全文获取类型
收费全文 | 1083篇 |
免费 | 64篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 88篇 |
妇产科学 | 11篇 |
基础医学 | 101篇 |
口腔科学 | 25篇 |
临床医学 | 134篇 |
内科学 | 216篇 |
皮肤病学 | 19篇 |
神经病学 | 24篇 |
特种医学 | 308篇 |
外科学 | 98篇 |
综合类 | 10篇 |
预防医学 | 28篇 |
眼科学 | 6篇 |
药学 | 27篇 |
肿瘤学 | 61篇 |
出版年
2023年 | 2篇 |
2021年 | 9篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 14篇 |
2017年 | 3篇 |
2016年 | 7篇 |
2015年 | 15篇 |
2014年 | 19篇 |
2013年 | 23篇 |
2012年 | 9篇 |
2011年 | 10篇 |
2010年 | 28篇 |
2009年 | 26篇 |
2008年 | 11篇 |
2007年 | 30篇 |
2006年 | 20篇 |
2005年 | 24篇 |
2004年 | 21篇 |
2003年 | 10篇 |
2002年 | 12篇 |
2001年 | 15篇 |
2000年 | 12篇 |
1999年 | 29篇 |
1998年 | 98篇 |
1997年 | 74篇 |
1996年 | 77篇 |
1995年 | 54篇 |
1994年 | 54篇 |
1993年 | 61篇 |
1992年 | 12篇 |
1991年 | 9篇 |
1990年 | 14篇 |
1989年 | 40篇 |
1988年 | 25篇 |
1987年 | 38篇 |
1986年 | 23篇 |
1985年 | 29篇 |
1984年 | 24篇 |
1983年 | 16篇 |
1982年 | 22篇 |
1981年 | 23篇 |
1980年 | 28篇 |
1979年 | 6篇 |
1978年 | 16篇 |
1977年 | 18篇 |
1976年 | 20篇 |
1975年 | 13篇 |
1932年 | 1篇 |
1930年 | 1篇 |
排序方式: 共有1158条查询结果,搜索用时 0 毫秒
1.
2.
3.
Huisman JA; Paulussen RJ; Geurts TB; Odink J; Rekers H 《Human reproduction (Oxford, England)》1997,12(1):34-38
The objective was to demonstrate bioequivalence between s.c. and i.m.
administration of Humegon (FSH/LH ratio 1:1) and Normegon (FSH/LH ratio
3:1). In two randomized, single-centre, cross-over studies, 18 healthy
volunteers on each formulation were assigned to one of the two
administration sequences. Subjects were given single doses of one of the
above gonadotrophins after endogenous gonadotrophin production had first
been suppressed using high-dose oral contraceptive. Subsequently, rate
(Cmax, tmax) and extent (AUC) of absorption of follicle stimulating hormone
(FSH) and luteinizing hormone (LH) were determined for 14 days. For Cmax
and AUC, analysis of variance (ANOVA) was performed on log-transformed data
and for tmax ANOVA was performed on ranks. Intramuscular and s.c.
injections of Humegon were bioequivalent with respect to the main
pharmacokinetic parameters, being AUC and Cmax of FSH absorption.
Intramuscular and s.c. injections of Normegon were bioequivalent with
respect to the AUC of FSH and not bioequivalent with respect to the Cmax of
FSH. For tmax of FSH as well as for most LH variables of both preparations,
bioequivalence could not be proven due to the high intra- and
interindividual variability and/or concentrations being close to the
detection limit. Thus, the main pharmacokinetic FSH variables after i.m.
and s.c. administration of Humegon and Normegon were bioequivalent.
相似文献
4.
Frequency of the ATM IVS10-6T→G variant in Australian multiple-case breast cancer families 下载免费PDF全文
5.
Hypospadias trends in two US surveillance systems 总被引:6,自引:0,他引:6
OBJECTIVE: Hypospadias is a common congenital anomaly, the cause of which is unknown. Unexplained increases in the rates of hypospadias occurred in five European countries in the 1970s and 1980s. We examined data from two birth defects surveillance systems in the United States for evidence of similar trends. METHODOLOGY: The Metropolitan Atlanta Congenital Defects Program (MACDP) provided birth prevalence rates from 1968 to 1993. The nationwide Birth Defects Monitoring Program (BDMP) provided rates from 1970 to 1993. MACDP data are population-based and could be categorized by the severity of the hypospadias. BDMP data allowed analysis of rate trends for the four census regions of the United States. RESULTS: Data from both surveillance systems showed an approximate doubling of hypospadias rates in the 1970s and 1980s. MACDP data showed that the rate of severe cases increased while the ratio of mild to severe cases decreased. BDMP data showed that hypospadias rates increased markedly in all four regions of the United States. CONCLUSIONS: The observed increases are unlikely to be attributable to increased sensitivity of the surveillance systems or the identification of more mild cases by physicians over time, because either trend would have increased rather than decreased the ratio of mild to severe cases. If real, these trends represent the largest number of cases and the first report of an increase in hypospadias rates outside of Europe. Additional investigation of a possible increase in hypospadias rates is warranted. 相似文献
6.
Guo RJ; Wang Y; Kaneko E; Wang DY; Arai H; Hanai H; Takenoshita S; Hagiwara K; Harris CC; Sugimura H 《Carcinogenesis》1998,19(9):1539-1544
Mutations in the transforming growth factor beta type II receptor
(TGFbetaRII) gene have been detected in several human cancer types
exhibiting microsatellite instability. Using intron primers previously
reported for examination of the entire coding region of the TGFbetaRII
gene, 29 sporadic gastric cancers were screened with non-radioactive single
strand conformation polymorphism and subsequent DNA sequencing analysis.
Mutations of the TGFbetaRII gene were detected in three out of 29 tumors
(10%). Two cases showed deletions in a polyadenine tract in both alleles
and was positively associated with replication error. One case had an
insertion of GA dinucleotide sequence in one allele. Mutations of the
TGFbetaRII gene were restricted to exon 3 and other coding regions were not
affected. Loss of heterozygosity was detected by analyzing a polymorphic
site in intron 2. Three out of nine (33%) informative cases, which were all
of intestinal type and advanced cases, showed loss of heterozygosity but
neither TGFbetaRII mutation nor replication error was found in these cases.
Immunoreactivity of TGFbetaRII in tumor tissues was reduced to a different
extent in the gastric cancer with genetically abnormal transforming growth
factor. Although the numbers studied are small, homozygous (A)10 deletion
or loss of heterozygosity of TGFbetaRII is involved in tumorigenesis and
progression of at least some part of sporadic gastric cancer.
相似文献
7.
8.
D'Andrea RJ; Barry SC; Moretti PA; Jones K; Ellis S; Vadas MA; Goodall GJ 《Blood》1996,87(7):2641-2648
The hypothesis that extracellular truncation of the common receptor subunit for interleukin-3 (IL-3), granulocyte-macrophage colony- stimulating factor, and IL-5 (h beta c) can lead to ligand-independent activation was tested by infecting factor-dependent hematopoietic cell lines with retroviruses encoding truncated forms of h beta c. A truncation, resembling that in v-Mpl, and retaining 45 h beta c-derived extracellular residues, led to constitutive activation in the murine myeloid cell line, FDC-P1. However, infection of cells with retrovirus encoding a more severely truncated receptor, retaining only 7 h beta c- derived extracellular residues, did not confer factor independence on these cells. These experiments show that truncation activates the receptor and define a 37-amino acid segment of h beta c (H395-A431) which contains two motifs conserved throughout the cytokine receptor superfamily (consensus Y/H XX R/Q VR and WSXWS), as essential for factor-independent signaling. The mechanism of activation was also investigated in less severe truncations. A receptor that retains the entire membrane-proximal domain (domain 4) also conferred factor independent growth on FDC-P1 cells; however, a retrovirus encoding a truncated form of h beta c having two intact membrane proximal domains did not have this ability, suggesting that domain 3 may have an inhibitory role in h beta c. The ability of these receptors to confer factor independence was cell specific as demonstrated by their inability to confer factor-independent growth when introduced into the murine IL-3-dependent pro-B cell line BaF-B03. These results are consistent with a model in which activation requires unmasking of an interactive receptor surface in domain 4 and association with a myeloid- specific receptor or accessory component. We suggest that in the absence of ligand intramolecular interactions prevent inappropriate signaling. 相似文献
9.
The experiences in treating 93 consecutive patients (56 males, 37 females; mean age, 38.5 years; range, 4-69 years), including 76 patients with primary malignant bone tumors and 17 patients with soft tissue sarcomas involving the innominate bone, are reported. Oncologic and functional results were investigated in relation to the tumor stage, to the achieved surgical margin, and to the surgical procedure (hemipelvectomy, internal hemipelvectomy and endoprosthetic replacement, and continuity resection). The mean followup was 48 months (range, 8-222 months). The 5-year survival was 86% in patients with low-grade malignant bone tumors, 42% in patients with high-grade malignant bone tumors, and 25% in patients with high-grade soft tissue sarcomas. Survival was influenced by the grade of malignancy, the tumor stage, and the achieved surgical margins. Forty-six patients who survived were examined an average of 36 months after primary surgery. Excellent and good functional results were seen in 82% of patients who underwent continuity resection and in 55.5% of patients who underwent partial or total internal hemipelvectomy. All patients who survived hemipelvectomy had poor functional results. Surgical treatment of pelvic sarcomas is an extensive procedure with a considerable incidence of complications. It requires the knowledge of different techniques of resection and reconstruction of bone, joints, soft tissue, and intrapelvic organs. 相似文献
10.