全文获取类型
收费全文 | 1405篇 |
免费 | 207篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 20篇 |
儿科学 | 51篇 |
妇产科学 | 21篇 |
基础医学 | 133篇 |
口腔科学 | 38篇 |
临床医学 | 217篇 |
内科学 | 337篇 |
皮肤病学 | 115篇 |
神经病学 | 42篇 |
特种医学 | 137篇 |
外科学 | 210篇 |
综合类 | 99篇 |
现状与发展 | 30篇 |
预防医学 | 54篇 |
眼科学 | 15篇 |
药学 | 36篇 |
中国医学 | 3篇 |
肿瘤学 | 72篇 |
出版年
2024年 | 18篇 |
2023年 | 180篇 |
2022年 | 13篇 |
2021年 | 19篇 |
2020年 | 56篇 |
2019年 | 25篇 |
2018年 | 54篇 |
2017年 | 47篇 |
2016年 | 42篇 |
2015年 | 57篇 |
2014年 | 88篇 |
2013年 | 67篇 |
2012年 | 30篇 |
2011年 | 43篇 |
2010年 | 77篇 |
2009年 | 90篇 |
2008年 | 37篇 |
2007年 | 57篇 |
2006年 | 26篇 |
2005年 | 22篇 |
2004年 | 11篇 |
2003年 | 14篇 |
2002年 | 20篇 |
2001年 | 17篇 |
2000年 | 22篇 |
1999年 | 29篇 |
1998年 | 38篇 |
1997年 | 52篇 |
1996年 | 42篇 |
1995年 | 35篇 |
1994年 | 33篇 |
1993年 | 35篇 |
1992年 | 12篇 |
1991年 | 16篇 |
1990年 | 14篇 |
1989年 | 30篇 |
1988年 | 23篇 |
1987年 | 21篇 |
1986年 | 9篇 |
1985年 | 16篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1982年 | 12篇 |
1981年 | 15篇 |
1980年 | 13篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1976年 | 14篇 |
1975年 | 10篇 |
1974年 | 3篇 |
排序方式: 共有1630条查询结果,搜索用时 0 毫秒
11.
12.
The GAP-related domain of tuberin, the product of the TSC2 gene, is a target for missense mutations in tuberous sclerosis 总被引:5,自引:0,他引:5
Maheshwar MM; Cheadle JP; Jones AC; Myring J; Fryer AE; Harris PC; Sampson JR 《Human molecular genetics》1997,6(11):1991-1996
Tuberous sclerosis is an autosomal dominant trait in which the
dysregulation of cellular proliferation and differentiation results in the
development of hamartomatous growths in many organs. The TSC2 gene is one
of two genes determining tuberous sclerosis. Inactivating germline
mutations of TSC2 in patients with tuberous sclerosis and somatic loss of
heterozygosity at the TSC2 locus in the associated hamartomas indicate that
TSC2 functions as a tumour suppressor gene and that loss of function is
critical to expression of the tuberous sclerosis phenotype. The TSC2
product, tuberin, has a region of homology with the GTPase activating
protein rap1GAP and stimulates the GTPase activity of rap1a and rab5a in
vitro. Here we show that the region of homology between tuberin and human
rap1GAP and the murine GAP mSpa1 is more extensive than previously reported
and spans approximately 160 amino acid residues encoded within exons 34-38
of the TSC2 gene. Single strand conformation polymorphism analysis of these
exons in 173 unrelated patients with tuberous sclerosis and direct
sequencing of variant conformers together with study of additional family
members enabled characterisation of disease associated mutations in 14
cases. Missense mutations, which occurred in exons 36, 37 and 38 were
identified in eight cases, four of whom shared the same recurrent change
P1675L. Each of the five different missense mutations identified was shown
to occur de novo in at least one sporadic case of tuberous sclerosis. The
high proportion of missense mutations detected in the region of the TSC2
gene encoding the GAP-related domain supports its key role in the
regulation of cellular growth.
相似文献
13.
Mahadevan MM; McIntosh Q; Miller MM; Breckinridge SM; Maris M; Moutos DM 《Human reproduction (Oxford, England)》1998,13(4):979-982
Cryopreservation of human zygotes and embryos has been routinely performed
by in-vitro fertilization clinics for many years. Karran and Legge (1996)
first reported that formaldehyde (FA) present in the cryoprotective
solutions can have a deleterious effect on mouse oocytes. FA is a
cytotoxic, carcinogenic and mutagenic chemical. The effect of FA on mouse
zygotes was investigated. In addition, the concentrations of FA in
propanediol (PROH) obtained from various sources were determined. Pooled
1-cell embryos were dispensed into droplets of modified Ham's F10 or human
tubal fluid containing various concentrations of FA. Since bovine serum
albumin (BSA) may minimize toxicity additional trials were done as above in
the absence of BSA. FA concentration in the standard 1.5 M PROH, from
different sources in water, was measured in the same assay using a standard
curve of 0-100 microM FA. FA in a complex medium had a significant
deleterious effect on embryo development and hatching but only at 1 mM
concentration (P < 0.000001; see Tables I-III). There was no significant
effect of FA at 100 microM. However, in a simple medium even 50 microM FA
decreased embryo hatching. FA was present in 1.5 M PROH from different
sources (range 1.0-35.3 microM concentration). It appears that FA
concentrations do not increase with storage because FA concentrations were
low even after opening and storage for 3 years on the shelf. This suggests
that FA is a contaminant during the manufacturing process and may vary from
manufacturer to manufacturer and batch to batch. Until further studies are
done to confirm the lack of toxicity to embryos during cryopreservation
(with or without FA scavengers) it may be prudent to screen all batches of
cryoprotectants for FA as part of quality control.
相似文献
14.
Renal gluconeogenesis and increased glucose utilization in shock 总被引:1,自引:0,他引:1
15.
Regulation of Epstein-Barr virus infection by recombinant interferons. Selected sensitivity to interferon-gamma 总被引:12,自引:0,他引:12
Interferons (IFN) are antiviral proteins that may be important in mediating cellular defenses against Epstein-Barr virus (EBV) infection. However, the means by which IFN-alpha, -beta and -gamma modify EBV infectivity are not clear. We have evaluated the effects of purified recombinant preparations of all three classes of IFN on EBV-induced B lymphocyte proliferation and Ig secretion. When added early after EBV infection, all three recombinant IFN reduced B cell outgrowth and Ig secretion. IFN-gamma exerted a 7-10-fold more potent antiviral effect than IFN-alpha or -beta. All three types of IFN act directly on B cells. Monocytes and natural killer cells are not necessary for the anti-EBV activity. Of the three recombinant IFN, only IFN-gamma reduced EBV-induced proliferation and Ig secretion when added 3-4 days after virus infection; IFN-alpha/beta were only effective up to 24 h. B lymphoblastoid lines already transformed by EBV are insensitive to the anti-proliferative actions of all three types of IFN. On the basis of these findings, we propose three phases of regulation during EBV infection. In the early phase, EBV-infected cells can be regulated by all IFN. Subsequently, there is an intermediate period where only IFN-gamma is capable of directly affecting EBV-induced B cell responses. In the third phase, B lymphocytes become insensitive to direct actions of all IFN and are now subject to regulation only by cytotoxic cells. 相似文献
16.
17.
18.
The meta-analysis was performed to assess the efficacy and safety of daily oral L-arginine and phosphodiesterase type 5 inhibitors (PDE5Is) alone or combination in treating patients with erectile dysfunction (ED). We performed a search of randomised controlled trials in the following databases: PubMed, EMBASE and Cochrane Library databases. Four articles including 373 patients were studied. Erectile functions were significantly improved in three therapy groups compared with baseline. Patients who received the combination of L-arginine and PDE5Is showed significant improvement compared to those treated with L-arginine and PDE5Is alone, as assessed by sexual function index (p <0.00001 and p =0.005, respectively) and total testosterone (p <0.00001 and p =0.0007, respectively). Furthermore, patients who treated with PDE5Is alone exhibited the better efficacy than those treated with L-arginine alone in respects of sexual function index (p <0.00001) and total testosterone (p =0.0001). However, the combination of L-arginine and PDE5Is had no obvious difference relative to PDE5Is alone in terms of various adverse events (AEs). Conclusively, compared with monotherapy, the combination of L-arginine and PDE5Is showed a greater improvement of sexual function and total testosterone, and did not significantly increase the AEs. Besides, PDE5Is alone revealed a better effect than those treated with L-arginine alone for patients with ED. 相似文献
19.
Jue Chen MD PhD Lei Guo MM Lian Gu MPsy Hui Han MPsy 《The International journal of eating disorders》2021,54(1):102-106
In the past 40 years, the prevalence of eating disorders (ED) in China has shown an increasing trend, leading to an urgent need to develop efficient treatment modes and methods. Since the beginning of the new century, the diagnosis, treatment, and research of ED in China have been under development. This article gives an introduction and commentary on the treatment modes, treatment methods and their applications in ED in China. There are two main treatment forms for ED until now, that is, inpatient treatment and outpatient treatment. Inpatient treatment is recommended as the first choice. Since 2008, clinical psychotherapies such as cognitive behavioral therapy (CBT), dialectical behavioral therapy (DBT), and family-based treatment (FBT), which are effective for pathological symptoms of ED, have been introduced into China and developed clinically. Group CBT and group DBT for patients with ED and group FBT for caregivers might be the most efficient psychotherapy in China nowadays. A multi-family FBT support group could be developed as the basic treatment of ED patients. Although these new types of psychotherapy have observed effectiveness in clinical application, the Randomized Controlled Trials (RCT) are rare and need to be developed. 相似文献
20.
Rohwer F Macmaster W Haseltine W Tsoukas C McGuire K 《International journal of oncology》1994,5(5):1163-1169
The retrovirus Human T cell Leukemia Virus type I (HTLV-I) is the causative agent of Adult T cell Leukemia Lymphoma (ATLL) and is associated with HTLV-I Myelopathy. HTLV-I mediated transformation of CD4(+) T cells, during the course of ATLL, is poorly understood. It has been suggested that HTLV-I is responsible for the immortalization of infected cells, but transformation is dependent on secondary events. To investigate this hypothesis, we have isolated an HTLV-I infected T cell line that is dependent on IL-2 for growth in tissue culture. Further, a subclone of this cell line that is able to grow in the absence of IL-2 has been isolated. Both cell lines have identical TCR chain rearrangements and cell surface markers. Each,cell line produces viral mRNAs and proteins. Finally, both of these cell lines are sensitive to rapamycin and cyclosporin A regardless of the presence of IL-2. We propose that this system will provide a unique opportunity to study transformation to IL-2 independence in HTLV-I infected cells. 相似文献