorded Ia discharges from the tibial nerve innervating the triceps surae muscle during dynamic movement of the ankle joint indicated that they mainly transmitted information on the angular velocity of the joint. However, the information on the position sense of the joint was not as well transmitted through Ia discharges. There was no correlation between the joint angle and the static response. However, the dynamic response of a Ia afferent was well correlated to the angular velocity. It is concluded that the human proprioception of the triceps surae muscle was not dependent on the position of the ankle joint, but largely on its movement by the stretching of the muscle. 相似文献
8.
Cystic hypersecretory carcinoma (CHC) is a rare variant of intraductal carcinoma. A CHC in a 50-year-old woman was excised and processed for light and electron microscopy and immunohistochemistry. The tumor had a marked cystic appearance. The walls of the cysts consisted of epithelial and myoepithelial cells and a well-developed basement membrane. The epithelial cells contained well-developed rough-surfaced endoplasmatic reticulum and Golgi apparatus. Secretory granules were not detected, with the exception of a few mucus-producing cells. The secretion was predominantly homogenous, reminiscent of thyroid colloid, and demonstrated distinct PAS positivity. The cells displayed a strong labeling with epithelial membrane antigen (EMA) and EMA-positive structures were observed within the intraluminal secretion, too. Some of these were stained by alcian blue. In addition, the colloid-like material was admixed with mucus showing a filamentous internal structure and lipid droplets resulting in some heterogenity of the secretion. Intraductal micropapillary proliferation in some of the cysts and adjacent nondistended ducts was a further defining feature of the tumor. Steroid hormone receptor and Ki-67 proliferation marker immuno his Tochemistry showed scattered positivity among the tumor cells. These results are in agreement with previous observations and further clarify the nature of this low-grade in situ cancer. 相似文献
9.
The purpose of this study was to compare the success rate of bony fusion and the clinical results of rigid instrumentation, nonrigid instrumentation, and no instrumentation for a single level lesion for degenerative lumbar spondylolisthesis. Thirty-three patients with degenerative spondylolisthesis of L4 who had undergone posterior decompression and posterolateral fusion with autogenous bone graft that included the facet joints had a single level stabilization with a newly designed syndesmoplasty using Leeds-Keio artificial ligaments (Group Leeds-Keio-nonrigid). Thirty-four patients with degenerative spondylolisthesis of L4 who had the same procedure were stabilized with the Steffee system (Group Steffee-rigid). Thirty-five patients who had the same decompression and bony fusion without instrumentation (Group Noninstrumented) were compared with the former two groups. Clinical results were correlated with the stage of bony fusion. The Steffee system was reliable for stabilizing intervertebral angular instability such as a preoperative intervertebral angle difference of more than 11 degrees in flexion and extension. In the patients who preoperatively had an angle difference of less than 10 degrees, no significant difference was seen between Group Leeds-Keio and Group Steffee. The authors concluded that nonrigid instrumentation can be used to achieve successful bony fusion in patients with degenerative spondylolisthesis, who have a preoperative angle difference less than 10 degrees, with excellent clinical results. 相似文献
10.
We traced and identified the ontogenetic expression of neural excitability related to the vagus nerve in the embryonic rat brain stem. Multiple-site optical recordings of neural activities revealed two response areas in the E12 rat brain stem: one corresponding to the dorsal motor nucleus of the vagus nerve, and the other reflecting the activities of sensory nerve fibers. In embryos younger than E11, no optical response was identified, suggesting that excitability of the motoneurons and/or sensory nerve fibers is first generated no later than E12. A contour line map of the neural responses suggested that, in contrast to older embryos, the functional organization of the vagal nucleus is not orderly at the time of the initial expression of neural excitability. 相似文献