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471.
Helga M. Ögmundsdóttir Ingibjörg Pétursdóttir Ingibjörg Gudmundsdóttir Laufey Ámundadóttir Lone Rønnov-Jessen Ole W. Petersen 《In vitro cellular & developmental biology. Animal》1993,29(12):936-942
Summary Breast carcinomas commonly contain varying amounts of fibrous stroma and infiltrates of lymphoid cells. Dickson and Lippman
(Endocrine Rev., 8,29, 1987) have proposed a model of growth regulation in breast cancer involving interactions between stroma
and carcinoma cells. This model is based on results obtained with established cell lines. In an effort to bring experimentation
closer to the clinical situation we have used short-term primary cultures from human breast cancer in co-cultures with lymphocytes
and fibroblasts. Cultures were established in a chemically defined serum-free medium (CDM3). Cell types were characterized
on the basis of live morphology and expression of vimentin and keratin 18. A semi-quantitative system was developed for measuring
growth of epithelial cells, thus defining two indices: maximal growth index (GI-max) and growth rate (GR). Moderate-to-good
growth was obtained from 34 out of 46 carcinoma samples (74%) and 30 out of 38 parallel samples of non-cancerous tissue (79%).
Success in culture was negatively correlated with the amount of hard stroma but unrelated to age of patient or clinical status.
Malignant epithelium was clearly identified in 12 out of 34 (35%) carcinoma samples. For the evaluation of responses of epithelial
cells in co-cultures, the cultures from each sample were ranked according to GI-max. From 20 co-culture experiments using
carcinoma samples, the following results were obtained: the highest GI-max was found in 11 of the co-cultures with lymphocytes;
in six of the co-cultures with fibroblasts; in one case in the control culture without partner cells; and in two experiments
there was no difference between controls and co-cultures. The corresponding values for non-cancerous samples were: 5 out of
17, 2/17, 2/17, and 8/17. Control experiments performed without partner cells confirmed that these differences in GI-max between
cultures were beyond random variations. Four samples displayed particularly vigorous responses to lymphocytes, and two samples
responded extensively to fibroblasts. In four of these six samples cancer cells proliferated. We conclude that it is feasible
to use primary cultures of breast carcinomas for experimentation. Fibroblasts did not have very marked effects on epithelial
cell growth, but, contrary to expectation, there was a clear tendency for lymphocytes to stimulate growth. 相似文献
472.
Background
In insects, circadian clocks play a key role in enhancing fitness by regulating life history traits such as developmental time and adult lifespan. These clocks use environmental light/dark (LD) cycles to fine-tune a wide range of behavioral and physiological processes. To study the effect of environmental LD conditions on pre-adult fitness components, we used two dark-dwelling sympatric species of ants (the night active Camponotus compressus and the day active Camponotus paria), which normally develop underground and have fairly long pre-adult developmental time. 相似文献473.
Ewa Rajpert-De Meyts Christina E. Hoei-Hansen Anne Marie Ottesen Lone Frydelund-Larsen Mette Holm Niels E. Skakkebaek 《Andrologie》2002,12(3):262-268
The incidence of testicular germ cell cancer has been increasing over recent decades in many countries of the world. Many studies over recent years have reported adverse trends in other aspects of male reproductive health, such as high and possibly increasing frequencies of undescended testis and hypospadias, declining semen quality, and an apparently growing demand for assisted reproduction due to male infertility. This article summarises the available evidence supporting a new concept that these male reproductive abnormalities may be signs of a single underlying entity: testicular dysgenesis syndrome (TDS). This syndrome, caused by nonspecific delays and aberrations of early testicular development, may be increasingly common because of deteriorating environmental and life-style factors that impair gonadal development. Geographical and ethnic differences in the incidence of various forms of TDS could be explained either by differences in exposure to adverse factors or by differences in genetic susceptibility to these factors. 相似文献